Front. Surg. Frontiers in Surgery Front. Surg. 2296-875X Frontiers Media S.A. 10.3389/fsurg.2023.1113659 Surgery Original Research The effect of carbon nanoparticles staining on lymph node tracking in colorectal cancer: A propensity score matching analysis LiuFei † PengDong † LiuXiao-Yu LiuXu-Rui LiZi-Wei WeiZheng-Qiang WangChun-Yi * Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China

Edited by: Bo Zhang, Sichuan University, China

Reviewed by: Alfonso De Stefano, G. Pascale National Cancer Institute Foundation (IRCCS), Italy Jin Tung Liang, National Taiwan University, Taiwan

 Correspondence: Chun-Yi Wang 1962989853@qq.com

These authors have contributed equally to this work and share first authorship

Specialty Section: This article was submitted to Surgical Oncology, a section of the journal Frontiers in Surgery

 01032023 2023 101113659 01122022 13022023 © 2023 Liu, Peng, Liu, Liu, Li, Wei and Wang. 2023Liu, Peng, Liu, Liu, Li, Wei and Wang

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

 Purpose

The aim of this study was to evaluate the effect of carbon nanoparticles staining (CNS) on colorectal cancer (CRC) surgery, lymph node tracing and postoperative complications using propensity score matching (PSM).

 Method

Patients who were diagnosed with CRC and underwent surgery were retrospectively collected from a single clinical center from Jan 2011 to Dec 2021. Baseline characteristics, surgical information and postoperative information were compared between the CNS group and the non-CNS group. PSM was used to eliminate bias.

 Results

A total of 6,886 patients were enrolled for retrospective analysis. There were 2,078 (30.2%) patients in the CNS group and 4,808 (69.8%) patients in the non-CNS group. After using 1: 1 ratio PSM to eliminate bias, there were 2,045 patients left in each group. Meanwhile, all of their baseline characteristics were well matched and there was no statistical significance between the two groups (P > 0.05). In terms of surgical information and short-term outcomes, the CNS group had less intraoperative blood loss (P < 0.01), shorter operation time (P < 0.01), shorter postoperative hospital stay (P < 0.01), less metastatic lymph nodes (P = 0.013), more total retrieved lymph nodes (P < 0.01), more lymphatic fistula (P = 0.011) and less postoperative overall complications (P < 0.01) than the non-CNS group before PSM. After PSM, the CNS group had less intraoperative blood loss (P = 0.004), shorter postoperative hospital stay (P < 0.01) and more total retrieved lymph nodes (P < 0.01) than the non-CNS group. No statistical difference was found in other outcomes (P > 0.05).

 Conclusion

Preoperative CNS could help the surgeons detect more lymph nodes, thus better determining the patient's N stage. Furthermore, it could reduce intraoperative blood loss and reduce the hospital stay.

 carbon nanoparticles colorectal cancer surgery lymph nodes tracing propensity score matching Introduction

Colorectal cancer (CRC) is one of the most common malignancies among both men and women and the second leading cause of cancer-related death in the world (1–3). Currently, there are about 185 million CRC patients worldwide (4). CRC increases the burden on world health, especially on the elderly (5). Although the treatment has developed, radical CRC surgery is still the main treatment at present (6, 7). The current mainstream surgical approach is usually performed laparoscopically or robotically assisted, and robotic assistance shows advantages (8). In recent years, carbon nanoparticles staining (CNS) technology has been widely used to improve surgical outcomes (9).

The applications of carbon nanoparticles were developing rapidly (10, 11). It was proved that carbon nanoparticles were safe and reliable tracers for CRC (9). Carbon nanoparticles could selectively penetrate lymphatic vessels rather than capillaries. When they entered the lymphatic vessels, they could be phagocytized by macrophages, and then stained the lymph nodes black (12). Thus, it facilitated the detection of lymph nodes during pathological examination. Meanwhile, a sufficient number of lymph nodes was crucial for accuracy of a patient's cancer stage (13). Studies reported that the number of lymph nodes dissected should be ≥ 12 for more accurate staging of the patient's N stage (14). Accurate cancer staging could guide post-operative treatment, furthermore, optimiz patients' short-term outcomes and improve patients' survival rates (14).

At present, CNS has been widely used in the localization of CRC and lymph node tracking (14–17). However, the number of metastatic lymph nodes detected remained controversial. The CNS group was considered to have more metastatic lymph nodes compared with the non-CNS group (5, 12). Other studies reported that there was no difference in the rate of metastatic lymph nodes between the two groups (18–20). Therefore, the aim of this study was to evaluate the effect of CNS on lymph node tracing and postoperative complications for CRC surgery.

 Method Patients

Patients who were diagnosed with CRC and underwent surgery were collected from a single clinical center from Jan 2011 to Dec 2021, retrospectively. A total of 6,886 patients were enrolled. This study was approved by the Institutional Ethics Committee of our hospital (2021–536), and informed consents were obtained from all patients.

 Inclusion and exclusion criteria

We included CRC patients who underwent radical surgery in a single clinical center (n = 8152). The exclusion criteria were as follows: 1, non-R0 resection (n = 22); 2, recurrent CRC surgery (n = 47); 3, incomplete baseline information (n = 148); and 4, incomplete information of carbon nanoparticles staining (n = 1049). Ultimately, a total of 6,886 patients were enrolled (Figure 1).

Flow chart of patient selection.

Abbreviations: CNS, carbon nanoparticles staining.

 Data collection

The baseline characteristics, operation information and short-term outcomes were collected from electronic medical records. The baseline characteristics were as follows: age, sex, body mass index (BMI), smoking, drinking, hypertension, type 2 diabetes mellitus (T2DM), coronary heart disease (CHD), surgical history, open surgery, tumor location, tumor nodes metastasis (TNM) stage, tumor size and CNS. The operation information included: intraoperative blood loss and operation time. The postoperative information included: postoperative hospital stay, metastatic lymph nodes, total retrieved lymph nodes, anastomotic fistula, lymphatic fistula, postoperative major complications and postoperative overall complications.

 PSM

PSM was used to reduce the intergroup bias in this study. We conducted PSM method including age, sex, BMI, smoking, drinking, hypertension, T2DM, CHD, surgical history, open surgery, tumor location, TNM stage and tumor size. The CNS group was matched to the non-CNS group by using the nearest neighbor matching at a 1:1 ratio, and within a caliper of 0.01.

 Procedures

Patients in the CNS group were injected carbon nanoparticles (1 ml; 50 mg, Chongqing lummy Co.) into the submucosal layer before surgery by electronic colonoscopy. The carbon nanoparticles entered the lymphatic vessels rather than the blood vessels. Then, the tumor and lymph nodes would be stained black (Figure 2).

(A), nanocarbon stained tumour; (B), tumour without nanocarbon staining; (C), nanocarbon stained lymph nodes; (D), lymph nodes without nanocarbon staining.

 Definition

The tumor node metastasis stage was diagnosed according to the AJCC 8th Edition (21). The complications were graded according to the Clavien-Dindo classification (22), and major complications were defined as ≥ III classification complications. The CNS group was defined as the patients who underwent injection of carbon nanoparticles before surgery, while the non-CNS group was defined as the patients who did not receive injection of carbon nanoparticles before surgery. R0 resection was defined as a negative margin on pathological examination.

 Statistical analysis

Continuous variables were expressed as mean ± standard deviation (SD). Categorical variables were expressed as n (%). The Chi-square test was used to analyze categorical variables and the t-test was used to analyze continuous variables between the CNS group and the non-CNS group. Statistical analysis was performed by the SPSS (version 22.0) software. P-value of < 0.05 was considered statistically significant.

 Results Patients

A total of 6,886 patients were included in this study according to the inclusion and exclusion criteria, and there were 2,078 (30.2%) patients in the CNS group and 4,808 (69.8%) patients in the non-CNS group. After 1:1 ratio PSM, there were 2,045 patients in each group (Figure 1). The mean age of the enrolled patients was 62.7 ± 12.4 years old. Meanwhile, 4,044 (58.7%) were males and 2,042 (41.3%) were females. In addition, more baseline characteristics including BMI, smoking, drinking, hypertension, T2DM, CHD, surgical history, open surgery, tumor location, TNM stage, tumor size, CNS, operation time, intraoperative blood loss and short-term outcomes were shown in Table 1.

Clinical characteristics of CRC patients.

Characteristics No. 6886
Age (mean ± SD), year 62.7 ± 12.4
Sex
 Male 4,044 (58.7%)
 Female 2,842 (41.3%)
BMI (mean ± SD), kg/m2 22.6 ± 3.2
Smoking 2,574 (37.4%)
Drinking 2,089 (30.3%)
Hypertension 1,685 (24.5%)
T2DM 746 (10.8%)
CHD 267 (3.9%)
Surgical history 1,717 (24.9%)
Open surgery 1,195 (17.4%)
Tumor location
 Colon 3,239 (47.0%)
 Rectum 3,647 (53.0%)
TNM stage
 I 1,238 (18.0%)
 II 2,785 (40.4%)
 III 2,546 (37.0%)
 IV 317 (4.6%)
Tumor size
  < 5cm 3,922 (57.0%)
  ≥ 5cm 2,964 (43.0%)
CNS 2,078 (30.2%)
Operation time, min 232.2 ± 83.6
Intraoperative blood loss 118.7 ± 186.7
Metastatic lymph nodes 1.5 ± 3.2
Total retrieved lymph nodes 14.3 ± 7.7
Post-operative hospital stay, day 11.3 ± 7.4
Post-operative major complications 176 (6.1%)
Post-operative overall complications 1,550 (22.5%)

Variables are expressed as the mean ± SD, n (%).

*P-value < 0.05.

 Baseline characteristics

The baseline characteristics before and after PSM were shown in Table 2. Before PSM, we found that the CNS group had a higher BMI (P < 0.01), a higher proportion of smoking (P = 0.037) and a higher proportion of open surgery (P < 0.01) than the non-CNS group. Meanwhile, significant difference was found in tumor location (P < 0.01) and TNM stage (P < 0.01). There was no difference in age, sex, drinking, hypertension, T2DM, CHD, surgical history or tumor size (P > 0.05). After PSM, all of these baseline characteristics were well matched and there was no statistical significance (P > 0.05).

Baseline characteristics before and after PSM.

Characteristics Before PSM After PSM
CNS (2078) Non-CNS (4808) P value CNS (2045) Non-CNS (2045) P value
Age, year 62.5 ± 11.9 62.7 ± 12.7 0.589 62.6 ± 11.9 62.5 ± 12.4 0.729
Sex 0.607 0.874
 Male 1,230 (59.2%) 2,814 (58.5%) 1,201 (58.7%) 1,206 (59.0%)
 Female 848 (40.8%) 1,994 (41.5%) 844 (41.3%) 839 (41.0%)
BMI, kg/m2 22.8 ± 3.2 22.4 ± 3.2 <0.01* 22.8 ± 3.2 22.7 ± 3.2 0.428
Smoking 667 (32.1%) 1,422 (29.6%) 0.037* 776 (37.9%) 802 (39.2%) 0.404
Drinking 55 (2.6%) 33 (0.7%) 0.898 641 (31.3%) 638 (31.2%) 0.919
Hypertension 524 (25.2%) 1,161 (24.1%) 0.343 511 (25.0%) 515 (25.2%) 0.885
T2DM 235 (11.3%) 511 (10.6%) 0.404 231 (11.3%) 225 (11.0%) 0.766
CHD 84 (4.0%) 183 (3.8%) 0.641 83 (4.0%) 89 (4.3%) 0.640
Surgical history 506 (24.4%) 1,211 (25.2%) 0.461 498 (24.4%) 477 (23.3%) 0.441
Open surgery 145 (7.0%) 1,050 (21.8%) <0.01* 145 (7.1%) 144 (7.0%) 0.951
Tumor location <0.01* 0.706
 Colon 1,149 (55.3%) 2,090 (43.5%) 1,116 (54.6%) 1,128 (55.2%)
 Rectum 929 (44.7%) 2,718 (56.5%) 0.668 929 (45.4%) 917 (44.8%) 0.668
Tumor size 0.613 0.570
  < 5cm 1,174 (56.5%) 2,748 (57.2%) 1,157 (56.6%) 1,175 (57.5%)
  ≥ 5cm 904 (43.5%) 2,060 (42.8%) 888 (43.4%) 870 (42.5%)
TNM stage <0.01* 0.671
 I 419 (20.2%) 819 (17.0%) 398 (19.5%) 370 (18.1%)
 II 880 (42.3%) 1,905 (39.6%) 868 (42.4%) 881 (43.1%)
 III 702 (33.8%) 1,844 (38.4%) 702 (34.3%) 709 (34.7%)
 IV 77 (3.7%) 240 (5.0%) 77 (3.8%) 85 (4.2%)

Variables are expressed as the mean ± SD, n (%).

P-value < 0.05.

 Surgical and postoperative characteristics

The operation and postoperative characteristics of the two groups were compared before and after PSM, and the outcomes were shown in Table 3. The operation information included intraoperative blood loss and operation time. The postoperative information included postoperative hospital stay, metastatic lymph nodes, total retrieved lymph nodes, anastomotic fistula, lymphatic fistula, postoperative overall complications and postoperative major complications. Before PSM, intraoperative blood loss (P < 0.01), operation time (P < 0.01), postoperative hospital stay (P < 0.01), metastatic lymph nodes (P = 0.013), total retrieved lymph nodes (P < 0.01), lymphatic fistula (P = 0.011) and postoperative overall complications (P < 0.01) had significant differences in the two groups.

Outcomes before and after PSM.

Before PSM After PSM
CNS (2078) Non-CNS (4808) P value CNS (2045) Non-CNS (2045) P value
Operative information
 Intraoperative blood loss, ml 96.1 ± 151.6 128.5 ± 199.2 <0.01* 95.7 ± 151.4 109.5 ± 151.2 0.004*
 Operation time, min 226.2 ± 85.3 234.9 ± 82.7 <0.01* 226.0 ± 84.6 230.9 ± 85.3 0.065
Postoperative information
 Post-operative hospital stay, day 10.6 ± 6.9 12.5 ± 9.1 <0.01* 10.7 ± 6.9 11.7 ± 9.0 <0.01*
 Metastatic lymph nodes 1.3 ± 3.6 1.5 ± 2.9 0.013* 1.3 ± 3.6 1.3 ± 2.8 0.885
 Total retrieved lymph nodes 17.1 ± 8.0 13.0 ± 7.2 <0.01* 17.2 ± 8.0 13.8 ± 7.7 <0.01*
 Anastomotic fistula 51 (2.5%) 115 (2.4%) 0.877 51 (2.5%) 42 (2.1%) 0.345
Lymphatic fistula 15 (0.7%) 14 (0.3%) 0.011* 15 (0.7%) 7 (0.3%) 0.087
 Post-operative major complications 47 (2.3%) 129 (2.7%) 0.309 46 (2.2%) 45 (2.2%) 0.916
 Post-operative overall complications 406 (19.5%) 1,144 (23.8%) <0.01* 401 (19.6%) 448 (21.9%) 0.070

Variables are expressed as the mean ± SD, n (%).

P-value < 0.05.

After PSM, the CNS group also had less intraoperative blood loss (P = 0.004), shorter postoperative hospital stay (P < 0.01) and more total retrieved lymph nodes than the Non-CNS group (P < 0.01).

 Discussion

There was a large sample size of 6,886 CRC patients in this study. After 1:1 ratio PSM, there were 2,045 patients left in each group. Before and after PSM, intraoperative blood loss, postoperative hospital stay and total retrieved lymph nodes were statistically significant. This suggested that CNS before surgery could help surgeons retrieve more lymph nodes, reduce intraoperative blood loss and reduce hospital stay. In term of total retrieved lymph nodes, we found that the CNS group retrieved more lymph nodes than the non-CNS group.

The guidelines of the European Society for Medical Oncology and the American Society of Clinical Oncology consider inadequate lymph nodes harvested to be one of the risk factors for stage II CRC (23, 24). Lymph nodes metastasis is an independent prognostic factor after radical resection for T1-2 CRC (25). Accurate TNM staging could guide postoperative chemoradiotherapy and improve the prognosis of CRC patients. However, it was required that the total number of lymph nodes detected exceeded twelve (26). Moreover, in order to accurately determine the pathological staging of patients with adenocarcinoma of esophagogastric junction, Zheng J et al. proposed that no less than 11 LNs must be resected in patients with stage T1-2 and no less than 16 LNs must be resected in patients with stage T3-4 (27). Meanwhile, it was found that the number of removed lymph nodes was positively correlated with the number of metastatic lymph nodes (28). Resection of more lymph nodes could improve the accuracy of postoperative pathological analysis. Lelin Pan et al. showed that the more lymph nodes were removed, the more accurate N-stage we obtained (18). However, a 2010 study indicated that lymph node detection rates for colorectal cancer remain low (29). A variety of lymph node staining were beginning to be used in clinical practice. Cawthorn et al. used xylene alcohol clearance technique to facilitate the identification of lymph nodes (30). Quadros et al. performed lymphoscintigraphy using technetium-99 m-phytate and patent blue to detect lymph nodes of rectal adenocarcinoma patients (31). However, these techniques are not widely used in clinical practice because they are time-consuming, labour-intensive and toxic to doctors (12). In this study, we used carbon nanoparticles for lymph node tracking and more total number of dissected lymph nodes in the CNS group were found than the non-CNS group. This could help surgeons obtain the accurate N stage of patients.

Although, the use of carbon nanoparticles increased the total number of lymph nodes detected, the number of metastatic lymph nodes detected remained controversial. Some studies reported that the rate of lymph node metastasis detected in the CNS group was higher than the non-CNS groups (5, 12). Other studies reported that there was no difference in the rate of metastatic lymph nodes between the two groups (18–20). The mechanism was not clear, but there were possible reasons as follows: first, CNS allowed for better anatomical clarity, making it more convenient for the operator to clear the lymph nodes. Second, it was found that there were many other factors that affected metastasis lymph node dissection, such as the patient's sex, age, tumor stage, type of surgery, and neoadjuvant chemotherapy (32–35). Although the information underlying the two groups was not statistically significant after PSM, we were still unable to determine their combined effect on metastatic lymph node dissection. We searched nine similar articles and listed some information in Table 4 (5, 12, 14, 18–20, 36–38). The main outcomes reported in these articles were the total or mean number of lymph nodes detected. Dissections of metastatic lymph nodes were reported in five articles (5, 12, 18–20). Two articles also reported that the dissections of microscopic lymph nodes in the CNS group was more than the non-CNS group (5, 12). Wang Q et al. reported the effect of CNS on intraoperative information (14). Complications and long-term survival without difference were reported by Wang LY et al. (20).

The difference between CNS and Non-CNS group were reported from previous studies.

Author Year Country Sample size CNS Non-CNS Others Outcomes
Hong-Ke Cai 2012 China 80 20 20 20 There were no statistically significant were observed among the tree groups in age, gender, tumor location, tumor diameter, T-stage, degree of differentiation, postoperative complications and peritoneal drainage retention time. The mean number of detected lymph nodes per patient was significantly higher in CNS group than in Non-CNS group.
Qingxuan Wang 2016 China 54 27 27 – The time for detecting the tumor, operation time, and blood loss during the operation were lower in the CNS group than in the Non-CNS group. Average numbers of dissected lymph nodes in the CNS group exceeded those in the Non-CNS group, and the rate of dissected lymph nodes 12 was higher in the CNS group than in the Non-CNS group.
Xing-Mao Zhang 2016 China 87 35 52 – The mean number of lymph nodes removed in CNS group was higher than that in Non-CNS group. And the mean number of lymph nodes smaller than 5 mm in diameter in CNS group was more than Non-CNS group.
Li-yu Wang 2017 China 444 327 117 26 The number of positive lymph nodes was higher and the prevalence of blood loss was lower in the CNS group than in the control group. There were no significant differences in the operative time, number of lymph nodes detected, or the prevalence of postoperative complications, survival, metastasis, or recurrence between the two groups at 3 years.
Jie Sun 2018 China 80 40 40 – There were no statistically significant differences in the metastasis rate and lymph node metastasis rate between the two groups. The total number of lymph nodes and the number of lymph nodes with micrometastases (<2 mm) in the observation group were larger than those in the control group; the ratio of fewer than 12 lymph nodes in the observation group was lower than that in the control group.
L. Tang 2018 China 80 40 39 1 The average number of lymph nodes harvested from each patients was markedly more in the CNS group than in the Non-CNS group, and the average number of lymph nodes less than 5 mm in greatest dimension was significantly more in the CNS group than in the Non-CNS group.
Lelin Pan 2018 China 99 52 47 – The number of total harvested LNs and the number of positive patients in the CNS group increased significantly compared with the Non-CNS group.
Renjie Wang 2019 China 239 123 116 – All the patients characteristics between two groups did not achieve statistical significance. Patients in CNS group were more likely to be associated with more lymph nodes retrieved totally compared with Non-CNS group. The number of lymph nodes retrieved in CNS group were more likely to be 12 than that in the Non-CNS group.
Wei Ge 2021 China 132 60 72 – The mean number of lymph nodes harvested from patients in CNS group was higher than that in Non-CNS group. And the mean number of positive lymph nodes got from patients in CNS group was also higher than Non-CNS group.

So far, CNS has been widely used. Studies reported that CNS could avoid aggressive axillary treatment of breast cancer (39). CNS was also reported to improve the outcomes of surgery for thyroid papillary carcinoma (40). In addition, CNS had a positive impact on the surgical results of early gastric cancer (41, 42). It was also reported that CNS played an essential role in lymph node dissection for non-small cell lung cancer (43). Fortunately, no significant adverse effects of CNS on patients have been identified at present. Van Tongeren MJ et al. did not demonstrate mutagenic or carcinogenic effects of carbon nanoparticles (44). Meanwhile, Magrez A et al. proved that CNS had no adverse effects on the central serious system, cardiovascular system and respiratory system (45). Expectantly, more systematic reactions to carbon nanoparticles are looking forward to be discovered. In the future, CNS may be widely used to improve patients' survival.

The application of CNS could also help surgeon obtain more convenience. Previous study found that CNS could help surgeons distinguish tissue structure (9). This finding could lead to less intraoperative blood loss and shorter postoperative hospital stay. Expectedly, it was found that the CNS group had less intraoperative blood loss and shorter postoperative hospital stay than the non-CNS group in this study. More benefits of CNS are waiting to be discovered by researchers.

To our knowledge, this was the first study to use PSM to analyze CNS on lymph node dissection, operation information and short-term outcomes for CRC. However, there were some limitations in this study. First, our data in this study came from a single clinical center. Second, we did not analyze the influence of other factors on lymph node dissection in detail. Third, there was no agreement on when patients should be injected carbon nanoparticles. Forth, lack of long-term patient outcomes. Therefore, prospective studies with a larger sample size were needed.

 Conclusion

Preoperative CNS could help the surgeons detect more lymph nodes, thus better determining the patient's N stage. Furthermore, it could reduce intraoperative loss and reduce the hospital stay.

 Data availability statement

The original contributions presented in the study are included in the article/Supplementary Material, further inquiries can be directed to the corresponding author.

 Ethics statement

This study was approved by the Institutional Ethics Committee of our hospital (2021–536), and informed consents were obtained from all patients.

 Author contributions

All authors contributed to data collection. All the authors have agreed on the manuscript that will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work. All authors contributed to the article and approved the submitted version.

 Acknowledgments

The authors are grateful to all the colleagues who helped in the preparation of this article.

 Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

 Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

 References KangBLiuXYLiZWYuanCZhangBWeiZQ The effect of the intraoperative blood loss and intraoperative blood transfusion on the short-term outcomes and prognosis of colorectal cancer: a propensity score matching analysis. Front Surg. (2022) 9:837545. 10.3389/fsurg.2022.83754535445077 PengDLiuXYChengYXTaoWChengY. Improvement of diabetes Mellitus after colorectal cancer surgery: a retrospective study of predictive factors for type 2 diabetes Mellitus remission and overall survival. Front Oncol. (2021) 11:694997. 10.3389/fonc.2021.69499734295822 SiegelRLMillerKDJemalA. Cancer statistics. CA Cancer J Clin. (2020) 70(1):7–30. 10.3322/caac.2159031912902 LiuXYKangBChengYXYuanCTaoWZhangB The short-term and oncologic outcomes of younger VS older colorectal cancer patients undergoing primary surgery: a propensity score matching analysis. BMC Cancer. (2022) 22(1):153. 10.1186/s12885-022-09246-435130849 SunJZhangJ. Assessment of lymph node metastasis in elderly patients with colorectal cancer by sentinel lymph node identification using carbon nanoparticles. J BUON. (2018) 23(1):68–72. PMID: 2955276229552762 ChengYXLiuXYKangBTaoWWeiZQPengD. Comparison of surgical and oncologic outcomes in very elderly patients (≥ 80 years old) and elderly (65-79 years old) colorectal cancer patients: a propensity score matching. BMC Gastroenterol. (2022) 22(1):205. 10.1186/s12876-022-02277-y35468733 JinZWuQDengXWangZ. The clinic factors in evaluating long-term outcomes of patients with stage I colorectal cancer. Asian J Surg. (2022) 45(11):2231–8. 10.1016/j.asjsur.2021.11.05535012854 ChenPJSuWCChangTKChenYCLiCCYinTC Oncological outcomes of robotic-assisted total mesorectal excision after neoadjuvant concurrent chemoradiotherapy in patients with rectal cancer. Asian J Surg. (2021) 44(7):957–63. 10.1016/j.asjsur.2021.01.01833622595 LiuPTanJTanQXuLHeTLvQ. Application of carbon nanoparticles in tracing lymph nodes and locating tumors in colorectal cancer: a concise review. Int J Nanomedicine. (2020) 15:9671–81. 10.2147/IJN.S28191433293812 DaiLCYaoXWangXNiuSQZhouLFFuFF In vitro and in vivo suppression of hepatocellular carcinoma growth by midkine-antisense oligonucleotide-loaded nanoparticles. World J Gastroenterol. (2009) 15(16):1966–72. 10.3748/wjg.15.196619399928 WuTZhengWLZhangSZSunJHYuanH. Bimodal visualization of colorectal uptake of nanoparticles in dimethylhydrazine-treated mice. World J Gastroenterol. (2011) 17(31):3614–22. 10.3748/wjg.v17.i31.361421987608 CaiHKHeHFTianWZhouMQHuYDengYC. Colorectal cancer lymph node staining by activated carbon nanoparticles suspension in vivo or methylene blue in vitro. World J Gastroenterol. (2012) 18(42):6148–54. 10.3748/wjg.v18.i42.614823155345 ChenSLBilchikAJ. More extensive nodal dissection improves survival for stages I to III of colon cancer: a population-based study. Ann Surg. (2006) 244(4):602–10. 10.1097/01.sla.0000237655.11717.5016998369 WangQChenECaiYChenCJinWZhengZ Preoperative endoscopic localization of colorectal cancer and tracing lymph nodes by using carbon nanoparticles in laparoscopy. World J Surg Oncol. (2016) 14(1):231. 10.1186/s12957-016-0987-127577559 GillABrunsonALaraPJrKhatriVSemradTJ. Implications of lymph node retrieval in locoregional rectal cancer treated with chemoradiotherapy: a California cancer registry study. Eur J Surg Oncol. (2015) 41(5):647–52. 10.1016/j.ejso.2015.01.03725800934 LiZAoSBuZWuAWuXShanF Clinical study of harvesting lymph nodes with carbon nanoparticles in advanced gastric cancer: a prospective randomized trial. World J Surg Oncol. (2016) 14:88. 10.1186/s12957-016-0835-327009101 LiuCLYangTLChenBF. Sentinel lymph node mapping with emulsion of activated carbon particles in patients with pre-mastectomy diagnosis of intraductal carcinoma of the breast. J Chin Med Assoc. (2003) 66(7):406–10. PMID: 1450940214509402 PanLYeFLiuJJBaXQShengQS. A study of using carbon nanoparticles to improve lymph nodes staging for laparoscopic-assisted radical right hemicolectomy in colon cancer. Int J Colorectal Dis. (2018) 33(8):1131–4. 10.1007/s00384-018-3050-629663069 GeWLiQLiuWJZhangXQFanXSShaoLH Carbon nanoparticle suspension could help get a more accurate nodal staging for patient with rectal cancer. Sci Rep. (2021) 11(1):9933. 10.1038/s41598-021-89541-533976352 WangLYLiJHZhouXZhengQCChengX. Clinical application of carbon nanoparticles in curative resection for colorectal carcinoma. Onco Targets Ther. (2017) 10:5585–9. 10.2147/OTT.S14662729200873 WeiserMR. AJCC 8th Edition: colorectal cancer. Ann Surg Oncol. (2018) 25(6):1454–5. 10.1245/s10434-018-6462-129616422 ClavienPABarkunJde OliveiraMLVautheyJNDindoDSchulickRD The clavien-dindo classification of surgical complications: five-year experience. Ann Surg. (2009) 250(2):187–96. 10.1097/SLA.0b013e3181b13ca219638912 BensonAB3rdSchragDSomerfieldMRCohenAMFigueredoATFlynnPJ American Society of clinical oncology recommendations on adjuvant chemotherapy for stage II colon cancer. J Clin Oncol. (2004) 22(16):3408–19. 10.1200/JCO.2004.05.06315199089 LabiancaRNordlingerBBerettaGDMosconiSMandalàMCervantesA Early colon cancer: eSMO clinical practice guidelines for diagnosis, treatment and follow-up. Ann Oncol. (2013) 24(Suppl 6):vi64–72. 10.1093/annonc/mdt35424078664 HuangXLiuHLiaoXXiaoZHuangZLiG. Prognostic factors for T1-2 colorectal cancer after radical resection: lymph node distribution is a valuable predictor of its survival. Asian J Surg. (2021) 44(1):241–6. 10.1016/j.asjsur.2020.06.01332792113 BensonAB3rdVenookAPCederquistLChanEChenYJCooperHS Colon cancer, version 1.2017, NCCN clinical practice guidelines in oncology. J Natl Compr Canc Netw. (2017) 15(3):370–98. 10.6004/jnccn.2017.003628275037 ZhengJYanQHuWLuoBLiY. Minimum number of lymph nodes necessary for the accurate staging of adenocarcinoma of esophagogastric junction. Asian J Surg. (2022) S1015- 9584(22):01147–2. 10.1016/j.asjsur.2022.08.034 KotakeKHonjoSSugiharaKHashiguchiYKatoTKodairaS Number of lymph nodes retrieved is an important determinant of survival of patients with stage II and stage III colorectal cancer. Jpn J Clin Oncol. (2012) 42(1):29–35. 10.1093/jjco/hyr16422102737 BaxterNNVirnigDJRothenbergerDAMorrisAMJessurunJVirnigBA. Lymph node evaluation in colorectal cancer patients: a population-based study. J Natl Cancer Inst. (2005) 97(3):219–25. 10.1093/jnci/dji02015687365 CawthornSJGibbsNMMarksCG. Clearance technique for the detection of lymph nodes in colorectal cancer. Br J Surg. (1986) 73(1):58–60. 10.1002/bjs.18007301243512023 QuadrosCALopesAAraújoI. Retroperitoneal and lateral pelvic lymphadenectomy mapped by lymphoscintigraphy for rectal adenocarcinoma staging. Jpn J Clin Oncol. (2010) 40(8):746–53. 10.1093/jjco/hyq06020457722 ChouJFRowDGonenMLiuYHSchragDWeiserMR. Clinical and pathologic factors that predict lymph node yield from surgical specimens in colorectal cancer: a population-based study. Cancer. (2010) 116(11):2560–70. 10.1002/cncr.2503220499400 NgSKLuCTPakneshanSLeungMSiuSLamAK. Harvest of lymph nodes in colorectal cancer depends on demographic and clinical characteristics of the patients. Int J Colorectal Dis. (2018) 33(1):19–22. 10.1007/s00384-017-2927-029134274 SarliLBaderGIuscoDSalveminiCMauroDDMazzeoA Number of lymph nodes examined and prognosis of TNM stage II colorectal cancer. Eur J Cancer. (2005) 41(2):272–9. 10.1016/j.ejca.2004.10.01015661553 LiJJiaSWangYZhangYKongLCaoY Long-term tracing and staining of carbon nanoparticles for axillary lymph nodes in patients with locally advanced breast cancer treated with neoadjuvant chemotherapy. Asian J Surg. (2022) 45(1):89–96. 10.1016/j.asjsur.2021.03.02033926797 TangLSunLZhaoPKongD. Effect of activated carbon nanoparticles on lymph node harvest in patients with colorectal cancer. Colorectal Dis. (2019) 21(4):427–31. 10.1111/codi.1453830580490 WangRMoSLiuQZhangWZhangZHeY The safety and effectiveness of carbon nanoparticles suspension in tracking lymph node metastases of colorectal cancer: a prospective randomized controlled trial. Jpn J Clin Oncol. (2020) 50(5):535–42. 10.1093/jjco/hyaa01132083298 ZhangXMLiangJWWangZKouJTZhouZX. Effect of preoperative injection of carbon nanoparticle suspension on the outcomes of selected patients with mid-low rectal cancer. Chin J Cancer. (2016) 35:33. 10.1186/s40880-016-0097-z27044280 DuJZhangYMingJLiuJZhongLLiangQ Evaluation of the tracing effect of carbon nanoparticle and carbon nanoparticle-epirubicin suspension in axillary lymph node dissection for breast cancer treatment. World J Surg Oncol. (2016) 14(1):164. 10.1186/s12957-016-0925-227335011 LiuYLiLYuJFanYXLuXB. Carbon nanoparticle lymph node tracer improves the outcomes of surgical treatment in papillary thyroid cancer. Cancer Biomark. (2018) 23(2):227–33. 10.3233/CBM-18138630198867 YanJZhengXLiuZYuJDengZXueF A multicenter study of using carbon nanoparticles to show sentinel lymph nodes in early gastric cancer. Surg Endosc. (2016) 30(4):1294–300. 10.1007/s00464-015-4358-826150223 ZhangLHuangYYangCZhuTLinYGaoH Application of a carbon nanoparticle suspension for sentinel lymph node mapping in patients with early breast cancer: a retrospective cohort study. World J Surg Oncol. (2018) 16(1):112. 10.1186/s12957-018-1414-629914538 HeJLiSShaoWWangDChenMYinW Activated carbon nanoparticles or methylene blue as tracer during video-assisted thoracic surgery for lung cancer can help pathologist find the detected lymph nodes. J Surg Oncol. (2010) 102(6):676–82. 10.1002/jso.2168420721962 Van TongerenMJKromhoutHGardinerK. Trends in levels of inhalable dust exposure, exceedance and overexposure in the European carbon black manufacturing industry. Ann Occup Hyg. (2000) 44(4):271–80. 10.1016/S0003-4878(99)00109-X10831731 MagrezAKasasSSalicioVPasquierNSeoJWCelioM Cellular toxicity of carbon-based nanomaterials. Nano Lett. (2006) 6(6):1121–5. 10.1021/nl060162e16771565