Retroperitoneal liposarcoma (RPLS) is the most prevalent malignancy among retroperitoneal sarcomas (RPS), which accounts for approximately 0.15% of all adult cancers and has an incidence of 0.5–1 case per 100,000 (1, 2). RPLS poses significant challenges for treatment due to its potential of adjacent organ involvement and frequent recurrence. The role of radiation and systemic therapy in RPLS is not well defined, and surgery is currently the only potentially curative treatment choice (3, 4). Macroscopic complete resection (CR) combined with the resection of involved adjacent organs has been recommended for the treatment of RPLS. However, local recurrence remains common (40–85%) (4).

The inability to achieve a true R0 resection with the susceptive microscopic involvement of adjacent organs, structures, and surfaces might contribute to the high rate of postoperative recurrence in RPLS (5). Multiple satellite tumor foci may exist in the perceived normal adipose tissue that can be separated from the visible tumor (5, 6). Complications arising from recurrence, such as ileus, cachexia, and multiple organ dysfunction are the main cause of tumor related death. Many surgical oncologists recommend extended resection for RPLS to improve prognosis based on experience or clinical research (7, 8). However, Controversy exists over whether normal adipose tissue adjacent to the tumor should be removed in addition to combined resection of organs invaded by the tumor and abnormal adipose tissue.

In this regard, we reviewed primary RPLS patients treated with CR or TRL in our department, a center focused on the treatment of retroperitoneal tumors, to further clarify the effect of TRL in treating primary RPLS compared with traditional CR.

Retroperitoneal liposarcoma (RPLS) is a relatively rare malignant tumor with four distinct histological subtypes. The most common subtypes are well-differentiated liposarcoma and dedifferentiated liposarcoma. Other less common types include myxoid liposarcoma and pleomorphic liposarcoma. Well-differentiated liposarcomas (LPS) are characterized by low-grade malignancy, slow growth, and minimal symptoms. These tumors can reach a substantial size before diagnosis, and achieving R0 resections (complete removal) is often challenging (9). Notably, the rate of local recurrence for retroperitoneal LPS is significantly higher than that for LPS with distant metastasis. In contrast, dedifferentiated LPS can exhibit extreme aggressiveness. Multifocal disease is common in retroperitoneal LPS. At initial presentation, 34% of patients have multifocal disease, and 57% of patients with unifocal disease progress to multifocal disease upon recurrence after chemotherapy or radiation (5, 10, 11). Therefore, when treating patients with retroperitoneal liposarcoma, both the extent of surgical resection and tumor biology must be carefully considered (6).

The current standard of care for treating RPLS involves complete resection (CR). However, CR is associated with a high rate of recurrence, necessitating more extensive resections (12–14). A novel surgical technique, known as total (ipsilateral) retroperitoneal lipectomy (TRL), has emerged. In TRL, the surgeon removes the ipsilateral retroperitoneal adipose tissue en bloc with the tumor, aiming not only for complete resection but also to address multifocal disease while preserving organs rather than performing aggressive resections. Despite being proposed by sarcoma surgeons, clinical studies evaluating the safety and efficacy of TRL remain limited. In our study, patients who underwent TRL surgery showed no significant difference in overall complication rates and rates of severe complications (Grade 3 or higher) compared to patients who underwent traditional CR surgery. These findings demonstrate excellent safety. Furthermore, when compared to other studies, our results also indicate satisfactory safety (15, 16).

In all enrolled patients, TRL significantly improved patients’ recurrence-free survival (RFS) and overall survival (OS). Notably, subgroup analysis revealed that this survival benefit was only present in patients with dedifferentiated liposarcoma (DDLS). This suggests that due to the generally milder and less aggressive nature of WDLS, satisfactory treatment outcomes can be achieved with CR surgery alone. However, it is common for tumors in the same patient to contain both well-differentiated and dedifferentiated components (17). Histologic type has long been considered the most important factor affecting the prognosis of retroperitoneal soft tissue sarcomas, including its impact on overall survival, recurrence-free survival, and distant metastasis (18–20). The impact stems from poorly differentiated sarcomas, known for their high invasiveness and indistinct margins, often infiltrating nearby structures. This can result in microscopic residual tumors at the surgical margin, even when an R0 resection appears successful macroscopically, thereby increasing recurrence risk and reducing disease-free survival. There is currently no established method for effectively assessing pathological margins and the extent of infiltration in retroperitoneal soft tissue sarcomas, either preoperatively or intraoperatively. Surgeons must depend on their experience to determine tumor borders or the depth of invasion into nearby organs, which guides decisions on the extent of resection. The possibility of postoperative complications affects the decision-making process regarding combined organ resection to secure clear margins. For instance, removing organs like the colon, kidney, and psoas generally poses a low risk of severe postoperative complications, whereas resections involving the pancreas, duodenum, or major blood vessels are associated with higher risks of severe complications. Assessing tumor differentiation based solely on imaging and gross examination is unreliable. Therefore, relying solely on imaging to determine the differentiation type and depth of tumor invasion for retroperitoneal liposarcomas (LPS) when deciding between CR or TRL surgery is not feasible (8, 21–23). Studies by Singer et al. indicates that the condition of the surgical margin independently influences the prognosis of RPLS (24–26). Therefore, on the basis of controlling the risk of complications, adopting more aggressive surgical techniques to achieve negative margins becomes essential. Unfortunately, due to the lack of description of margin status in the postoperative pathological results of most patients, we were unable to incorporate and analyze data on margins in this study. Nevertheless, considering the similar safety profiles observed in the study for both surgical approaches, we still recommend TRL surgery for all retroperitoneal LPS cases.

Multifocal disease has profound effects on the oncological outcomes of retroperitoneal liposarcoma (RPLS) patients. In a recent study, 20% of patients presented with multifocal disease, and the 5-year overall survival (OS) rate was significantly lower in the multifocal group than the unifocal group (11). Another study found that 25% of RPLS patients presented with multifocal disease, which was associated with curtailed OS (23). Additionally, a clinical study that included both primary and recurrent RPLS cases showed that the proportion of multifocal disease at initial presentation was 45% (23% for primary cases and 22% for first-recurrent RPLS). Interestingly, the 3-year OS rate after TRL was significantly higher than the 3-year OS rate after CR in patients with multifocal disease (27). Our own research findings indicate that although TRL did not demonstrate improved RFS and OS compared to CR surgery for multifocal liposarcomas among primary RPLS patients, it also did not perform worse than CR. Therefore, our results are consistent with the recommendation of TRL for multifocal RPLS based on the previous study.

Our study had several limitations. First, due to its retrospective nature, our study had inherent biases. Second, the low incidence rate of RPLS results in a scarcity of specialized centers dedicated to diagnosing and treating this disease. Patients are often dispersed across various surgical specialties such as gastrointestinal surgery and urology. Conducting standardized, multicenter clinical studies specifically targeting this condition becomes challenging, which in turn limits the number of patients included in our research. Nevertheless, the critical clinicopathological characteristics were comparable between the two groups. Notably, the proportion of patients receiving adjuvant therapy was relatively low. This allowed us to more accurately compare the effectiveness of the two surgical approaches while minimizing interference from nonsurgical therapies.

Total (ipsilateral) retroperitoneal lipectomy (TRL) is a relatively safe surgical approach for primary retroperitoneal liposarcoma (RPLS) patients. It has been associated with significantly better recurrence-free survival (RFS) and overall survival (OS) in particular subsets of patients. Further clinical research is needed, particularly in experienced sarcoma centers, to design more standardized and larger-scale studies that can validate the therapeutic efficacy of TRL for RPLS.