Breast cancer (BC) remains the most commonly occurring malignant tumor in women worldwide and represents the second cause of cancer-related death (1).

BC is a highly heterogeneous disease, and over the last decades significant improvements have been achieved in anticipation and accuracy of radiological diagnosis, biomolecular classification precision, and effectiveness of local treatments (2). Therefore, several options for systemic treatment of early breast cancer (EBC) and metastatic breast cancer (MBC) are currently available, and the therapeutic approach should be tailored to the individual patient.

The complexity in the management of BC increased dramatically along with the development of precision medicine. For this reason, diagnostic and decision-making processes require the integrated expertise of different healthcare professionals, such as medical oncologists, surgeons, radiologists, radiation oncologists, pathologists, palliative care specialists, and breast nurses.

Hence, multidisciplinary team meeting (MDM)-based care is in widespread use nowadays in Western countries, and it is recommended in several guidelines (3–5).

Despite the limited number of randomized controlled studies, there is growing evidence that the MDM approach is crucial in making decisions about adjuvant treatments since it provides meaningful improvements in adherence to evidence-based medicine with a better patient clinical outcome, treatment-related satisfaction, and quality of life (6–12).

Furthermore, MDM discussion enhances professional expertise, encourages the enrollment in clinical trials (8, 13), and increases the number of patients receiving neoadjuvant and adjuvant strategies (11, 14), minimizing the time between diagnosis and treatment (15). On the other hand, it seems to reduce medical costs, preventing unnecessary diagnostic procedures (16).

In the great part of MDMs, decisions are commonly based on reported clinical data and patients do not take part to the discussion (17); thus, some patient-center information such as performance status, social vulnerability factors, and preferences might be underestimated. In fact, in the major international guidelines, there is no clear recommendation about what specific clinical records have to be presented during MDM discussions (3, 4).

Accordingly, compliance with MDM recommendations could be influenced by several factors including, among others, age, comorbidity, and polypharmacy, as highlighted by Ring et al., which reported a higher rate of discordance among older BC patients, especially in adjuvant settings (18).

There is lack of studies evaluating the consistency between final decision on adjuvant strategies in early BC and MDM recommendations. The aim of this study was to investigate the rate of discrepancy between recommendations issued by MDMs and final face-to-face decision about medical adjuvant strategies for EBC.

The aim of this study was to investigate the rate, the reasons and factors associated with discordance between MDM decision and what currently applied by the oncologist after the face-to face examination with patient.

The increasing complexity in management of cancer care requires a multimodal approach; consequently, meetings involving different specialists progressively gained relevance. Despite the lack of solid evidence, breast MDMs are widely accepted by the medical community; they increase the level of satisfaction of participating, supporting improvement of decision making and overall quality of treatment. They also promote more coordinated patient care and evidence-based treatment decisions (17, 22).

The association between MDM-based treatment plans and improvements in pathological and radiological assessment and an increased number of neoadjuvant and adjuvant strategies proposed have already been described (15, 23). It has also been suggested that tumor boards might increase survival outcomes in different tumors, including BC, although evidence is not conclusive (15, 24). Several studies highlighted the association between multidisciplinary discussion and subsequent changes in treatment plans (15, 25). However, to our best knowledge there is a paucity of evidence describing the concordance between MDM recommendation and what was proposed to the patient.

In our retrospective study, a discordance rate of 15.8% was found between what collegiality proposed during MDMs and what was subsequently applied by the oncologists during a face-to-face consultation with the patient. This discrepancy was predominantly caused by a medical decision based on patients’ clinical and psychological conditions (87% of cases) rather than a patient choice. Intriguingly, a de-escalation of treatment intensity was performed in most cases, with adjuvant ET preferred to sequential CT and ET proposed within the MDM in 35% of women. Furthermore, clinical follow-up based on scheduled physical examination and breast imaging was chosen instead of CT and ET in 15% and 39% of patients, respectively.

Focusing on cases in which follow-up was preferred to ET, 44.5% were DCIS, for which the clinical impact of adjuvant tamoxifen should be discussed with each patient for a correct risk and benefit balance, particularly in elderly women.

As emerged by univariate analysis, high CCS index, concomitant medications, age older than 70 years, and consequent postmenopausal status were factors associated with discordance. Intuitively, patients with several comorbidities and advanced age are considered less likely to be offered active anticancer treatment, especially in adjuvant settings. Hence, post-MDM treatment de-escalation observed in our series could be related to new information about comorbidities highlighted during the oncological examination, in line with other studies (26, 27). Blazeby et al., in a series of 271 upper gastrointestinal cancer patients, observed that 15.1% of MDM decisions were not implemented and patients mostly received a more conservative treatment due to new data concerning health status (26). Similarly, in another study evaluating 201 MDM decisions in colorectal patients, the discordance rate was 10.0% and a more conservative treatment was chosen in all cases mainly due to patients’ related factor (comorbidities or personal decisions) (27).

In addition, in the great part of centers, patients do not participate in MDMs and thus the panel decision is taken on available clinical record data and without considering patients’ preferences.

On the other hand, it might be more difficult for MDM members to define a clear treatment plan in multi-pathological patients and, when an agreement is reached, recommendations are less likely concordant with anticancer treatment guidelines for patients with comorbidities and older age (28). As confirmed in a series of breast cancer patients older than 70 years, age might be an independent factor associated with a lower rate of adjuvant CT proposed within the tumor board, especially older than 80 years (29). A correlation between older age and reduced adjuvant CT performed was also highlighted in a French study (30).

Patients’ social status, psychological conditions, and caregiver attendance are additional elements of complexity that might not always be adequately discussed during MDMs, emerging subsequently during oncological visit and supporting the decision of a lower intensity of care. Indeed, in a survey performed by the Korea Breast Cancer Society, only 2.1% of meetings also considered patients’ psychosocial issues (31).

When considering disease-associated characteristics, in our series Ki-67 between 14% and 30% emerged as the only factor associated with discordance, in both uni- and multivariate logistic regressions. Tumor proliferation activity is a well-known prognostic factor, and in hormone-positive tumors the cutoff of 20% (previously 14%) separates luminal A and B cancers (32). At the state of the art, it is not possible to define a specific threshold value above which BC is considered highly proliferative, to predict the efficacy of adjuvant CT or ET. Thus, in the “gray zone” between 14% and 30%, other clinicopathological factors might impact the medical decision on adjuvant treatment, increasing the approach variability and justifying the post-MDM discordance observed in our series.

The present study has several limitations, the first of which are the retrospective design and the small number of patients enrolled. Furthermore, despite that in our center both pre- and postoperative breast cancer cases are routinely discussed at MDMs, in this report we focused only on patients who previously underwent radical surgery. Although the tumor board indication is registered and available electronically, the physician taking charge of the patient might have not attended the multidisciplinary discussion and might disagree with the board’s decision.

This interindividual variability could be a further element explaining the discordance between what was decided during the MDMs and what was consequently applied by the oncologist. Indeed, the panel’s opinion should be interpreted as a recommendation and not as the final decision, which is up to the oncologist who takes charge of the patients.

Genomic testing was not available in clinical practice at the time of the data collection of the present study. Several studies highlighted its utility in predicting benefit from chemotherapy and established the importance of integrating these tools in EBC management, hence in MDM discussions.

Notwithstanding the limitation cited above, our study provides a pragmatic real-life view on breast cancer decision-making processes.

MDM is gaining momentum as a gold-standard resource in BC healthcare management since it improves decision-making processes, empowers medical team professional skills, and ensures comprehensive taking charge of patients. In our opinion, every effort should be made to promote MDM development, improving their reliability and cost-effectiveness. However, it should be recognized that discrepancy could be forecast between MDM recommendation and final clinical decision with the patient. This study suggests that, in order to optimize time and resources, vulnerability factors such as age, comorbidity, and social impairments should be properly assessed, routinely presented, and discussed during MDMs.

Furthermore, the participation of a greater number of professionals; the integration of psychologists, onco-geriatricians, and social care professionals in the MDM’s team; and the systematic adoption of geriatric assessment scale could be meaningful to improve clinical outcomes.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by Comitato Etico Unico Regionale - CEUR FVG. Written informed consent for participation was not required for this study in accordance with the national legislation and the institutional requirements.

LB, MG, MB, and AM designed the study. LB, GT, and CN wrote the initial manuscript. GT, MG, LP, DZ, and EB performed the data collection and cleaning. DB performed the data analysis. All authors contributed to the article and approved the submitted version.

Fees for open access were provided by Azienda Sanitaria Universitaria Friuli Centrale (ASUFC).

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.

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