Planning resection margins for soft tissue sarcomas is a compromise between functional sacrifice and therapeutic safety. In practice, the histological analysis of the resection margins often shows that the preoperative objective has not been achieved. We studied the prevalence and factors of risk of this surgical outcome.

This was a prospective monocentric study of 133 patients. The resection objectives, pathological results and operative reports were examined. Margins were classified according to the UICC (R0, R1, R2). Data were included in a grid which also included patient related and tumour related preoperative information. Inadequate resection was noted as planned R0 with R1 or R2 outcome. Statistical analysis was performed with Statview 5.0.

The prevalence of inadequate resection was 25.2%. Among the factors analysed, the aspect of tumor limits (badely or well defined) was significantly related to poor surgical results (odds ration 2.85 [1.47–5.52], p < 0.005). No other significant risk factor could be identified. Margins greater than two mm were associated with adequate surgery in every case.

No preoperative risk factor predictive of inadequate resection margins was clearly identified in this study. Postoperatively, the microscopic aspect of the proliferation limits at the final pathology examination is for us significantly associated with inadequate resection. However the current classification for resection margins lacks precision, especially regarding R0 and R1 when margins are small, in defining the risk of inadequate resection. This appears to be the source of the difficulties encountered in interpreting pathology samples and therefore in choosing the right treatment. Further follow-up is needed to clarify such questions.

We conclude that where resection margins are thin (less than two mm), the definition of R0 or R1 resections should be clarified to optimize patient care. To achieve this, potential risk factors for inadequate resection such as tumor limits should be taken into account and further studied.

Purpose of the study: Planning resection margins for soft tissue sarcomas is a compromise between functional sacrifice and therapeutic safety. In practice, the histological analysis of the resection margins often shows that the preoperative objective has not been achieved. We defined this as anatomo-surgical discordance and studied its prevalence and factors of risk.

Materials and Methods: This was a prospective mono-centric study of 133 patients. The resection objectives, pathological results and operative reports were examined. Margins were classified according to the UICC (R0, R1, R2). Data were included in a grid which also included patient related and tumour related preoperative information. Discordance was noted as planned R0 with R1 or R2 outcome. Statistical analysis was performed with Statview 5.0.

Results: The prevalence of anatomo-surgical discordance was 25.2%. Among the factors analysed, the aspect of the margins was significantly related to poor surgical results (odds ration 2.85 [1.47–5.52], p=0.0031). No other significant risk factor could be identified. Margins greater than 2mm were associated with adequate surgery in every case.

Discussion: No preoperative risk factor predictive of inadequate resection margins was clearly identified in this study. Postoperatively, the microscopic aspect of the proliferation margins at the final pathology examination is for us significantly associated with inadequate resection. But the current classification of resection margins (R0 and R1), especially for poorly delimited tumours lacks precision. This appears to be the source of the difficulties encountered in interpreting pathology samples and therefore in choosing the right treatment. Further follow-up is needed to clarify such questions.

Conclusion: We were unable to identify any preoperative factor predictive of inadequate resection. A poorly-defined microscopic aspect of the tumour is significantly associated with inadequate resection but the current classification system raises certain interpretation problems for resections with margins less than 2 mm. Concerning these cases, the definition of margins must be clarified to optimize patient care.