Aim: Although many factors affecting recurrence, including surgical margin involvement, have been considered in rectum cancer surgery, there is no consensus on the definition of a safe distal surgical margin (DSM).We aimed to investigate the oncological safety of a DSM closer than 10 mm and the factors affecting relapse in mid-distal located rectum tumours.
Method: Patients who underwent sphincter-preserving rectal curative resection following neoadjuvant chemoradiotheraphy between February 2006 and June 2019 for mid-distal lying rectum tumours were investigated retrospectively. Patients with radial or distal surgical margin involvement, having a complete pathologic response, or being lost to follow-up were excluded from the study. Patients and tumour characteristics, clinical and pathological disease stages, and recurrence and disease-free survival rates were compared between groups created along a cut-off value of 10 mm in DSM (DSM <10 and DSM ≥10).
Results: The study group consisted of 23 patients (DSM <10, n=11; DSM ≥10, n=12). Most of the tumours were located distally (70% , n=16). Handsewn anastomosis was performed in 81.8% of patients in the DSM <10 group (Turnbull-Cutait, n=5; coloanal anastomosis, n=4) and in 33% of patients in the DSM ≥10 group (Turnbull-Cutait, n=2; coloanal anastomosis, n=2). During a median follow-up time of 72 (6-158) months, three cases of systemic recurrence developed while no local recurrence was faced. The recurrence rates and disease-free survival rates were similar (p=0.17 and p=0.184, respectively). Younger age, bulkier tumour, presence of perineural invasion, ypN stage, and number of metastatic lymph nodes were associated with recurrence (p=0.017, p=0.00, p=0.014, p=0.030, and p=0.024, respectively).
Conclusion: Our study supports the view that obtaining a DSM closer than 10 mm but without tumour can be sufficient in terms of oncological safety, allowing permanent colostomy to be avoided. Young age, large tumour size, presence of perineural invasion and increased number of metastatic lymph nodes stand out as risk factors for recurrence.