Aim: Although total mesorectal excision (TME) is still considered as the gold standard for all rectal cancers, partial mesorectal excision (PME) is being increasingly performed in upper third rectal cancer with preservation of a longer rectal stump to ensure better outcomes without jeopardizing the oncological results. Furthermore, several publications have shown that PME could also be a reasonable approach even for the mid-rectal cancer but data is very limited. We aimed to assess the short-term clinicopathological outcomes of PME versus TME in mid-rectal cancer.

Method: The Turkish Society of Colon and Rectal Surgery (TSCRS) colorectal cancer database was queried for patients who underwent surgery for mid-rectal cancer between July 2018 and December 2022. Mid-rectal cancer was defined as cancer located from 5 to 10 cm from the anal verge. Patients were divided into two groups according to PME and TME procedures. Histopathological data of resection margins and 30-day clinical outcomes were compared between the groups.

Results: A total of 158 (62% men) patients, 24 (15%) in the PME group and 134 (85%) in the TME group, met the inclusion criteria. There were no significant differences between the groups regarding demographics, perioperative and postoperative data (intraoperative complications, 0 vs 5.2%, p=0.54; anastomotic leak, 4.2% vs 8.9%, p=0.70) except for cN stage, cTNM stage, neoadjuvant treatment use (37.5 vs 87.3%) and diverting stoma creation (58.3 vs 85.8%) (p <0.05). Regarding histopathological results, there were no differences with respect to mean nodal harvest (18.6±8.5 vs 15.6±9.2, p=0.09), quality of mesorectal excision, radial and distal resection margin positivity (8.4 vs 5.1%, p> 0.99). The length of distal resection margin was 3.3±1.4 cm and 3.3±1.6 cm in the PME and TME groups, respectively (Table 1). In the multivariate analyses, compared to TME, PME was associated with a similar likelihood of distal resection margin positivity (OR 0.77, 95% CI 0.02-19.08, p=0.88), radial resection margin positivity (OR 9.95, 95% CI 0.22-522.17, p=0.22), similar number of lymph nodes harvested (1.28, 95% CI -1.62-7.70, p=0.20), similar likelihood of anastomotic leak (OR 0.3, 95% CI 0.01-2.60, p=0.33) and diverting stoma formation (OR 0.67, 95% CI 0.19-2.44, p=0.53).

Conclusion: This study suggests that PME does not jeopardize the surgical resection margins and short-term outcomes in patients with mid-rectal cancer. These results must be confirmed with larger cohorts and further studies are needed to evaluate functional outcomes.