The possibility of a permanent stoma should be considered when planning surgery for treating rectal cancer. It might be preferable in older patients, in poor condition and with more advanced rectal cancers, to consider an abdominoperineal resection or Hartmann procedure instead of a low anterior resection.

The high cancer-specific survival justifies transanal endoscopic microsurgery alone as curative treatment in low-risk rectal carcinoma. Complete resection is essential to lower the risk of local recurrence. The high local recurrence rate in patients with high-risk rectal carcinoma restricts the use of TEM alone as compromise therapy.

Background In rectal cancers, radical surgery should follow local excisions, in cases of unexpected, unfavorable tumor characteristics. The oncological results of this completion surgery are inconsistent. This retrospective cohort study assessed the clinical and long-term oncological outcomes of patients that underwent completion surgery to clarify whether a local excision compromised the results of radical surgery. Methods Forty-six patients were included, and the reasons for completion surgery, intraoperative complications, residual tumors, local recurrences (LRs), distant metastases, and cancer-specific survival (CSS) were assessed. The results were compared to 583 patients that underwent primary surgery without adjuvant therapy, treated with a curative intention during the same time period. Results The median follow-up was 14.6 years. The reasons for undergoing completion surgery were positive resection margins (24%), high-risk cancer (30%), or both (46%). Intraoperative perforations occurred in 10/46 (22%) cases. Residual tumor in the rectal wall or lymph node involvement occurred in 12/46 (26%) cases. The risk of intraoperative perforation and residual tumor increased with the pT category. Intraoperative perforations did not increase postoperative complications, but they increased the risk of LRs in cases of intramural residual tumors (p = 0.003). LRs occurred in 2.6% of pT1/2 and 29% of pT3 tumors. Both the 5- and 10-year CSS rates were 88.8% (95% CI 80.0–98.6). Moreover, the LRs of patients with pT1/2 cancers were lower in patients with completion surgery than in patients with primary surgery. Conclusions Rectal wall perforations at the local excision site and residual cancer were the main risks for poor oncological outcomes associated with completion surgery. Local excisions followed by early radical surgery did not appear to compromise outcomes compared to patients with primary surgery for pT1/2 rectal cancer. Improvements in clinical staging should allow more appropriate selection of patients that are eligible for a local excision of rectal cancer.

The results suggest that most LRs after TEM for low-risk rectal cancer were caused by residual tumor at the previous excision site and not by undetected lymph node metastases. By improved standardization of surgical techniques to ensure complete resection of carcinomas and thorough pathological assessments, most LRs seem to be avoidable.

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