The influence of histopathologic criteria on the long-term prognosis of locally excised pT1 rectal carcinomas: results of local excision (transanal endoscopic microsurgery) and immediate reoperation.

Purpose: Local excision of early rectal cancer is a controversial issue, which is in part because of differences in the evaluation of histopathologic criteria. This prospective study was designed to determine prognostic factors for recurrences and the need for reoperation.

Methods: In 105 of 118 patients with pT1 carcinomas and local excision, results of recurrence rates and ten-year cancer-free survival were studied separately according to different histologic criteria (R0, R1, Rx, R < or = 1 mm, high-/low-risk situation), tumor localization (anterior, posterior, lateral wall and third of rectum), size, and degree of resection (full-thickness/partial wall). Patients were grouped into local excision (n = 89) and local excision followed by reoperation (n = 21). Risk classification was performed by division into "low-risk" carcinomas after local R0-resection (Group A) and unfavorable histologic results after local resection (R1, Rx, R < or = 1 mm, high-risk situation; Group B).

Results: Local recurrence rates after local R0-resection of low-risk carcinomas were 6 percent, whereas patients in Group B with local resection were 39 percent. The recurrence risk in those patients was significantly reduced to 6 percent by reoperation (P = 0.015). In addition, ten-year, cancer-free survival was 93 percent in Group B after reoperation compared with 89 percent in patients of Group A after local excision alone.

Conclusions: Local R0-resection in cases with low-risk pT1 carcinomas represents an oncologically adequate therapy, which results in similar survival rates compared with primary radical surgery of pT1N0M0 rectal carcinomas. High recurrence rates are observed in tumors with unfavorable histologic result (Group B) requiring further treatment. In these cases immediate reoperation reduces the recurrence rate to 6 percent.