T-level downstaging and complete pathologic response after preoperative long-term radiochemotherapy for locally advanced rectal cancer.

Advantages of neoadjuvant chemoradiotherapy for locally advanced carcinoma of the middle and the lower third of the rectum are downstaging and downsizing of the tumor. Results of pathologic results are affected by post-treatment tissue changes and may influence the choice of surgical procedure. Forty-three consecutive patients (27 male, 16 female; mean age 64 years) were operated after receiving a long-term chemoradiotherapy during a period of 16 months. The data of initial staging procedure (high resolution magnetic resonance imaging) and results of pathological examination of the surgical specimens were analyzed. Regression of tumor was assessed by the absence of vital tumor cells and the post-treatment fibrotic tissue alterations. Regression of tumor size was seen in 42/43 patients leading to an improved T-stage in 27 patients. R0-resection was possible in all cases, although there was a perirectal tumor infiltration to less than 2 mm to circumference of the surgical specimen in 2 cases and unexpected small liver metastasis in 5 cases. Complete remission rate was 23.3% (10 cases). Detecting small amounts of vital tumor cells in altered tissue after chemoradiotherapy is a major problem of pathological examination procedure and should be taken into consideration by the surgeons. The choice of operation (resection vs. abdominoperineal extirpation vs. local excision) should be committed to the initial imaging procedure and not to any restaging procedure after neoadjuvant chemoradiotherapy.