Tumor height from the anal verge before and after complete mobilization of the rectum

ABSTRACT

Rectal tumor height has been observed to increase after complete mobilization.OBJECTIVES: 1.) to measure tumor height in resectable rectal cancers before and after complete mobilization, 2.) to describe changes in tumor height measurements at different levels of the rectum, and 3.) to determine the probability of a two centimeter increase in tumor height after mobilization in low rectal cancers. METHODS: Prospective cross-sectional series including all resectable rectal cancer treated at our hospital from January to December, 2003. Proctoscopy measurements of rectal tumor height after induction of anesthesia were compared to measurements done after complete rectal mobilization. Logistic curve fitting was used to calculate the probability of a two centimeter increase in tumor height for low rectal cancers after complete mobilization.RESULTS: In the 12-month period, 37 patients with adenocarcinoma of the rectum were seen. Ages of patients ranged from 26 to 86, with mean age of 57.8 years. Thirty-three patients had resectable rectal cancer. Tumor height ranged from zero to 11 cm, with mean height of 5.7 cm. After complete mobilization, tumor height increased in 50 percent of upper rectal cancers, 92 percent of mid-rectal cancers, and 32 percent of low rectal cancers. Logistic curve fitting showed probability of a two-centimeter increase in tumor height was 52 percent at seven centimeters, 40 percent at six centimeters, 28 percent at five centimeters, and 19 percent at four centimeters. DISCUSSION: The decision to perform APR for low rectal cancers must not be based solely in pre-operative tumor height measurements since pre-operative measurements of rectal tumor height can increase when the rectum is completely mobilized.