Pelvic wall involvement denotes a poor prognosis in T4 rectal cancer

PURPOSE: An aggressive surgical approach with en bloc resection of involved structures is often possible with anterior rectal cancers that invade adja cent visceral organs, but is rarely possible in tumors that invade the pelv ic wall. However, most staging systems include both situations in the same group of T4 rectal cancers. We performed a retrospective study of patients with stage T4 rectal cancer undergoing surgery to assess the influence of d ifferent organ involvement on resectability and survival. METHODS: A retros pective review was conducted of 84 patients with T4 rectal cancer treated a t the University of Minnesota and affiliated hospitals over a ten-year peri od. Forty-seven patients (56 percent) were staged for local invasion on the basis of final pathology, 19 (23 percent) on the basis of operative findin gs, and 18 (21 percent) on the basis of ultrasound images. Patients were di vided into two groups, those with or without pelvic wall involvement. Resec tability, local control, and overall survival were compared between groups. Survival curves were estimated by the Kaplan-Meier method and compared by log-rank test. Multivariate analysis was performed with Cox proportional an d logistic regression. RESULTS: Thirty-one patients (37 percent) had involv ement of the pelvic wall, whereas 53 patients (63 percent) had visceral inv olvement only. Ali 29 patients with distant metastasis died of their diseas e. Forty-seven of the 55 patients without distant metastasis underwent tumo r resection. Age and pelvic wall involvement were the only two factors inde pendently associated with the probability of resection in logistic regressi on analysis (P = 0.0067 and P = 0.037, respectively). The only factor that affected median survival in patients without distant metastasis was tumor r esection (49.1 months for resection vs. 6.1 months for no resection. P = 0. 017). Patients with visceral involvement had a longer median survival (49.2 months) than those with pelvic wall involvement (13.2 months), but the dif ference did not reach statistical significance (P = 0.058). CONCLUSION: Rec tal cancers with pelvic and visceral involvement have different rates of re sectability and median survival. These differences should be reflected in t he TNM classification system.