Prognostic significance of tumor fixation of rectal carcinoma: Implications for adjunctive radiation therapy

Abstract

This study was conducted to assess the prognostic significance of adjunctive radiation in the surgical management of rectal carcinoma patients with tumor fixation. Two hundred and ninety-seven patients with a histologic diagnosis of adenocarcinoma of the rectum were treated with high dose preoperative radiation ( > or = 45 Gray [Gy]) followed by surgical resection of the tumor (Group A). One hundred and seventy-four patients underwent initial curative surgery (Group B) followed by selective postoperative radiation (45-50 Gy) for those with pathologic T3, T4, or N+ (B2, C) cancers (N = 143). The two patient groups were compared by presenting clinical stage of the disease to assess the prognostic significance of tumor fixation on results of adjunctive therapy. Follow-up ranged from 24 months to 180 months. The 5-year actuarial survival of Groups A and B was similar, 69% and 61% respectively. Survival was significantly better for Group A patients with fixed cancer (57% vs. 33%, P = 0.003). Survival was also better for patients in Group A with tumors located in the distal rectum (70% vs. 56%, P = 0.02). The local recurrence rate for patients with tumors located in the distal rectum was 17% for Group A and 19% for Group B (P = 0.74). The local recurrence rate for fixed cancers was 23% and 50% for Group A and Group B respectively (P = 0.0009). The incidence of small bowel complications (Grade 3 or 4) was lower for patients undergoing preoperative radiation compared with patients treated with postoperative radiation, (4% vs. 13%, P < 0.05). When special considerations of sphincter-preserving surgery are not an issue, mobile rectal carcinoma may be effectively treated with surgery and selective postoperative radiation. However, fixed tumors, especially those located in the distal rectum, are better treated with high dose preoperative radiation.