A SELECTIVE APPROACH TO ADJUNCTIVE THERAPY FOR CANCER OF THE RECTUM

Purpose: To present results of a selective approach to adjunctive therapy and surgery based on a new model of clinical staging for rectal cancer. Methods and Materials: Three hundred and sixty-two patients with rectal cancer treated with adjunctive radiation therapy and surgery have been analyzed to define patient selection criteria based on clinical assessment of disease. Clinical prognostic features of tumor mobility and level of lesion in the rectum with reference to the anorectal junction were used. Mobile, early fixed (partial), advanced fixed (total) and frozen pelvis are defined as clinical Stages I, II, III, and IV. Tumors above 6 cm (middle valve), 3-6 cm (inferior to middle valve), 0-3 cm (anorectum to inferior valve), and into the anal canal are defined as levels a, b, c, d, respectively. Based on this model, patients with mobile tumors of the proximal rectum (CS Ia, b) are treated with 500 cGy preoperative radiation and selective postoperative radiation (4500 cGy) for Stages B2 and C cancer. All other patients are treated with escalating doses of preoperative radiation. Follow-up in these patients ranges from 1 year to 14 years with a median of 5 years. Results: Overall 5-year survival of the total group of patients is 69%. Survival by pathological stage is 82% for O, A, B1, 67% for B2, 74% for C1, and 51% for C2. Survival by clinical stages is 77% for CS I, 67% for CS II, 57% for CS III, and 21% for CS IV. Overall local recurrence is 43/362 (12%). L.R. by pathological stages is 5% for O, A, B1, 18% for B2, 10% for C1, and 17% for C2. L.R. by clinical stages is 9% for CS I, 14% for CS II, 17% for CS III, and 50% for CS IV. Conclusion: An integrated adjunctive therapy and selective surgical approach based on careful clinical staging of rectal cancer results in a global improvement in overall local control and survival of patients.