PURPOSE: The aim of this study was to determine the effect of surgeon specialty on disease-free survival and local control in patients with adenocarcinoma of the rectum. Patients underwent curative treatment with neoadjuvant external beam radiotherapy and proctectomy by colorectal surgeons and noncolorectal surgeons. METHODS: The records of 384 consecutive patients treated by colorectal surgeons (n = 251) and noncolorectal surgeons (n = 133) from 1977 to 1995 were reviewed independently by physicians in the Division of Radiation Oncology. Local recurrence was defined as pelvic recurrence occurring in the presence or absence of distant metastatic disease. RESULTS: The study population comprised 213 males, mean age 64 (range, 19-97) years. Preoperative radiotherapy was delivered as 4,500 cGy in 25 fractions six to eight weeks before surgery (n = 293) or 2,000 cGy in 5 fractions immediately before surgery (n = 91). Concurrent preoperative chemotherapy was given to 14 patients, postoperative chemotherapy to 55. Overall actuarial disease-free survival and local control rates were 74 and 90 percent, respectively, at five years. Actuarial disease-free survival and local control rates at five years were 77 and 93 percent for colorectal surgeons vs. 68 and 84 percent for noncolorectal surgeons (P ≤ 0.005 for both, Tarone-Ware). Multivariate analysis revealed that pathologic stage and background of the surgeon were the only independent predictors of disease-free survival (both P ≤ 0.006, Cox proportional hazards) and that pathologic stage, background of the surgeon, and proximal location of the tumor were independent predictors of local control (all P ≤ 0.02, Cox proportional hazards). Radiation dose and use of chemotherapy were not significant factors. Sphincter preservation was more common by colorectal surgeons (131/251, 52 percent) than noncolorectal surgeons (40/133, 30 percent; P = 0.00004, Fisher's exact test, two-tailed). CONCLUSION: Good outcome for patients with adenocarcinoma of the rectum who undergo neoadjuvant external beam radiotherapy and proctectomy is associated with subspecialty training in colon and rectal surgery.