Five fractions of preoperative radiotherapy for selected cases of rectal carcinoma: Long-term tumor control and tolerance to treatment

Background: Randomized Swedish studies demonstrate the efficacy of a 5-frac tion course of preoperative radiotherapy for rectal carcinoma. The present study evaluates the results in a single U.S. institution over a 20-year per iod with a similar regimen. Methods and Materials: During the period of 1975-1995, 83 patients received pelvic radiotherapy of 20 Gy/5 fractions, followed by immediate surgery fo r rectal cancer. These patients represented 21% of cases receiving preopera tive treatment; the remainder received 45-50 Gy preoperatively. The 5-fract ion course was used for lesions deemed readily resectable but too bulky for conservative endocavitary treatment. Since 1990, it has been our policy to administer postoperative chemotherapy to medically fit patients who prove to have pathologic Stage II or III disease. Patient characteristics includi ng age (mean 65 years, range 23-90), gender (45% male), and location within the rectum were comparable to our previously reported cases that received 45 Gy/25 fractions preoperatively. However, the group selected for 5 fracti ons preoperatively had relatively fewer lesions that were tethered (20% vs. 61%), circumferential(11% vs. 20%), or near obstructing (1% vs. 16%). Results: With a post treatment follow-up of 1-15 years (mean 4.7), there ha ve been 3 local failures and 12 distant failures, with an actuarial local c ontrol of 95%, and disease-specific survival of 77% at 5 and 10 years. Grad e greater than or equal to 3 perioperative or late toxicity occurred in 11 cases (13%), including 3 (3.5%) late bowel obstructions. Stage II or III di sease was found in 56% of the cases, 74% of which were free of disease at l ast follow-up. However, patients with Stage II or III lesions that were sig nificantly tethered or fixed had a 40% greater likelihood of recurring than similar stage lesions that were, at most, slightly tethered. Sphincter-pre serving surgery was possible in 60% of the patients. In recent years, posto perative chemotherapy has been administered to 16 patients with Stage II or III disease; this has been well tolerated, with only 1 late toxicity (cyst itis managed medically). When compared with a matched group of cases receiv ing conventionally fractionated preoperative radiation, there were no signi ficant differences in perioperative morbidity and nonradiotherapeutic cost generating factors (length of hospital stay, duration of postoperative anti biotics, blood loss at surgery). Conclusion: Patients with resectable rectal cancer who received 20 Gy/5 fra ctions preoperative radiotherapy to the pelvis had excellent local and dist ant control of disease. These patients were able to undergo sphincter-prese rving surgery and postoperative chemotherapy. It would be of interest to co nduct a randomized trial comparing short course with longer course (45 or 5 0 Gy) preoperative radiotherapy for resectable T3 lesions. The results of t his study suggest that, in general, differences in toxicity, local control, and disease-free survival would probably be < 10%. However, since the resu lts of this study suggest that patients with significantly tethered lesions may be better served with the higher dose and longer duration course of ra diation, clinical degree of fixation should be included as a stratification parameter, and stopping criteria should be included for tethered lesions. (C) 1999 Elsevier Science Inc.