Radiation Therapy Alone Can Be Used to Treat Rectal Cancer

Radiation therapy alone is an adequate treatment for some patients with rectal cancer, according to a study published in a recent issue of the International Journal of Radiation Oncology, Biology, Physics (54:142-149, 2002).

The most common treatment for rectal cancer, surgery, is sometimes combinedwith radiation therapy to improve outcome. This study is the first of long-termlocal control and survival in patients treated with radiation therapy alone, andthe results suggest that this is a suitable treatment for patients who are notcandidates for surgery.

Study Data

Between 1986 and 1998, 63 patients were entered into the pilot study.Eligibility criteria included T2-3, N0-1, M0 adenocarcinoma of the middle orlower rectum involving less than two-thirds of the circumference. Radiationtherapy began with contact x-rays, followed by external-beam radiation therapywith a concomitant boost. After a 4- to 6-week interval, an iridium implantdelivered a completion dose to the tumor. No chemotherapy was administered.

The median age of patients was 72 years. Of the 63 enrolled patients, 41 hadT2 and 22 had T3 tumors. The mean distance of the tumor from the anal verge was3.6 cm. All patients completed treatment according to the protocol, with theexception of seven who did not receive brachytherapy. With a median follow-up of54 months, the primary local tumor control rate was 63%; after salvage surgery,the ultimate pelvic control rate was 73% (46 of 63). The 5-year overall survivalrate was 64.4% , and for 42 patients aged less than 80 years, it was 79%, with10 patients alive at 10 or more years.

Adverse Effects

No severe toxicity was seen, and although proctitis developed in mostpatients, it did not require an interruption in treatment. Late rectal bleedingoccurred in 24 patients, but only one required a blood transfusion. Goodanorectal function was maintained in 92% of living patients. The T stage was astrong prognostic factor, with a 5-year overall survival rate of 84% and 53% forT2 and T3 lesions, respectively, in patients under age 80.

"Surgery remains, without doubt, the main treatment of rectaladenocarcinoma. Nevertheless, in inoperable patients, combined radiation therapyshould be considered," said lead author Jean-Pierre Gerard, md, of theCentre Antoine-Lacassagne in France. "Research aimed at improving thequality of life of patients with rectal cancer is ongoing, and this studycontributes to that body of knowledge."