Weight loss during pelvic irradiation: cobalt-60 vs. 10 MV.

The effect of radiotherapy treatment unit and technique on body weight loss during 5 to 6 weeks of pelvic irradiation was assessed in 129 patients with cervix or endometrial cancer. The patients treated with the 60Co APPA technique lost 2.91 +/- 2.28 percent, whereas the patients treated with the 10-MV APPA technique lost only 1.30 +/- 2.58 percent (P = 0.003). The patients treated with the 60Co "box" technique lost 4.36 +/- 3.85 percent and the patients treated with the 10-MV "box" technique lost 2.00 +/- 2.69 percent (P = 0.04). Patients treated with 60Co experienced more nausea during treatment than the 10-MV patients but the incidence of diarrhea was similar for the treatment units. Weight loss during radiotherapy was somewhat greater for cervix patients and for patients having advanced disease but was not adversely affected by previous pelvic surgery. We conclude technical factors such as treatment unit and technique can influence the amount of weight lost by patients during pelvic irradiation.