Radiation therapy for early stage seminoma of the testis. Analysis of survival and gastrointestinal toxicity in patients treated with modern megavoltage techniques over 10 years.

Seventy-seven patients treated with megavoltage irradiation to the para-aortic and/or pelvic nodal areas, for stage I and non-bulky (< 5 cm) stage II seminoma of the testis, were studied at the Royal Adelaide Hospital from 1981 to 1990. The aim was not only to assess overall and relapse-free survival, but also early and late gastrointestinal toxicity in a group of patients treated in a uniform manner using modern techniques. The 10 year actuarial survival was 96.1% for all patients, being 95.6% for stage I and 100% for stage II. The 10 year actuarial complication rate for all late gastrointestinal effects was 9.1%. This consisted of a 6.5% risk of peptic ulceration and a 2.6% risk of chronic diarrhoea at 10 years. At least one acute gastrointestinal effect occurred during radiotherapy in the vast majority of patients (90.9%). Analysis of the effect of age (< or = 34 years vs > 34 years), stage (I vs II) and dose of radiation (< or = 30 Gy vs > 30 Gy), showed none of these variables to have a significant influence on overall survival or on the incidence of late complications. The results of these findings are discussed in the light of recent studies of a surveillance policy following orchidectomy for stage I seminoma of the testis. Given that gastrointestinal toxicity is the major toxicity associated with the treatment of stage I patients, the data from this study should assist clinicians and their patients to arrive at an informed decision regarding adjuvant radiotherapy.