A single dose of chemotherapy is equally effective and less toxic than radiation therapy for early-state testicular cancer, according to a presentation at the annual meeting of the American Society of Clinical Oncology.

The study was the first randomized trial to evaluate long-term outcome after a single dose of chemotherapy compared with radiation therapy, the current standard of care. The study, the largest ever in testicular cancer, also showed that after five years, patients receiving chemotherapy had a decreased risk of developing a second tumor in the other testicle, although longer follow-up is needed.

All patients in the study had stage I seminomas. After surgical resection of the affected testicle, patients were randomized to a single dose of carboplatin given over one hour on an outpatient basis (573 patients) or a course of daily radiation therapy given for two or three weeks (904 patients).

The dose of carboplatin varied because it was based on each patient's kidney function. After five years, the rate of cancer recurrence was comparable in both arms - 5 percent of patients in the chemotherapy group and 4 percent of patients in the radiation therapy group. With a median follow-up of 6.5 years, patients who received carboplatin were 78 percent less likely to develop a tumor in the remaining testicle (15 patients in the radiation therapy arm versus 2 patients in the carboplatin arm).

One patient in the radiation therapy arm died of seminoma versus none in the chemotherapy arm. Side effects for both treatments were few, although those in the radiation therapy group reported higher levels of moderate or severe lethargy (24 percent versus 7 percent for patients receiving carboplatin) four weeks after starting treatment.

"Personal preference is becoming a more important factor in determining the best treatment for patients with testicular cancer. We've also seen this in prostate cancer, where there are a number of equally strong treatment options," said Tim Oliver, MD, professor emeritus of medical oncology at St. Bartholomew's Hospital in London and the study's lead author. "This study establishes surgery followed by carboplatin chemotherapy as a safe new alternative for patients who have early-stage seminoma and would prefer a treatment that lasts a shorter period of time."

The researchers said that future studies will investigate the option of lumpectomy and single-dose carboplatin for men who present early enough with small tumors, allowing them to avoid losing the diseased testicle.