A large study of testicular cancer patients has shown that radiation therapy is a better treatment than chemotherapy for patients with stage IIa disease (where one or more regional lymph nodes contain cancer cells but they are less than 2cms in diameter).

These findings, published in Clinical Oncology, are important because, until now, there has been little evidence about which treatment for testicular seminoma is more effective, and there has been a tendency to move away from radiation therapy towards chemotherapy for treating stage IIa-b patients. Guidelines from the US National Cancer Comprehensive Network recommend radiotherapy for stage IIa, while those from the European Association of Urology allow for either radiation therapy or chemotherapy; both sets of guidelines are equivocal for stage Iib.

Testicular cancer is divided into two main types: seminoma and non-seminoma. Both develop from the germ cells in the testes. Testicular seminoma is one of the most treatable and curable cancers with a survival rate of over 95 percent if it is discovered in the early stages.

The study of 2,437 patients is the largest group of patients with stage II testicular seminoma evaluated so far, and researchers found that 99 percent of patients with IIa disease were alive after five years if they had been treated with radiation therapy, versus 93 percent of patients treated with chemotherapy. For patients with IIb disease, the five-year overall survival was 95 percent for those treated with radiation therapy and 92 percent for those treated with chemotherapy.

Dr. Scott Glaser, resident physician at the University of Pittsburgh Cancer Institute, USA, said, "For patients with IIa testicular seminoma, this improvement in outcome with radiation over chemotherapy persisted after adjustments for all available factors that could introduce a bias. For patients with stage IIb disease, similar rates of overall survival were seen regardless of treatment with multi-agent chemotherapy or radiation therapy. This suggests that an individualized approach is necessary for such patients."

The study, led by Dr. Sushil Beriwal, an associate professor of radiation oncology at the University of Pittsburgh, analyzed data from 2,437 patients with stage II testicular seminoma diagnosed between 1998-2012 and treated with radiation therapy or multi-agent chemotherapy after removal of the cancerous testicle. Of the total number, 960 patients had IIa disease, of whom 78 percent received radiation therapy and 22 percent received chemotherapy; 812 had IIb disease, with 54 percent and 46 percent receiving radiation therapy and chemotherapy respectively; and 665 had IIc disease, with 4 percent and 96 percent receiving radiation therapy and chemotherapy respectively.

"For stage IIc patients, there is clear consensus that multi-agent chemotherapy is the preferred treatment as the risk of distant progression is high, whereas for stage IIa-b there is no such consensus as to the optimal treatment and practice patterns vary significantly. In our series, 96 percent of stage IIc patients received multi-agent chemotherapy, which also severely limits meaningful comparison to other treatments," explained Dr. Glaser.

He said the results support the recommendation that radiation therapy should be the preferred option for treating patients with stage IIa. "We view stage IIb disease as a spectrum where smaller volume disease patients (i.e. those with a 2-3 cm tumour in a single lymph node) may act more like IIa disease and attain the greatest benefit from radiation therapy, whereas patients with a larger volume of disease (i.e. 4-5 cm tumor or that has spread to multiple lymph nodes) may act more like IIc disease and attain the greatest benefit from chemotherapy."

Dr. Glaser concluded: "Our results demonstrate the need for a collaborative group effort to open a randomized trial for stage IIa-b testicular seminoma patients examining the role of radiation therapy and chemotherapy."