"Many doctors expected that using a higher dose of radiation would mean better outcomes for patients, so this was a surprising result," Swain said. "This study should put an end to discussions about higher dose treatments."
A second study looked at the efficacy of post-surgery chemotherapy and radiation for patients with seminoma, a common type of testicular cancer, versus follow-up monitoring of the patients.
Researchers looked at 1,800 patients with stage 1 seminoma in Denmark, where the typical post-surgery treatment protocol calls for regular clinic visits, CT scans, X-rays and blood work -- not chemo or radiation. However, many U.S. treatment centers do use chemo and radiation as part of post-surgery treatment.
More than 80% of patients did not relapse after surgery, the study found, eliminating the need for follow-up chemotherapy or radiation. In those who did relapse, follow-up treatment led to a 99.5% survival rate.
"In this study, we see that surveillance alone was safe," said Dr. Clifford Hudis, president-elect of the American Society of Clinical Oncology.
The final study looked at whether patients with a particular form of non-Hodgkin lymphoma should have regular CT scans to detect relapses after they finish treatment. The study showed most relapses weren't detected by the scans, but by patients' complaints of symptoms, routine physical exams or blood work.
"We can spare patients from the cost and excessive radiation from follow-up CT scans," Hudis said.
The final study looked at a new class of drugs called PI3K delta inhibitors, being tested in patients with chronic lymphocytic leukemia.
The specific drug tested in the trial -- Idelalisib -- was shown in a first phase of study to be safe in high-risk populations, and to help reduce the size of affected lymph nodes for long periods of time. It may soon lead to alternatives to chemo for slow-growing blood cancers, Swain said.