Brachytherapy is one of the more advanced cancer treatments. It's a form of radiation therapy where radioactive seed implants or sources are placed in or near the tumor itself. This implants a high radiation dose to the tumor while reducing the radiation exposure in the surrounding healthy tissues. It is a particularly popular approach against prostate cancer.

External beam therapy is a non-invasive procedure for delivering high-energy x-ray beams to a cancerous tumor.  The beams are typically generated by a linear accelerator and targeted to destroy the cancer cells while sparing surrounding normal tissue – as with brachytherapy.

Very often, brachytherapy is used in conjunction with external beam therapy.

But isn't that overkill?

Some scientists decided to find out. They gathered 588 patients with intermediate risk prostate cancer. The patients had either a Gleason score between two and six and a PSA ranging from 10 to 20, or a Gleason score of seven and a PSA lower than 10.

292 out of the 588 were randomized to receive brachytherapy alone and 287 received external beam therapy to the pelvic area in addition to brachytherapy.

In the follow-up analysis five years later (consisting of 443 eligible patients) revealed that men who received brachytherapy alone had similar progression-free survival rates to those who received more aggressive radiation therapy – 85 percent, compared with 86 percent.

But there was bad news for those who also received external beam therapy. They exhibited late severe side effects more commonly (12 percent vs. 7 percent) than those who received brachytherapy. Worse yet, severe gastrointestinal and genitourinary toxicities were more common in the group that received more aggressive treatment. However, the acute side effects that occur shortly after treatment were similar in both groups, with eight percent of patients exhibiting grade 3 or higher side effects.

“These findings suggest that many men with intermediate risk prostate cancer can be well-managed with seed implant alone and do not require the addition of external beam radiation,” Dr. Bradley Prestidge, lead author of the study and medical director of the Bon Secours Cancer Institute at DePaul Medical Center in Norfolk, Virginia, said in a press release. “Contrary to expectations, the more aggressive, combined treatment did not result in superior cancer control rates at five years follow-up, indicating that men can achieve a similar survival benefit with fewer late side effects through brachytherapy alone.”

“These findings suggest that many men with intermediate risk prostate cancer can be well-managed with seed implant alone and do not require the addition of external beam radiation,” Dr. Bradley Prestidge, lead author of the study and medical director of the Bon Secours Cancer Institute at DePaul Medical Center in Norfolk, Virginia, wrote. “Contrary to expectations, the more aggressive, combined treatment did not result in superior cancer control rates at five years follow-up, indicating that men can achieve a similar survival benefit with fewer late side effects through brachytherapy alone.”

Prestidge presented his findings at the 2016 American Society for Radiation Oncology 2016 Annual Meeting in Boston, and published it in Radiation Oncology.