A new clinical trial shows the benefits of an innovative form of radiation therapy, which delivers the radiation in only five sessions instead of the usual 37.

The National Cancer Institute (NCI) estimate that prostate cancer affects over 160,000 people in the United States. In 2018, almost 30,000 people will die from the disease.

As with most forms of cancer, treatment options range from surgery to radiation therapy, hormone therapy, and chemotherapy.

Usually, radiotherapy involves 37 sessions. That said, a new clinical trial tests a radical form of radiotherapy that could reduce that number down to just five.

The trial examined the effects of stereotactic ablative radiotherapy (SABR), a highly targeted form of radiotherapy that uses several beams of radiation at once.

The beams intersect at the tumor, delivering a high dose of radiation to the malignancy but a very low dose to the surrounding healthy tissue.

However, SABR may have some side effects, including tiredness, itchy or dry skin, and soreness or swelling where the treatment was applied. In the case of prostate cancer, radiation therapy may cause urinary problems, bowel problems, and even impotence.

In the new trial, however, the participants also benefited from SpaceOAR, which is a hydrogel previously shown to minimize the side effects of radiation therapy in prostate cancer.

The trial was jointly led by Suneil Jain, a clinical senior lecturer at Queen's University in Belfast, United Kingdom, together with Ciaran Fairmichael, a clinical research fellow also at Queen's University.

The researchers published the results of the trial in the British Journal of Radiology.

Spacer improves high-dose treatment

SpaceOAR is a minimally invasive hydrogel rectal spacer. Co-lead researcher Fairmichael explains, "One of the complications from using radiotherapy is the potential damage that can be inflicted on neighboring tissues."

"In this trial," he adds, "we are evaluating the performance of the SpaceOAR hydrogel which is inserted between the prostate gland and the rectum of the patient."

"This creates a greater distance between the prostate tumor and other tissues, which allows us to concentrate the radiotherapy dosage provided to the tumor and thus reducing the chance of radiation harming other tissues close to the tumor such as the bowel."

The trial tested the tolerability and toxicity of inserting this spacer in six people living with prostate cancer. The researchers used computed tomography (CT) scans to plan the insertion, delivered local anesthetic, and used CT scans again to assess the position of the spacer.

Inserting the spacer minimized the probability of side effects and reduced rectal bleeding. "This is one of the first studies to investigate the efficacy of a hydrogel spacer in prostate SABR treatments," write the authors.

"Observed dose sparing of the rectum is predicted to result in meaningful clinical benefit," they conclude.

The trial participants also comment on how the treatment benefited them. Gordon Robinson, who is 70 years old and took part in the trial, says, "If it wasn't for this research, I simply would not be here. My family and I are so thankful to the doctors who have helped us. This treatment has allowed me to live my life again."

"Taking part in this trial meant I was offered a high-dose five-treatment course instead of enduring 2 months of treatment. The treatment was really successful in getting rid of my tumor."

Gordon Robinson

"I knew about the side effects of treatment," Robinson continues, "and they really frightened me, but this trial meant I had very little discomfort or complications and can return to normal life."