Chemotherapy, Radiation Therapy Recommended First for Certain Prostate Cancers, Lymphomas

Chemotherapy and radiation therapy should be the first line of treatment for certain prostate cancers and lymphomas with a major genetic weakness, according to researchers at the University of Virginia School of Medicine. Approximately 10% to 15% of prostate cancers and lymphomas may be particularly vulnerable to these treatments, and taking advantage of this genetic weakness could help save patient lives.

According to Anindya Dutta, MD, PhD, chairman of the Department of Biochemistry and Molecular Genetics at the School of Medicine, many cancers are not treated with radiotherapy or chemotherapy at the outset. Instead, someone with prostate cancer gets surgery or androgen deprivation first.

“But suppose you find the patient’s cancer belongs to this 10% group…those patients should really be treated with chemotherapy and radiotherapy right at the outset, because those cancer cells will be much more susceptible, while the normal cells around the cancer won’t be hurt at the doses needed,” Dutta said in a statement.

Dutta’s team discovered that a gene that plays an important role in repairing damaged DNA had a second, different gene overlapping it. The researchers found that when 1 gene is deleted, the other gene is absent as well, which leaves cells highly susceptible to treatments that damage the DNA inside cancer cells.

When these patients are treated with radiation and chemotherapy, the resulting DNA breaks in the cancecr cells are difficult to fix, therefore, causing the cancer cells to die.

“And now we discover that certain cancer cells—these 10% of prostate cancer and lymphomas—have this natural genetic vulnerability,” Dutta said. “They have lost the genes important for stitching the DNA back together, so they’re extremely susceptible to chemotherapy and radiotherapy.”

Using these findings, a blood test can be developed that determined which patients would benefit from being treated with chemotherapy and radiation. Decreasing the activity of repair genes while treating a patient with radiotherapy or chemotherapy will make the cancer more susceptible to treatment, Dutta added.

“The biochemical pathway we’ve unraveled for [one of the genes] gives us hope that we should be able to find small chemicals that could interrupt this activity,” he said.