Scientists combine radiation treatment with suicide gene therapy to treat prostate cancer

A new study is suggesting that combining “suicide gene therapy” with radiation treatment can treat prostate cancer safely and effectively.

For those who don’t know: suicide gene therapy is a treatment procedure marked by genetic modification of prostate cancer cells. By genetically modifying the cells, doctors prepare the ailing cells to signal the patient’s immune system to attack them.

During the study, researchers representing the Houston Hospital in the United States compared two groups of patients diagnosed with prostate cancer. They found that 97% and 94% of patients in those two groups respectively had 5 year overall survival rates. The study had a total of 66 patients as participants divided into two groups; they took part in clinical trials between the years 1999 and 2003.

Patients in the first group, named as Arm A, had the cancer confined only to their prostate. The other group, which was named as Arm B, included patients suffering from a more aggressive form of the disease. Individuals in Arm A was treated only with radiotherapy while those in Arm B received a combination of hormonal and radiation therapies.

During the course of the study, Arm A patients received the experimental gene therapy called suicide gene therapy twice. The same treatment was given to Arm B patients three times during the study.

E Brian Butler of Houston Methodist said that he and other researchers conducting the study deliberately incorporated an adenovirus, with similar features as that of the virus causing common cold, for carrying the therapy agent, which happens to be a herpes virus gene that produces an enzyme called thymidine kinase (TK), into the patients’ tumor cells.

Butler added that once the gene got delivered into the tumor cells and started producing TK, the patients were given valacyclovir, a standard anti-herpes drug. This combination immediately attacked the herpes DNA and induced self-destruction of the TK-producing tumor cells. As the technique involves self-destruction of cells, the therapy is called suicide gene therapy.

The researchers informed that when valacyclovir begins destroying the tumor cells, it simultaneously alerts the immune system of the patient (which was so far not aware of the presence of cancer) that it’s time to initiate a substantial attack.