Chemotherapy Can Remain Useful After Targeted Therapy in Cancer Treatment

Researchers examine use of docetaxel in patients with castration-resistant metastatic prostate cancer following androgen-deprivation therapy.

A recent study found chemotherapy can still be useful in prostate cancer treatment, even following targeted therapy.

Originally, docetaxel was the go-to treatment option for patients with castration-resistant metastatic prostate cancer (mCRPC). Now, however, physicians are giving androgen receptor targeted therapy first.

"The question was whether docetaxel still has a role in these patients treated with abiraterone,” said study principal investigator Thomas W. Flaig, MD. “We're no longer using docetaxel first -- should we even be using it second?"

In order to test this question, researchers studied 1088 patients treated in the trial COU-AA-302. This clinical trial is what originally led to abiraterone become a first-line therapy. Researchers sought to determine how patients were treated after the trial was over.

The results of the study showed that 67% of abiraterone-treated patients received further therapies. Only 36% of patients received 2 additional therapies, while 17% got 3 or more.

Evidence suggested the efficacy of docetaxel following treatment, even after androgen-deprivation therapy. Of the abiraterone-treated patients, only half were treated with docetaxel in the next therapy. Forty percent showed a decrease in PSA by more than half.

"Surprisingly, the next most common "treatment" in this setting after docetaxel was no treatment at all," Dr. Flaig said.

A comparison of young patients and patients older than 75-years-old showed older patients were twice as likely to receive no therapy after treatment.

The trial, which ended in 2010, occurred before the approval of enzalutamide, a pre-chemotherapy treatment for mCRPC patients. Dr. Flaig believes that more patients of differentiating ages are getting additional anti-androgren therapy before chemotherapy treatments like docetaxel.

"This confirms the activity of abiraterone followed by docetaxel and represents important data on the sequencing of medical therapies under this new paradigm," Dr. Flaig said. "The fact that a substantial portion of patients received no subsequent therapy after the study was done, needs additional study to be certain we are maximizing effective therapy for these patients."