Histological slide showing prostate cancer

ASCO 2015: Notable Reports on Prostate Cancer Treatment

This year’s American Society of Clinical Oncology (ASCO) annual meeting was short on any truly exciting developments in prostate cancer treatment. In stark contrast to other cancers, such as lung, breast, kidney, and melanoma, there were no reports of note on targeted and immunotherapies in prostate cancer. The two presentations summarized here offered new strategies in chemotherapy.

Previous reports have shown evidence from clinical trials of the efficacy of the drug docetaxel for advanced prostate cancer, A new report at ASCO 2015 provided evidence that adding chemotherapy to standard treatment improves survival in men with high-risk, localized prostate cancer. The standard first-line treatment for these patients is radiation therapy (RT) followed by androgen deprivation therapy (ADT, or hormonal treatment) for 2 years. Chemotherapy is considered only if the cancer stops responding to ADT. However, the results of a fairly large trial (562 men) suggest that addition of the chemotherapy drug docetaxel to the standard treatment provides an additional benefit.

In the trial, 66% of men who received standard RT plus ADT were still alive 5 years after treatment. But for men who received docetaxel along with RT and ADT, this percentage increased to 73%; a fairly significant improvement. Chemotherapy, if adopted based on these results, will be given to high-risk patients, but not those with intermediate-risk disease.

Chemotherapy has long been used to treat patients with metastatic castration-resistant prostate cancers, even though its benefits have not been great. The drugs of choice are docetaxel or cabazitaxel, both of which are taxanes (a class of related drugs). At ASCO 2015, researchers from The University of Texas MD Anderson Cancer Center presented the results of a trial that combined two different chemotherapy drugs: cabazitaxel and carboplatin. The trial measured, among other factors, the time that passed without cancer worsening (progression-free survival) in patients who received cabazitaxel only, or cabazitaxel in combination with carboplatin. The cabazitaxel-only group experienced disease progression an average of 4.4 months after treatment, compared to a slightly longer 6.7 months in the group that received the combination therapy.

Image Credit: Histological slide showing prostate cancer. (Otis Brawley, National Cancer Institute)