The Gleason score can predict which prostate cancer patients can benefit the most from docetaxel therapy

This study re-examines data from a previous study and aims to identify which patients with prostate cancer would benefit the most from docetaxel (Taxotere) therapy.

Prostate cancer grows in response to testosterone, the main male sex hormone. In order to reduce the effect of testosterone, castration is the mainstay of advanced prostate cancer therapy. Castration may involve surgery to remove the testicles (surgical castration), or medications to stop the production of testosterone (medical castration). A prostate cancer that continues growing despite castration therapy is referred to as castration resistant prostate cancer (CRPC). In patients that no longer respond to castration therapy, the most frequently used treatment is chemotherapy such as docetaxel. Docetaxel inhibits cell division, stops cancer growth, and has been shown in previous trials to increase survival in patients with CRPC that has spread to distant organs and tissues (metastatic). Chemotherapy is often given in combination with prednisone, a steroid drug which reduces inflammation and alleviates pain. Mitoxantrone (Novantrone) is another chemotherapy drug frequently used in patients with CRPC.

There is no way to know beforehand how a patient will respond to chemotherapy. Until now, the Gleason score (GS) was used as a predictor of the aggressiveness of prostate cancer. The GS is a grading system that ranges from 2 to 10 based on how prostate cancer cells look under a microscope. A GS of 6 or less is considered well differentiated, or less invasive in appearance, whereas a score of 7 or more reflects increasingly invasive appearance of the cancer. This study aimed to evaluate whether the GS at initial diagnosis could predict a group of patients who would benefit the most from docetaxel therapy. 

This study derived its data from a previous study of docetaxel and included overall 482 patients with metastatic CRPC. Of these, 349 patients had a GS of 7 or higher and 133 patients had a 6 or lower GS. All patients were randomly assigned to receive docetaxel every 3 weeks (D3), weekly docetaxel (D1) or mitoxantrone every 3 weeks (M1), each along with prednisone. Results showed that patients with a GS of 7 or higher at first diagnosis who received D3 had a higher overall survival or OS (the average time patients survived after treatment) compared to patients treated with M3 (18.9 months versus 14.5 months). Although patients with an initial GS of 6 or lower also benefitted from D3 (21.6 months OS) compared to M3 (20.7 OS), this benefit was smaller than in patients with a higher GS.

In summary, patients with higher GSs (7 or higher) had a more significant benefit from docetaxel therapy than from mitoxantrone compared to patients with a 6 or lower GS. 

The data from this study comes from a study that had taken place in the past (retrospective study), thus the information provided is considered to have a weaker statistical power. 

Ask your doctor whether docetaxel is appropriate for you, given your Gleason score and your personal history.