The impact of 6 vs 18 months of androgen-suppression therapy, with or without Zolendronic Acid, on quality of life in men with prostate cancer

This clinical trial evaluated the quality of life of men with locally advanced prostate cancer (PCa) treated with Leuprorelin and radiotherapy, with or without Zolendronic Acid (ZA). Quality of life measures improved with shorter duration of Leuprorelin treatment, regardless of combining ZA.

Prostate cancer depends on testosterone (male sexual hormone) to grow. Leuprorelin (Eligard) is an FDA approved drug for the treatment of prostate cancer, that reduces testosterone production (androgen suppression therapy), thereby shrinking or stopping the growth of prostate cancer. Longer periods of androgen suppression improve cancer-related survival rates, but usually cause more side-effects. One side effect of hormone therapy for PCa patients is loss of bone mass which leads to Osteoporosis and increases risk of fractures. Zolendronic Acid (Reclast, Zometa) is an Osteoporosis medication, also known to increase bone mass in men receiving androgen suppression therapy, thus reducing fracture risk. It is also known to improve bone function in patients with bone metastases from prostate cancer.

This study evaluated the side effects of Leuprorelin, given with radiotherapy for 6 or 18 months, with or without the addition of ZA.

The clinical trial included 1071 men with localized PCa patients who were randomly assigned to four treatment groups (each included 268 men):

1. Leuprorelin for 6 months (short-term androgen suppression, or STAS), combined with ZA given intravenously every 3 months
2. 6 months of Leuprorelin without ZA
3. Leuprorelin for 18 months (intermediate-term androgen suppression, or ITAS) combined with ZA given intravenously every 3 months
4. 18 months of Leuprorelin without ZA

All patients received radiotherapy 5 months after the trial began.

The study found that after 6 months of follow-up side effects such as sleep trouble, fatigue, sexual and social function and hormone therapy-related symptoms (HTRS) such as hot flashes, weight gain and enlargement of breast tissue were worse in the ITAS group compared to STAS, whether or not ZA was added. However, with the exception of HTRS, all symptoms disappeared after 36 months of follow-up.

In summary, this study demonstrated that Leuprorelin produces worse side-effects when given for longer periods, however, all symptoms except for HTRS were reversible. The use of ZA did not result in additional unwanted changes in patients’ status.

The study evaluated only treatment-relted side effects. It should be noted that shorter-duration androgen suppression therapy may lead to earlier cancer recurrence.