Treatment with the drug clodronate does not improve overall survival for men with localized prostate cancer or delay the disease?s progression to metastatic cancer, according to the results of a randomized clinical trial.
Bone is the most common site of metastasis from prostate cancer. Treatment with bisphosphonates?a class of bone-strengthening drugs including clodronate?has been shown to improve the outcome of patients with metastatic breast cancer.
Malcolm Mason, M.D., of the Medical Research Council clinical trials unit in London, and colleagues randomly assigned 508 men with non-metastatic locally advanced prostate cancer to receive daily doses of sodium clodronate or a placebo for up to five years. The researchers measured whether clodronate could prolong the period before the cancer spread.
After a median follow-up of 10 years, the researchers found no improvement in metastatic-free or overall survival in men taking clodronate, compared with the placebo group.
“Sodium clodronate should not be further used in trials in the adjuvant setting, but more potent bisphosphonates should be investigated,” the authors write.
In an accompanying editorial, Timothy Wilt, M.D., and Kristine Ensrud, M.D., of the Minneapolis Veterans Affairs Center for Chronic Disease Outcomes Research, write that research on bisphosphonates and prostate cancer should continue despite this negative result. “The presence of relatively early bony metastases may be the best predictor to determine whether bisphosphonates provide clinical benefit in men with prostate cancer. But inconsistency across published trials and lack of improvement in length or quality of life using high doses of potent intravenous bisphosphonates does not rule out the possibility that no benefit exists,” the authors write.