Some recent randomized clinical trials have demonstrated that adding ADT to radiation therapy can improve outcomes in some circumstances. However, a new study from Memorial Sloan Kettering Cancer Center (MSKCC) suggests that its use may require caution in some patients.
Kohutek et al. retrospectively analyzed the records of 2,211 MSKCC patients treated with radiation therapy from 1998 to 2008. Almost half (45%) received adjuvant ADT with their radiation for a median of 6.1 months. Some of the men (17%) received salvage ADT after radiation failure. They found:
- · Incidence of cardiovascular events (CE) was significantly higher among men who received the adjuvant ADT (20%) compared to those who didn’t (14%).
- · The following risk factors were associated with CE: adjuvant ADT, salvage ADT, older age, smoking, diabetes, and previous history of CE. Those factors predict CE with 81% accuracy.
We should use a bit of caution in interpreting these findings. First, this was a retrospective analysis and not a randomized clinical trial, so it is entirely possible that the men selected to receive adjuvant ADT were also more prone to CE for other reasons. Also, CEs increase with age, but so does the incidence of more aggressive prostate cancer, so it is hard to separate cause and effect here. Finally, the increase in risk from 14% to 20%, while statistically significant, may not be clinically meaningful enough to forgo adjuvant treatment.
The New Prostate Cancer Infolink has recently reported on cardiovascular risk associated with ADT in the Swedish registry, and in the SEER database. Just as with those studies, this one does not constitute proof, but it does suggest caution until such time as a clear link is proven or disproven. In particular, we have no proof of oncological benefit of adding ADT to radiation treatment of favorable risk prostate cancer, or when the radiation is hypofractionated. Patients should be clearly apprised of the risk and be alert for early symptoms.