A new study suggests that radiation therapy for prostate cancer (PC) may be less effective for overweight and obese men than for men of normal weight. The study, published in the Journal Cancer (May 29, 2015 issue), reports higher rates of prostate cancer relapse, prostate cancer death and death from other causes in obese and overweight men.
The U.S. Centers for Disease Control and Prevention estimates that obesity among U.S. adults has more than doubled in the past four decades. While obesity has been linked to several types of cancers, its association with prostate cancer is not clearly explained. This study attempted to do this.
The researchers analyzed 1,442 men of average age 68 years who underwent radiation therapy for localized prostate cancer between the years 2001 and 2010. These patients were systematically followed for an average of four years. They found that overweight or obesity reduces the effectiveness of radiation therapy treatment for prostate cancer.
- Being overweight or obese was associated with a small (3 percent) higher rate of PC relapse and 7 percent higher rate of cancer spreading.
- Heavier patients had a 15 percent higher mortality rate due to the cancer and 5 percent higher chances of dying from other causes.
- While thinner patients could have surgical treatment, radiation therapy was the only option for those who were obese.
- Obesity was associated with worse outcomes even with state-of-the-art radiation therapy (which includes better imaging and higher doses).
The researchers say that further study is needed to confirm the link between obesity and poorer outcomes for prostate cancer. According to one expert, this could be due to the “more rapid progression [of the tumor] to distant metastasis after treatments begin to fail”.
The study highlights the fact that overweight people require different treatment for the disease. Based on these results, the researchers opine that the next step could be to study if prostate cancer patients who enrolled in a weight loss program during and after their treatment could improve their chances of being cured of the disease.