Comorbidities May Limit Benefits of Combination Prostate Therapy
Adapted from the NCI Cancer Bulletin.
The addition of androgen suppression therapy (AST) to radiation therapy (RT) improves overall survival in men with localized prostate cancer and risk factors for disease recurrence, but the survival benefit may apply only to men who do not have moderate to high levels of other illnesses (comorbidities), researchers report in the January 23, 2008, Journal of the American Medical Association (see the journal abstract).
In the current study, researchers randomly assigned 206 men with localized prostate cancer and a high risk of recurrence to either RT alone or RT plus AST for six months. The men, whose average age was 72.5, were classified into subgroups based on the severity of their other illnesses, such as diabetes or a previous heart attack.
After 7.6 years median follow-up, estimated eight-year survival was 74 percent for men randomized to RT plus AST compared with 61 percent for men assigned to RT alone. A total of 74 men had died - 44 of those assigned to RT alone and 30 assigned to RT plus AST.
Among the 157 men with only minor comorbidities, 31 of those treated with RT alone had died, compared with 11 of those in the RT plus AST group. Among the 49 men with moderate to severe comorbidities, however, 19 of those randomized to RT plus AST had died, compared with 13 of those assigned to RT alone.
"Preexisting comorbid illness may increase the negative effects of specific anticancer treatments such as AST," conclude the researchers, who were led by Dr. Anthony V. D'Amico of Brigham and Women's Hospital in Boston. They recommend that follow-up clinical trials be designed to further assess this interaction and identify which illnesses in particular may shorten life expectancy among men undergoing treatment with AST.