Comorbidities affect success of PSA screening to reduce prostate cancer deaths
MedWire News: Prostate-specific antigen (PSA) screening reduces the risk for prostate cancer-specific mortality (PCSM) to a larger degree in men with no or minimal comorbidities than those with at least one significant comorbidity, report US researchers.
This risk reduction can be achieved with minimal overtreatment, says the team, as the treatment of just five additional men is needed to eliminate one death from prostate cancer over 10 years. This compares with the 48 additional men (with no specified comorbidity status) needed to treat to eliminate one death in 9 years, as indicated by a previous European study (and reported in MedWire News).
Anthony D'Amico (Brigham and Women's Hospital, Boston, Massachusetts, USA) and colleagues evaluated whether there is an association between the extent of pre-existing comorbidities and the risk for PCSM in the context of PSA screening. The current study included 73,378 participants of the Prostate, Lung, Colorectal, and Ovarian cancer screening trial who were randomly assigned to receive a PSA screening intervention (annual PSA tests; n=37,285), or usual care.
In all, 35.7% of the cohort had no or minimal comorbidities - defined as those unlikely to increase the risk for dying from one of the leading causes of death (cardiovascular disease or cancer) - and were significantly younger than the remainder, at a median of 61 versus 63 years.
After 10 years of follow-up, 164 men had died of prostate cancer.
Of those in the intervention group, fewer men with no or minimal comorbidities experienced PCSM compared with those with at least one comorbidity, at 22 versus 38 deaths, giving a 44% increased risk for PCSM in the latter group.
Indeed, in men with at least one comorbidity, being assigned to the intervention as opposed to the usual care group did not reduce the risk for PCSM, with 62 versus 42 prostate cancer-specific deaths in these groups, respectively.
The overall estimates of 10-year PCSM risk in men with no or minimal comorbidities were low, at 0.17% for those in the intervention group, and 0.31% in the usual care group, write D'Amico et al in the Journal of Clinical Oncology. The corresponding rates for men with at least one comorbidity were 0.27% and 0.19%.
However, in a related commentary, Peter Carroll and colleagues from the University of San Francisco, USA, warn that "despite mounting evidence in support of screening, it is important that the benefits not be overstated.
"Most men with prostate cancer - even those with high-risk disease - ultimately die as a result of other causes."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Sarah Guy