BMI, age, and comorbidity predict non-prostate cancer-specific death after treatment
MedWire News: Obesity, old age, and having moderate-to-severe comorbidities are all associated with non-prostate cancer-specific death in men who experience a prostate-specific antigen (PSA) recurrence after radiotherapy (RT), report US researchers.
This finding will help physicians distinguish patients who require adjuvant hormone therapy (HT) from those who are suitable for an active surveillance (AS) protocol, thus sparing some men from unnecessary HT and its associated side effects, says the research team.
“Some men with a post-RT PSA recurrence will die of non-cancer causes before developing metastasis,” explain Paul Nguyen, from the Dana-Faber Cancer Institute and Brigham and Women’s Hospital in Boston, Massachusetts, and colleagues.
“Our ability to determine who would benefit from salvage HT would be enhanced if an individual’s risk of non-prostate cancer-specific morality were known,” they write in the journal Cancer.
Nguyen et al assessed whether body mass index (BMI) and the presence of comorbidities affected non-prostate cancer-related mortality rates among 87 men with unfavorable risk prostate cancer. The men were treated with RT or RT with adjuvant HT, and all men experienced a PSA recurrence after treatment.
At the time of allocation to treatment group, the median BMI among the men was 27.4 kg/m2. Their median age was 76.2 years when PSA recurrence occurred, and the median follow-up duration was 4.4 years.
Comorbidity was scored using the Adult Comorbidity Evaluation-27 index and showed that 72% of patients had no comorbidity, 10% had mild comorbidity, and 1% had severe comorbidity.
After accounting for patient age, strong predictors for non-prostate cancer-specific mortality were identified as moderate-to-severe comorbidities (hazard ratio [HR]= 3.15), obesity (BMI above the median; HR= 2.98), and an increased age (above the median) at the time of PSA recurrence (HR= 1.17).
A total of 15 non-prostate cancer-related deaths and 16 prostate cancer-specific deaths were reported during follow-up.
The researchers then calculated the cumulative incidence of mortality for the cohort and grouped patients according to risk.
At 5 years after treatment, 0% of low-risk patients (with age and BMI below the median, and no or mild comorbidity), 19% of intermediate-risk (no or mild comorbidity and either age or BMI above the median), and 38% of high-risk patients (moderate or severe comorbidity) would die from non-prostate cancer causes.
“This information can be used alongside the known risk factors for prostate cancer-specific mortality to select men for entry onto AS protocols after a PSA recurrence,” the team concludes.
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By Sarah Guy