Changes in functional status associated with radiation for prostate cancer in older veterans

Although older men value maintaining independence and avoiding functional decline, little is known about their functional trajectories with receipt of prostate radiation.

We performed a retrospective cohort study including veterans age 65+ with localized prostate cancer who resided in a VA nursing facility while receiving prostate radiation from 2005 to 2015. We evaluated the change in Minimum Data Set (MDS) activities of daily living (ADL) score during 6 months from the start of treatment. Because prior studies have shown Charlson Comorbidity Index (CCI) to be a strong predictor of treatment-related toxicity, analysis included interaction with CCI.

We identified 487 patients with median age 73 (range 65-94). For the average patient in our cohort, the predicted MDS-ADL score worsened from 2.9 (95% CI 2.4-3.6) at the start of radiation to 3.8 (95% CI 3.1-4.8) at 3 months and then 4.5 (95% CI 3.5-5.7) at month 6. Patients with greater comorbidity (CCI ≥ 4) had worse functional outcomes in months 0-3 compared to patients with less comorbidity (CCI 0-3). MDS-ADL score worsened by 1.9 in the CCI ≥4 patients compared to 0.3 in the CCI 0-3 group During months 3-6, patients in both Charlson groups experienced similar worsening of MDS-ADL score.

In a vulnerable population of older patients with localized prostate cancer, radiation was associated with a decline in functional independence. Patients with higher comorbidity experienced more severe functional decline within the first 3 months of radiation therapy. In all comorbidity levels, functional status had not returned to baseline by 6 months.