Western Dietary Pattern, Prudent Dietary Pattern, and Cancer-Specific Quality of Life in Prostate Cancer Survivors in the Health Professionals Follow-Up Study.

BACKGROUND

Prostate cancer survivors often experience reduced health-related quality of life (QOL). Diet is related to QOL in the general population and prostate cancer survivors, with benefits observed from greater consumption of a plant-based diet after treatment. We examined whether postdiagnostic Western and prudent dietary patterns were associated with cancer-specific QOL.

METHODS

We studied 1,032 participants in the Health Professionals Follow-Up Study diagnosed with nonmetastatic prostate cancer (2005-2014). Diet scores were cumulatively averaged from validated food frequency questionnaires after diagnosis. QOL was assessed with the Expanded Prostate Cancer Index Composite Short Form 2 to 5 years after diagnosis/treatment (2010-2016). We assessed associations between the two diet patterns and cancer-specific QOL domains (sexual function, urinary irritation/obstruction, urinary incontinence, bowel function, hormonal/vitality function), adjusting for patient, tumor, and lifestyle characteristics.

RESULTS

Median age at diagnosis was 75 years; 93% had clinically localized cancer. Higher Western diet scores were associated with worse bowel function by 3 points (P trend = 0.02), below the 4 to 6 point threshold for clinical relevance, with suggestive trends among radiation-treated patients (P trend = 0.07). Higher prudent diet scores tended to be associated with better bowel function (P trend = 0.09). Neither diet score was associated with bowel function among patients receiving radical prostatectomy or active surveillance. There were no associations with sexual, urinary, or hormonal/vitality function.

CONCLUSIONS

Among survivors of nonmetastatic prostate cancer, dietary patterns were largely unrelated to cancer-specific QOL across domains and treatment subgroups.

IMPACT: In the 2- to 5-year window, QOL was largely unaffected by postdiagnostic dietary patterns, warranting further research with longer follow-up to assess potential latency.