Multivitamin use may reduce prostate Ca recurrence

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Long-term use of a multivitamin may protect against recurrence of prostate cancer, particularly in those men who have had radical prostatectomy.

Although the association between multivitamin use and a reduced incidence of prostate cancer recurrence was not significant overall, men who were taking a multivitamin for at least 10 years had a 56% lower risk of recurrence compared with never use (p trend 0.006), reported Erin Van Blarigan, ScD, at the Genitourinary Cancers Symposium in San Francisco.

The Physician’s Health Study, a large randomized controlled trial, found that multivitamin supplements modestly reduced the risk of incident cancer, not specific to prostate cancer, in healthy men, but little data exist on the effect of multivitamin use after a diagnosis of prostate cancer, noted Dr. Van Blarigan, of the University of California, San Francisco.

“One of the interesting subanalyses of the Physician’s Health Study is that individuals who had cancer when they were enrolled had a substantially lower risk of being diagnosed with a second cancer if they were using multivitamins,” she told Urology Times. “So, there has been some evidence to suggest that there might be some benefit of multivitamins, particularly after a cancer diagnosis.”

To examine the relationship between multivitamin use after prostate cancer diagnosis and risk of disease recurrence, 1,375 men initially diagnosed with non-metastatic prostate cancer who completed a lifestyle survey a median of 2 years after diagnosis were followed through 2016. About two thirds of men (63%) were current multivitamin users, 16% reported past use, and 22% were never users.

“Our hypothesis coming in was that there would be no association between multivitamins and prostate cancer recurrence, but given how common multivitamins are, and the potential harm we’ve seen with some other supplements such as selenium after diagnosis, we thought it was important to evaluate this,” Dr. Van Blarigan said.

Some 142 men had a recurrence, defined as either biochemical recurrence, initiation of secondary treatment, development of bone metastases, or death due to prostate cancer.

Adjustments were made for time between diagnosis and the survey, age at diagnosis, Gleason grade, clinical T-stage, the level of PSA at diagnosis, smoking, body mass index, walking pace, and primary treatment.

Next: What the authors found

Relative to never use, the hazard ratio (HR) for prostate cancer recurrence was 0.82 for past multivitamin use and 0.69 for current use (p-trend 0.09). When analyzed by the duration of current multivitamin use, the HRs for recurrence were 0.94 for use <5 years, 1.04 for use from 5 to 9 years, and 0.44 for use of 10 years or longer (p-trend 0.006).

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When the risk of recurrence was examined according to post-diagnostic multivitamin use and whether or not the patient underwent RP as primary treatment, the HR was 0.56 for current multivitamin users who underwent RP (n=845) compared with past or never users. Current multivitamin users who had not undergone RP (n=441) had a HR for recurrence of 1.24 relative to past or never users. The interaction between multivitamin use, primary treatment, and recurrence was significant at p-interaction: 0.02. No other clinical, lifestyle, or sociodemographic variables modified the association between multivitamins and risk of prostate cancer recurrence.

“It’s likely that most long-term users of multivitamins were taking the supplements before they were diagnosed with prostate cancer,” said Dr. Van Blarigan. “More research is needed to determine whether multivitamin use lowers the risk of being diagnosed with a more aggressive type of prostate cancer or influences cancer progression after diagnosis.”