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TNF Inhibitors for RA: No Link to Breast Cancer

Tue, Aug 19, 2014

Clinical News Room

starting RA treatment after cancer diagnosis was 9.4 years; the control patients had been matched for time since breast cancer diagnosis (± 3 years). Median follow-up came to 4.9 years for the TNFi group and 4.6 years for the biologics-naive group.

For the TNFi group, 9 patients developed a recurrence of breast cancer during a total of 592 person-years of follow-up compared with 9 patients in the biologics-naive group during 550 person years of follow-up.

The researchers calculated hazard ratios (HRs) for recurrence, using Cox regression analysis, adjusting for nodal status and type of surgery and chemotherapy for index cancer.

They found that the HR for TNFi-treated individuals compared with biologics-naive individuals was 0.8 (95% confidence interval [CI], 0.3 – 2.1). For TNFi patients who started treatment within 5 years of cancer diagnosis, the HR was 1.4 (95% CI, 0.3 – 2.4), and for those who started treatment 5 years after cancer diagnosis, the HR was 0.8 (95% CI, 0.3 – 2.4). None of the measures reached statistical significance.

“With an average follow-up of 5 years, we found no difference in the risk of breast cancer recurrence between TNFi-treated and matched biologics-naive patients with RA and a history of breast cancer,” the researchers write.

Support Guidelines

“In essence, our results support most current clinical guidelines, which indicate that TNFi could be initiated if more than 5 years after solid cancer,” Dr. Raaschou said. “It must be remembered that our study participants were selected in clinical practice to receive TNFi in spite of having a history of breast cancer. Through careful review of the medical history, we observed that the cancers among the patients later receiving TNFi tended to have a slightly better prognosis. It may be that the findings of our study do not apply to individuals with aggressive or very recent breast cancers. Thus, it is premature to suggest any major changes in current guidelines.”

She noted, however, that she was surprised by “the often elaborate and very well informed discussion [related in the medical records], involving both patients and clinicians, about the pros and cons of initiating TNFi against a background of breast cancer.”

Exciting, Needs Confirmation

“This is an excellent population-based study,” Jonathan Kay, MD, director of clinical research in rheumatology and professor of medicine at the University of Massachusetts Medical School in Worcester, told Medscape Medical News. “This is somewhat reassuring, but it needs confirmation in other populations. It needs to be extended to other malignancies.”

Such a study would be difficult in the United States, he said, because of privacy requirements and deidentification of health information. In contrast, the Swedish Cancer register has records on more than 95% of primary cancers, including diagnosis date, cancer morphology, and type of cancer, and reporting is mandatory for clinicians and pathologists, the study authors write.

Dr. Kay continued, “The results of this study suggest that one may be able to treat patients who have had breast cancer treated appropriately with a TNF inhibitor without significant risk of recurrence of that malignancy. As a result, patients with rheumatoid arthritis may be able to receive appropriate treatment for their joint disease, regardless of their history of breast cancer.”

Medscape Medical News, 2014-08-17

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