Background/Purpose: There have been concerns about the use of tumor necrosis factor inhibitors (TNFi) in patients with rheumatoid arthritis (RA) and concomitant cancer. Few studies have examined cancer outcomes in these patients, and they have mostly included long-term survivors, rather than patients with early cancer. Therefore, the safety of TNFi in patients with recent cancer is unknown. Our aim was to examine the survival of patients with RA recently diagnosed with early-stage breast cancer (BC), who received TNFi in the first year after BC diagnosis.

Methods: We conducted a retrospective cohort study of patients with RA diagnosed with BC and RA identified in two databases from 2008 onwards: Optum’s de-identified Clinformatics® Data Mart Database, and the combined Surveillance, Epidemiology, and End Results Program (SEER) and Texas Cancer Registry (TCR) – Medicare linked databases. Early BC was ascertained in Clinformatics by surgical claims codes and in SEER/TCR by stage (excluding distant BC). Use of disease modifying antirheumatic drugs (DMARDs) and glucocorticoids in the year after BC diagnosis was identified from claims and prescriptions files. Outcomes were overall survival (OS) and BC-specific survival (BCSS; only in SEER/TCR-Medicare) defined as the time from BC diagnosis to death from all causes or from BC. Survival was truncated at 5 years. We compared patients who received TNFi with those who received conventional cDMARDs, or no DMARDs, during the first year after BC diagnosis. We estimated a propensity score for use of TNFi through a logistic regression model. We conducted multivariate Cox proportional hazards regression, controlling for various covariates and for the propensity score.

Results: We identified 970 patients with RA and early-stage BC in Clinformatics (mean age 67 years, SD 10.6) and 1,246 in SEER/TCR-Medicare (mean age 74 years, SD 6). In the first year after BC diagnosis 165 (17%) received TNFi in the Clinformatics cohort, and 201 (16.1%) in the SEER/TCR-Medicare cohort. After multivariate and propensity score adjustment, no significant differences in OS were observed between patients treated with TNFi (alone or with cDMARDs) and patients treated with cDMARDs alone in Clinformatics (hazard ratio, HR=0.75 95% CI 0.41-1.37), or in SEER/TCR-Medicare (HR=0.86 95%CI 0.55-1.34). BCSS was only available for SEER/TCR-Medicare and was significantly better in patients receiving TNFi than in those receiving cDMARDs (HR=0.29 95%CI 0.09-0.98). No significant differences in OS or BCSS were observed when comparing patients who did not receive any DMARDs to those receiving TNFi. Patients receiving prednisone-equivalent doses of ³ 7.5mg/day had worse survival than those who did not receive glucocorticoids in Clinformatics, HR=2.51, 95%CI 1.32-4.76; in SEER/TCR-Medicare, HR=1.63, 95%CI 0.93-2.87.

Conclusion: TNFi therapy in patients with RA during the first year after early-stage BC diagnosis did not have a detrimental effect on survival. Glucocorticoids were associated with a significant increase in overall mortality in one of the databases. Additional studies are needed to determine the effects of other biologics on cancer outcomes, and of TNFi in patients with other cancer types.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/survival-in-patients-with-rheumatoid-arthritis-and-early-breast-cancer-treated-with-tumor-necrosis-factor-inhibitors/