Table 3. Analysis of breast cancer recurrence in subgroup of methotrexate, thiopurine, or anti-TNF users prior to start of follow-up who continued or discontinued their therapy.
| Methotrexate | Thiopurinesa | Anti-TNF | ||||
|---|---|---|---|---|---|---|
| Continuerb | Discontinuer | Continuer | Discontinuer | Continuer | Discontinuer | |
| Cases of Recurrent breast cancer | 42 | 15 | <11 | 0 | 17 | <11 |
| Person-years of Follow-up | 1,858 | 726 | -- | -- | 725 | -- |
| Crude incidence of breast cancer recurrence (per 1000-py) | 22.6 (16.3-30.6) | 20.7 (11.6-34.1) | 34.6 (9.4-88.5) | -- | 23.5 (13.7-37.6) | 14.1 (5.7-29.1) |
| Adjusted (HR, 95%) | 1.15c (0.63-2.08) | Reference | -- | Reference | 1.37d (0.57-3.30) | Reference |
Person-years for thiopurine exposure are not shown to avoid calculation of absolute number of cases
Prevalent users of methotrexate, thiopurines, or an anti-TNF at the start of follow-up
No covariates modified the HR by > 10%; covariates assessed included: age, race, calendar year, time from breast cancer surgery to start of follow-up, post surgery hormonal or HER2 therapy, use of non-steroid anti-inflammatory medications in the prior 90 days, prior or concurrent use of immunosuppressive therapy (methotrexate, thiopurines, anti-TNF, or other biologic therapy [abatacept, rituximab, tocilizumab], and histories of chronic kidney disease, chronic liver disease, diabetes mellitus, coronary artery disease, and congestive heart failure.
Adjusted for prior or concurrent other biologic use (none, within 90 days, > 90 days prior to start of follow-up); no other covariates modified the HR by > 10%.