Evidence from small cohorts of patients with various types of cancer suggests that the use of immunosuppressive therapies in patients with rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) is not associated with cancer recurrence. Reassuringly, a new retrospective study with 5,196 person-years of follow-up reports that the risk of breast cancer recurrence 365 days after primary surgery is not significantly different between matched cohorts of users and nonusers of methotrexate (n = 892 and n = 892, respectively), thiopurines (n = 52 and n = 208) or anti-TNF therapy (n = 291 and n = 1,164). However, the use of thiopurines showed a trend towards increased risk of breast cancer recurrence (HR 2.10, 95% CI 0.62–7.14). Subgroup analyses revealed no difference in breast cancer recurrence rates between patients commencing immunosuppressive therapy before or after surgery.