Continuing chemotherapy or not after the induction treatment in advanced breast cancer patients: clinical outcomes and oncologists’ preferences

The optimal duration of cytostatic treatment for metastatic breast cancer is still a matter of debate. Possible gain in the duration of remission has to be weighed against the side-effects of treatment. Our aim was to define the optimal duration of cyclophosphamide, methotrexate, 5-fluorouracil (CMF) treatment by studying the time to treatment failure, overall survival and using a Q-TWiST analysis. The treating physician's opinion was asked. The European Organization for Research and Treatment of Cancer (EORTC) Breast Cancer Group conducted a randomised trial in 204 non-progressing metastatic breast cancer patients after induction chemotherapy (CMF) to stop or continue treatment. Progression-free (PFS) and overall survival (OS) were studied. To gain more insight into the burden of treatment-related side-effects, Q-TWiST was analysed. In addition, we asked for oncologists’ preferences as patients are likely to be influenced by their physicians’ opinion. Continuation of CMF had a significantly longer time to treatment failure (TTF) 5.2 versus 3.5 months (P=0.011). There was no overall survival (OS) difference 14.0 versus 14.4 months (P=0.77). Mean quality-adjusted survival time was equal to 8.4 months for no further treatment and decreased to 7.9 months for continuation of CMF (95% Confidence Interval (CI) of difference equals 0.5±2.5 months). Almost half of the oncologists said they would favour continuous treatment for a 3-month gain in time to progression—a difference which was not found in this study. Based on these data, an interruption of chemotherapy (CMF), if this is the wish of the patient, is justified.