Compliance and patient reported toxicity from oral adjuvant bisphosphonates in patients with early breast cancer. A cross sectional study.

Adjuvant bisphosphonates (BPs) are recommended as part of routine early breast cancer treatment for many postmenopausal (PM) women within the past year. There is a paucity of 'real world' data on compliance and patient satisfaction with oral BPs in this population. The aim of our study was to investigate patient reported compliance and toxicity of these drugs in a retrospective cohort study. 413 patient were identified as receiving adjuvant oral BPs as part of their breast cancer treatment in the past 12 months from five NHS hospitals. The validated Osteoporosis Patient Treatment Satisfaction Questionnaire (OPSAT-Q) was sent to all suitable patients ( 295 (76%) of patients responded. Average age was median (range) 67 (35-89). The majority of patients had T1 (52%), N0 (61%) grade 2 (58%) ER positive (87%), HER2 negative (84%) breast cancer and were PM at diagnosis of breast cancer (93%). All patients had been prescribed at least 1 month of oral ibandronate 50 mg daily. Review of items rated on the 7-point scale (1 = very dissatisfied to 7 = very satisfied), the mean item scores ranged from 5.0 (lowest) for time required to take oral BPs, to 6.1 (highest) for how easy it is to remember to take the medication. <10% of patients were extremely bothered by heartburn or stomach upset. 16% of responders stopped oral BPs with 10% of those converting onto IV BPs. Prevalence of severe side effects in a 'real world' population of PM women receiving adjuvant BPs is low and these drugs are generally well accepted and tolerated by patients.