Prescribing tamoxifen in primary care for the prevention of breast cancer: a national online survey of GPs’ attitudes

Samuel G Smith, Robbie Foy, Jennifer A McGowan, Lindsay C Kobayashi, Andrea de Censi, Andrea DeCensi, Karen Brown, Lucy Side, Jack Cuzick

The cancer strategy for England (2015-2020) recommends GPs prescribe tamoxifen for breast cancer primary prevention among women at increased risk. To investigate GPs' attitudes towards prescribing tamoxifen. In an online survey, GPs in England, Northern Ireland, and Wales (n = 928) were randomised using a 2 × 2 between-subjects design to read one of four vignettes describing a healthy patient seeking a tamoxifen prescription. In the vignette, the hypothetical patient's breast cancer risk (moderate versus high) and the clinician initiating the prescription (GP prescriber versus secondary care clinician [SCC] prescriber) were manipulated in a 1:1:1:1 ratio. Outcomes were willingness to prescribe, comfort discussing harms and benefits, comfort managing the patient, factors affecting the prescribing decision, and awareness of tamoxifen and the National Institute for Health and Care Excellence (NICE) guideline CG164. Half (51.7%) of the GPs knew tamoxifen can reduce breast cancer risk, and one-quarter (24.1%) were aware of NICE guideline CG164. Responders asked to initiate prescribing (GP prescriber) were less willing to prescribe tamoxifen than those continuing a prescription initiated in secondary care (SCC prescriber) (68.9% versus 84.6%, P<0.001). The GP prescribers reported less comfort discussing tamoxifen (53.4% versus 62.5%, P = 0.01). GPs willing to prescribe were more likely to be aware of the NICE guideline (P = 0.039) and to have acknowledged the benefits of tamoxifen (P<0.001), and were less likely to have considered its off-licence status (P<0.001). Initiating tamoxifen prescriptions for preventive therapy in secondary care before asking GPs to continue the patient's care may overcome some prescribing barriers.