medwireNews: Serum analysis suggests that within a year of beginning endocrine therapy after early breast cancer treatment, around one in six premenopausal women are no longer adherent to tamoxifen.
As presented at the ESMO 2018 Congress in Munich, Germany, only 84% of the 1177 premenopausal breast cancer patients, aged a median of 45 years, had a serum tamoxifen level of at least 60 ng/mL at their 1 year follow-up, indicating adherence to therapy.
Barbara Pistilli, from Gustave Roussy in Villejuif, France, reported, however, that just 12% of patients had admitted their treatment had been interrupted, discontinued, or switched, and only 45% of patients with a nonadherent serum sample had reported they were not following their treatment plan.
There was only a “modest” concordance of 86% between the serum results and patient self-declarations on adherence to tamoxifen, she added, while analysis indicated that adherence was predicted by receipt of adjuvant chemotherapy and absence of musculoskeletal adverse events.
The results of the therapeutic drug monitoring in CANTO COMPLETE will be used to develop a multidisciplinary program to encourage patients to be open about their difficulties with treatment and support women through endocrine therapy side effects with the aim of raising adherence, Pistilli told medwireNews.
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