[Factors Affecting Adherence to Adjuvant Endocrine Therapy in Japanese Patients with Breast Cancer-An Observational Study].

The purpose of this study was to investigate adherence to adjuvant endocrine therapy (ET) and the factors affecting demotivation and motivation to continue adjuvant ET. In patients with hormone receptor-positive breast cancer in Japan, an online survey was conducted from June to July 2021 to investigate the treatment effects, side effects, concerns about side effects(for demotivation only), convenience of hospital visits, treatment duration, concerns about recurrence/progression, treatment cost, support from healthcare professionals, and support from family, the patient association, and peers(for motivation only). According to the responses from 263 patients, the most common factor affecting demotivation to continue adjuvant ET was the burden of side effects, and the most common factor affecting motivation to continue adjuvant ET was concerns about recurrence/progression. Continuous relief of the burden of side effects from the early stage of treatment, and mental support for concerns about recurrence/progression, as well as explaining and promoting the risks and benefits of continuing treatment, are considered to lead to motivation to continue adjuvant ET(Fig. 1: Summary of this survey).

Overnight fasting before lapatinib administration to breast cancer patients leads to reduced toxicity compared with nighttime dosing: a retrospective cohort study from a randomized clinical trial.

BACKGROUND: The bioavailability of lapatinib is affected by food, even following the 1 hour fast recommended by the package insert. We hypothesized that overnight fasting would minimize food-drug interactions. Here, we investigated if lapatinib administration timing is associated with its tolerability, efficacy, and pharmacokinetics. METHODS: This is a retrospective cohort study utilizing the medical records of patients enrolled in the JBCRG-16/Neo-LaTH randomized phase 2 trial for breast cancer patients treated with lapatinib. Lapatinib administration timing was divided into three groups: before breakfast (BB), between meals (BM), and at bedtime (AB). Side effects (SE), treatment discontinuation rate (TDR), relative dose intensity (RDI), pathological complete response (pCR) rate, and lapatinib serum trough concentration were compared between groups. RESULTS: About 140 patients were included in this study: BB 15, BM 51, and AB 74. A reduced risk of diarrhea {adjusted hazard ratio (HR), 0.51, 95% confidence interval (CI), 0.27-0.89, p = 0.018}, and rash {adjusted HR, 0.37; 95% CI, 0.17-0.70, p = 0.002} was seen in BB versus AB. Fewer patients with low RDI (< 0.85/<0.6) were in the BB group (BB 13% / 0%, BM 22% / 3.9%, AB 24% / 14%, p = 0.70 / 0.11). pCR was not diminished (p = 0.75). BB group had the lowest serum lapatinib concentration and variability (mean ±SD were 0.35 ± 0.15, 0.65 ± 0.32, 0.96 ± 0.43 µg/ml). CONCLUSIONS: Compared to bedtime administration, lapatinib administration after overnight fasting reduces its toxicity without diminishing its therapeutic efficacy.