Background

In recent years, there have been many advancements – both pharmacologically and surgically – in breast cancer treatment, particularly for women with HER2+ disease (e.g., trastuzumab). Historically, breast cancer treatment utilization has followed a socioeconomic gradient, with people living in areas of high deprivation less likely to receive breast cancer treatment.  It is unknown if these socioeconomic inequalities persist for the newer, more recently developed, HER2+ breast cancer treatments.  The aim of this work was, therefore, to examine the association between socioeconomic status and trastuzumab or surgical treatment utilization for women with HER2+ breast cancer.

Method

Data from the English population-based national cancer registration database and linked Systemic Anti-Cancer Therapy (SACT) dataset on 40,179 HER2+ breast cancer cases, diagnosed between 01/01/2012 – 31/12/2017, was used for the analysis.  Likelihood of receipt of 1. trastuzumab, 2. Surgery by socioeconomic status (measured in by IMD quintile) was examined, adjusting for age and stage, diagnosis year, ethnicity, rural/urban categorisation, grade, ER status, comorbidities and whether or not discussed at MDT.

Results

HER2+ breast cancer treatment follows a socioeconomic gradient. These inequalities persisted after adjusting for a range of confounding factors, and were more pronounced for surgery than trastuzumab. Women living in the most deprived areas were significantly less likely to receive surgery (multivariable odds ratio (mvOR) 0.79 [95% CI] 0.73, 0.86) or trastuzumab (mvOR 0.92 [95% CI] 0.85, 0.99), compared to women living in the most affluent areas.

Conclusion

Despite the advancements in the biomedical sciences to pioneer the development of new pharmacological and surgical treatments for HER2+ breast cancer, socioeconomic inequalities in treatment utilization still persist.  It is not known if, or how, these socioeconomic inequalities contribute to the overall survival gap, between the rich and the poor, for breast cancer.  Future research is urgently needed to explore why these inequalities exist, to develop approaches to ensure these treatment advancements are available to all.

Impact statement

Socioeconomic inequalities in treatment uptake still persist for new breast cancer treatments: as well as focusing on treatment effectiveness, future cancer strategies should also consider the concept of treatment fairness.