A rapid rise in hormone receptor-positive and HER2-positive breast cancer subtypes in Southern Thai women: A population-based study in Songkhla

The incidence of breast cancer is increasing in low- and middle-income countries, including Thailand. However, its molecular immunohistochemical (M-IHC) subtypes have not been summarized in a population-based cancer registry. Thus, we aimed to estimate the breast cancer incidence and trends based on the hormone receptor and human epidermal growth factor receptor 2 (HER2) status. This cross-sectional study included 2,883 women diagnosed with primary invasive breast cancer between 2009 and 2018 from the Songkhla Cancer Registry. After imputing the missing values of estrogen receptor (ER), progesterone receptor (PR), and HER2 status, the cases were classified into four subtypes: HR+/HER2-, HR+/HER2+, HR-/HER2-, and HR-/HER2+. The age-specific incidence rate of 5-year age groups and age-standardized incidence rate (ASR) were calculated. An age-period-cohort (APC) model was used to describe the effects of age, birth cohort, and period of diagnosis. Finally, the incidence trends were extrapolated to 2030 based on the APC and joinpoint models. The results showed, HR+/HER2- had the highest ASR in breast cancer. The incidence trends of HR+/HER2- and HR+/HER2+ increased with an annual percent change of 5.4% (95%CI: 2.5% to 8.3%) and 10.1% (95%CI: 4.9% to 15.5%), respectively. The rate ratio was high in the younger generation and recent period of diagnosis. The joinpoint and APC model projections showed that the ASR of HR+/HER2- would reach 30.0 and 29.2 cases per 100,000 women, while ASR of the HR+/HER2+ would reach 8.8 and 10.4 cases per 100,000 women in 2030. On the other hand, the incidence trends of the HR-/HER2- and HR-/HER2+ subtypes were stable. The rising trends of HR-positive and a part of HER2-positive breast cancer forecast a dynamicity of the future health care budgeting, resource allocation, and provision of facilities.

Pathum Raksa Project: Addressing Disparity in Breast Cancer Care Through National Innovation in Thailand

Purpose

Breast cancer is a growing public health challenge in Thailand. Pathum Raksa project was launched in 2015, as a result of higher than expected rate of triple-negative breast cancers in Thai women. The purpose of this project was to identify the cause(s) and address the issue(s), hence improving the quality of breast cancer biomarker testing in Thailand.

Materials and Methods

Nineteen hospitals across the country, with 902 breast cancer patients were enrolled in this study during 2015–2020. The pre- and post-data from Pathum Raksa initiative was only available for Khon Kaen University (KKU) and Udonthani hospitals in Northeast Thailand. We developed a resource-stratified strategic plan that included designing a unique specimen container, forming multidisciplinary teams from the Surgery and Pathology Departments, and employing locally developed innovative technologies to optimize the entire process of breast cancer diagnostics and biomarker testing.

Results

The rate of triple-negative breast cancers in KKU and Udonthani decreased 52.8% (p = 0.02) and 28.9% (p = 0.48), respectively. The rate of ER+ breast cancers in both hospitals increased 5% post-Pathum Raksa implementation. The rate of HER2-neu+ (score 3+) also increased in both hospitals (particularly an increased 65% rate in KKU). Luminal A/B cancers were the most common subtype in both KKU and Udonthani hospitals.

Conclusion

Pathum Raksa project has significantly improved breast cancer biomarker testing in Thailand. As a result of this national innovation, false-negative rates of breast biomarkers have significantly decreased, resulting in improving prognosis, treatment, and survival of breast cancer women in Thailand.

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