Treatment and survival of patients diagnosed with high-risk HR+/HER2− breast cancer in the Netherlands: a population-based retrospective cohort study ☆

Abstract

Background

Several factors may increase the risk of recurrence of patients diagnosed with hormone receptor-positive human epidermal growth factor receptor 2-negative (HR+/HER2−) breast cancer (BC). We aim to determine the proportion of patients with high-risk HR+/HER2− BC within the total HR+/HER2− BC cohort and compare their systemic treatments and survival rates with those of patients with low- and intermediate-risk HR+/HER2− BC and triple-negative (TN) BC.

Patients and methods

Women diagnosed with nonmetastatic invasive HR+/HER2− BC and TNBC in the Netherlands between 2011 and 2019 were identified from the Netherlands Cancer Registry. Patients with HR+/HER2− BC were categorised according to risk profile, defined by nodal status, tumour size, and histological grade. High-risk HR+/HER2− BC was defined by either four or more positive lymph nodes or one to three positive lymph nodes with a tumour size of ≥5 cm or a histological grade 3 tumour. Overall survival (OS) and relative survival (RS) were calculated using the Kaplan–Meier and Pohar–Perme method.

Results

In this study of 87 455 patients with HR+/HER2− BC, 44 078 (50%) patients were diagnosed with low risk, 28 452 (33%) with intermediate risk, and 11 285 (13%) with high-risk HR+/HER2− BC. In 3640 (4%) patients, the risk profile could not be defined. Endocrine therapy and chemotherapy were used in 38% and 7% of low-risk, 90% and 47% of intermediate-risk, and 94% and 73% of high-risk patients, respectively. The 10-year OS and RS rates were 84.1% [95% confidence interval (95% CI) 83.5% to 84.7%] and 98.7% (95% CI 97.3% to 99.4%) in low-risk, 75.1% (95% CI 74.2% to 76.0%) and 91.7% (95% CI 89.7% to 93.3%) in intermediate-risk, and 63.4% (95% CI 62.0% to 64.7%) and 72.3% (70.1% to 74.3%) in high-risk patients. The 10-year OS and RS rates of 12 689 patients with TNBC were 69.7% (95% CI 68.6% to 70.8%) and 79.1% (95% CI 77.0% to 80.9%), respectively.

Conclusion

The poor prognosis of patients with high-risk HR+/HER2− BC highlights the need for a better acknowledgement of this subgroup and supports ongoing clinical trials aimed at optimising systemic therapy.

Highlights

• •

  High-risk HR+/HER2− BC was defined by ≥4 positive nodes or 1-3 positive nodes + a tumour size of ≥5 cm or a grade 3 tumour.

• •

  One in eight women with HR+/HER2− BC were diagnosed with high-risk disease in the Netherlands between 2011 and 2019.

• •

  In the real world, 94% and 73% of patients with high-risk HR+/HER2− BC received endocrine therapy and chemotherapy.

• •

  The 10-year OS (63.4%) and RS rates (72.3%) of patients with high-risk HR+/HER2− BC were poor.

• •

  Survival rates of patients with high-risk HR+/HER2− BC remained constant over the years.