# The Association Between Alignment to the Breast Cancer Optimal Care Pathways and Patient Survival in Victoria, Australia, 2012–2019: A Retrospective Population‐Based Cohort Study

## TL;DR

Following breast cancer treatment guidelines in Victoria, Australia, was linked to lower death rates, emphasizing the importance of adhering to best practice care pathways.

## Contribution

This study provides real-world evidence that aligning breast cancer treatment with optimal care pathways improves patient survival outcomes.

## Key findings

- Women whose treatment aligned with the optimal care pathways had 23% lower breast cancer death risk and 34% lower all-cause death risk.
- Stage II and III cancer patients saw the largest reductions in breast cancer death risk with pathway alignment.
- All-stage cancer patients experienced significant all-cause death risk reductions when treatments followed the pathways.

## Abstract

To quantify the association between care alignment to the treatment step of the Cancer Council Victoria and Department of Health Victoria Optimal care pathways for people with breast cancer (OCP) (second edition) and survival.

Retrospective population‐based cohort study using the Victorian Cancer Registry and linked administrative health datasets.

Adult women diagnosed with invasive, unilateral breast cancer from 1 July 2012 to 31 December 2019 in Victoria, Australia.

Breast cancer‐specific and overall survival for women whose care did or did not align to the treatment step of the OCP expressed as adjusted hazard ratios. Interaction between OCP alignment and cancer stage at diagnosis was also assessed.

Of 29,591 eligible women, 17,152 (58.0%) were fully aligned, 7086 (23.9%) were partially aligned and 5353 (18.1%) were not aligned to the treatment step of the breast cancer OCP. Median follow‐up was 1481 days (interquartile range, 850–2210 days). Adjusting for measured sociodemographic and clinical factors, OCP treatment alignment was associated with 23% (95% confidence interval [CI], 14%–31%) and 34% (95% CI, 29%–40%) lower risk of death from breast cancer and all causes, respectively, compared with non‐alignment. By cancer stage, OCP alignment was significantly associated with 40% (95% CI, 27%–50%) and 30% (95% CI, 14%–42%) lower risk of breast cancer death for Stage II and III cancers, respectively, and 39% (95% CI, 26%–49%), 49% (95% CI, 42%–55%) and 33% (21%–44%) lower risk of all‐cause death for Stage I, II and III cancers, respectively.

Risk of death was lower for women with breast cancer whose treatment aligned to the OCP compared with women whose treatment did not align. Our findings support the promotion and implementation of the breast cancer OCP.

The Cancer Council Victoria and Department of Health Victoria Optimal care pathways for people with breast cancer (second edition) describes key elements of best practice cancer care including treatment. While nationally endorsed, there is limited evidence on care alignment in real‐world practice and its associations with survival.

Women with breast cancer whose treatments aligned to the optimal care pathways had 23% and 34% lower risk of breast cancer and all‐cause death, respectively, than patients whose treatments did not align.

Our findings highlight the importance of timely best practice breast cancer treatments as well as policies that support routine implementation of the optimal care pathways.