Women who have at least one instance of delayed treatment for breast cancer face a 43% increased risk of death compared to those receiving timely treatment, Queensland cancer epidemiologists have found.

They say their finding highlights the importance of treatment within recommended timeframes, with the most critical intervals diagnosis to surgery, surgery to chemotherapy, and chemotherapy to radiotherapy.

Their Breast Cancer Outcomes Study involved 3044 women aged 20–79 with an invasive breast cancer diagnosis recorded in the Queensland Cancer Register between March 2010 and June 2013, and followed to 31 December 2020.

The team also drew from patient medical records and state and national death databases, and collected further information from patient telephone interviews.

They identified 45% of women had at least one instance of non-compliance with recommended intervals as per Cancer Australia’s 2020 guidelines [link here].

Guideline non-compliance most commonly occurred for surgery to radiotherapy (interval 5: 49%) and was less common for diagnosis to surgery (interval 3: 4.5%).

Findings published in the Medical Journal of Australia [link here] showed increased risk of death from breast cancer overall for women who received delayed treatment compared with those within the guideline timeframes (adjusted hazard ratio, aHR 1.43).

Risk of death was greatest for those undergoing surgery more than 29 days after diagnosis (aHR, 1.76), commenced chemotherapy more than 36 days after surgery (aHR, 1.63) or radiotherapy more than 31 days post chemotherapy (aHR, 1.83).

The surgery-to-radiotherapy interval did not appear to significantly influence breast cancer survival, even though the guideline recommended commencing radiation therapy within eight weeks of surgery for women not receiving chemotherapy.

The researchers also identified that treatment intervals longer than recommended were more frequent for breast cancer cases detected by public facility screening (adjusted odds ratio 1.58) or by symptoms (aOR 1.39) than by private screening.

Delayed treatment was also more frequent for women who completed or started treatment in December or January rather than February to November (aOR, 2.05).

Women who smoked (aOR, 1.41), earned below $52,000 pa (aOR, 1.30), did not have private insurance (aOR, 1.96), lived outside big cities (aOR, 1.38) or had no family history of breast or ovarian cancer (aOR, 1.22) were also more affected.

“Health system practices and hospital burden, as well as factors such as geographic and cultural diversity, probably influence the timeliness of breast cancer care,” wrote the authors from the Viertel Cancer Research Centre, Cancer Council Queensland, and the the University of Queensland in Brisbane.

“Opportunities for shortening the diagnosis-to-treatment window while maintaining quality of care may be facilitated by digital health care innovations integrated with person-centred care and a survivorship approach.”