Treatment intervals and survival for women diagnosed with early breast cancer in Queensland: the Breast Cancer Outcomes Study, a population‐based cohort study

Abstract

AbstractObjectivesTo assess associations between breast cancer‐specific survival and timeliness of treatment, based on 2020 Australian guidelines for the treatment of early breast cancer.DesignPopulation‐based cohort study; analysis of linked Queensland Cancer Register, patient medical record, and National Death Index data, supplemented by telephone interviews.Setting, participantsWomen aged 20–79 years diagnosed with invasive breast cancer during 1 March 2010 – 30 June 2013, followed to 31 December 2020.Main outcome measuresBreast cancer‐specific survival for women who received or did not receive treatment within the recommended timeframe, overall and for six treatment intervals; optimal cut‐points for each treatment interval; characteristics of women for whom treatment was not provided within the recommended timeframe.ResultsOf 5426 eligible women, 4762 could be invited for interviews; complete data were available for 3044 women (56% of eligible women, 65% of invited women). Incomplete compliance with guideline interval recommendations was identified for 1375 women (45%); their risk of death from breast cancer during the follow‐up period was greater than for those for whom guideline compliance was complete (adjusted hazard ratio [aHR], 1.43; 95% confidence interval [CI], 1.04–1.96). Risk of death was greater for women for whom the diagnosis to surgery interval exceeded 29 days (aHR, 1.76; 95% CI, 1.19–2.59), the surgery to chemotherapy interval exceeded 36 days (aHR, 1.63; 95% CI, 1.13–2.36), or the chemotherapy to radiotherapy interval exceeded 31 days (aHR, 1.83; 95% CI, 1.19–2.80). Treatment intervals longer than recommended were more frequent for women for whom breast cancer was detected by public facility screening (adjusted odds ratio [aOR], 1.58; 95% CI, 1.22–2.04) or by symptoms (aOR, 1.39; 95% CI, 1.09–1.79) than when cancer had been detected in private facilities, and for women without private health insurance (aOR, 1.96; 95% CI, 1.66–2.32) or living outside major cities (aOR, 1.38; 95% CI, 1.18–1.62).ConclusionsBreast cancer‐specific survival was poorer for women for whom the diagnosis to surgery, surgery to chemotherapy, or chemotherapy to radiotherapy intervals exceeded guideline‐recommended limits. Our findings support 2020 Australian guideline recommendations regarding timely care.