Adherence to Recommended Treatments for Early Invasive Breast Cancer: Decisions of Women Attending Surgeons in the Breast Cancer Audit of Australia and New Zealand

Aim: The study aim was to determine the frequency with which women decline clinicians’ treatmentrecommendations and variations in this frequency by age, cancer and service descriptors. Design: The studyincluded 36,775 women diagnosed with early invasive breast cancer in 1998-2005 and attending Australian andNew Zealand breast surgeons. Rate ratios for declining treatment were examined by descriptor, using bilateraland multiple logistic regression analyses. Proportional hazards regression was used in exploratory analyses ofassociations with breast cancer death.
Results: 3.4% of women declined a recommended treatment of sometype, ranging from 2.6% for women under 40 years to 5.8% for those aged 80 years or more, and with parallelincreases by age presenting for declining radiotherapy (p<0.001) and axillary surgery (p=0.006). Multipleregression confirmed that common predictors of declining various treatments included low surgeon case load,treatment outside major city centres, and older age. Histological features suggesting a favourable prognosiswere often predictive of declining various treatments, although reverse findings also applied with women withpositive nodal status being more likely to decline a mastectomy and those with larger tumours more likely todecline chemotherapy. While survival analyses lacked statistical power due to small numbers, higher risksof breast cancer death were suggested, after adjusting for age and conventional clinical risk factors, (1) forwomen not receiving breast surgery for unstated reasons (RR=2.29; p<0.001); and (2) although not approachingstatistical significance p≥ 0.200), for women declining radiotherapy (RR=1.22), a systemic therapy (RR1.11),and more specifically, chemotherapy (RR=1.41).
Conclusions: Women have the right to choose their treatmentsbut reasons for declining recommendations require further study to ensure that choices are well informed andclinical outcomes are optimized.