Accuracy of preoperative imaging estimates: Opportunities to de-escalate surgery for early invasive breast cancer.

BACKGROUND: There is current concern for overtreatment of breast cancer and rising mastectomy rates. This study compared preoperative imaging size (PIS) to postoperative pathology sizes (PPS) with a view to identifying opportunities to de-escalate surgery. METHODS: Patients having surgery from 2013 to 2017 for first invasive breast cancers were identified and PIS was compared to PPS looking at correlation and concordance. Associated clinical features were evaluated by regression models stratified by clinical T stage. RESULTS: We identified 1512 tumors among 1502 patients. Ultrasound, mammogram, and MRI correlated to PPS with increasing discordance with increasing PIS. Ultrasound underestimated T1 and T2 tumors, and mammogram underestimated T1 tumors and overestimated T3 tumors. For T1 and T2 tumors ultrasound had the highest concordance with PPS. CONCLUSION: Patients can be reassured that imaging size can be used dependably by surgeons to plan lumpectomy for clinical T1 tumors. For larger tumors, overestimation by PIS should be considered in surgical planning.

Decreasing contralateral prophylactic mastectomy rates in average-risk women with unilateral breast cancer.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) is not recommended for average-risk women with breast cancer due to lack of evidence for survival benefit, yet recent studies demonstrate increasing CPM rates. METHODS: We identified patients with breast cancer treated with unilateral mastectomy (UM) with or without CPM. Rates of malignancy in CPM specimens and factors in CPM rates were assessed. RESULTS: From 2013 to 2017, 1353 patients had UM and 355 had CPM. Our institution's occult malignancy detection rate was 5.04%. CPM rates decreased from 31.6% to 17.3% (p < 0.001) over 5 years. Compared to patients receiving UM only, patients receiving CPMs had significantly higher reconstruction rates (p < 0.001), which did not significantly change over time (p = 0.551) and tended to be younger (p < 0.001). CONCLUSIONS: Patients having UM have low risk of contralateral malignancy. CPM is associated with younger age and breast reconstruction, suggesting factors to identify for patient and provider education.

De-Escalating Breast Cancer Surgery: Should We Apply Quality Indicators from Other Jurisdictions in Canada?

Quality Indicators (QIs), including the breast-conserving surgery (BCS) rate, were published by the European and American Breast Cancer Societies and this study assesses these in a Canadian population to look for opportunities to de-escalate surgery. A total of 2311 patients having surgery for unilateral, unifocal breast cancer between 2013 and 2017 were identified and BCS QIs calculated. Reasons for mastectomy had been prospectively collected with synoptic operative reporting. Our BCS rate for invasive cancer < 3 cm was 77.1%, invasive cancer < 2 cm was 84.1%, and DCIS < 2 cm was 84.9%. There was no statistically significant change in BCS rates over a five-year period, but there was a reduction in contralateral prophylactic mastectomies (CPM) from 28% in 2013 to 16% in 2017 (p < 0.001). Trend analysis looking at tumour size and medical need for mastectomy indicated that 80% of patients at our centre would be eligible for BCS with tumour cut off of 2.5 cm. Our institution met American but not European QI standards for BCS rates, potentially indicating a difference in patient demographics compared to Europe. Our results support the understanding that BCS rates are influenced by multiple factors and are challenging to compare across jurisdictions. CPM rates may offer a more actionable opportunity to de-escalate surgery for breast cancer.