Re-excision rate after sector resection for breast cancer: A 5-year retrospective cohort study.

BACKGROUND: Positive margins after Breast conserving surgery (BCS) for breast cancer can result in local recurrence (LR) requiring further surgery. This can lead to unnecessary patient anxiety, poor prognosis and impose additional economic burden to our health system. The aim of this study is to assess the rate of re-excision for positive margins after BCS using the sector resection technique. METHODS: This single centre retrospective cohort study included all women who underwent BCS using sector resection between the years of 2012 and 2016. A total of 456 patients underwent sector resection. We evaluated the margin status, re-excision rates and their predictive risk factors. RESULTS: 415 (91%) patients had clear margins. 41 (9%) patients underwent further re-excision for positive or close margin. 75.6% of those patients had DCIS and 51% had invasive carcinoma involving the margins. Patient and tumour characteristics associated with an increased risk of positive margin were women under the age of 50 (p = 0.19), tumours >50 mm (p = 0.001), grade-2 (p = 0.48) and grade-3 (p = 0.63), HER-2 positivity (p = 0.02), sentinel lymph node positivity (p = 0.03), and patients undergoing axillary lymph node dissection (p = 0.01). CONCLUSION: BCS using the sector resection technique has a low re-excision rate for positive margins. Younger patients and aggressive tumour biology are important predictive risk factors for positive margins.

Role of radiotherapy in women over the age of 65 after breast conserving surgery for breast cancer: A 5-year retrospective study.

BACKGROUND/OBJECTIVE: This study aimed to analyse the local recurrence (LR) and breast cancer related mortality (BCRM) in older women who underwent breast-conserving surgery (BCS) with and without adjuvant radiotherapy (XRT). METHODS: This retrospective study included a total of 299 women who underwent BCS for early breast carcinoma, between the years of 2007 and 2011. Predictive risk factors, local recurrence (LR) and breast cancer related mortality (BCRM) were assessed with a mean follow-up period of 84 months. RESULTS: Women over the age of 65 in the XRT and No-XRT groups showed similar incidence of LR (5.8% vs 5%, p = 0.838). Women over 65 years old with XRT had a higher rate of BCRM (5.8% vs 0%, p = 0.05). Resection margins >5 mm had a lower rate of BCRM (HR 0.395, p = 0.05). Women under the age of 65, invasive ductal carcinoma, grade-3 tumours, HER-2 positive, triple negative, lympho-vascular invasion, axillary lymph node positivity, high breast density on mammography were associated with increased risk of LR and BCRM. CONCLUSIONS: XRT in women over the age of 65 did not decrease the risk of LR. Adjuvant XRT in older women should be offered to selective patients with high risk patient and tumour factors.

A patient-derived explant (PDE) model of hormone-dependent cancer.

Breast and prostate cancer research to date has largely been predicated on the use of cell lines in vitro or in vivo. These limitations have led to the development of more clinically relevant models, such as organoids or murine xenografts that utilize patient-derived material; however, issues related to low take rate, long duration of establishment, and the associated costs constrain use of these models. This study demonstrates that ex vivo culture of freshly resected breast and prostate tumor specimens obtained from surgery, termed patient-derived explants (PDEs), provides a high-throughput and cost-effective model that retains the native tissue architecture, microenvironment, cell viability, and key oncogenic drivers. The PDE model provides a unique approach for direct evaluation of drug responses on an individual patient's tumor, which is amenable to analysis using contemporary genomic technologies. The ability to rapidly evaluate drug efficacy in patient-derived material has high potential to facilitate implementation of personalized medicine approaches.