Breast conserving therapy(BCT) and its clinical outcome after neoadjuvant chemotherapy in Hong Kong : a single-centre retrospective cohort study

Abstract

Neoadjuvant chemotherapy (NACT) has been shown to facilitate surgery through downsizing inoperable tumours to operable or reducing mastectomy-required tumours to make it treatable by breast conserving surgery (BCT), preserving more breast tissue. Chinese patients can benefit immensely from BCT due to their relatively small breast size. Currently, BCT rate and its clinical outcome after neoadjuvant therapy are understudied in Hong Kong. Most NACT studies done in the West only look at the total number of BCT attempted and neglect the initial surgical assignment of the subjects. With the use of targeted therapy alongside with chemotherapy, many patients are able to significantly downsize their tumours for BCT. As a matter of fact, the rate of pathological complete response has improved drastically since the development of targeted therapy, however, BCT rate has remained more or less unchanged. Studying surgical assignment before and after NACT can help identifying the underlying causes of this phenomenon. Our study aims (1) to investigate BCT assignment conversion rate from mastectomy (MX) to BCT, (2) to study the rate of BCT with tumour-free margins, (3) to examine the correlation between pCR and BCT assignment, and (4) to compare clinical outcomes between MX and BCT. Data is retrieved from a prospectively built database and retrospectively analyzed. Patients who were diagnosed with invasive carcinoma of stage I to III who received NACT and underwent surgery between January 2000 and December 2014 at the Department of Surgery, University of Hong Kong Li Ka Shing Faculty of Medicine were included in this study. Patients’ characteristics, including their demographics, tumour characteristics, response to neoadjuvant therapy, and treatment details and information of their follow-ups were extracted from the database. Our findings revealed that MX was preferred to BCT in our study population even though similar recurrence rate and survival outcome could be achieved in both surgical methods after NACT. Advanced disease was found to be one of the major reasons why MX was preferred. Detailed and elaborated information about the surgical assignment by doctors and patients’ preferences, if it is available, will greatly enhanced the quality of this study.