Serum tumor markers and positron emission tomography-computed tomography scan as post-breast cancer treatment surveillance

Michael Co, Vivian Man, Ava Kwong

Abstract

Background: Post-operative surveillance is an important aspect in managing breast cancers. The primary aim is to allow early detection of metachronous breast cancers. However, post-operative breast cancer surveillance has not been standardized. Mammography has been the only evidence-based imaging modality for detecting metachronous breast cancers. The value of regular monitoring with serum carcinoembryonic antigen (CEA) and CA 15-3 has been controversial. The aim of this study is to evaluate the efficacy of using tumor markers as a surveillance tool in post-operative patients.
Methods: This is a retrospective review of all post-breast cancer surgery patients monitored with tumor markers from 2005–2010. Correlation between tumor markers and subsequent detection of metachronous breast cancer was evaluated. Long-term survival data was analyzed.
Results: Six hundred and forty-nine patients underwent positron emission tomography-computed tomography (PET-CT) scan, 250 patients had regular tumor markers monitoring. By using 5 ng/mL as cutoff for CEA, and 23 U/mL for CA 15.3, elevated levels are associated with development of metachronous breast cancer (P=0.004 and P<0.001). The positive predictive values of CEA and CA 15.3 were 61.8% and 64.1% respectively. After median follow-up interval of 8 years after primary operation (range, 2–13 years). There were 93 breast-cancer related mortalities, 47 had elevated tumor marker, 142 patients remained disease free, 27 patients had elevated tumor marker levels. Elevated tumor marker during surveillance is associated with breast-cancer mortality in the current study (P<0.001).
Conclusions: Elevated serum CEA and CA 15-3 is associated with metachronous breast cancer and is associated with adverse long-term survival outcome.