Preoperative Pectoralis Muscle Index Predicts Distant Metastasis-Free Survival in Breast Cancer Patients

Abstract

BackgroundBreast cancer is one of the most commonly diagnosed cancers, and the fourth leading cause of cancer deaths in females worldwide. Sarcopenia is related to adverse clinical outcomes in patients with malignancies. Muscle index is a key parameter in evaluating sarcopenia. However, there is no data investigating the association between muscle index and distant metastasis in breast cancer. The aim of this study was to explore whether muscle index can effectively predict distant metastasis and death outcomes in breast cancer patients.Study DesignThe clinical data of 493 breast cancer patients at the Harbin Medical University Cancer Hospital between January 2014 and December 2015 were retrospectively analyzed. Quantitative measurements of pectoralis muscle area and skeletal muscle area were performed at the level of the fourth thoracic vertebra (T4) and the eleventh thoracic vertebra (T11) of the chest computed tomography image, respectively. The pectoralis muscle index (PMI) and skeletal muscle index (SMI) were assessed by the normalized muscle area (area/the square of height). Survival analysis was performed using the log-rank test and Cox proportional hazards regression analysis.ResultThe patients with metastases had lower PMI at T4 level (PMI/T4) and SMI at T11 level (SMI/T11) compared with the patients without metastases. Moreover, there were significant correlations between PMI/T4 and lymphovascular invasion, Ki67 expression, multifocal disease, and molecular subtype. In addition, multivariate analysis revealed that PMI/T4, not SMI/T11, was an independent prognostic factor for distant metastasis-free survival (DMFS) and overall survival (OS) in breast cancer patients.ConclusionsLow PMI/T4 is associated with worse DMFS and OS in breast cancer patients. Future prospective studies are needed.

Association of body composition with clinical outcome in Chinese women diagnosed with breast cancer

“…In addition, we found that sarcopenia was an independent prognostic factor in worse DFS ( p = 0.038) and OS ( p = 0.049), consistent with most previous studies ( 4 , 6 , 7 , 20 , 21 ). Villasenor et al ( 7 ) recruited 471 patients with non-metastatic breast cancer and found that sarcopenia (defined as ASMI <5.45 kg/m 2 ) measured by DEXA was associated with an increased risk of overall mortality (HR, 2.86; 95% CI, 1.67–4.89).…”

“…Deluche et al ( 20 ) reported sarcopenia (defined as SMI <41.0 cm 2 /m 2 ) as an independent risk factor for DFS after analyzing the medical records of 119 early breast cancer patients ( p =0.02). A recent study demonstrated that sarcopenia (defined as pectoralis muscle index <19.5 cm 2 /m 2 ) measured by CT was an independent prognostic factor for distant metastasis-free survival and OS in early breast cancer ( 21 ). Whereas some researchers had come to different conclusions, Del Fabbroh et al ( 6 ) disclosed that the higher the skeletal muscle index, the greater the risk of death, and in this study, the cutoff for sarcopenia was defined as SMI ≤38.5 cm 2 /m 2 .…”

“…The inconsistency of evaluation tools may explain the conflicting statements from the studies mentioned above. Villasenor et al ( 7 ) used DEXA to measure body composition, we used BIA, and all other studies ( 4 , 6 , 20 , 21 ) used CT scans. Although the accuracy of these three methods has been verified, there are inevitably differences among the measurement tools.…”

“…Our study adopted the cutoff point from the Asian Sarcopenia Working Group ( 11 ): ASMI <5.7 kg/m 2 was diagnosed as sarcopenia for females. Other studies used 19.5 cm 2 /m 2 ( 21 ), 38.5 cm 2 /m 2 ( 6 ), 40.0 cm 2 /m 2 ( 4 ), and 41.0 cm 2 /m 2 ( 20 ) [all units are muscle area (cm 2 ) divided by height (m 2 ) squared] as cutoff points for sarcopenia diagnosis. Therefore, the differences among calculation methods and cutoff points of sarcopenia diagnosis are likely to cause contradicting results in the studies mentioned above, suggesting that future studies on sarcopenia need to have unified diagnostic criteria.…”

Sarcopenia does not limit overall survival after interstitial brachytherapy for breast cancer liver metastases

“…In a meta-analysis including 81 studies, low lean mass was associated with an decreased OS across different definitions, including the international consensus of cancer cachexia and different cut-off points for skeletal muscle mass [51]. Huang et al identified low PMI at the L4 level to be associated with overall survival and distant metastases-free survival before surgery [52]. Low skeletal muscle mass is therefore a relevant patient-related condition that warrants early detection for optimal prevention, prognostication, and management.…”