ARRS 2022 Abstracts

RETURN TO ABSTRACT LISTING


E2106. Exploring Total Muscle Area at T4 as a Surrogate Marker for Sarcopenia in Evaluating Post-Surgical Lung Cancer Outcomes
Authors
  1. Sameer Hanfi; University of Massachusetts Medical School, UMass Memorial Medical Center
  2. Efaza Siddiqui; University of Massachusetts Medical School, UMass Memorial Medical Center
  3. Gracijela Bozovic; University of Massachusetts Medical School, UMass Memorial Medical Center
  4. Adam Cellurale; University of Massachusetts Medical School, UMass Memorial Medical Center
  5. Bryce Bludevich; University of Massachusetts Medical School, UMass Memorial Medical Center
  6. Keren Guiab; University of Massachusetts Medical School, UMass Memorial Medical Center
  7. Lacey McIntosh; University of Massachusetts Medical School, UMass Memorial Medical Center
Objective:
Sarcopenia, defined as the loss of skeletal muscle mass, has been associated with post-operative morbidity and mortality. It is most often assessed by a skeletal muscle index of total muscle area (SMI TMA) at L3, but this level is not routinely included in the FOV for chest CT. We correlated SMI TMA at T4 on chest CT (which is always included in the chest CT FOV) with SMI TMA at L3 from contemporaneous PET/CT scans to explore SMI TMA at T4 use as a surrogate area for assessing sarcopenia. We also looked for associations with any postoperative complications (APOC).

Materials and Methods:
A retrospective, single institution study was performed on patients who underwent curative lung cancer resections between November 2011 and June 2019. Baseline preoperative chest CT and PET/CT were reviewed by three radiology trainees with 3–5 years of experience and an attending radiologist with 10 years of experience (intraclass correlation coefficient [ICC] > 0.98, 95% CI 0.96–0.99). Using TeraRecon software, skeletal muscle was quantified using –29 to +150 Hounsfield Unit (HU) thresholds, and TMA was measured at T4 on chest CT and at L3 on PET/CT using the “fat analysis” tool. T4 average pectoralis muscle (PEC) area (pectoralis major and minor) was manually drawn using the “polygon tool,” and waist to hip ratio (WHR) 4 was calculated. TMA was divided by height, and this value was reported as the SMI (cm2/m2). The primary outcomes were the correlation of SMI TMA at T4 on chest CT with SMI TMA at L3 on PET/CT and occurrence of APOC. Secondary outcomes were major postoperative complications (MPOC) and length of stay (LOS). Univariate and multivariate logistic regressions were performed.

Results:
A total of 250 individuals were included, with the mean age of 67 ± 9 years, and 63.2% were women. Most patients underwent minimally invasive resections with a median LOS of 5 days (IQR 3–7). There was an association between lower SMI TMA at T4 with increased APOC, although not statistically significant. Given the observed associations between sarcopenia at L3 and APOC, based on patients identified as sarcopenic by L3 standards using the mean, we found a cutoff value at T4 of < 48.27 for women and < 63.91 for men. The rates of APOC and MPOC were 24.0% and 17.6%, respectively. In the multivariate model, sarcopenia at T4 (OR 2.12, p = 0.028), anatomic resection (OR 3.85, p = 0.002), and WHR (OR 3.66, p = 0.004) correlated with increased APOC, and anatomic resections (OR 3.97, p = 0.002) and WHR (OR 2.74, p = 0.03) correlated with MPOC. Although sarcopenia was associated with increased MPOC, it was not statistically significant (OR 1.73, p = 0.14). The median LOS was 5 days in sarcopenic subjects and 4 days in non-sarcopenic subjects (p = 0.202).

Conclusion:
Sarcopenia, defined by SMI TMA at L3, has a statistically significant association with postoperative complications after primary lung cancer resection. Postoperative complications were observed in a higher percentage of individuals with sarcopenia at T4, even though there is no statistically significant association (possibly due to small sample size).