Scaling of computed tomography body composition to height: relevance of height‐normalized indices in patients with colorectal cancer

Abstract

Background Body weight scales to height with a power of ≈2 (weight/height2), forming the basis of body mass index (BMI). The corresponding scaling of body composition measured by abdominal computed tomography (CT) to height has not been established. The objective of this analysis was to quantify the scaling of body composition measured by a single‐slice axial abdominal CT image (skeletal muscle, and visceral, subcutaneous, and total adipose tissue) to height in patients with colorectal cancer (CRC). Methods This cross‐sectional study included non‐Hispanic white males and females, aged 18–80 years, who were diagnosed with stage I–III CRC at an integrated health care system in North America between January 2006 and December 2011. Body composition was measured by a single‐slice axial CT image of the third lumbar vertebra and analysed with a semi‐automated threshold segmentation procedure. Allometric regression models were used to quantify height scaling powers (β ± standard error) for each body composition measure, adjusted for age, for males and females. An interaction test was used to determine if height scaling powers were statistically significantly different between males and females. Results Among 2036 subjects, the mean (standard deviation) age was 64 ± 11 years, 1008 (49.5%) were female, and the mean (standard deviation) BMI was 27.9 ± 5.4 kg/m2. Powers for skeletal muscle area were 1.06 ± 0.12 for males and 0.80 ± 0.12 for females (P = 0.049). Powers for visceral adipose tissue area were 1.81 ± 0.64 for males and 0.57 ± 0.79 for females (P = 0.16). Powers for subcutaneous adipose tissue area were 2.04 ± 0.42 for males and 0.81 ± 0.45 for females (P = 0.056). Powers for total abdominal adipose tissue area were 1.80 ± 0.46 for males and 0.76 ± 0.50 for females (P = 0.20). Conclusions Body composition measured by single‐slice axial abdominal CT, particularly muscle area, scales to height with age‐adjusted powers that are different than 2 and are distinct between males and females. These observations may have implications for the development of height‐adjusted body composition indices in patients with cancer.

Progressive Skeletal Muscle Loss After Surgery and Adjuvant Radiotherapy Impact Survival Outcomes in Patients With Early Stage Cervical Cancer

“…Skeletal muscle was defined based on Hounsfield unit (HU) thresholds ranging from −29 to +150 HU. The skeletal muscle index (SMI) was calculated as the cross-sectional muscle area divided by height in square meters (cm 2 /m 2 ) ( 32 ). The cut-off values for sarcopenia were set at the lowest tertile for SMI based on previous studies ( 33 – 36 ).…”

Can AI-based body composition assessment outperform body surface area in predicting dose-limiting toxicities for colonic cancer patients on chemotherapy?

“…It has also been known that sarcopenia is related to reduced completion of oxaliplatin-based regimens in patients with CRC and is strongly associated with severe chemotherapy toxicity in patients with metastatic CRC (Shiraishi 2023 ; Barret 2014 ). In addition, patients who are obese have been shown to have an increased risk of chemotherapy toxicities, suggesting that the distribution pattern and overall quantity of adipose tissue (SAT and VAT) have a significant impact on colonic cancer chemotherapy storage and metabolism (Cespedes Feliciano 2017 ; Brown 2022a , b ; Shiraishi et al 2023 ; Jung 2015 ). These findings have highlighted the crucial role body composition may play in determining whether or not a patient will experience DLT.…”

“…For each patient, a trained human grader (author JoY) manually selected one CT slice as the most representative of the L3 in line with the Alberta Protocol ( https://tomovision.com/SarcopeniaHelp/index.html ). This slice referred to as the mid-L3 slice, has generally been considered as the gold standard for analysing body segmentation measures in the majority of CRC studies (Arayne 2023 ; Brown et al 2022a , b ; Kotti 2022 ).…”

Body composition and cancer survival: a narrative review

“…The resulting metrics, fat mass index (FMI) and lean mass index (LMI) have the appealing property of summing to BMI, thus representing a decomposition into its constituent tissue compartments [ 109 ]. It is not clear that applying the same normalization to individual area-based measures achieves the same goal, and other scaling factors may be more appropriate [ 110 ]. Ultimately, different uses of area-based and height-adjusted index measures may contribute to the variations noted in the literature on adiposity and survival [ 83 ].…”