Relation between skeletal muscle volume and prognosis in rectal cancer patients undergoing neoadjuvant therapy

Table 1 Included studies with the main outcome measures

Ref.	Type of study	Measure of muscle mass	Definition of sarcopenia	CT	Inclusion criteria	Exclusion criteria	Pts age	Mean outcome	Follow-up (mo)	Results
Berkel et al[22], 2019	Retrospective	TPA and TAMA at L3 and both the superior and inferior border of L4 (+ measurement of skeletal muscle radiation attenuation)	Normalized TPA or TAMA at each level below the median (males and females)	After NCRT	cT3 or cT4 (CRM < 1 mm) and/or cN2 rectal cancer undergoing NCRT	No preoperative CT scan or of poor quality	99; 66 (40-81)	Correlation between TAMA radiation attenuation and OS	Median: 32.9 (range: 19.4-51.1)	Sarcopenia (at TAMA L4 inferior) correlated to OS
Choi et al[23], 2018	Retrospective	Skeletal muscle index at L3 level	SMI < 52.4 cm2/m2 for male and 38.5 cm2/m2 for female	Before NCRT	cT ≥ 3 or cN ≥ 1 rectal cancer undergoing NCRT	Metastasis/recurrence. No CT at initial diagnosis	188; 61.3 (27-84)	Correlation between SMI and OS and DFS	Median: 52 (range: 5-91)	Worse OS in sarcopenic patients
Chung et al[24], 2020	Retrospective	Skeletal muscle index at L3 level	SMI < 52.4 cm2/m2 for male and < 38.5 cm2/m2 for female	Before and after NCRT	Locally advanced non metastatic rectal cancer undergoing NCRT	Not reported	93	Correlation between SMI and skeletal muscle loss during NCRT and OS and DFS	Not found	Worse 5-yr OS in sarcopenic pts after NCRT. Worse OS in pts with severe muscle loss during NCRT. CT4 independent risk factor for severe muscle loss
De Nardi et al[25], 2020	Retrospective	Skeletal muscle index at L3 level	SMI < 52 cm2/m2 for male and < 42 cm2/m2 for female	Before and after NCRT	cT ≥ 3 and N+ cancers undergoing NCRT	Not reported	52; 63 (32-79)	Correlation between skeletal muscle change during NCRT and OS and DFS	Median: 56 (range: 32-8)	Worse DFS in pts with SML > 2%. In stage II subgroup, worse DFS in SML > 2% or > 5%
Fukuoka et al[26], 2019	Retrospective	Psoas muscle index at the level of the navel	No definition	Before and after NCRT or NAC	cT3N+ rectal cancer undergoing NCRT or NAC	Distant metastasis. History of other malignancies	47; 66 (27-88)	Correlation between change in PMI during neoadjuvant treatment and OS and DFS	Median: 24.1	Worse OS and DFS in patients with PMI decrease > 10%
Levolger et al[27], 2018	Retrospective	Skeletal muscle index at L3 level	SMI < 52 cm2/m2 for male and < 39.5 cm2/m2 for female	Before and after NCRT	cT3 and cT4 rectal cancer and/or cN+ undergoing NCRT	Not reported	12261 (53-66.3)	Correlation between change in skeletal muscle mass during NCRT and OS, DFS, metastases	Median: 41 (range: 26-62)	Lower SMI in patients with cT4 tumors than cT3. SMI variation associated to worse DFS and metastases
Park et al[28], 2018	Retrospective	Skeletal muscle index at L3 level	SMI < 55 cm2/m2 for male and < 39 cm2/m2 for female	Before NCRT	> 65-yr-old pts with rectal cancer undergoing NCRT	RT or CT alone	30; 72 (66-87)	Correlation between sarcopenia and OS and DFS	Median: 98.2 (range 73.5-122.8)	Worse OS and DFS in sarcopenic patients
Takeda et al[29], 2018	Retrospective	Skeletal muscle index at L3 level	SMI < 45 cm2/m2 for male and 33.8 cm2/m2 for female	Before NCRT	cII or cIII advanced rectal cancer undergoing NCRT	Lack of baseline CT scan	144. Sarcopenic: 65 (42-81). Not sarcopenic: 60 (32-65)	Correlation between sarcopenia and OS and DFS	Median: 67 (range: 5.7-137.1)	Worse OS and DFS in sarcopenic patients

TPA: Total psoas area; TAMA: Total abdominal muscle area; c: Clinical; NCRT: Neoadjuvant chemo-radiotherapy; NAC: Neoadjuvant chemotherapy; SMI: Skeletal muscle index (cross sectional skeletal muscle area normalized by the square of the height); PMI: Psoas muscle index; L3: Third lumbar vertebra; L4: Fourth lumbar vertebra; OS: Overall survival; DFS: Disease free survival; SML: Skeletal muscle loss; CT: Computed tomography.