Adjusted Skeletal Muscle Index (aSMI) correlates with outcome in metastatic Renal Cancer Cell (mRCC) patients (pts) treated with first line (1L) immunotherapy (IT)

Background: Sarcopenia, loss of muscle mass and strength, is a hallmark of cancer and may impact on pts outcome. Skeletal Muscle Index (SMI) represents muscle mass quantity divided by height squared (h2), derived from Computed tomography (CT) images. mRCC has heterogeneous behavior and, with different 1L treatment options, biomarkers may be useful to optimize tailored therapy. Body composition (BC) and inflammatory parameters (INF) are being studied for this reason. Methods: We conducted a multicentric retrospective analysis on mRCC pts with intermediate and high risk International mRCC Database Consortium (IMDC) score treated in 1L with tyrosine kinase inhibitors (TKI) (25 pts) or immunotherapy (IT) within the Italian Expanded Access Program with Ipilimumab and Nivolumab (32 pts). General characteristics, BC and INF were recorded. CT images at baseline and at I revaluation were analyzed for muscle and adipose tissue. aSMI was calculated considering skeletal muscle mass with subtraction of infiltrating fat divided by h2. Results: 21,1% of pts were female (F), more than 70% mRCC at diagnosis, clear cell and ECOG 0. 57,9% had nefrectomy. At diagnosis of mRCC: median (m) BMI was 24,4, m age 61 years (range 25-79), m Neutrophils/lymphocytes ratio (NLR) 2,73 and m Systemic Immune- Inflammation Index (SII) 931,4. Sarcopenic pts defined with Martin et al 2013 were 20% of TKI and 25,8% of IT. m SMI for male (M) was 50,68 (range 32,77-74,54), for F 46,99 (range 35,81-74,26). m aSMI for M was 41,91 (range 26,33-71,59), for F 33,79 (range 29,99-56,05). SMI decreased ⩾5% in 64% of TKI and 53,6% of IT (p=0,58). m Overall Survival (mOS) for TKI was 12,2 months (mo) and 35,13 mo for IT. m Progression Free Survival (mPFS) for TKI was 7,47 mo and 11,12 mo for IT. OS was not significantly different neither in TKI nor IT for BMI ⩾25 vs <25, SII above vs below m, SMI according m and sex, SMI according to Martin, total and subcutaneous adipose tissue according m and sex. Conversely, better OS was observed with low basal NLR (< m) for TKI (p=0,008) and IT (p=0,018) and with high aSMI according m and sex in IT (0,039), but not in TKI (p=0,774). Conclusions: INF and BC could help to optimize tailored 1L treatment for mRCC. The role of NLR was already known, but, in particular for pts receiving IT, better muscle quality and quantity expressed with aSMI seems to have a favorable impact on outcome. Further studies are needed, but these results look of interest.