BACKGROUND: FIGHTDIGO study has shown the feasibility of handgrip strength (HGS) measurements in 201 consecutive digestive cancer patients undergoing chemotherapy. OBJECTIVE: This study focuses on a secondary aim of FIGHTDIGO study: the relationship between muscle mass and HGS. DESIGN: Two consecutive bilateral measures of HGS were performed using a Jamar dynamometer before the start of each chemotherapy. The highest value was chosen for final evaluation. Dynapenia (loss of muscle strength) was defined as HGS < 30 kg (men) and < 20 kg (women). Muscle mass was measured at lumbar level (L3) on Computed Tomography (CT) scans performed less than 3 weeks before or after the measurement of HGS. Muscle mass loss was defined by skeletal muscle index (SMI) < 53 cm2 /m2 (in men with a body mass index (BMI)> 25 kg/m2 ), < 43 cm2 /m2 (in men with a BMI < 25 kg/m2 ), and < 41 cm2 /m2 (in women regardless of BMI). Sarcopenia was defined by the association of a dynapenia and a loss of muscle mass. RESULTS: A total of 150 patients were included in this analysis (mean age: 65.6 ± 10.9 years, 87 males (58%), colorectal cancer (47.3%), metastatic stage (76.7%)). A total of 348 CT scans were evaluated. For the 348 measurements, mean SMI and HGS were 41.8 ± 8.7 cm2 /m2 and 32.1 ± 11.0 kg, respectively. Muscle mass loss, dynapenia, or sarcopenia were reported at least once, in 120 (80%), 45 (30%), and 30 (20%) patients, respectively. SMI was significantly correlated with HGS (Pearson coefficient = 0.53, P < 0.0001). At concordance analysis, 188 dyad SMI/HGS (54%) were in agreement (Kappa = 0.14 [95% CI, 0.07-0.21]). CONCLUSION: Correlation between the measurements of HGS and SMI is strong but the concordance between dynapenia and muscle mass loss is poor. Further studies should be performed to confirm the diagnostic thresholds, and to study the chronology of dynapenia and loss of muscle mass.