Background:Body composition is an important predictor of drug toxicity and outcome. Ipilimumab (Ipi), a monoclonal antibody used to treat metastatic melanoma, has specific toxicities. No validated biomarkers that predict Ipi toxicity and efficacy exist. Also, the impact of Ipi on body composition has not been established.Methods:Patients with metastatic melanoma treated with Ipi between 2009 and 2015 were included. Body composition was assessed by computed tomography at baseline and after four cycles of Ipi. Sarcopenia and low muscle attenuation (MA) were defined using published cut-points. All adverse events (AEs) and immune-related AEs (irAEs) were recorded (Common Terminology Criteria For Adverse Event V.4.0).Results:Eighty-four patients were included in this study (62% male, median age 54 years). At baseline, 24% were sarcopenic and 33% had low MA. On multivariate analysis, sarcopenia and low MA were significantly associated with high-grade AEs (OR=5.34, 95% CI: 1.15–24.88, P=0.033; OR=5.23, 95% CI: 1.41–19.30, P=0.013, respectively), and low MA was associated with high-grade irAEs (OR=3.57, 95% CI: 1.09–11.77, P=0.036). Longitudinal analysis (n=59) revealed significant reductions in skeletal muscle area (SMA), total body fat-free mass, fat mass (all P<0.001) and MA (P=0.030). Mean reduction in SMA was 3.3%/100 days (95% CI: −4.48 to −1.79%, P<0.001). A loss of SMA ⩾7.5%/100 days (highest quartile) was a significant predictor of overall survival in multivariable Cox regression analysis (HR: 2.1, 95% CI: 1.02–4.56, P=0.046).Conclusions:Patients with sarcopenia and low MA are more likely to experience severe treatment-related toxicity to Ipi. Loss of muscle during treatment was predictive of worse survival. Treatments to increase muscle mass and influence outcome warrant further investigation.

Since its introduction in the 1970s, computed tomography (CT) has revolutionized diagnostic decision-making. One of the major concerns associated with the widespread use of CT is the associated increased radiation exposure incurred by patients. The link between ionizing radiation and the subsequent development of neoplasia has been largely based on extrapolating data from studies of survivors of the atomic bombs dropped in Japan in 1945 and on assessments of the increased relative risk of neoplasia in those occupationally exposed to radiation within the nuclear industry. However, the association between exposure to low-dose radiation from diagnostic imaging examinations and oncogenesis remains unclear. With improved technology, significant advances have already been achieved with regards to radiation dose reduction. There are several dose optimization strategies available that may be readily employed including omitting unnecessary images at the ends of acquired series, minimizing the number of phases acquired, and the use of automated exposure control as opposed to fixed tube current techniques. In addition, new image reconstruction techniques that reduce radiation dose have been developed in recent years with promising results. These techniques use iterative reconstruction algorithms to attain diagnostic quality images with reduced image noise at lower radiation doses.

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Percutaneous splenic biopsy and drainage are relatively safe and accurate procedures. The risk of major complication (1.3%) following percutaneous splenic biopsy does not exceed that of other solid intra-abdominal organ biopsies, and it has less morbidity and mortality than splenectomy. Both computed tomography and ultrasound can be used to provide image guidance for biopsy and drainage. The safety profile of fine-needle aspiration cytology is better than core needle biopsy, but core biopsy has superior diagnostic accuracy.