Michael B. Sawyer

Cancer Cachexia in the Age of Obesity: Skeletal Muscle Depletion Is a Powerful Prognostic Factor, Independent of Body Mass Index

PURPOSE Emerging evidence suggests muscle depletion predicts survival of patients with cancer. PATIENTS AND METHODS At a cancer center in Alberta, Canada, consecutive patients with cancer (lung or GI; N = 1,473) were assessed at presentation for weight loss history, lumbar skeletal muscle index, and mean muscle attenuation (Hounsfield units) by computed tomography (CT). Univariate and multivariate analyses were conducted. Concordance (c) statistics were used to test predictive accuracy of survival models. RESULTS Body mass index (BMI) distribution was 17% obese, 35% overweight, 36% normal weight, and 12% underweight. Patients in all BMI categories varied widely in weight loss, muscle index, and muscle attenuation. Thresholds defining associations between these three variables and survival were determined using optimal stratification. High weight loss, low muscle index, and low muscle attenuation were independently prognostic of survival. A survival model containing conventional covariates (cancer diagnosis, stage, age, performance status) gave a c statistic of 0.73 (95% CI, 0.67 to 0.79), whereas a model ignoring conventional variables and including only BMI, weight loss, muscle index, and muscle attenuation gave a c statistic of 0.92 (95% CI, 0.88 to 0.95; P < .001). Patients who possessed all three of these poor prognostic variables survived 8.4 months (95% CI, 6.5 to 10.3), regardless of whether they presented as obese, overweight, normal weight, or underweight, in contrast to patients who had none of these features, who survived 28.4 months (95% CI, 24.2 to 32.6; P < .001). CONCLUSION CT images reveal otherwise occult muscle depletion. Patients with cancer who are cachexic by the conventional criterion (involuntary weight loss) and by two additional criteria (muscle depletion and low muscle attenuation) share a poor prognosis, regardless of overall body weight.

Sarcopenia as a Determinant of Chemotherapy Toxicity and Time to Tumor Progression in Metastatic Breast Cancer Patients Receiving Capecitabine Treatment

Purpose: Body composition has emerged as an important prognostic factor in cancer patients. Severe depletion of skeletal muscle (sarcopenia) and, hence, of overall lean body mass may represent an occult condition in individuals with normal or even high body weight. Sarcopenia has been associated with poor performance status, 5-fluorouracil toxicity, and shortened survival in cancer patients. Here, we prospectively studied patients with metastatic breast cancer receiving capecitabine treatment in order to determine if sarcopenia was associated with a higher incidence of toxicity and a shorter time to tumor progression (TTP). Experimental Design: Fifty-five women with metastatic breast cancer resistant to anthracycline and/or taxane treatment were included. Skeletal muscle cross-sectional area at the third lumbar vertebra was measured by computerized tomography, and sarcopenia was defined using a previously published cutoff point. Toxicity was assessed after cycle 1 of treatment, and TTP was determined prospectively. Results: Approximately 25% of patients were classified as sarcopenic, and this feature was seen in normal weight, overweight, and obese individuals. Toxicity was present in 50% of sarcopenic patients, compared with only 20% of nonsarcopenic patients (P = 0.03), and TTP was shorter in sarcopenic patients (101.4 days; confidence interval, 59.8-142.9) versus nonsarcopenic patients (173.3 days; confidence interval, 126.1-220.5; P = 0.05). Conclusion: Sarcopenia is a significant predictor of toxicity and TTP in metastatic breast cancer patients treated with capecitabine. Our results raise the potential use of body composition assessment to predict toxicity and individualize chemotherapy dosing.

Muscle Wasting Is Associated With Mortality in Patients With Cirrhosis

BACKGROUND & AIMS Sarcopenia, defined as a low level of muscle mass, occurs in patients with cirrhosis. We assessed its incidence among cirrhotic patients undergoing evaluation for liver transplantation to investigate associations between sarcopenia and mortality and prognosis. METHODS We studied 112 patients with cirrhosis (78 men; mean age, 54 ± 1 years) who were consecutively evaluated for liver transplantation and had a computed tomography scan at the level of the third lumbar (L3) vertebrae to determine the L3 skeletal muscle index; sarcopenia was defined by using previously published, sex-specific cutoffs. RESULTS Of the patients studied, 45 (40%) had sarcopenia. Univariate Cox analysis associated mortality with ascites (hazard ratio [HR], 2.12; P = .04), encephalopathy (HR, 1.99; P = .04), level of bilirubin (HR, 1.007; P < .01), international normalized ratio (HR, 7.69; P < .001), level of creatinine (HR, 1.01; P = .005), level of albumin (HR, 94; P = .008), serum level of sodium (HR, 89; P < .001), Model for End-Stage Liver Disease (MELD) score (HR, 1.14; P < .01), Child-Pugh score (HR, 2.84; P < .001), and sarcopenia (HR, 2.18; P = .006). By multivariate Cox analysis, only Child-Pugh (HR, 1.85; P = .04) and MELD scores (HR, 1.08; P = .001) and sarcopenia (HR, 2.21; P = .008) were independently associated with mortality. The median survival time for patients with sarcopenia was 19 ± 6 months, compared with 34 ± 11 months among nonsarcopenia patients (P = .005). There was a low level of correlation between L3 skeletal muscle index and MELD (r = -0.07; P = .5) and Child-Pugh scores (r = -0.14; P = .1). CONCLUSIONS Sarcopenia is associated with mortality in patients with cirrhosis. It does not correlate with the degree of liver dysfunction evaluated by using conventional scoring systems. Scoring systems should include evaluation of sarcopenia to better assess mortality among patients with cirrhosis.

Body Composition as an Independent Determinant of 5-Fluorouracil–Based Chemotherapy Toxicity

Purpose: Evidence suggests that lean body mass (LBM) may be useful to normalize doses of chemotherapy. Data from a prospective study were used to determine if the highest doses of 5-fluorouracil (5-FU) per kilogram LBM would be associated with dose-limiting toxicity in stage II/III colon cancer patients treated with 5-FU and leucovorin. Experimental Design: Toxicity after cycle 1 was graded according to National Cancer Institute Common Toxicity Criteria, version 2.0. Muscle tissue was measured by computerized tomography. An extrapolation to the LBM compartment of the whole body was employed. Results: Mean values of 5-FU/LBM of the entire population were different in terms of presence or absence of toxicity (P = 0.036). A cut point of 20 mg 5-FU/kg LBM seemed to be a threshold for developing toxicity (P = 0.005). This observation was pertinent to women (odds ratio, 16.73; P = 0.021). Women in this study had a relatively low proportion of LBM relative to their body surface area. Conclusion: Our study shows that low LBM is a significant predictor of toxicity in female patients administered 5-FU using the convention of dosing per unit of body surface area. We conclude that variation in toxicity between females and males may be partially explained by this feature of body composition.

Nucleoside anticancer drugs: the role of nucleoside transporters in resistance to cancer chemotherapy.

The clinical efficacy of anticancer nucleoside drugs depends on a complex interplay of transporters mediating entry of nucleoside drugs into cells, efflux mechanisms that remove drugs from intracellular compartments and cellular metabolism to active metabolites. Nucleoside transporters (NTs) are important determinants for salvage of preformed nucleosides and mediated uptake of antimetabolite nucleoside drugs into target cells. The focus of this review is the two families of human nucleoside transporters (hENTs, hCNTs) and their role in transport of cytotoxic chemotherapeutic nucleoside drugs. Resistance to anticancer nucleoside drugs is a major clinical problem in which NTs have been implicated. Single nucleotide polymorphisms (SNPs) in drug transporters may contribute to interindividual variation in response to nucleoside drugs. In this review, we give an overview of the functional and molecular characteristics of human NTs and their potential role in resistance to nucleoside drugs and discuss the potential use of genetic polymorphism analyses for NTs to address drug resistance.

Low body mass index and sarcopenia associated with dose-limiting toxicity of sorafenib in patients with renal cell carcinoma

BACKGROUND Patients with severe depletion of skeletal muscle (sarcopenia) are prone to dose-limiting toxicity (DLT) during fluoropyrimidine therapy. We hypothesized that sarcopenia may also predict toxicity of targeted therapy drugs. MATERIALS AND METHODS Metastatic renal cell cancer (RCC) patients (n = 55) received sorafenib 400 mg b.i.d. Weight, height and skeletal muscle cross-sectional area at the third lumbar vertebra were measured by computed tomography (CT). Toxicity was assessed. RESULTS DLT occurred in 22% of patients overall, of which three-quarters were dose reductions to 400 mg and the remainder entailed termination of treatment. DLT was most common (41%) in sarcopenic patients whose body mass index (BMI) was <25 kg/m(2) and least common (13%) in patients who were not sarcopenic and/or overweight or obese (P = 0.03). Toxicity was especially prevalent in sarcopenic male patients with BMI < 25, with 71% of men with these characteristics being unable to continue treatment at 800 mg/day. By contrast, only 5% of male patients whose muscle index was above the cut-off for sarcopenia and only 11% of male patients whose BMI was >25 experienced a DLT. CONCLUSION BMI < 25 kg/m(2) with diminished muscle mass is a significant predictor of toxicity in metastatic RCC patients treated with sorafenib.

Association of Skeletal Muscle Wasting With Treatment With Sorafenib in Patients With Advanced Renal Cell Carcinoma: Results From a Placebo-Controlled Study

PURPOSE Effects of specific antineoplastic therapies on progression of cancer-associated wasting remain uncharacterized. We selected a targeted therapy, sorafenib, because of its reported association with weight loss. PATIENTS AND METHODS Patients with metastatic renal cell cancer (RCC) who were resistant to standard therapy (N = 80) received sorafenib 400 mg twice daily or placebo in a randomized, double-blinded clinical trial. Computed tomography image analysis, which has high precision and specificity for evaluation of specific muscles and adipose tissues, was used to define change in total skeletal muscle and adipose tissue. Results At inclusion, 51% of patients were overweight or obese (ie, body mass index [BMI] > 25 kg/m(2)). Only 5% were underweight. Advanced muscle wasting (ie, sarcopenia) was present in 72% of patients with BMI less than 25 and in 34% of those with a BMI greater than 25. Patients received placebo for an average of 6 months and received sorafenib for 1 year. Patients in the placebo group had stable body weight during 6 months (0.8 kg +/- 0.7 kg), with no significant alteration of muscle or fat. Patients who received sorafenib lost 2.1 kg +/- 0.6 kg (P < .01) in 6 months and lost 4.2 kg +/- 0.7 kg (P < .01) by 1 year. Sorafenib-treated patients lost skeletal muscle progressively at 6 months (decrease of 4.9%; P < .01) and 12 months (decrease of 8.0%; P < .01). CONCLUSION Sarcopenia is prevalent in patients with metastatic RCC and is an occult condition in patients with normal or high BMI. Muscle loss is specifically exacerbated by sorafenib, consistent with the evidence for a role of kinases in regulating muscle mass. Muscle loss is a sorafenib adverse effect that may relate to asthenia, fatigue, and physical disability.

Urine metabolite analysis offers potential early diagnosis of ovarian and breast cancers.

Purpose: Metabolomics is a new, rapidly expanding field dedicated to the global study of metabolites in biological systems. In this article metabolomics is applied to find urinary biomarkers for breast and ovarian cancer. Experimental Design: Urine samples were collected from early- and late-stage breast and ovarian cancer patients during presurgical examinations and randomly from females with no known cancer. After quantitatively measuring a set of metabolites using nuclear magnetic resonance spectroscopy, both univariate and multivariate statistical analyses were employed to determine significant differences. Results: Metabolic phenotypes of breast and ovarian cancers in comparison with normal urine and with each other revealed significance at Bonferroni-corrected significance levels resulting in unique metabolite patterns for breast and ovarian cancer. Intermediates of the tricarboxylic acid cycle and metabolites relating to energy metabolism, amino acids, and gut microbial metabolism were perturbed. Conclusions: The results presented here illustrate that urinary metabolomics may be useful for detecting early-stage breast and ovarian cancer. Clin Cancer Res; 16(23); 5835–41. ©2010 AACR.

The potential for treatment with dietary long-chain polyunsaturated n-3 fatty acids during chemotherapy

Dietary intake of long-chain omega-3 (or n-3) polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) can affect numerous processes in the body, including cardiovascular, neurological and immune functions, as well as cancer. Studies on human cancer cell lines, animal models and preliminary trials with human subjects suggest that administration of EPA and DHA, found naturally in our diet in fatty fish, can alter toxicities and/or activity of many drugs used to treat cancer. Multiple mechanisms are proposed to explain how n-3 PUFA modulate the tumor cell response to chemotherapeutic drugs. n-3 PUFA are readily incorporated into cell membranes and lipid rafts, and their incorporation may affect membrane-associated signaling proteins such as Ras, Akt and Her-2/neu. Due to their high susceptibility to oxidation, it has also been proposed that n-3 PUFA may cause irreversible tumor cell damage through increased lipid peroxidation. n-3 PUFA may increase tumor cell susceptibility to apoptosis by altering expression or function of apoptotic proteins, or by modulating activity of survival-related transcription factors such as nuclear factor-kappaB. Some studies suggest n-3 PUFA may increase drug uptake or even enhance drug activation (e.g., in the case of some nucleoside analogue drugs). Further research is warranted to identify specific mechanisms by which n-3 PUFA increase chemotherapy efficacy and to determine the optimal cellular/membrane levels of n-3 PUFA required to promote these mechanisms, such that these fatty acids may be prescribed as adjuvants to chemotherapy.

Central tenet of cancer cachexia therapy: do patients with advanced cancer have exploitable anabolic potential?

BACKGROUND Skeletal muscle wasting is considered the central feature of cachexia, but the potential for skeletal muscle anabolism in patients with advanced cancer is unproven. OBJECTIVE We investigated the clinical course of skeletal muscle wasting in advanced cancer and the window of possible muscle anabolism. DESIGN We conducted a quantitative analysis of computed tomography (CT) images for the loss and gain of muscle in population-based cohorts of advanced cancer patients (lung, colorectal, and pancreas cancer and cholangiocarcinoma) in a longitudinal observational study. RESULTS Advanced-cancer patients (n = 368; median survival: 196 d) had a total of 1279 CT images over the course of their disease. With consideration of all time points, muscle loss occurred in 39% of intervals between any 2 scans. However, the overall frequency of muscle gain was 15.4%, and muscle was stable in 45.6% of intervals between any 2 scans, which made the maintenance or gain of muscle the predominant behavior. Multinomial logistic regression revealed that being within 90 d (compared with >90 d) from death was the principal risk factor for muscle loss (OR: 2.67; 95% CI: 1.45, 4.94; P = 0.002), and muscle gain was correspondingly less likely (OR: 0.37; 95% CI: 0.20, 0.69; P = 0.002) at this time. Sex, age, BMI, and tumor group were not significant predictors of muscle loss or gain. CONCLUSIONS A window of anabolic potential exists at defined early phases of the disease trajectory (>90 d survival), creating an opportunity for nutritional intervention to stop or reverse cachexia. Cancer patients within 90 d of death have a low likelihood of anabolic potential.