Ketogenic and low-sugar diets for patients with cancer: perceptions and practices of medical oncologists in Canada.

PURPOSE: Many patients with cancer are interested in complementary therapies, including strategies such as reduced carbohydrate diets. Guidelines regarding the use of these diets during cancer treatment are lacking; therefore, we aimed to explore the perceptions and practices of medical oncologists in Canada regarding low-sugar and ketogenic diets. METHOD: A cross-sectional, online multiple-choice survey was distributed to 206 Canadian medical oncologists. Questions explored frequency of patient interactions, oncologist perceptions of efficacy, advice given to patients, and concerns about side effects related to reduced carbohydrate diets. RESULTS: Responses were received from 57 medical oncologists in seven of thirteen provinces and territories, with an overall response rate of 28%. Forty-nine percent of respondents were asked at least weekly about a low-sugar diet, and 9% about the ketogenic diet. Eighty-five percent supported the use of a low-added sugar diet in patients with diabetes or hyperglycemia, while conversely 87% did not support the use of a ketogenic diet for any of their patients undergoing active cancer treatment. Respondents felt either that a ketogenic diet was not effective (31%) or that the effect on cancer outcomes was unknown (69%). Ninety-six percent of respondents had concerns about a ketogenic diet for patients receiving active cancer treatment. CONCLUSION: The role of reduced carbohydrate diets during cancer treatment is topical. Canadian oncologists are particularly reluctant to support a ketogenic diet for patients on active cancer treatment, with concerns about side effects and unknown efficacy. There may be a role for continuing medical education and institutional guidelines to inform these discussions with patients.

Call for standardization in assessment and reporting of muscle and adipose change using computed tomography analysis in oncology: A scoping review.

Investigators are increasingly measuring skeletal muscle (SM) and adipose tissue (AT) change during cancer treatment to understand impact on patient outcomes. Recent meta-analyses have reported high heterogeneity in this literature, representing uncertainty in the resulting estimates. Using the setting of palliative-intent chemotherapy as an exemplar, we aimed to systematically summarize the sources of variability among studies evaluating SM and AT change during cancer treatment and propose standards for future studies to enable reliable meta-analysis. Studies that measured computed tomography-defined SM and/or AT change in adult patients during palliative-intent chemotherapy for solid tumours were included, with no date or geographical limiters. Of 2496 publications screened by abstract/title, 83 were reviewed in full text and 38 included for extraction, representing 34 unique cohorts across 8 tumour sites. The timing of baseline measurement was frequently defined as prior to treatment, while endpoint timing ranged from 6 weeks after treatment start to time of progression. Fewer than 50% specified the actual time interval between measurements. Measurement error was infrequently discussed (8/34). A single metric (cm2 /m2 , cm2 or %) was used to describe SM change in 18/34 cohorts, while multiple metrics were presented for 10/34 and no descriptive metrics for 6/34. AT change metrics and sex-specific reporting were available for 10/34 cohorts. Associations between SM loss and overall survival were evaluated in 24 publications, with classification of SM loss ranging from any loss to >14% loss over variable time intervals. Age and sex were the most common covariates, with disease response in 50% of models. Despite a wealth of data and effort, heterogeneity in study design, reporting and statistical analysis hinders evidence synthesis regarding the severity and outcomes of SM and AT change during cancer treatment. Proposed standards for study design include selection of homogenous cohorts, clear definition of baseline/endpoint timing and attention to measurement error. Standard reporting should include baseline SM and AT by sex, actual scan interval, SM and AT change using multiple metrics and visualization of the range of change observed. Reporting by sex would advance understanding of sexual dimorphism in SM and AT change. Evaluating the impact of tissue change on outcomes requires adjustment for relevant covariates and concurrent disease response. Adoption of these standards by researchers and publishers would alter the current paradigm to enable meta-analysis of future studies and move the field towards meaningful application of SM and AT change to clinical care.

Muscle and Adipose Wasting despite Disease Control: Unaddressed Side Effects of Palliative Chemotherapy for Pancreatic Cancer.

Muscle and adipose wasting during chemotherapy for advanced pancreatic cancer (aPC) are associated with poor outcomes. We aimed to quantify the contributions of chemotherapy regimen and tumour progression to muscle and adipose wasting and evaluate the prognostic value of each tissue loss. Of all patients treated for aPC from 2013-2019 in Alberta, Canada (n = 504), computed-tomography (CT)-defined muscle and adipose tissue index changes (∆SMI, ∆ATI, cm2/m2) were measured for patients with CT images available both prior to and 12 ± 4 weeks after chemotherapy initiation (n = 210). Contributions of regimen and tumour response to tissue change were assessed with multivariable linear regression. Survival impacts were assessed with multivariable Cox's proportional hazards models. Tissue changes varied widely (∆SMI: -17.8 to +7.3 cm2/m2, ∆ATI: -106.1 to +37.7 cm2/m2) over 116 (27) days. Tumour progression contributed to both muscle and adipose loss (-3.2 cm2/m2, p < 0.001; -12.4 cm2/m2, p = 0.001). FOLFIRINOX was associated with greater muscle loss (-1.6 cm2/m2, p = 0.013) and GEM/NAB with greater adipose loss (-11.2 cm2/m2, p = 0.002). The greatest muscle and adipose losses were independently associated with reduced survival (muscle: HR 1.72, p = 0.007; adipose: HR 1.73, p = 0.012; tertile 1 versus tertile 3). Muscle and adipose losses are adverse effects of chemotherapy and may require regimen-specific management strategies.