This is a pilot trial using 18F-FDG PET and DXA scans to determine whether these investigations are objective tools to assess cachexia.

This pilot study will establish the differences in BAT uptake of 18F-FDG in cachectic and non-cachectic cancer patients using PET imaging.

Patients willbe assessed for sarcopenia using a dual energy X-ray absorptiometry or bone densitometry scan (DXA). Given the variables which may affect uptake of BAT in cancer patients, this study will standardise patient preparation and PET scan procedure in order to obtain the most reliable assessment of BAT activity in all patients on study.

It is hypothesisd that use of this PET imaging technique, which is part of standard care to assess cancer progression, may assist clinicians in early identification of metabolic changes in a patient, with potential for early intervention and utility in monitoring success of treatments of cachexia.

A total of 40 patients will be evaluated, 20 patients with advanced/metastatic colorectal, non-small cell lung cancer (NSCLC) or pancreatic cancer without cachexia, and 20 patients with advanced/metastatic colorectal, non-small cell lung cancer (NSCLC), or pancreatic cancer with documented cachexia, all of whom are referred for standard of care 18F-FDG PET scans.

Inclusion Criteria:

• Patients with malignant disease;
• ECOG Performance score of 0-2;
• Age ≥ 18 years;
• Life expectancy of >4 months at screening;
• Cachexia patient group only: Fulfils diagnostic criteria for cachexia: unintentional weight loss more than 5% over the previous 6 months, or more than 2% in individuals with a decreased body-mass index of <20kg/m2, or skeletal muscle wasting (sarcopenia).

Exclusion Criteria:

Patients with uncontrolled Diabetes Mellitus;

• Psychological unstable persons presumed unfit to perform the investigations;
• Persons unable to lie or sit still for 1-2 hours;
• Pregnant patients;
• Patients who received high doses of radiotherapeutic radiation of the neck and/or upper chest in their medical history limiting nutritional intake;
• Patients who are receiving any chemotherapeutic agents which is limiting nutritional intake;
• Persons that received cervical or thoracic sympathectomy or have a nerve dysfunction which is likely to influence sympathetic nerves;
• The use of medication that influences the sympathetic nerve system: ß-blockers, α-blockers, central anti-hypertensives, certain anti-depression drugs (MAO inhibitors, tricyclic antidepressives), reserpine, cocaine, calcium channel blockers, labetalol, and certain tranquillizers (fenothiazines).

Cohort data will be shared via journal and conference presentations