Rationale: One of the greatest challenges in the field of cancer treatment is cachexia, a multifactorial syndrome characterized by substantial loss of body weight (muscle and fat mass), leading to progressive functional impairment. Cancer cachexia significantly impairs quality of life and survival as well as treatment outcome. Despite its considerable relevance for the prognosis of cancer patients, the diagnosis of cachexia is problematic. The current consensus definition of cancer cachexia is based on weight loss over the last six months. In practice, this is assessed by subjective reporting by the patient, which is subject to error and bias. Novel technologies enable accurate, standardized, and objective assessment of body weight and physical activity by newly diagnosed cancer patients in the home situation. Because of the increasing implementation of neo-adjuvant treatment strategies that offer an extended time-window for the collection of these data, there is a great opportunity to use this information in risk analyses by treating physicians, optimization of pre-habilitation programs, and in the shared-decision making process with the patient.

Objective: The central aim of the 'Patient-Recorded Indexing MeasurementS' (PRIMS) study is to improve the accuracy of the diagnosis of cachexia in patients with cancer. This aim will be achieved by focusing on two objectives. The primary objectives are to compare self-reported and objectively measured pre-treatment weight change. The secondary objectives are to define host phenotypes and to investigate longitudinal associations between body weight and physical activity patterns.

Study design: Explorative pilot study

Study population: Patients ≥18 years old undergoing curative-intent chemotherapy or surgery for cancer. Patients will be included in two referral centers specialized in treatment of patients with upper gastrointestinal, hepatobiliary, pancreatic, colorectal, and ovarian cancer.

Main study parameters/endpoints: The primary endpoint is body weight change over time. Objectively measured body weight will be compared to subjectively reported body weight change. Their respective association with treatment-related adverse events and survival will be investigated. Survival will be calculated from date of start of treatment until death. Chemotherapy related adverse event will be recorded using the Common Terminology Criteria for Adverse Events. Postoperative adverse events will be scored according to the Clavien-Dindo classification.

Secondary endpoints: The secondary endpoints will be the association between other cachexia-related parameters that are investigated in the study and adverse events / survival. Other parameters include physical activity over time, using accelerometry, baseline physical assessment, anthropometric measurements, body composition, and laboratory results. Besides this, other endpoints that will be assessed are disease-free survival (calculated from the first day of treatment until first recurrence) and response to chemotherapy according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria.

Patients undergoing curative-intent chemotherapy or surgery for cancer will be included. All types of cancer might be included. To date, the two participating centers are referral hospitals focused on the care of hepatobiliary, pancreatic, upper-GI, colorectal, and ovarian cancer.

Upon informed consent, patients will undergo extensive pre-treatment screening. The screening consists of physical assessment and anthropometric measurements. The physical assessment consists of a modified steep-ramp test, 30-second chair stand test, handgrip strength, timed-up-and-go-test, and 2-minute walk test. For anthropometric measurements the study personnel will measure current BMI (kg/m^2), waist circumference (cm), upper arm circumference (cm), triceps skinfold (mm), and wrist circumference (cm). Upper arm muscle and fat area (cm^2) will be calculated based on triceps skinfold and upper arm circumference.

All measurements will be performed by a trained physiotherapist or nurse practitioner, if available. The study team will also be trained to perform measurements.

Moreover, body composition will be measured at baseline and after treatment. Body composition will be assessed at the level of the third lumbar level (L3) where both processi transversi are visible. Body composition analysis will be performed using an automated segmentation algorithm (MosaMatic (TM) ). The assessed areas are skeletal muscle, visceral adipose tissue, and subcutaneous adipose tissue. For each area indices (cm^2/m^2) corrected for body length and radiation attenuation (HU) will be measured.

Laboratory results include, but are not limited to, C-reactive protein (CRP) (mg/L), lymphocyte count, albumin (g/L), HbA1c, haemoglobin, CRP, TNF-α, interleukin-6, blood lipids, and additional parameters related to inflammation

Then, patients receive a weight scale for daily at-home measurements of body weight and an accelerometer for assessing physical activity. Body weight data will be collected using an electronic weight scale with integrated memory SD cards for automated autonomous storage of data (CE licensed). Physical activity will be monitored through a research grade wrist-worn accelerometer that records movement in three axes as well as body position (sedentary versus standing position). Data on frequency, intensity, and duration of activity will be collected. Activity can be summarized into light, moderate and (very) vigorous activity. Additionally, data on sedentary behavior will be collected.

Monitoring plan for patients treated with chemotherapy:

T0 Start of monitoring: When patients first present at the outpatient clinic, they will receive extensive physical analysis as described above. Additionally, the investigators will collect one blood sample. Patients will receive equipment (weight scale and accelerometer) for at home monitoring. The patient will start using the weight scale daily and wear the accelerometer continuously after screening.

T1: Start of chemotherapy: During chemotherapy, the body weight and physical activity measurements will continue. Patients will use the scale once daily and the accelerometer continuously.

T2: End of chemotherapy: The monitoring will continue until two weeks after chemotherapy.

T3: End of monitoring ( usually 2-3 weeks after completion of chemotherapy). A routine CT-scan to assess the effect of the chemotherapy will be performed. Patients will hand in all equipment to the researcher during regular follow-up.

Body composition measurement on the diagnostic CT-scan will be repeated, as described above.

Monitoring plan for patients treated with surgery:

T0 start of monitoring: When patients first present at the outpatient clinic, they will receive extensive physical analysis as described above. Additionally, the investigators will collect one blood sample. Patients will receive equipment (weight scale and accelerometer) for at home monitoring. The patient will start using the weight scale daily and wear the accelerometer continuously.

T1: Hospital admission:

At the day of admission, the patient will not bring the weight scale and accelerometer to the hospital. Monitoring will be paused for the length of hospital stay for primary surgery.

T2: Discharge from hospital:

At the day of discharge after primary surgery, length of stay at the hospital will be recorded. The patient will be reminded to restart monitoring and use the weight scale daily and wear the accelerometer continuously.

T3: End of monitoring:

During the regular follow-up visit 2-3 weeks after discharge, monitoring will end. Patients will hand in all equipment to the researcher during the regular follow-up visit. Over the course of the oncological follow-up, a routine CT-scan will be performed. Body composition analysis at the L3-level will be repeated as described above.

Outcome measurements:

Outcome measurements are presented in their order of registry.

The first outcome measurement is treatment-related adverse events. During chemotherapy adverse events will be recorded according to the Common Toxicity Criteria version 5.0 (www.eortc.be/services/doc/ctc/). For each adverse event the respective number of cycle, type of adverse event, and grade thereof will be recorded. Moreover, for chemotherapy delay, reason for delay, and dose reduction (including %of dose reduction of the respective drug) will be recorded.

Adverse events after surgery will be recording using the Clavien-Dindo classification up to 30 days after surgery. For each complication, the Clavien-Dindo grade will be recorded. Major complications are defined as ≥III.

Averse events will be recorded by a trained physician.

Treatment response after treatment will be graded based on Response Evaluation Criteria in Solid Tumor (RECIST) after chemotherapy. RECIST-criteria will be scored as 'complete response' , 'partial response', 'stable disease', and 'progressive disease'. The criteria will be scored by the radiologist according to international criteria.

Moreover, pathological outcomes will be recorded for solid tumor using the TNM-classification. This includes the extent of the tumor (T), extent of spread to lymph nodes (N), number of resected lymph nodes and number of positive lymph nodes, metastatic disease (M), resection margin (R), perineural invasion, and vascular invasion. The pathological analysis will be performed according to national guidelines.

Survival and disease-free survival will also be recorded. The follow-up will continue up to five years after the last treatment.

Survival will be calculated from the first day of treatment until death. If available, reason of death will also be recorded.

Disease-free survival is defined from the first day of treatment until first sign of recurrence.

Sample size calculation The sample size calculation was based on the primary objective, which is to assess the agreement of cancer cachexia diagnosis based on self-reported weight loss versus objectively measured weight loss. Assuming a null hypothesis intraclass correlation coefficient (ICC) of 0.75, based on previously published literature, and an expected ICC of 0.65, with a significance level of 0.05 and statistical power of 90%, 270 subjects will be required. With an expected dropout rate of 10%, the total sample size is 300.

Data analysis plan Data analysis will be performed using R in the latest version available at the time of analysis (R Foundation for Statistical Computing, Vienna, Austria).

A short data analysis plan is presented here. For the primary objectives of the study, namely, to detect the agreement of cancer cachexia diagnosis based on self-reported weight versus objectively measured body weight and their respective association with treatment-related adverse events and treatment outcomes, the subjective self-reported weight change over the last six months and objective body weight data before treatment from the digital body weight scale will be used. The association between predictive variables and the occurrence of adverse events will be investigated through univariable and multivariable logistic regression analysis.

Predictive parameters include baseline measurements, body composition measurements, and physical activity. Moreover, the correlation between self-reported pre-treatment weight changes versus objectively measured weight changes will be evaluated.

Dissemination policy Research results, negative or positive, will be submitted for publication in peer-reviewed scientific journals. A writing committee, assigned by the principal investigators, will prepare the manuscripts. Co-authorship is reserved for all who contributed constructively to the study at the discretion of the principal investigators.

Inclusion Criteria:

• Age ≥ 18
• Diagnosed with cancer
• Planned for curative-intent surgery or neo-adjuvant chemotherapy

Exclusion Criteria:

• ASA-classification V,
• severe liver cirrhosis Child grade C,
• end stage renal disease requiring dialysis,
• severe heart disease New York Heart Association class IV,
• chronic obstructive pulmonary disease (COPD) requiring (home)oxygen therapy,
• Patients must be "mobile". They may not be bedridden or in a wheelchair.

Adults, requiring neo-adjuvant chemotherapy or curative-intent surgery for cancer