Patient preferences for whole-body MRI or conventional staging pathways in lung and colorectal cancer: a discrete choice experiment

Abstract

Objectives: To determine the importance placed by patients on attributes associated with whole-body MRI (WB-MRI) and standard cancer staging pathways and ascertain drivers of preference.

Methods: Patients recruited to two multi-centre diagnostic accuracy trials comparing WB-MRI with standard staging pathways in lung and colorectal cancer were invited to complete a discrete choice experiment (DCE), choosing between a series of alternate pathways in which 6 attributes (accuracy, time to diagnosis, scan duration, whole-body enclosure, radiation exposure, total scan number) were varied systematically. Data were analysed using a conditional logit regression model and marginal rates of substitution computed. The relative importance of each attribute and probabilities of choosing WB-MRI-based pathways were estimated.

Results: A total of 138 patients (mean age 65, 61% male, lung n = 72, colorectal n = 66) participated (May 2015 to September 2016). Lung cancer patients valued time to diagnosis most highly, followed by accuracy, radiation exposure, number of scans, and time in the scanner. Colorectal cancer patients valued accuracy most highly, followed by time to diagnosis, radiation exposure, and number of scans. Patients were willing to wait 0.29 (lung) and 0.45 (colorectal) weeks for a 1% increase in pathway accuracy. Patients preferred WB-MRI-based pathways (probability 0.64 [lung], 0.66 [colorectal]) if they were equivalent in accuracy, total scan number, and time to diagnosis compared with a standard staging pathway.

Conclusions: Staging pathways based on first-line WB-MRI are preferred by the majority of patients if they at least match standard pathways for diagnostic accuracy, time to diagnosis, and total scan number.

Key points: • WB-MRI staging pathways are preferred to standard pathways by the majority of patients provided they at least match standard staging pathways for accuracy, total scan number, and time to diagnosis. • For patients with lung cancer, time to diagnosis was the attribute valued most highly, followed by accuracy, radiation dose, number of additional scans, and time in a scanner. Preference for patients with colorectal cancer was similar. • Most (63%) patients were willing to trade attributes, such as faster diagnosis, for improvements in pathway accuracy and reduced radiation exposure.

Keywords: Cancer; Magnetic resonance imaging; Patient preference; Positron emission tomography; Tomography, X-ray computed.

Fig. 1

Flow diagram of participants through the study (May 2015–September 2016)

Fig. 2

Example of a choice set

Fig. 3

Predicted probabilities of choosing an alternate staging pathways in comparison to a default staging pathway (PET-CT plus one additional scan) (lung cancer patients). Description of tests: Default staging pathway (PET-CT plus 1 additional scan) in every case: 30-min time in a scanner, 3 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 1 additional scan, 90% accuracy, no need for whole body and head to be in a scanner. Worst possible test: 60-min time in a scanner, 5 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 2 additional scans, 85% accuracy, need for whole body and head to be in a scanner. PET-CT plus 2 additional scans: 30-min time in a scanner, 5 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 2 additional scans, 90% accuracy, no need for whole body and head to be in a scanner. CT plus 2 additional scans: 10-min time in a scanner, 5 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 2 additional scans, 90% accuracy, no need for whole body and head to be in a scanner. WB-MRI scenario 1: longer scan time, no radiation, whole body enclosed, longer time to diagnosis, more scans = 60-min time in a scanner, 5 weeks to diagnosis, 0/1000 cancer risk due to radiation dose, 2 additional scans, 90% accuracy, need for whole body and head to be in a scanner. CT plus 1 additional scan: 10 min time in a scanner, 3 weeks to diagnosis, 1/1000 cancer risk due to radiation dose, 1 additional scan, 90% accuracy, no need for whole body and head to be in a scanner. WB-MRI scenario 2: longer scan time, no radiation, whole body enclosed = 60-min time in a scanner, 3 weeks to diagnosis, 0/1000 cancer risk due to radiation dose, 1 additional scan, 90% accuracy, need for whole body and head to be in a scanner. WB-MRI scenario 3: longer scan time, no radiation, whole body enclosed, more accurate = 60-min time in a scanner, 3 weeks to diagnosis, 0/1000 cancer risk due to radiation dose, 1 additional scan, 95% accuracy, need for whole body and head to be in a scanner. WB-MRI scenario 4: longer scan time, no radiation, whole body enclosed, quicker time to diagnosis, fewer scans = 60-min time in a scanner, 1 week to diagnosis, 0/1000 cancer risk due to radiation dose, 0 additional scans, 90% accuracy, need for whole body and head to be in a scanner. WB-MRI scenario 5: longer scan time, no radiation, whole body enclosed, more accurate, quicker time to diagnosis, fewer scans = 60-min time in a scanner, 1 week to diagnosis, 0/1000 cancer risk due to radiation dose, 0 additional scans, 95% accuracy, need for whole body and head to be in a scanner. Best possible pathway: 10-min time in a scanner, 1 week to diagnosis, 0/1000 cancer risk due to radiation dose, 0 additional scans, 95% accuracy, no need for whole body and head to be in a scanner. The comparison indicated by the dashed box (WB-MRI scenario 2) is one in which WB-MRI differs from the default staging pathway according to established differences (time in a scanner, exposure to ionising radiation, need for the whole body and head to be inside the scanner) but for which other attributes (time to diagnosis, number of additional scans, accuracy) are assumed to be the same between the two pathways

Fig. 4

Predicted probabilities of choosing an alternate staging pathways in comparison to a default staging pathway (CT plus one additional scan) (colorectal cancer patients). Description of tests: Default staging pathway (CT plus 1 additional scan) in every case: 10-min time in a scanner, 3 weeks to diagnosis, 1/1000 cancer risk due to radiation dose, 1 additional scan, 90% accuracy, no need for whole body and head to be in a scanner. Worst possible pathway: 60-min time in a scanner, 5 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 2 additional scans, 85% accuracy, need for whole body and head to be in a scanner. PET-CT plus 2 additional scans: 30-min time in a scanner, 5 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 2 additional scans, 90% accuracy, no need for whole body and head to be in a scanner. CT plus 2 additional scans: 10-min time in a scanner, 5 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 2 additional scans, 90% accuracy, no need for whole body and head to be in a scanner. WB-MRI scenario 1: longer scan time, no radiation, whole body enclosed, longer time to diagnosis, more scans = 60-min time in a scanner, 5 weeks to diagnosis, 0/1000 cancer risk due to radiation dose, 2 additional scans, 90% accuracy, need for whole body and head to be in a scanner. PET-CT plus 1 additional scan: 30-min time in a scanner, 3 weeks to diagnosis, 2/1000 cancer risk due to radiation dose, 1 additional scan, 90% accuracy, no need for whole body and head to be in a scanner. WB-MRI scenario 2: longer scan time, no radiation, whole body enclosed = 60-min time in a scanner, 3 weeks to diagnosis, 0/1000 cancer risk due to radiation dose, 1 additional scan, 90% accuracy, need for whole body and head to be in a scanner. WB-MRI scenario 3: longer scan time, no radiation, whole body enclosed, more accurate = 60-min time in a scanner, 3 weeks to diagnosis, 0/1000 cancer risk due to radiation dose, 1 additional scan, 95% accuracy, need for whole body and head to be in a scanner. WB-MRI scenario 4: longer scan time, no radiation, whole body enclosed, quicker time to diagnosis, fewer scans = 60-min time in a scanner, 1 week to diagnosis, 0/1000 cancer risk due to radiation dose, 0 additional scans, 90% accuracy, need for whole body and head to be in a scanner. WB-MRI scenario 5: longer scan time, no radiation, whole body enclosed, more accurate, quicker time to diagnosis, fewer scans = 60-min time in a scanner, 1 week to diagnosis, 0/1000 cancer risk due to radiation dose, 0 additional scans, 95% accuracy, need for whole body and head to be in a scanner. Best possible pathway: 10-min time in a scanner, 1 week to diagnosis, 0/1000 cancer risk due to radiation dose, 0 additional scans, 95% accuracy, no need for whole body and head to be in a scanner. The comparison indicated by the dashed box (WB-MRI scenario 2) is one in which WB-MRI differs from the default staging pathway according to established differences (time in a scanner, exposure to ionising radiation, need for the whole body and head to be inside the scanner) but for which other attributes (time to diagnosis, number of additional scans, accuracy) are assumed to be the same between the two pathways