Stated Preferences in Non-Small-Cell Lung Cancer: A Discrete Choice Experiment

Figures & data

Table 1 Selected Attributes and Levels for Hypothetical Scenarios About Lung Cancer Treatment

Attributes	Description	Levels
Tiredness	Some treatments may make you weak or tired, and this may limit your daily activities	(1) Mild (does not limit daily activities) (2) Moderate (limits some daily activities) (3) Severe (limits activities such as bathing or dressing alone)
Hair loss	Some treatments may cause hair loss	(1) No hair loss (2) 15 out of 100 people have hair loss (15%) (3) 40 out of 100 people have hair loss (40%)
Skin rash	Some treatments can cause rashes (eg, blisters with pus, red swollen plaques, and itching). Antibiotics may be necessary	(1) No skin lesions (2) Moderate (up to 30% of body) (3) Severe (more than 30% of the body or antibiotics are required)
Hospitalization	There is a risk of hospitalization related to some side effects	(1) No hospitalization (2) 5 out of 100 people are hospitalized (5%) (3) 15 out of 100 people are hospitalized (15%)
Administration mode	Medicines may be administered orally or intravenously. Orally, you can take the pills at home. If intravenously you have to go to the hospital, where you will receive the medication and stay there for at least 2 hours	(1) Intravenous (1x every 3 weeks) (2) 1 tablet per day
Survival	Survival reflects the expectation of living longer. Different treatments may have different survival expectations	(1) 4 months (2) 8 months (3) 12 months

Figure 1 Example choice task.

Table 2 Main Characteristics of Study Sample

	n = 65
Age – Years (range)	65.5 (35–84)
Gender – N (%)
Male	35 (53.8)
Female	30 (46.2)
Education level – No (%)
Less than high school	34 (52.3)
High school	19 (29.2)
Bachelor’ degree	12 (18.4)
Marital status
Married	37 (57)
Single	15 (23.1)
Other	13 (20)
Monthly Income – mean (SD)*	U$ 479.25 (626.18)
Cancer stage – No (%)
II	3 (4.6)
III	18 (27.7)
IV	44 (67.7)
Treatment received – No (%)
Conventional chemotherapy	57 (87.7)
Target therapy	8 (12.3)
Radiotherapy	28 (43.1)
Surgery	8 (12.3)

Notes: The target therapies used were erlotinib and gefitinib. *Monthly average income in Brazil = $ 469,97.

Abbreviations: N, number of participants; SD, standard deviation.

Table 3 Estimated Relative Preference Weights

Attributes	Coefficients	Standard Error	Rob.t.ratio
Severe tiredness	‐0.0633	0.1423	−4.45
Moderate tiredness	‐0.0538	0.1417	−0.38
Hair loss	‐0.0135	0.0034	−3.97
Moderate skin rash	‐0.4497	0.1144	−3.93
Severe skin rash	‐1.0652	0.1577	−6.75
Hospitalization	‐0.0133	0.0099	−1.34
Administration mode	‐0.1913	0.1127	−1.70
Survival	0.054	0.0226	2.39

Table 4 Estimated Relative Preferences, MAR and OR

Attributes	Coefficients (CI 95%)	MAR (CI 95%)	OR (CI 95%)
Severe tiredness	‐0.0633 (‐0.9119; - 0.3540)	‐11.72 (‐10.28; ‐4.22)	0.531 (0.402; 0.702)
Moderate tiredness	‐0.0538 (0.3831; ‐0.1723)	‐0.99 (‐7.09; ‐0.27)	0.948 (0.682; 1.188)
Hair loss	‐0.0135 (‐0.0331; ‐0.0198)	‐0.25 (‐0.22; ‐0.09)	0.986 (0.967; 0.980)
Moderate skin rash	‐0.4497 (‐1.106; ‐0.657)	‐8.32 (‐20.47; ‐12.17)	0.638 (0.331; 0.518)
Severe skin rash	‐1.0652 (‐2.3969; ‐1.7787)	‐19.72 (‐17.31; ‐7.09)	0.345 (0.091; 0.168)
Hospitalization	‐0.0133 (‐0.0067; ‐0.0455)	‐0.2463 (‐0.2161; ‐0.0885)	0.987 (0.955; 0.993)
Administration mode	‐0.1913 (‐0.0455; ‐0.0067)	‐3.542 (‐3.108; ‐1.274)	0.826 (0.551; 0.857)
Survival	0.054 (0.0615; 0.1501)	1.00	1.055 (1.063; 1.162)

Abbreviations: CI, confidence intervals; MAR, maximum acceptable risk; OR, odds ratio.

Table 5 Utilities and Market Share

Treatment Alternative	Hair Loss	Freq	Sev. Tiredness	Freq	Mod. Tiredness	Freq	Sev. Skin Rash	Freq	Mod. Skin Rash	Freq	Survival	Months	Utility	Market Share
Paclitaxel + carboplatin	−0.0135	0.58	−0.633	0.02	−0.0538	0.42	−1.065	0.01	−0.4497	0.22	0.054	17.3	0.7837	31%
Gefitinib	−0.0135	0.11	−0.633	0.003	−0.0538	0.16	−1.065	0.03	−0.4497	0.64	0.054	18.6	0.6726	27%
Erlotinib	−0.0135	0.14	−0.633	0.06	−0.0538	0.51	−1.065	0.13	−0.4497	0.67	0.054	19.3	0.5351	24%
Docetaxel	−0.0135	0.35	−0.633	0.09	−0.0538	0.38	−1.065	0.01	−0.4497	0.1	0.054	7.6	0.2769	18%

Abbreviations: Freq, frequency; Sev., severe; Mod., moderate.