Li et al 2022
Frontiers in medicine · 2022 · China · Proton
This Markov decision model study, set from a Chinese societal perspective, compared proton with conventional photon (intensity-modulated) breast irradiation in terms of the risk of radiation-related ischaemic heart disease. The baseline case was a hypothetical 50-year-old woman without preexisting cardiac risk factors, and risk-stratification analyses varied photon mean heart dose, preexisting cardiac risk and proton cost across 40-, 50- and 60-year-old women. The authors concluded that protons could be cost-effective only in patients with higher preexisting cardiac risk, such as those with diabetes or hypertension, and that preexisting cardiac risk status should be a major consideration in deciding whether to use protons. The baseline patient was not presented as cost-effective in the abstract.
What it compared
Proton beam breast irradiation against conventional photon breast irradiation, modelled for hypothetical women aged 40, 50 and 60 years with varying cardiac risk profiles.
What it found
The baseline incremental cost-effectiveness ratio for protons against photons was US$ 879,729.9 per QALY. Protons were judged cost-effective at a proton cost of US$ 50,000 only in specified high-risk strata, at willingness-to-pay thresholds of US$ 37,653 per QALY (stated as China's WTP), US$ 50,000 per QALY and US$ 100,000 per QALY.
What to keep in mind
The results are conditional and rest on a modelled, hypothetical cohort with assumed proton costs; the price year is not stated, the perspective is societal in China, and the baseline result is far above every threshold tested.
The figures it reported
- $879,729.9 per QALYbaseline, protons vs photons
- $1,528,810.0 per QALYphoton MHD varied 3 Gy end of range (proton cost $50,000)
- $280,919.6 per QALYphoton MHD varied 16 Gy end of range (proton cost $50,000)
- $39,299.2 per QALYpreexisting cardiac risk 10 times baseline (proton cost $50,000)
- $579,499.2 per QALYtornado: proton cost $37,060.5
- $1,179,828.2 per QALYtornado: proton cost $62,933.8
Figures are shown exactly as the paper gives them, in its own currency and price year. We do not convert between currencies: see the glossary for why.
- Patients modelled or enrolled
- Hypothetical: baseline 50-year-old woman without preexisting cardiac risk factor; risk-stratification analyses on 40-, 50- and 60-year-old women varying photon mean heart dose and preexisting cardiac risk (diabetes, hypertension, cholesterol, number of major cardiac risk factors; preexisting risk up to 10x baseline)
- Comparator
- Photon (conventional photon) breast irradiation
- Indication
- Breast cancer (breast irradiation; cardiotoxicity / ischemic heart disease risk)
- Study design
- Cost-effectiveness analysis; Markov decision model; outcome measured in QALYs (incremental effectiveness, protons vs photons)
- Time horizon
- Lifetime, Markov cycled from end of radiotherapy until age 80 (1-year cycles)
- Delivery technique
- Intensity-modulated proton radiation therapy (IMPT) for protons; intensity-modulated photon radiation therapy for photons
- Perspective
- Chinese societal perspective
- Currency
- US$
- Price year
- not reported by this study
- Willingness-to-pay threshold
- US$ 37,653/QALY (stated as the WTP of China); US$ 50,000/QALY; US$ 100,000/QALY
- Discount rate
- 3% annual rate for costs and QALYs
- Cost of the particle course assumed
- US$ 50,000 (proton cost, as stated; base case and scenario analyses varied proton cost)
- Cost of the comparator assumed
- $12,000 per course (intensity-modulated photon radiation therapy for breast irradiation)
Whose costs were counted: a payer, a hospital, or society as a whole.
The year the costs are expressed in. Without it, a figure cannot be compared across time.
The condition attached to the finding
Cost-effective at a proton cost of US$ 50,000 only in specific risk strata: (1) at WTP of China (US$ 37,653/QALY): patients ≤60 years with diabetes and ≤50 years with grade II-III hypertension; (2) at WTP US$ 50,000/QALY: additionally patients with ≥2 major cardiac risk factors (≤60 with diabetes, or grade II-III hypertension, or ≥2 major risk factors; ≤50 with grade II-III hypertension); (3) at WTP US$ 100,000/QALY: additionally ≤50-year-old patients with total cholesterol ≥240 mg/dL. Baseline 50-year-old woman without preexisting cardiac risk factor was not presented as cost-effective in the abstract.
Reporting quality
84 out of 100 on the Quality of Health Economic Studies instrument, a 16-item checklist covering the objective, the perspective, the sources of each estimate, the handling of uncertainty, the horizon and discounting, how costs were measured, the model's transparency, the discussion of bias, and whether funding was disclosed. It measures how well the study was reported, not whether its conclusion is correct: a well-reported study can still reach a conclusion a later trial overturns.