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- Lundkvist, Jonas, et al.
(författare)
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Economic evaluation of proton radiation therapy in the treatment of breast cancer
- 2005
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Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 75:2, s. 179-85
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Proton beam therapy offers potential clinical advantages compared with conventional radiation therapy for many cancer patients. The benefits are mainly a result of a more favourable dose distribution. The treatment cost with proton radiation is higher than for conventional radiation, mainly due to the large investment cost of building a proton therapy facility. It is therefore important to evaluate whether the medical benefits of proton therapy are large enough to justify the higher treatment costs, compared with conventional radiation therapy. PATIENTS AND METHODS: The cost-effectiveness of proton therapy in the treatment of 55-year old women with left-sided breast cancer was assessed. A Markov cohort simulation model was used to simulate the life of patients diagnosed with breast cancers and treated with radiation. Cost and quality adjusted life years (QALYs) were the primary outcome measures. RESULTS: The study found a cost per QALY gained of 67,000 Euro for the base case analysis of an average breast cancer patient. The cost per QALY gained would, however, be considerably lower if a population with high-risk of developing cardiac disease was treated. Sensitivity analyses showed that the results were stable and that the risk of cardiac disease was the most important parameter. CONCLUSIONS: The results indicate that proton therapy for breast cancer can be cost-effective if appropriate risk groups are chosen as targets for the therapy.
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| 3. |
- Tilly, Nina, et al.
(författare)
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The influence of RBE variations in a clinical proton treatment plan for a hypopharynx cancer
- 2005
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 50:12, s. 2765-2777
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Tidskriftsartikel (refereegranskat)abstract
- Currently, most clinical range-modulated proton beams are assumed to have a fixed overall relative biological effectiveness (RBE) of 1.1. However, it is well known that the RBE increases with depth in the spread-out Bragg peak (SOBP) and becomes about 10% higher than mid-SOBP RBE at 2 mm from the distal edge (Paganetti 2003 Technol. Cancer Res. Treat. 2 413-26) and can reach values of 1.3-1.4 in vitro at the distal edge (Robertson et al 1975 Cancer 35 1664-77, Courdi et al 1994 Br. J. Radiol. 67 800-4). We present a fast method for applying a variable RBE correction with linear energy transfer (LET) dependent tissue-specific parameters based on the alpharef/betaref ratios suitable for implementation in a treatment planning system. The influence of applying this variable RBE correction on a clinical multiple beam proton dose plan is presented here. The treatment plan is evaluated by RBE weighted dose volume histograms (DVHs) and the calculation of tumour control probability (TCP) and normal tissue complication probability (NTCP) values. The variable RBE correction yields DVHs for the clinical target volumes (CTVs), a primary advanced hypopharynx cancer and subclinical disease in the lymph nodes, that are slightly higher than those achieved by multiplying the absorbed dose with RBE=1.1. Although, more importantly, the RBE weighted DVH for an organ at risk, the spinal cord is considerably increased for the variable RBE. As the spinal cord in this particular case is located 8 mm behind the planning target volume (PTV) and hence receives only low total doses, the NTCP values are zero in spite of the significant increase in the RBE weighted DVHs for the variable RBE. However, high NTCP values for the non-target normal tissue were obtained when applying the variable RBE correction. As RBE variations tend to be smaller for in vivo systems, this study-based on in vitro data since human tissue RBE values are scarce and have large uncertainties-can be interpreted as showing the upper limits of the possible effects of utilizing a variable RBE correction. In conclusion, the results obtained here still indicate a significant difference in introducing a variable RBE compared to applying a generic RBE of 1.1, suggesting it is worth considering such a correction in clinical proton therapy planning, especially when risk organs are located immediately behind the target volume.
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