The influence of the use of CT-planning on the irradiated boost volume in breast conserving treatment

• Published in: Radiotherapy and oncology 2009-10, Vol.93 (1), p.87-93
• Main Authors: Uwini, Shafak Al, Antonini, Ninja, Poortmans, Philip M, Boersma, Liesbeth, Hurkmans, Coen, Leer, Jan Willem, Horiot, Jean-Claude, Struikmans, Henk, Bartelink, Harry
• Format: Article
• Language: English
• Subjects: Adult; Boost; Boost volume; Breast cancer; Breast conserving therapy; Breast Neoplasms - diagnostic imaging; Breast Neoplasms - radiotherapy; Breast Neoplasms - surgery; Clinical Trials, Phase III as Topic; Dose-Response Relationship, Radiation; Female; Follow-Up Studies; Hematology, Oncology and Palliative Medicine; Humans; Mastectomy, Segmental - methods; Middle Aged; Multivariate Analysis; Postoperative Care - methods; Preoperative Care - methods; Probability; Prospective Studies; Radiation Injuries - prevention & control; Radiotherapy; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy, Adjuvant; Radiotherapy, Conformal - methods; Randomized Controlled Trials as Topic; Risk Assessment; Tomography, X-Ray Computed - methods; Treatment Outcome
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2009.05.002

Abstract Background and purpose The purpose of this study was to investigate the effect of CT-based delineation and planning on the irradiated boost volume. For this specific purpose we used the data as derived from 2 prospective phase III randomised trials. Patients and methods Data from 1331 patients (⩽50 years) were analyzed with a reported boost volume from a simulation-based treatment plan (EORTC boost vs no boost trial, n = 922), and a CT-scan-based treatment plan (Young Boost Trial, n = 409) group. Tumour diameter, irradiation technique (photons vs electrons), lumpectomy size, and age were used as covariates. Results Median V95% in the conventional simulation-based treatment plans was 99 cc (range 9–628) for photons and was 98 cc (13–651) for electrons, whereas in the CT-planned patients, these figures were 178 cc (37–2699) and 150 cc (43–1272), respectively. Multivariable analysis showed an association of the irradiated boost volume with tumour size ( p < 0.0067), lumpectomy size ( p < 0.0002), and boost technique ( p < 0.0004). The use of a CT-scan for volume delineation and treatment planning remained significant ( p < 0.0001). Conclusions The use of a CT-scan for delineation and treatment planning led to a significant increase of the irradiated boost volume by a factor of 1.5–1.8, compared to conventional simulator-based plans.