Dosimetric consequences of the shift towards computed tomography guided target definition and planning for breast conserving radiotherapy

Background: The shift from conventional two-dimensional (2D) to three-dimensional (3D)conformal target definition and dose-planning seems to have introduced volumetric as well as geometric changes. The purpose of this study was to compare coverage of computed tomography (CT)-based breast and boost planning target volumes (PTV), absolute volumes irradiated, and dose delivered to the organs at risk with conventional 2D and 3D-conformal breast conserving radiotherapy. Methods: Twenty-five patients with left-sided breast cancer were subject of CT-guided target definition and 3D-conformal dose-planning, and conventionally defined target volumes and treatment plans were reconstructed on the planning CT. Accumulated dose-distributions were calculated for the conventional and 3D-conformal dose-plans, taking into account a prescribed dose of 50 Gy for the breast plans and 16 Gy for the boost plans. Results: With conventional treatment plans, CT-based breast and boost PTVs received the intended dose in 78% and 32% of the patients, respectively, and smaller volumes received the prescribed breast and boost doses compared with 3D-conformal dose-planning. The mean lung dose, the volume of the lungs receiving > 20 Gy, the mean heart dose, and volume of the heart receiving > 30 Gy were significantly less with conventional treatment plans. Specific areas within the breast and boost PTVs systematically received a lower than intended dose with conventional treatment plans. Conclusion: The shift towards CT-guided target definition and planning as the golden standard for breast conserving radiotherapy has resulted in improved target coverage at the cost of larger irradiated volumes and an increased dose delivered to organs at risk. Tissue is now included into the breast and boost target volumes that was never explicitly defined or included with conventional treatment. Therefore, a coherent definition of the breast and boost target volumes is needed, based on clinical data confirming tumour control probability and normal tissue complication probability with the use of 3D-conformal radiotherapy

Guideline adherence for early breast cancer before and after introduction of the sentinel node biopsy

This population-based study aimed to analyse variations in surgical treatment and guideline compliance with respect to the application of radiotherapy and axillary lymph node dissection (ALND), for early breast cancer, before and after the sentinel node biopsy (SNB) introduction. The study included 13 532 consecutive surgically treated stage I–IIIA breast cancer patients diagnosed in 1989–2002. Hospitals showed large variation in breast-conserving surgery (BCS) rates, ranging between 27 and 72% for T1 and 14 and 42% for T2 tumours. In multivariate analysis marked inter-hospital and time-dependent variation in the BCS rate remained after correction for case-mix. The guideline adherence was markedly lower for elderly patients. In 25.2% of the patients aged ⩾75 years either ALND or radiotherapy were omitted. The proportion of patients with no ALND after an SNB increased from 1.8% in 1999 to 37.8% in 2002. However, in 2002 also 12.2% of the patients with a positive SNB did not have an ALND. Guideline compliance for BCS, with respect to radiotherapy and ALND, fell since the SNB introduction, from 96.1% before 2000 to 91.4% in 2002 (P<0.001). Noncompliance may however reflect patient-tailored medicine, as for elderly patients with small, radically resected primary tumours. The considerable variation in BCS-rates is more consistent with variations in surgeon preferences than patient's choice

Radiotherapeutische mogelijkheden voor het kind met een hersentumor

Brain tumours in children require a multidisciplinary approach. The relapse rate after surgery alone is high in certain types of tumours, so adjuvant treatment is necessary. Radiotherapy is the treatment after surgery in most of the brain tumours. The goal of radiotherapy is to give the optimal dose to the target volume and to spare the normal tissues. These aspects can be reached with the newer three dimensional techniques. In this article the treatment of a few tumours will be described as well as the late effects of radiation therapy.Brain tumours in children require a multidisciplinary approach. The relapse rate after surgery alone is high in certain types of tumours, so adjuvant treatment is necessary. Radiotherapy is the treatment after surgery in most of the brain tumours. The goal of radiotherapy is to give the optimal dose to the target volume and to spare the normal tissues. These aspects can be reached with the newer three dimensional techniques. In this article the treatment of a few tumours will be described as well as the late effects of radiation therapy.</p

Three-dimensional conformal radiotherapy with a simultaneously integrated boost-technique in early stage breast cancer:First results on local control and survival

Purpose: Purpose of our study was to report on local control, locoregional control (LRC), disease-free-survival (DFS) and overall survival (OS) in women with early stage breast cancer treated with lhe 3D-CRT Simultaneously Integrated Boost-technique (3D-CRT-SIB) as part of breast conserving radiotherapy (RT). In previous reports from our institution, the 3D-CRT-SIB was superior to the sequential boost (SB)-technique regarding unwanted excessive dose to the boost area and shorter overall treatment time. However, clinical outcome remains to be determined. Materials: The study population was composed of 482 consecutive female invasive breast cancer patients (stage I-III) treated with 3D-CRT-SIB, following breast conserving surgery, at the University Medical Center Groningen between 2005-2008. Data was collected retrospec1ively from medical files. The fractionation scheme used was 28 times 1.8 Gy to the whole ipsilateral breast and simultaneously delivered 2.3 Gy (74.5%) to the tumour bed or 2.4 Gy in case of close or focally positive resection margins. The total applied breast dose was 50.4 Gy with a dose to the boost area of 64.4 or 67.2 Gy. These schedules are biologically equivalent to 25 x 2 Gy with a sequential boost dose of 8 x 2 Gy or 10 x 2 Gy using an αβ of 10 for tumour control. Next to outcome report, we identified prognostic factors for any recurrence (LRR and metastases as first event) by using multivariate Cox regression survival analysis. Results: At diagnosis, the mean age was 57.6 (SO 10.7 years). Mean follow-up was 33.9 (SO 11.3) months. Tumours≤2 cm were observed in 363 (75.3%) patients and 149 (30.9%) patients had node positive disease. Chemotherapy was given in 178 (36.9%), hormonal therapy in 188 (39.0%) and regional RT in 26 (5.4%) women, respectively. Local control with 2 ipsilateral in-breast recurrences was 99.4% at 36 months. The 36-months LRC, DFS and OS were 99.1%, 94.9% and 99.0%, respectively. During followup, 4 women had a LRR, 20 developed distant metastases and 7 died, all of breast cancer. In muitivariate analysis, tumours larger than 2 cm (Hazard ratio (HR) 3.2: 95%-confidence interval (CI) 1.3-7.5, p=0.009) and grade II/III differentiation (HR 2.71; 95%-CI 1.15-6.39: p=0.023) were risk factors for any recurrence. Conclusions: The 3D-CRT-SIB technique In breast conservinq therapy results in excellent local control, regional control and overall survival. Longer follow-up is needed to further confirm these results