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

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

Abstract 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.</p

Three-dimensional conformal simultaneously integrated boost technique for breast-conserving radiotherapy

PURPOSE: To compare the target coverage and normal tissue dose with the simultaneously integrated boost (SIB) and the sequential boost technique in breast cancer, and to evaluate the incidence of acute skin toxicity in patients treated with the SIB technique. METHODS AND MATERIALS: Thirty patients with early-stage left-sided breast cancer underwent breast-conserving radiotherapy using the SIB technique. The breast and boost planning target volumes (PTVs) were treated simultaneously (i.e., for each fraction, the breast and boost PTVs received 1.81 Gy and 2.3 Gy, respectively). Three-dimensional conformal beams with wedges were shaped and weighted using forward planning. Dose-volume histograms of the PTVs and organs at risk with the SIB technique, 28 x (1.81 + 0.49 Gy), were compared with those for the sequential boost technique, 25 x 2 Gy + 8 x 2 Gy. Acute skin toxicity was evaluated for 90 patients treated with the SIB technique according to Common Terminology Criteria for Adverse Events, version 3.0. RESULTS: PTV coverage was adequate with both techniques. With SIB, more efficiently shaped boost beams resulted in smaller irradiated volumes. The mean volume receiving > or =107% of the breast dose was reduced by 20%, the mean volume outside the boost PTV receiving > or =95% of the boost dose was reduced by 54%, and the mean heart and lung dose were reduced by 10%. Of the evaluated patients, 32.2% had Grade 2 or worse toxicity. CONCLUSION: The SIB technique is proposed for standard use in breast-conserving radiotherapy because of its dose-limiting capabilities, easy implementation, reduced number of treatment fractions, and relatively low incidence of acute skin toxicity

Dosimetric consequences of the shift towards computed tomography guided target definition and planning for breast conserving radiotherapy-1

V).<p><b>Copyright information:</b></p><p>Taken from "Dosimetric consequences of the shift towards computed tomography guided target definition and planning for breast conserving radiotherapy"</p><p>http://www.ro-journal.com/content/3/1/6</p><p>Radiation Oncology (London, England) 2008;3():6-6.</p><p>Published online 31 Jan 2008</p><p>PMCID:PMC2270860.</p><p></p

Five year outcomes of hypofractionated simultaneous integrated boost irradiation in breast conserving therapy; patterns of recurrence

<p>In 2005, we introduced hypofractionated 3-dimensional conformal radiotherapy with a simultaneous integrated boost (3D-CRT-SIB) technique after breast conserving surgery. In a consecutive series of 752 consecutive female invasive breast cancer patients (stages I-III) the 5-year actuarial rate for local control was 98.9%. This new technique gives excellent 5-year local control. (C) 2013 Elsevier Ireland Ltd. All rights reserved.</p>

Systolic and diastolic dysfunction in long-term adult survivors of childhood cancer

Aim: To assess systolic and diastolic function in adult childhood-cancer survivors (CCS) after treatment entailing potential cardiovascular toxicity. Methods: The study cohort consisted of 277 adult CCS (median age 28 [range 18-48] years), who had been treated with anthracyclines, platinum, and/or radiotherapy between 1976 and 1999, along with 130 healthy sibling controls. The assessments included echocardiography, baroreflex sensitivity measurement, and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP). Echocardiography measurements were shortening fraction (SF) (abnormal Results: At 18 (5-31) years post-treatment, the prevalence of both impaired SF and abnormal WMSI was increased in CCS compared to controls (p = 0.003 and p <0.001, respectively). CCS also had an increased prevalence of diastolic dysfunction compared to the controls (12% versus 1%, p <0.001). Abnormal SF and/or abnormal diastolic function were found in 43% of CCS. NT-proBNP was higher in CCS and was associated to increased WMSI. Baroreflex sensitivity was lower in CCS and was associated with diastolic dysfunction. Systolic as well as diastolic dysfunction was associated with cumulative dose of anthracyclines and mediastinal irradiation. Conclusion: After treatment with potential cardiovascular toxic therapies, the risk of systolic and diastolic dysfunction in CCS is considerable. Since these abnormalities, in particular diastolic dysfunction, are age related, the observed effects might be considered a sign of precocious cardiac ageing. (C) 2011 Elsevier Ltd. All rights reserved

Long-Term Risk of Skin Cancer among Childhood Cancer Survivors : A DCOG-LATER Cohort Study

BACKGROUND: Skin cancer is common after radiotherapy among childhood cancer survivors (CCSs). We studied risks and risk factors for subsequent skin cancers, with emphasis on radiation dose, exposed skin surface area, and chemotherapeutic agents. METHODS: The DCOG-LATER cohort study includes 5-year Dutch CCSs diagnosed 1963-2001. Subsequent skin cancers were identified from record linkages with the Netherlands Cancer Registry and Dutch Pathology Registry. Incidence rates were compared with general population rates. Multivariable Cox regression models were used, applying a novel method of case-control sampling enabling use of tumor location in cohort analyses. All statistical tests were two-sided. RESULTS: Among 5843 CCSs, 259 developed 1061 basal cell carcinomas (BCCs) (standardized incidence ratio [SIR] = 29.8, 95% confidence interval [CI] = 26.3 to 33.6; excess absolute risk per 10 000 person-years (EAR) = 24.6), 20 had melanoma (SIR = 2.3, 95% CI = 1.4 to 3.5; EAR = 1.1), and 10 had squamous cell carcinoma (SIR = 7.5, 95% CI = 3.6 to 13.8; EAR = 0.8). Cumulative incidence of BCC 40 years after childhood cancer was 19.1% (95% CI = 16.6 to 21.8%) after radiotherapy vs 0.6% expected based on general population rates. After a first BCC, 46.7% had more BCCs later. BCC risk was associated with any radiotherapy to the skin compartment of interest (hazard ratio [HR] = 14.32, 95% CI = 10.10 to 20.29) and with estimated percentage in-field skin surface area (26-75%: HR = 1.99, 95% CI = 1.24 to 3.20; 76-100%: HR = 2.16, 95% CI = 1.33 to 3.53, vs 1-25% exposed; Ptrend among exposed = .002), but not with prescribed radiation dose and likelihood of sun-exposed skin-area. Of all chemotherapy groups examined, only vinca alkaloids increased BCC risk (HR = 1.54, 95% CI = 1.04 to 2.27). CONCLUSION: CCSs have a strongly, 30-fold increased BCC risk. BCC risk appears to increase with increasing skin surface area exposed. This knowledge underscores the need for awareness by survivors and their health care providers

Colorectal adenomas and cancers after childhood cancer treatment: A DCOG-LATER record linkage study

Background: Although colorectal adenomas serve as prime target for colorectal cancer (CRC) surveillance in other high-risk groups, data on adenoma risk after childhood cancer are lacking. We evaluated the risk of histologically confirmed colorectal adenomas among childhood cancer survivors. A secondary aim was to assess CRC risk. Methods: The DCOG-LATER cohort study includes five-year Dutch childhood cancer survivors and a sibling comparison group (n=883). Colorectal tumors were identified from the population-based Dutch Pathology Registry (PALGA).We calculated cumulative incidences of adenomas/CRCs for survivors and siblings. For adenomas, multivariable Cox regression models were used to evaluate potential risk factors. All statistical tests were two-sided. Results: Among 5843 five-year survivors (median follow-up = 24.9 years), 78 individuals developed an adenoma. Cumulative incidence by age 45 years was 3.6% (95% confidence interval [CI] = 2.2% to 5.6%) after abdominopelvic radiotherapy (AP-RT; 49 cases) vs 2.0% (95% CI=1.3% to 2.8%) among survivors without AP-RT (28 cases; Pdifference = .07) and vs 1.0% (95% CI=0.3% to 2.6%) among siblings (6 cases) (Pdifference = .03). Factors associated with adenoma risk were AP-RT (hazard ratio [HR] = 2.12, 95% CI=1.24 to 3.60), total body irradiation (TBI; HR=10.55, 95% CI=5.20 to 21.42), cisplatin (HR=2.13; 95% CI=0.74 to 6.07 for <480 mg/m2; HR=3.85, 95% CI=1.45 to 10.26 for 480 mg/m2; Ptrend = .62), a hepatoblastoma diagnosis (HR=27.12, 95% CI=8.80 to 83.58), and family history of early-onset CRC (HR=20.46, 95% CI=8.10 to 51.70). Procarbazine was statistically significantly associated among survivors without AP-RT/TBI (HR=2.71, 95% CI=1.28 to 5.74). Thirteen CRCs occurred. Conclusion: We provide evidence for excess risk of colorectal adenomas and CRCs among childhood cancer survivors. Adenoma risk factors include AP-RT, TBI, cisplatin, and procarbazine. Hepatoblastoma (familial adenomatous polyposisassociated) and family history of early-onset CRC were confirmed as strong risk factors. A full benefit-vs-harm evaluation of CRC screening among high-risk childhood cancer survivors warrants consideration