Partial Breast Irradiation Techniques Research Articles

Dosimetric Comparison of Treatment Techniques: Brachytherapy, Intensity-Modulated Radiation Therapy, and Proton Beam in Partial Breast Irradiation

Abstract Purpose: To perform a dosimetric comparison of 3 accelerated partial breast irradiation techniques: catheter-based brachytherapy (BT), intensity-modulated radiation therapy (IMRT), and proton beam therapy (PBT). Patients and Methods: Twelve patients with left-sided breast cancer treated with SAVI (Strut-Adjusted Volume Implant) were selected in this study. The original BT plans were compared with optimum plans using IMRT and PBT for 34 Gy (RBE) with 1.1 RBE in 10 fractions using identical parameters for target and organs at risk. Results: Significant reduction in maximum dose to the ipsilateral breast was observed with PBT and IMRT (mean 108.58% [PBT] versus 107.78% [IMRT] versus 2194.43% [BT], P = .001 for both PBT and IMRT compared to BT). The mean dose to the heart was 0%, 1.38%, and 3.85%, for PBT, IMRT, and BT, respectively (P < .001 and P = .026). The chest wall mean dose was 10.07%, 14.65%, and 29.44% for PBT, IMRT, and BT, respectively (P = .001 and .013 compared to BT). The PBT was super...

Report on the Clinical Outcomes of Permanent Breast Seed Implant for Early-Stage Breast Cancers

Permanent breast seed implant is an accelerated partial breast irradiation technique realizing the insertion of (103)Pd seeds in the seroma after lumpectomy. We report the 5-year efficacy and tolerance for a cohort, pooling patients from 3 clinical trials. The trials accrued postmenopausal patients with infiltrating ductal carcinoma or ductal carcinoma in situ ≤3 cm and clear surgical margins, who were node negative, and had a planning target volume <120 cm(3). The outcomes included overall and disease-free survival and local and contralateral recurrence at 5 years. The true local recurrence rate was compared using 2-tailed paired t tests for estimates calculated using the Tufts University ipsilateral breast tumor recurrence and Memorial Sloan Kettering ductal carcinoma in situ nomograms. The cohort included 134 patients, and the observed local recurrence rate at a median follow-up period of 63 months was 1.2% ± 1.2%, similar to the estimate for whole breast irradiation (P=.23), significantly better than for surgery alone (relative risk 0.27; P<.001), and significantly lower than contralateral recurrence (relative risk 0.33; P<.001). The 5-year overall survival rate was 97.4% ± 1.9%, and the disease-free survival rate was 96.4% ± 2.1%. At 2 months, 42% of the patients had erythema, 20% induration, and 16% moist desquamation. The rate of mainly grade 1 telangiectasia was 22.4% at 2 years and 24% at 5 years. The rate of asymptomatic induration was 23% at 2 years and 40% at 5 years. The 5-year data suggest that permanent breast seed implantation is a safe accelerated partial breast irradiation option after lumpectomy for early-stage breast cancer with a tolerance profile similar to that of whole breast irradiation.

Is IORT ready for roll-out?

Two large randomised controlled trials of intraoperative radiotherapy (IORT) in breast-conserving surgery (TARGIT-A and ELIOT) have been published 14 years after their launch. Neither the TARGIT-A trial nor the ELIOT trial results have changed the current clinical practice for the use of IORT. The in-breast local recurrence rate (LRR) after IORT met the pre-specified non-inferiority margins in both trials and was 3.3% in TARGIT-A and 4.4% in the ELIOT trial. In both trials, the pre-specified estimates for local recurrence (LR) with external beam radiation therapy (EBRT) significantly overestimated actual LRR. In the TARGIT-A trial, LR with EBRT was estimated at the outset to be 6%, and in the ELIOT trial, it was estimated to be 3%. Surprisingly, LRR in the EBRT groups has been found to be significantly lower, 1.3% in the EBRT arm of the TARGIT-A and 0.4% in the EBRT arm of the ELIOT trial, respectively. Median follow-up was 2.4 years for the TARGIT-A trial and 5.8 years for the ELIOT trial. However, the initial cohort of patients in the TARGIT-A trial (reported in 2010) now have a median follow-up of 3.8 years and data on LR were available at 5 years follow-up on 35% of patients (18% who received IORT). Although further follow-up will increase confidence with the data, it will also further delay clinical implementation. By carefully weighing the risks and benefits of a single-fraction radiation treatment with patients, IORT should be offered within agreed and strict protocols. Patients deemed at low risk of LR or those deemed suitable for partial breast irradiation, according to the GEC-ESTRO and ASTRO recommendations, could be considered as candidates for IORT. These guidelines apply to all partial breast irradiation techniques, and more specific guidelines for IORT would assist clinicians.

État de l’art et perspectives de l’irradiation partielle et accélérée du sein en 2014

In the frame of treatment de-escalation and personalization, accelerated partial breast irradiation is taking its place in the breast cancer therapeutic options. This study analyzed the results of phase III randomized trials having compared accelerated partial breast irradiation versus whole breast irradiation. Currently, among those trails, six proposed some results regarding efficacy and/or toxicity. Globally, the non-randomized studies confirmed the expected results showing a low rate of local recurrence and toxicity. The first results of the phase III randomized trials showed encouraging data in terms of local control while the toxicity varied mainly according to the accelerated partial breast irradiation technique used. However, the follow-up of the majority of these studies remains insufficient. The strict respect of accelerated partial breast irradiation indications likely represents one of the key factors of the therapeutic success. The next results could allow proposing a better definition of the accelerated partial breast irradiation selection criteria.

Intraoperative radiotherapy for breast cancer: the lasting effects of a fleeting treatment.

In well-selected patients who choose to pursue breast conservation therapy (BCT) for early-stage breast cancer, partial breast irradiation (PBI) delivered externally or intraoperatively, may be a viable alternative to conventional whole breast irradiation. Two large, contemporary randomized trials have demonstrated breast intraoperative radiotherapy (IORT) to be noninferior to whole breast external beam radiotherapy (EBRT) when assessing for ipsilateral breast tumor recurrence in select patients. Additionally, IORT and other PBI techniques are likely to be more widely adopted in the future because they improve patient convenience by offering an accelerated course of treatment. Coupled with these novel techniques for breast radiotherapy (RT) are distinct toxicity profiles and unique cosmetic alterations that differ from conventional breast EBRT and have the potential to impact disease surveillance and patient satisfaction. This paper will review the level-one evidence for treatment efficacy as well as important secondary endpoints like RT toxicity, breast cosmesis, quality of life, patient satisfaction, and surveillance mammography following BCT with IORT.

Accelerated partial breast irradiation with intensity-modulated radiotherapy is feasible for chinese breast cancer patients.

PurposeSeveral accelerated partial breast irradiation (APBI) techniques are being investigated in patients with early-stage breast cancer. The present study evaluated the feasibility, early toxicity, initial efficacy, and cosmetic outcomes of accelerated partial breast intensity-modulated radiotherapy (IMRT) for Chinese female patients with early-stage breast cancer after breast-conserving surgery.MethodsA total of 38 patients met the inclusion criteria and an accelerated partial breast intensity-modulated radiotherapy (APBI-IMRT) plan was designed for each patient. The prescription dose was 34 Gy in 10 fractions, 3.4 Gy per fraction, twice a day, in intervals of more than 6 hours.ResultsOf the 38 patients, six patients did not meet the planning criteria. The remaining 32 patients received APBI-IMRT with a mean target volume conformity index of 0.67 and a dose homogeneity index of 1.06. The median follow-up time was 53 months and no local recurrence or distant metastasis was detected. The most common acute toxicities observed within 3 months after radiotherapy were erythema, breast edema, pigmentation, and pain in the irradiated location, among which 43.8%, 12.5%, 31.3%, and 28.1% were grade 1 toxicities, respectively. The most common late toxicities occurring after 3 months until the end of the follow-up period were breast edema, pigmentation, pain in the irradiated location, and subcutaneous fibrosis, among which 6.2%, 28.1%, 21.9%, and 37.5% were grade 1 toxicities, respectively. Thirty-one patients (96.8%) had fine or excellent cosmetic outcomes, and only one patient had a poor cosmetic outcome.ConclusionIt is feasible for Chinese females to receive APBI-IMRT after breast conserving surgery. The radiotherapeutic toxicity is acceptable, and both the initial efficacy and cosmetic outcomes are good.

Intraoperative radiotherapy of the breast - really a valide option or "only" comfortable.

Intraoperative radiotherapy (IORT) of the breast is an innovative treatment option for early breast cancer and has rapidly entered clinical practice in the last years. There are several indications using a breast IORT. Generally accepted because of excellent long-term results is the intraoperative tumorbed boost followed by an external whole breast irradiation (WBI) (1,2). Considering that most in-breast tumor recurrences are seen in or near to the initial tumor site (3-7) partial breast irradiation (PBI) as the sole radiotherapy treatment modality is of large interest. Different PBI techniques, such as an IORT with electrons or 50 kV X-rays (Intrabeam © ), the interstitial multicatheter or balloncatheter (Mammosite © ) brachytherapy or also the 3D conformal external beam radiotherapy are in clinical use [overview in (8,9)], whereby no superiority could be shown for one of them.

Cost-efficacy of acceleration partial-breast irradiation compared with whole-breast irradiation

The purpose of this study was to analyze the cost-efficacy of multiple accelerated partial-breast irradiation (APBI) techniques compared with whole breast irradiation (WBI) delivered utilizing 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT). A previously reported matched-pair analysis consisting of 199 patients receiving WBI and 199 patients receiving interstitial APBI formed the basis of this analysis. Cost analyses included a cost minimization analysis, incremental cost- effectiveness ratio (ICER) analysis, and cost per quality adjusted life year (QALY) analysis. Per 1,000 patients treated, the cost savings with the utilization of APBI compared to WBI IMRT is $14.9 million, $10.9 million, $8.8 million, $5.0 million, and $9.7 million for APBI 3D-CRT, APBI IMRT, APBI single-lumen (SL), APBI multi-lumen (ML), and APBI interstitial, respectively. Per 1,000 patients treated, the cost savings with the utilization of APBI compared to WBI 3D-CRT is $6.0 million, $2.0 million, and $0.7 million for APBI 3D-CRT, APBI IMRT, and APBI interstitial, respectively. The cost per QALY for APBI SL, APBI ML, and APBI interstitial compared with APBI 3D-CRT are $12,273, $66,032, and $546, respectively. When incorporating non-medical costs and cost of recurrences the cost per QALY was $54,698 and $49,009 for APBI ML compared with APBI 3D-CRT. When compared to WBI IMRT, all APBI techniques are cost-effective based on cost minimization, ICER, and QALY analyses. When compared to WBI 3D-CRT, external beam APBI techniques represent a more cost-effective approach based on cost minimization with brachytherapy representing a cost-effective approach based on cost per QALY.

Comparison study of the partial-breast irradiation techniques: Dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations

The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant—superficial (LIQ-S) and lower inner quadrant—deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue.

Dosimetry of MammoSite® applicator: Comparison between Monte Carlo simulation, measurements, and treatment planning calculation

To investigate the dosimetric characteristics of accelerated partial breast irradiation technique by MammoSite® applicator using thermoluminescent dosimeter (TLD) and Monte Carlo simulation to comparing them with treatment planning system calculation for planning target volume (PTV) and organs at risk such as skin, lung and chest wall. The Monte Carlo MCNP-5 code was used to simulate dose rate in the PTV that is a MammoSite® balloon with 1 cm margin around it. Experimental dosimetry was carried out within a female-equivalent chest phantom with TLD dosimeter after insertion of 192 Ir source into the MammoSite® applicator. Three dimensional planning (TP) was done for dose delivery to the specific points within the phantom by means of FlexiPlan software. Statistical comparisons were done between TP calculation, Monte Carlo simulation and TLD. Our results showed good agreement for surface doses between simulation and measurement. The mean skin dose for the simulation and TLD result was 61.7% and 56.8% of prescription dose, respectively. The maximum dose to the chest wall for Monte Carlo and TLD were 114.4% and 111.8% of prescription dose, respectively. The maximum dose to the lung for Monte Carlo and TLD results were 28.4% and 27.3% of prescription dose, respectively. Using Monte Carlo simulation and an average female chest phantom, it was possible to demonstrate the accuracy on the calculated dose rate in the PTV of a MammoSite® dose delivery system with 192 Ir HDR sources. The results showed acceptable agreement between simulation, treatment planning, and experimental dosimetry results.

Prone Partial Breast Coronal Arc Irradiation: Combining Intensity Modulated Delivery With Dynamic Motion of the Couch

A novel LINAC based technique for partial breast irradiation, consisting of the combination of dynamic motion of the couch, intensity modulated delivery, and a non-isocentric prone breast setup is developed in order to enable large angular coronal arc irradiation about the lumpectomy cavity, without transmittal of radiation through the thorax. The method is experimentally implemented, and evaluated dosimetrically against prone implementations of a 5-field IMRT protocol, and en face Volumetric Modulated Arc Therapy (VMAT) techniques.

Inter‐ and intra‐fraction motion during radiation therapy to the whole breast in the supine position: A systematic review

Inter- and intra-fraction motion during radiation therapy for breast cancer has been a widely researched topic. Recently, however, with the emergence of new technologies and techniques such as intensity modulated radiation therapy (IMRT), field in field, volumetric modulated arc therapy (VMAT), tomotherapy and partial breast irradiation (PBI), the magnitude of this movement has become more important. The aim of this study is to provide a comprehensive summary of the literature relating to the magnitude of motion during radiation therapy for a breast cancer patient. A systematic review of the literature was conducted using Medline, Cinhal, Embase, Scopus and Web of Science. Studies included were limited to women having radical radiation therapy to the whole breast in the supine position. Studies needed to report quantitatively on the magnitude of inter- and intra-fraction motion using electronic portal imaging, port films or kilovoltage imaging techniques. Eighteen articles fitted the selection criteria. The averages of random and systematic error for inter- and intra-fraction movement were reported using central lung distance, central irradiated width, central beam edge to skin distance and cranio-caudal distance measurements, or isocentric matching techniques. Inter-fraction motion was consistently larger than intra-fraction motion but, on average, within a 5 mm tolerance. There were, though, large maximum inter- and intra-fraction variations observed in the measurements of individual patients, which indicate the need for daily inter- and intra- fraction motion management before implementing IMRT, VMAT, tomotherapy or PBI techniques.

Radiothérapie des cancers du sein en 2012 : quelles stratégies ?

Postoperative radiotherapy remains essential in breast cancer in 2012. After conserving surgery, it reduces local recurrence risks from 50 to 70%, both for ductal carcinoma in situ and invasive cancers. This was confirmed in several randomized trials and three meta-analyses. The boost increases local control in invasive cancers, but its role should be better defined in ductal carcinoma in situ. Among the latter, there is no clearly identified subgroup for which radiotherapy could be avoided. Local recurrence risk factors are now well-identified both for ductal carcinoma in situ and invasive cancers, with an inclusion, for the latter, of new molecular subgroups. After mastectomy, radiotherapy reduces local recurrence rates from 60 to 70%, especially among patients with axillary nodal involvement, with, in parallel, a 7 to 9% increased survival rate. In order to reduce the waiting list and to avoid under treatment, especially in the elderly, several hypofractionated radiotherapy schemes have been developed for several years. Three randomized trials confirmed similar results to classical radiotherapy. For ten years, several techniques of partial breast irradiation have been developed, with various doses and treated volumes. The optimal indications should be defined according to the new international guidelines.

SU-E-T-566: A Dosimetric Comparison of Partial Breast Irradiation Technique Depending on the Tumor Locations in Patient's Breast.

The present study was designed to suggest the optimal treatment modalities among 3D-conformal radiation therapy, electron beam therapy and helical-tomotherapy depending on classified tumor locations in patient's breast using Partial Breast Irradiation (PBI) technique. The CT dataset of six patients who had received lumpectomy treatments was used to treatment plans of 3D-conformal radiation therapy, electron beam therapy and helical-tomotherapy. The tumor locations were classified into eight sections according to the quadrants of the breast and to the superficial or deep positions. To evaluate the dosimetric results from the suggested treatment modalities and tumor locations, conformation number, radical dose-homogeneity and delivered doses to normal tissue were calculated. Kruskall-Wallis, Mann-Whitney U and Bonferroni method was used as statistical analysis. Helical-tomotherapy is not recommendable method in PBI technique because the dosimetric results from radical dose- homogeneity and the delivered dose to organ at risk showed worse results at all tumor locations compared to other modalities. For helical-tomotherapy, the volume of heart received more than 2.5 Gy was maximized more than 90% of total heart volume at all tumor locations. Electron beam therapy showed good sparing effect to normal tissues and acceptable target coverage in Lower Inner Quadrant-Superficial (LIQ-S) and Lower Inner Quadrant- Deep (LIQ-D) cases. Electron beam therapy could be recommendable method to treat tumor at LIQ-S, LIQ-D locations rather than 3D-conformal radiation therapy, helical-tomotherapy at PBI technique because electron beam therapy is considered to provide the acceptable target coverage and the greatly lower dose to surrounding tissue.

Clinical Outcomes Using Accelerated Partial Breast Irradiation in Patients With Ductal Carcinoma In Situ

BackgroundLimited data exist on the use of accelerated partial breast irradiation (APBI) in patients with ductal carcinoma in situ (DCIS). The purpose of this analysis was to evaluate clinical outcomes after APBI in patients with DCIS. Patients and MethodsBetween December 2002 and December 2010, 99 patients with DCIS underwent APBI as part of their breast-conserving therapy (BCT). Partial breast irradiation techniques included interstitial brachytherapy, balloon-based brachytherapy, and 3-dimensional conformal radiotherapy (3D-CRT). Clinical outcomes including local recurrence, regional recurrence, disease-free survival (DFS), cause-specific survival, and overall survival (OS) were analyzed. ResultsMean follow up was 3.0 years, with a mean patient age of 61.8 years. At 5 years, the rates of local recurrence and regional recurrence were 1.4% and 0%, respectively. Overall survival was 94%, whereas cause-specific survival was 100%. No difference was noted in local control for each treatment technique. When comparing rates using the Eastern Cooperative Oncology Group (ECOG) E-5194 trial groupings, the rate of local recurrence in our cohort was 2.0% for patients with grade I/II disease < 2.5 cm and 0% for grade III < 1.0 cm, representing a 50% and 100% decrease, respectively, in local recurrence compared with excision alone. ConclusionsPatients with DCIS treated with APBI had excellent clinical outcomes regardless of the APBI technique used. Until the publication of prospective phase III trials, these data confirm previous reports highlighting the efficacy of APBI in the treatment of noninvasive carcinoma of the breast.

Accelerated Partial Breast Irradiation in Early Breast Cancer: Focus on Intraoperative Treatment with Electrons (ELIOT)

Wide tumor resection plus postoperative whole breast irradiation is standard treatment for early breast cancer. Irradiation decreases recurrence rates, but may cause poor cosmesis, breast pain, and cardiac and lung toxicity. Accelerated partial breast irradiation is increasingly used in the hope of increasing convenience, decreasing sequelae and maintaining cure rates. Intraoperative radiotherapy with electrons is an attractive accelerated partial breast irradiation technique because collimator placement is under the direct control of the surgeon who removes the tumor, the skin is spared, shielding protects the chest wall and complete irradiation can be given in a single intraoperative session (avoiding 5-7 weeks of whole breast irradiation). Intraoperative radiotherapy with electrons seems as safe as whole breast irradiation; however, long-term results on local control and survival are not available yet.

A comparison of postimplant dosimetry for 103Pd versus 131Cs seeds on a retrospective series of PBSI patients

Permanent breast seed implantation (PBSI) is an accelerated partial breast irradiation technique performed using stranded (103)Pd radioactive seeds (average energy of 21 keV, 16.97 day half-life). Since 2004, (131)Cs brachytherapy sources have become clinically available. The (131)Cs radionuclide has a higher energy (average energy of 30 keV) and a shorter half-life (9.7 days) than (103)Pd. The purpose of this study was to determine whether or not there are dosimetric benefits to using (131)Cs brachytherapy seeds for PBSI. The prescribed dose for PBSI using (103)Pd is 90 Gy, which was adjusted for (131)Cs implants to account for the shorter half-life. A retrospective cohort of 30 patients, who have already undergone a (103)Pd implant, was used for this study. The treatments were planned using the Variseed treatment planning system. The air kerma strength of the (131)Cs seeds was adjusted in all preimplantation treatment plans so that the V(100) (the volume within the target that receives 100% or more of the prescribed dose) were equivalent at time of implantation. Two month follow-up CT scans were available for all 30 patients and each patient was reevaluated using (131)Cs seeds. The postimplant dosimetric parameters were compared using a two tailed t-test. The prescribed dose for (131)Cs was calculated to be 77 Gy; this dose would have the same biological effect as a PBSI implant with (103)Pd of 90 Gy. The activities of the (131)Cs sources were adjusted to an average of 2.2 ± 0.8 U for (131)Cs compared to 2.5 ± 1.1 U for (103)Pd in order to get an equivalent V(100) as the (103)Pd preimplants. While the use of (131)Cs significantly reduces the preimplant V(200) (the volume within the target that receives 200% or more of the prescribed dose) compared to (103)Pd by 13.5 ± 9.0%, the reduction observed on the 2 month postimplant plan was 12.4 ± 5.1% which accounted for seed motion, implantation inaccuracies and tissue changes. This translates into an absolute reduction of 4.1 cm(3) of tissue receiving 200% of the dose. This analysis of 30 early stage breast cancer patients who underwent the PBSI procedure shows that there is a theoretical dosimetric advantage to using (131)Cs. However, in a realistic implant that will have seed misplacements and tissue changes, the use of (131)Cs may not result in any clinically significant benefit.

Comparison of Five Year Clinical Outcomes between Interstitial, Balloon-Based, and 3-D Conformal Partial Breast Irradiation Techniques in ASTRO Suitable and Cautionary Risk Category Patients

Comparison of Five Year Clinical Outcomes between Interstitial, Balloon-Based, and 3-D Conformal Partial Breast Irradiation Techniques in ASTRO Suitable and Cautionary Risk Category Patients

SU‐E‐T‐829: Dosimetric Comparison of Three Different External Beam Partial Breast Irradiation Techniques: Three‐Dimensional Conformal Radiotherapy, Intensity‐Modulated Radiotherapy and Volumetric Modulated Arc Radiotherapy

Purpose: To compare the dosimetric differences of three‐dimensional conformal radiotherapy (3D‐CRT), inverse intensity‐modulated radiotherapy (IMRT) and volumetric modulated arc radiotherapy(V‐MAT) for external beam partial breast irradiation. Methods: Twelve patients with breast cancer receiving breast‐conserving surgery and external beam partial breast irradiation were enrolled in the study.Three treatment techniques including 3D‐CRT, IMRT and V‐MAT were designed for each patient.The dose distribution in the target,the dose to the organs at risk,total MU and delivery time were compared. Results: 3D‐CRT plans showed the worst conformity in target.V‐MAT plans provided the lowest target coverage and homogeneity in target.All three plans met the clinical requirement.3D‐CRT plans showed the lowest values for the V5,V10 and mean dose and the highest values for V30 in the ipsilateral lung. No statistically significant differences were observed in V20 of the ipsilateral lung between three plans.The ipsilateral normal breast volume receiving 5Gy,10Gy,30Gy and 34Gy doses were significantly lower in IMRT and V‐MAT compared with 3D‐CRT.V‐MAT showed the lowest values in ipsilateral normal breast volume receiving 15Gy,20Gy and 25Gy doses.For V5,mean and max dose in heart,the mean dose in contralateral lung and the mean,max dose in thyroid, IMRT and 3D‐CRT showed the highest and lowest value respectively.The MUs were 417.6±34.4,772.8±54.4 and 631.0±109.0 respectively in 3D‐CRT,IMRT and V‐MAT.The delivery times were 9–10min, 8–10min and 1–1.1 min respectively in 3D‐CRT,IMRT and V‐MAT. V‐MAT could significantly reduced the delivery time. Conclusions: All three plans met the clinical requirement.V‐MAT significantly reduced the irradiated volume of high dose region in the ipsilateral normal breast,but the other dosimetric parameters didnˈt show better in V‐MAT compared with IMRT.V‐MAT significantly decreased the delivery time.Overall,V‐MAT showed a similar or better dose distribution and could significantly reduce the delivery times compared with 3D‐CRT and IMRT.

Doses to internal organs for various breast radiation techniques - implications on the risk of secondary cancers and cardiomyopathy

BackgroundBreast cancers are more frequently diagnosed at an early stage and currently have improved long term outcomes. Late normal tissue complications induced by adjuvant radiotherapy like secondary cancers or cardiomyopathy must now be avoided at all cost. Several new breast radiotherapy techniques have been developed and this work aims at comparing the scatter doses of internal organs for those techniques.MethodsA CT-scan of a typical early stage left breast cancer patient was used to describe a realistic anthropomorphic phantom in the MCNP Monte Carlo code. Dose tally detectors were placed in breasts, the heart, the ipsilateral lung, and the spleen. Five irradiation techniques were simulated: whole breast radiotherapy 50 Gy in 25 fractions using physical wedge or breast IMRT, 3D-CRT partial breast radiotherapy 38.5 Gy in 10 fractions, HDR brachytherapy delivering 34 Gy in 10 treatments, or Permanent Breast 103Pd Seed Implant delivering 90 Gy.ResultsFor external beam radiotherapy the wedge compensation technique yielded the largest doses to internal organs like the spleen or the heart, respectively 2,300 mSv and 2.7 Gy. Smaller scatter dose are induced using breast IMRT, respectively 810 mSv and 1.1 Gy, or 3D-CRT partial breast irradiation, respectively 130 mSv and 0.7 Gy. Dose to the lung is also smaller for IMRT and 3D-CRT compared to the wedge technique. For multicatheter HDR brachytherapy a large dose is delivered to the heart, 3.6 Gy, the spleen receives 1,171 mSv and the lung receives 2,471 mSv. These values are 44% higher in case of a balloon catheter. In contrast, breast seeds implant is associated with low dose to most internal organs.ConclusionsThe present data support the use of breast IMRT or virtual wedge technique instead of physical wedges for whole breast radiotherapy. Regarding partial breast irradiation techniques, low energy source brachytherapy and external beam 3D-CRT appear safer than 192Ir HDR techniques.