Progress of research on adjuvant radiotherapy for breast cancer / 中国辐射卫生

@#Breast cancer is the most common malignancy and the fifth leading cause of cancer-related mortality in the world. Breast cancer is a global health problem that poses a heavy burden on patients and their families as well as socioeconomic development. As an important component in the management of breast cancer, radiotherapy plays a vital role in its comprehensive treatment. This review describes advances made toward the application of adjuvant radiotherapy in the treatment of breast cancer.

Research progress on accelerated partial breast irradiation for early breast cancer after breast-conserving surgery / 中华放射肿瘤学杂志

Currently, whole breast radiotherapy (WBRT) is the standard treatment for early breast cancer after breast-conserving surgery, which effectively reduces the recurrence rate. Accelerated partial breast irradiation (APBI), a special radiotherapy that only targets the limited volume of tissues surrounding the primary lesion, has attracted more and more attention because of the high proportion of tumor recurrence adjacent to the tumor resection cavity. In recent years, a number of prospective randomized controlled trails have demonstrated its safety and effectiveness, which is a feasible choice for specific low-risk patients after breast-conserving surgery. Compared with WBRT, APBI shortens the treatment time, reduces the treatment cost and improves the cosmetic effect. At the same time, more and more APBI technologies have been developed, which enhance the accessibility and possess unique advantages for partial patients undergoing breast-conserving surgery. Nevertheless, the efficacy and side effects of APBI technologies still differ, which need to be treated differently. In this paper, multiple APBI technologies, research progresses at home and abroad and applicable population were reviewed. The unresolved problems were proposed and development prospect was predicted, aiming to provide reference for clinical application.

Intraoperative radiotherapy with electrons as partial breast irradiation in limited stage breast cancer: Early term clinical and cosmetic outcomes

Purpose: We aimed to report the experience of intraoperative electron radiation therapy (IOERT) with Mobetron (Intraop Medical Incorporated, Santa Clara, CA, USA) as a partial breast irradiation (PBI) for patients with early-stage breast cancer and explanation of IOERT application and present early clinical and cosmetic result. Materials and Methods: Between November 2012 and February 2014, in Ankara Oncology Hospital, Radiation Oncology Clinic, was performed IOERT as a PBI with a single dose of 21 Gy for 21selected patients. Median tumor size was 1.5 cm (range, 0.6–2.8 cm). Median treatment duration was 2.04 min (range, 1.26–2.44 min). According to final pathology, two patients were found to have close margin and mastectomy was applied. Three cases (two were N1 mic and one case had perineural invasion and tumor size was >2 cm) received whole breast irradiation. Results: Median follow-up time was 3 years (range, 26–42 months). One patient died because of nonbreast cancer reason, all of the other patients (except one) alive without disease. There was no Grade 3 or 4 toxicities related to the IOERT. Good or excellent cosmesis was revealed 79% (15/19) and 95% (18/19), by physician and patient, respectively. Conclusion: IOERT, for patients with early-stage breast cancer as a part of breast-conserving treatment, offer patients better cosmetic results with less skin toxicity and increases comfort of patients by shortening duration of treatment time

Progress of hypofractionated radiotherapy after breast-conserving surgery / 中国肿瘤临床

Breast-conserving surgery plus adjuvant whole-breast irradiationmay reduce the risk of local tumors and improve living con-ditions of patients. Conventional whole-breast radiotherapy confers good tumor control and esthetic effects with lower toxicity. How-ever, treatment periods of 5-7 weeks are inconvenient for patients and may lead to the wastage of medical resources. Thus, increasing-ly more individuals tend to choose a short-term radiotherapy mode, such as hypofractionated radiotherapy or partial breast irradia-tion. Many published reports suggest that short-term radiotherapy is safe and effective, similar to conventional fractionation, with comparable tumor control and fewer side effects than noted with conventional fractionation. Therefore, in contrast to conventional whole-breast radiotherapy, short-time radiotherapy shows remarkable advantages in shortening the total treatment duration, reduc-ing medical costs, saving medical resources, and improving the quality of life of patients.

A comparative study of target volumes based on deformation registration using preoperative prone magnetic resonance imaging and postoperative prone computed tomography imaging for patients undergoing breast-conserving surgery / 中华放射医学与防护杂志

Objective@#To explore the differences and correlation between the target volumes based on deformation registration (DIR) using preoperative prone diagnostic magnetic resonance (MR) imaging and postoperative prone computed tomography (CT) simulation imaging for patients undergoing breast-conserving surgery (BCS).@*Methods@#Eighteen breast cancer patients suitable for external-beam partial breast irradiation (EB-PBI) after BCS were enrolled. Preoperative prone diagnostic MR and postoperative prone CT scan sets were acquired during free breathing for all patients. The gross tumor volume (GTV) delineated on the preoperative diagnostic MR images was defined as GTVMRI, the clinical target volumes (CTVMRI+ 1 and CTVMRI+ 2)were defined as 10 and 20 mm margins around the GTVMRI, and the planning target volume (PTVMRI+ 1 and PTVMRI+ 2) were defined as 15 and 25 mm margins around the GTVMRI, respectively. Tumor bed (TB) delineated on the postoperative prone CT simulation images acquired during free breathing was defined as GTVTB, CTV and PTV were defined as 10 and 15 mm margins around the GTVTB, respectively. The target volume of the whole breast contoured on the MR and CT images were defined as CTVBreast-MRI and CTVBreast-CI, respectively. The MR and CT images were registered deformably in MIM software system.@*Results@#The GTVTB, CTVTB and PTVTB were significantly greater than GTVMRI, GTVMRI+ 1 and PTVMRI+ 1, respectively (Z=-3.593, -3.593, -2.983, P<0.05). Meanwhile, the CTVTB and PTVTB were significantly less than the CTVMRI+ 2 and PTVMRI+ 2, respectively(Z=-2.722, -2.853, P<0.05). The conformal index (CI) and degree of inclusion (DI) of GTVTB-GTVMRI, GTVTB-CTVMRI+ 1, CTVTB-GTVMRI and CTVTB-GTVMRI+ 1 based on center-coincidence of the compared targets were better than those based on DIR of the thorax(Z=-3.724、-3.724、-2.591、-3.593, P<0.05; Z=-3.724、-3.724、-3.201、-3.724, P<0.05).@*Conclusions@#For the patients enrolled for prone EB-PBI, target volumes delineated on the preoperative prone MR images were significantly smaller compared to that on the postoperative prone CT images, but a statistically significant positive correlation was found between the MR and CT target volumes. There were still relatively poor spatial overlap whether for the whole breast or the targets between the preoperative prone diagnostic MR images and the postoperative prone simulation CT images based on DIR. Therefore, it is infeasible to guide postoperative EB-PBI target delineation using the preoperative prone diagnostic MR images.

Clinical characteristics and prognosis of patients with ipsilateral breast tumor recurrence after breast conservation therapy / 中华肿瘤杂志

Objective@#To analyze the clinical features and prognosis of the ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery.@*Methods@#From 1999 to 2013, 63 women with IBTR after breast conserving surgery were retrospectively reviewed. All patients had adequate information on tumor location both at first presentation and at recurrence, with or without regional recurrence or distant metastasis. The histologic changes between true local recurrence and elsewhere recurrence groups were compared. The local recurrence, the overall survival after IBTR (IBTR-OS), the disease-free survival after IBTR (IBTR-DFS) were also compared.@*Results@#All patients had undergone lumpectomy, including 38 cases with additional axillary lymph node dissection and 13 cases with sentinel lymph node biopsy. There were 11.3% (7/63) cases received neoadjuvant systemic therapy, 68.3% (43/63) had adjuvant radiotherapy, 60.3% (38/63) underwent adjuvant chemotherapy and 47.6% (30/63) received hormonal therapy. Forty-five cases (71.4%) had recurrence in the same quadrant, and 18 cases (28.6%) had elsewhere recurrence. Compared with histology at presentation, 10.3% of the patients (6/58) had different ones at recurrence and 28.9% of patients (13/45) had different molecular subtypes. The conversion rate of estrogen receptor status (33.3% vs 9.5%, P=0.012) and progesterone receptor status (56.3% vs 19.0%, P=0.005) in patients with elsewhere recurrence was significantly higher than that in patients with same quadrant recurrence. Fifty-nine cases had undergone surgery after IBTR, with 48 cases of secondary breast-conserving surgery and 11 cases of salvage mastectomy. The median time to IBTR of same quadrant recurrence and elsewhere recurrence groups were 26 months and 62 months (P=0.012), respectively. There were 84.4% and 44.4% cases who had local recurrence within 5 years after breast conserving surgery, respectively. Of all cases, the overall 5-year IBTR-OS and 5-year IBTR-DFS rates were 79.4% and 60.4%, respectively. There were no significant differences in 5-year IBTR-OS (77.4% vs. 83.6%, P=0.303) or 5-year IBTR-DFS (60.0% vs. 62.8%, P=0.780) between same quadrant recurrence and elsewhere recurrence groups. Univariate analysis showed that pN0-1 (P<0.001), luminal subtype (P=0.026), adjuvant endocrine therapy (P=0.007) at first presentation, recurrent tumor < 3 cm (P=0.036) and having surgery after IBTR(P=0.002) were favorable factors of IBTR-OS. pN0-1 (P<0.001) at first presentation, recurrent tumor stage Ⅰ-Ⅱ (P<0.001) and having surgery after IBTR(P=0.001) were favorable factors of IBTR-DFS. There was no significant difference between second breast-conserving surgery and salvage mastectomy in IBTR-OS and IBTR-DFS (P>0.05).@*Conclusions@#The IBTR after breast conserving surgery mainly occurred at the original quadrant. Second breast-conserving surgery did not affect patient′s prognosis. There were significant differences in biological features between the same quadrant recurrence and elsewhere recurrence, requiring different therapeutic strategies in the future.

Efficacy analysis of accelerated partial breast irradiation versus whole breast irradiation with simultaneous integrated boost after breast-conserving surgery for early-stage breast cancer / 中华放射医学与防护杂志

Objective To evaluate the efficacy of accelerated partial breast irradiation ( APBI ) and whole breast irradiation ( WBI ) with simultaneous integrated boost ( SIB ) from the perspective of economics, and provide a reference for postoperative adjuvant therapy mode selection for early-stage breast cancer after breast-conserving surgery. Methods A total of 355 early-stage breast cancer patients who underwent APBI or WBI-SIB after breast-conserving surgery were evaluated on efficacy and cost-effectiveness, of which 177 patients received APBI, and 178 patients received WBI-SIB. Survival analysis was done according to treatment received. NCI-CTC 3.0 was used to score the toxicities. Breast aesthetic outcome were evaluated with Harris standards. Results Median follow-up was 42 months ( 5.8 -92.7 months) . The 3-year locoregional recurrence free survival( LRFS) rates in APBI group and WBI-SIB group were 98.2％ and 97.6％, distant metastasis free survival( DMFS) were 94.3％ and 93.7％, disease-free survival ( DFS) were 93.1％ and 91.6％, and overall survival 95.5％ and 94.3％, respectively, without statistically significant differences(P>0.05). Compared with WBI-SIB group, the acute reaction rates in APBI group decreased from 5. 6％ to 3.4％(χ2 =6.044, P <0. 05), and late reactions from 5.6％ to 2.3％ (χ2 =6.149, P<0. 05), while the cosmetic outcome improved from 88.8％ to 93.8％(χ2 =5.22, P<0. 05). Moreover, the processing average time was shortened by 26.5 d (χ2 =40.76, P<0. 05). Conclusions After breast-conserving surgery, the efficacy of APBI showed no difference from WBI-SIB with respect to 3-year local control, disease-free survival, and overall survival, but displayed a significantly better toxicity profile and cost-effectiveness ratio for early breast cancer patients. It can be used as a good radiotherapy model after breast-conserving surgery in early-stage breast cancer.

Irradiación parcial acelerada de mama (apbi) después de cuadrantectomía más biopsia del ganglio centinela axilar: características clínico-patológicas e inmunohistoquímicas / Accelerated partial breast irradiation (apbi) after breast conservative surgery plus sentinel node biopsy: clinical-pathological and immunohistochemical characteristics

Introducción El tratamiento estándar en estadios tempranos del cáncer de mama es la cirugía conservadora (cc) más radioterapia del volumen total mamario (wbi). Dado que la mayoría de las recidivas locales ocurren cercanas al sitio del tumor (85%) y existiendo la posibilidad de acortar tiempos de irradiación ­debido a que esta insume varias semanas­, podría no ser necesario irradiar toda la mama, sino el área donde estaba situado el tumor más margen de seguridad, lo que insume un menor tiempo. Este el fundamento de la Irradiación Parcial Acelerada Mama (apbi). Consensos internacionales proporcionan guías para administrar apbi fuera de ensayos clínicos. Objetivos El objetivo principal de este trabajo es determinar y analizar las características clinico-anatomopatológicas e inmunohistoquímicas de las pacientes que fueron operadas y luego seleccionadas para ser irradiadas con técnica de apbi con radioterapia externa con intensidad modulada guiada por imágenes (imrt). Material y método Se trata de un trabajo prospectivo, no randomizado. La muestra está constituida por las primeras 20 pacientes ingresadas al protocolo apbi. El reclutamiento se realizó entre marzo de 2012 y julio de 2014. Se analizaron las características clínico-patológicas e inmunohistoquímicas de esas pacientes luego de cc más biopsia del ganglio centinela (bgc). Resultados Media de seguimiento en meses: 37,7 (r: 22-51); edad media: 65,7 años. Tamaño tumoral medio por anatomía patológica: 12,03 mm. Media de número de ganglios centinelas extirpados: 1,7. Todos los tumores fueron unifocales. Los márgenes quirúrgicos resultaron negativos en todos los casos. Tumores Luminal A: 19 pacientes; tumores Luminal B: 1 paciente. Hormonoterapia adyuvante en todas las pacientes. Control locorregional: 100%. Conclusiones A pesar del corto tiempo de seguimiento y del escaso número de pacientes, este análisis sugiere que la apbi en el lecho del tumor marcado intraoperatoriamente con fiduciales de titanio es factible para pacientes que reúnen los criterios estrictos clínico-patológicos e inmunohistoquímicos acordes con las guías internacionales.

Introduction The standard conservative treatment for early stage breast carcinomas is the breast conservative surgery plus whole breast irradiation. Because most local recurrences occur close to the site of the primary tumor (80- 90%) and the possibility of shortening the irradiation times ­because it takes several weeks­, it may not be necessary to irradiate the entire breast, but the area where the tumor was located plus a margin of safety in less time. This is the basis of Accelerated Partial Irradiation of the Breast Objectives Determination and analysis of clinical-pathological and immunohistochemical characteristics in patients selected for Accelerated Partial Breast Irradiation (apbi) performed by imrt + igrt technique after breast conservative surgery plus sentinel node biopsy. Materials and method A prospective, non-randomized study of the first 20 patients performed apbi strictly following the recommendations of international consensus. It was initiated in March 2012 until July 2014. Clinical-pathological and immunohistochemical characteristics of these patients were analyzed to be selected for apbi, after breast conservative surgery plus sentinel node biopsy. Results Median follow up: 37.7 months (r: 22-51); average age: 65.7 years. Mean tumor size by pathological analysis: 12.03 mm. Mean number of sentinel nodes removed: 1.7. All tumors were unifocal. Negative surgical margins in all cases. Luminal A tumors: 19 patients; Luminal B tumors: 1 patient. Adjuvant hormone therapy in all patients. Loco-regional control: 100%. Conclusions Despite the short time of follow up and the small numbers of patients, this analysis suggests that apbi performed by imrt + igrt technique added to the placement of fiduciary marks at the time of surgery is feasible for highly selected patients who meet the clinical-pathological and immunohistochemical selection criteria according to international guidelines

A comparison of rigid and deformable image registration at end-inhale and end-exhale phases based on 4DCT images for radiotherapy after breast-conserving surgery / 中华放射肿瘤学杂志

Objective To compare the geometric differences of gross tumor volumes(GTV)and displacements of selected clips propagated by rigid image registration(RIR)and deformable image registration (DIR)at end-inhale phase(CT0)and end-exhale phase(CT50)based on four-dimensional computed tomography(4DCT)of the whole breast after breast-conserving surgery(BCS). Methods Forty-four patients who underwent 4DCT simulation scans after BCS were selected. The GTV and displacements of selected metal clips at CT0and CT50were manually delineated by the same radiotherapy physician. Subsequently,the GTV and displacements of selected clips from CT0images were transformed and propagated to CT50images using RIR and DIR.The geometric differences of GTV and displacements of surgical clips from DIR were compared with those from RIR based on the dice similarity coefficient(DSC)and the displacements of the center of mass(COM)in the three-dimensional(3D)directions. Results The mean DSC was 0.86± 0.04 for RIR and 0.87± 0.04 for DIR(P=0.000).The displacements of COM in 3D directions from RIR were significantly greater than those from DIR(1.22 mm vs. 1.10 mm,P=0.000).In the anterior-posterior direction,the displacements from RIR were significantly greater than those from DIR for both GTV and selected clips(P=0.000).However,in the left-right and superior-inferior directions,there were no significant differences in displacements between RIR and DIR for both GTV and the selected clips(all P>0.05). Conclusions DIR can improve the overlap for GTV registration from 4DCT scans at CT0and CT50.Furthermore,DIR is superior to RIR in reflecting GTV and the displacements of selected clips in anterior-posterior direction induced by respiratory movement.

A comparison of dosimetric variance for external-beam partial breast irradiation using three-dimensional and four-dimensional computed tomography / 中华肿瘤杂志

Objective@#To investigate the potential dosimetric benefits of four-dimensional computed tomography (4DCT) compared to three-dimensional CT (3DCT) in the planning of radiotherapy for external-beam partial breast irradiation (EB-PBI).@*Methods@#Three-DCT and 4DCT scan sets were acquired for 20 patients who underwent EB-PBI. For each patient a conventional 3D conformal plan (3D-CRT) was generated based on end-inhalation phase (EI). The treatment plan based on the 4DCT EI phase images was copied and applied to the end-exhalation phase (EE) and 3DCT images (defined as EB-PBIEI, EB-PBIEE, EB-PBI3D, respectively).@*Results@#The median volumes of the tumour bed based on 3DCT, EI and EE were 20.99 cm3, 19.28 cm3, and 18.78 cm3, respectively. The tumour bed volume based on 3DCT was significantly greater than that of EI and EE volumes (P<0.05). The planning target volumes (PTV) coverage of EB-PBI3D, EB-PBIEI and EB-PBIEE were 96.85%, 97.51%, 97.03%, respectively. The planning target volume (PTV) coverage of EB-PBI3D was significantly less than that of EB-PBIEI and EB-PBIEE (P<0.05). The median homogeneity indexs (HI) based on 3DCT, EI and EE were 0.13, 0.13, 0.13, respectively. The median conformal indexs (CI) based on 3DCT, EI and EE were 0.68, 0.69, 0.68, respectively. The median mean doses (Dmean) based on 3DCT, EI and EE were 36.20 Gy, 36.20 Gy, 36.22 Gy, respectively. However there were no significant differences in the homogeneity index, conformity index and the mean dose of PTV between the three treatment plans (P>0.05). The EB-PBI3D plan resulted in the largest organs at risk dose (P<0.05).@*Conclusion@#There was a significant benefit when using 4DCT to plan 3D-CRT for EB-PBI with regard to reduced non-target organ exposure, and might result in poor dose coverage when the PTV is determined using 3DCT.

Dosimetric comparison of three dimensional conformal radiation therapy versus intensity modulated radiation therapy in accelerated partial breast irradiation.

AIM OF STUDY: Breast conserving surgery (BCS) is the standard treatment for stage I and II breast cancer. Multiple studies have shown that recurrences after lumpectomy occur mainly in or near the tumor bed. Use of accelerated partial breast irradiation (APBI) allows for significant reduction in the overall treatment time that results in increasing patient compliance and decreasing healthcare costs. We conducted a treatment planning study to evaluate the role of intensity modulated radiation therapy (IMRT) with regards to three‑dimensional conformal radiation therapy (3DCRT) in APBI. MATERIALS AND METHODS: Computed tomography planning data sets of 33 patients (20 right sided and 13 left sided) with tumor size less than 3 cm and negative axillary lymph nodes were used for our study. Tumor location was upper outer, upper inner, central, lower inner, and lower outer quadrants in 10, 10, 5, 4 and 4 patients, respectively. Multiple 3DCRT and IMRT plans were created for each patient. Total dose of 38.5 Gy in 10 fractions were planned. Dosimetric analysis was done for the best 3DCRT and IMRT plans. RESULTS: The target coverage has been achieved by both the methods but IMRT provided better coverage (P = 0.04) with improved conformity index (P = 0.01). Maximum doses were well controlled in IMRT to below 108% (P < 0.01). Heart V2 Gy (P < 0.01), lung V5 Gy (P = 0.01), lung V10 Gy (P = 0.02), contralateral breast V1 Gy (P < 0.01), contralateral lung V2 Gy (P < 0.01), and ipsilateral uninvolved breast (P < 0.01) doses were higher with 3DCRT compared to IMRT. CONCLUSION: Dosimetrically, IMRT–APBI provided best target coverage with less dose to normal tissues compared with 3DCRT‑APBI.

Dosimetric effects of target volume delineation with metal clip and seroma, alone or in combination, on external-beam partial breast irradiation :a study based on four-dimensional computed tomography / 中华放射肿瘤学杂志

Objective To evaluate the dosimetric effects of target volume delineation with metal clip and seroma,alone or in combination,on external-beam partial breast irradiation (EB-PBI) based on four-dimensional computed tomography (4DCT).Methods Twenty female patients undergoing EB-PBI from 2009 to 2013 were enrolled as subjects.The gross tumor volumes (GTVs),GTVC,GTVS,and GTVC+S,were delineated on 4DCT images at 10 phases using metal clip,seroma,and both of them,respectively.The GTVS on 4DCT images at 10 phases were fused to generate the internal gross tumor volumes (IGTVS),IGTVC,IGTVS,and IGTVC+S.The planning target volumes (PTVS),PTVC,PTVS,and PTVC+S,were obtained via expansion of margin by 15 mm.The three-dimensional conformal radiotherapy plans were made by one physician based on PTVC,PTVS,and PTVC+S on end-inhalation images.The target volume,homogeneity index (HI),conformity index (CI),and doses to organs at risk were compared between the three groups.Results The C+S group had the largest IGTV,PTV,and the ratio of PTV to diseased breast volume,which was followed by the C group and the S group (all P＜ 0.05).The S group had significantly lower doses to the ipsilateral normal breast and lung than the C group and the C+S group (all P＜0.05).There were no significant differences in HI or CI between the three groups (all P＞ 0.05).Conclusions The volume variation caused by target volume dehneation on 4DCT images based on different references has little impact on dose distribution in target volume.However,it has substantial impact on radiation doses to the ipsilateral normal breast and lung.

The impact of respiratory motion for target dose during external-beam partial breast irradiation / 中华放射医学与防护杂志

Objective To evaluate the impact of respiratory motion for dose of target and organ at risk during external-beam partial breast irradiation (EB-PBI).Methods 4D-CT scan sets were acquired for 20 patients who underwent EB-PBI.The volume of the tumour bed (TB) was determined based on seroma or surgical clips on the ten sets of 4D-CT images.For each patient a conventional 3D conformal plan (3D-CRT) was generated based on the 4D-CT end inhalation phase images,then copied and applied to the other phases.The following parameters were calculated to analyse:mean dose (D),homogeneity index (HI),conformal index (CI),and the volumes that received ≥ x Gy (Vx).Results During free breathing,the TB centroid motion was 0.90,0.75 and 0.80 mm in the lateral,anteroposterior and superior-inferior directions,respectively.The medium spatial motion vector was 0.95 mm.In the superiorinferior direction,TB motion significantly correlated with D HI,and CI of PTV (r =-0.458,-0.451 and 0.462,P ＜ 0.05),as well as D V20 and V30 received by the ipsilateral normal breast (r=0.527,0.488 and0.526,P ＜0.05).And in the motion vector,the D V5,V10,V20 of the ipsilateral lung all correlated with TB motion (r =0.416,0.503,0.522 and 0.498,P ＜ 0.05).A correlation also existed between dose and percent volume of heart and volume variation of heart (Dmean,V5 and V10) (r =0.727,0.704 and 0.695,P ＜ 0.05).Conclusions Small TB motion caused by respiratory motion during free breathing result in dosimetric variation of the target and potential dosimetric off-target or suboptimal dose coverage for EB-PBI.The doses of lung during free breathing were relatively sensitive to TB motion and thorax expansion,while heart doses were not influenced notably.

A Phase I/II Trial to Evaluate the Technical Feasibility of Partial Breast Irradiation with Three-Dimensional Conformal Radiation Therapy in Korean Women with Stage I Breast Carcinoma: An Initial Report of the Korean Radiation Therapy Oncology Group (KROG / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: This prospective study was designed to verify the technical feasibility of partial breast irradiation in breast cancer patients with small breasts, which are commonly encountered in Korean women. MATERIALS AND METHODS: A total of 40 Gy, administered in 10 fractions on consecutive days (one fraction per day), was prescribed to the isocenters of the fields using three-dimensional conformal radiotherapy (3-DCRT). For all patients, treatment planning and dose parameters strictly adhered to the constraints set forth in the Radiation Therapy Oncology Group (RTOG) 0319 protocol. This study was designed such that if fewer than five of the first 42 evaluable patients received unacceptable scores, the treatment would be considered reproducible. RESULTS: Ten treatment plans (23.8%) were determined to have major variations. There was no major variation in planning target volume (PTV) coverage. The ipsilateral and contralateral breast dose limitations were not met in four (9.5%) and four cases (9.5%), respectively. Major variations in ipsilateral and contralateral lung dose limitations were observed in two cases (4.8%). Major variations in the heart and thyroid dose limitations were observed in one (2.4%) and one case (2.4%), respectively. In multivariate analysis, a ratio of PTV to ipsilateral breast volume (PTV/IB) > 0.16 was the only significant factor that statistically affected major variations. CONCLUSION: We concluded that partial breast irradiation using 3-DCRT could not be reproduced in Korean breast cancer patients, particularly small-volumed breast surrogated as PTV/IB > 0.16. The dominant cause was the major variation in surrounding normal breast tissues.

Dosimetric comparison of three techniques in treatment of accelerated partial breast irradiation / 中华放射医学与防护杂志

Objective To dosimetrically compare three delivery techniques of VMAT,IMRT and 3D-CRT in the treatment of accelerated partial breast irradiation (APBI).Methods Twenty patients with T1/2N0M0breast cancer were treated with VMAT.These cases were subsequently re-planned using static gantry IMRT and 3D-CRT technology to evaluate dosimetric differences.Dosimetric parameters including dose conformity index (CI),dose volume histogram (DVH) analysis of normal tissue coverage,dose parameters of PTV and normal tissues were evaluated,the delivery parameters including MU and delivery time were also analyzed.Results The IMRT and VMAT plans provided lower maximum dose,better mean dose and more conformal target dose distributions than the 3D-CRT plans (F =14.86,8.57,18.23,P ＜0.05).The volume of ipsilateral breast receiving 5 Gy for VMAT technique was significantly less than that of3D-CRTor IMRT(F=5.83,P＜0.05).The ipsilateral lung volume receiving 20 Gy (V20),5 Gy(V5) and the 5％ volume dose (D5) of IMRT were superior to those of 3D-CRT and VMAT(F =16.39,3.62,4.81,P ＜ 0.05).The low volume dose distributions of D5 in contralateral lung for IMRT was better than that of VMAT and 3D-CRT(F =3.99,3.43,P ＜ 0.05).The total mean MUs for VMAT,3D-CRT and IMRT were 621.0 ± 111.9,707.3 ± 130.9 and 1161.4 ± 315.6,respectively (F =31.30,P ＜ 0.05).The average machine delivery time was(1.5 ± 0.2)min for the VMAT plans,(7.0 ± 1.6)min for the 3D-CRT plans and (11.5 ± 1.9)min for the IMRT plans.Conclusions VMAT and IMRT techniques offer improved dose conformity as compared with 3D-CRT techniques without increasing dose to the ipsilateral lung.In terms of MU and delivery time,VMAT is more efficient for APBI than conventional 3D-CRT and static beam IMRT.

Radioterapia externa parcial acelerada en pacientes con cáncer de seno en estado temprano / External Beam Partial Breast Irradiation for Early Breast Cancer

Objetivo: Demostrar la eficacia y efectividad de la radioterapia parcial acelerada en cáncer temprano de mama en pacientes tratadas con cirugía conservativa. Método: Se trataron cien mujeres con radioterapia externa parcial acelerada, con dosis en un rango de 35 a 38,5 Gy, en 10 fracciones en 5 días dos veces al día con un intervalo de 6 horas. Todas se trataron con 4 campos no cooplanares. El volumen tumoral clínico estuvo cubierto de forma homogénea con la isodosis del 100 %; así mismo el volumen de planeación del blanco, incluido en la isodosis del 95 %. Resultados: El seguimiento promedio fue de 54,3 meses. La tolerancia al tratamiento fue buena y ninguna mujer presentó toxicidad grado 2 o 3. Hasta el momento una paciente presentó recaída ganglionar, local y a distancia. Conclusión: El tratamiento fue bien tolerado, con toxicidad baja y con buenos resultados, en un tiempo corto, con posibles beneficios económicos especialmente en la población de países en vías de desarrollo...

Objective: In this study, our purpose was todemonstrate the feasibility and effectiveness ofexternal beam partial breast irradiation (PBI) inpatients with early-stage breast cancer treated withbreast-conserving surgery. Methods: 100 patientswere treated with PBI with doses ranging from 35to 38.5 Gy, in 10 fractions b.i.d. All patients weretreated with four non-coplanar fields. The clinicaltumor volume was well encompassed withinthe isodose line of 100 % as well as the planningtarget volume which was within the isodose lineof 95 %. Results: The median follow-up was of54.3 months. The treatment was well tolerated,with no more than grade I toxicity. So far, therehas been one patient with local and axillar recurrence.Conclusions: In our experience, thetreatment was well tolerated with low toxicityand with good results, in a shorter treatment time,with the economical benefits this has, especiallyfor populations in developing countries...

Comparison of displacement of the geometry constituted by silver clips in cavity in the different state of respiration assisted by active breathing control system in external-beam partial breast irradiation / 中华放射肿瘤学杂志

ObjectiveTo investigate the effect of the displacement of the selected silver clip in the different respiratory state achieved by active breathing control ( ABC ) system on the displacement of the geometry constituted by all of the silver clips at the border of the cavity in external-beam partial breast irradiation (EB-PBI).MethodsTwo sets of CT images in state of moderate deep inspiratory breathing hold (mDIBH),deep expiratory breathing hold (DEBH),and free breath (FB) were acquired in the same CT simulation assisted by ABC system for each of the 27 patients after breast conservative surgery.All silver clips in the cavity were delineated based on each set of CT images.Thereafter,the irregular geometry based on the silver clips as the vertices was automatically formed.Four selected clips located at the top,bottom,lateral border and medial border of the cavity were correspondingly manually registered based on automatic registration of the CT images acquired in the same or different state of respiration including mDIBH,FB,and DEBH.The displacement of center of the geometry in the direction of right-left (RL),anterior-posterior (AP),and superior-inferior (SI) separately based on automatic registration and manual registration was evaluated.The difference of the displacement was analyzed by Kruskal-Wallis H-test and Kolmogorov-Smirnov Z-test.Results When registered between mDIBH and mDIBH,FB and FB,DEBH and DEBH,the differences of the displacement of the center of geometry were not statistically significant (H =0.00 - 1.76,P=0.184-0.954). When registered between mDIBH and DEBH,the differences were statistically significant ( Z =11.31 - 23.00,P =0.000 - 0.001 ).There were statistically significant differences in the displacement of geometry center based on the selected silver clip between different registration forms in AP and SI directions (Z=4.76-25.54,P=0.000-0.029).ConclusionsThe difference of intrafraction displacement of the geometry constituted by the clips between the same respiratory states in the three dimensional direction is not statistically significant,but the difference is statistically significant between the different respiratory states in AP and SI directions.

Dosimetric comparison of three-dimensional conformal radiotherapy,intensity-modulated radiotherapy and volumetric modulated arc radiotherapy in partial breast irradiation / 中华放射医学与防护杂志

Objective To compare the dosimetric differences of three-dimensional conformal radiotherapy (3D-CRT), 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.Three different techniques including 3D-CRT,IMRT and V-MAT were designed for each patient.The dosimetry in the target,the dose to the organs at risk(OAR),the MU and delivery time were compared.Results All three plans met the clinical requirement. 3D-CRT showed the worst conformity in target. V-MAT provided the lowest target coverage and homogeneity in target.3D-CRT plans showed the lowest values for the V5,V10,mean dose and the highest values for V30 in the ipsilateral lung.No statistically significant differences were observed in V20 of the ipsilateral lung among three plans.V-MAT showed the lowest values in ipsilateral normal breast volume 15,20 and 25 Gy post-irradiation.For V5,the 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(z =-2.94 - -2.09,P ＜ 0.05 ).The MUs in 3D-CRT,IMRT and V-MAT were 417.6 ± 34.4,772.8 ± 54.4 and 631.0 ± 109.0,respectively (z =- 2.93, - 2.76,-2.93,P ＜ 0.05 ). V-MAT significantly reduced the delivery time. Conclusions V-MAT shows significant advantages in reducing the dose in the ipsilateral normal breast and the delivery time compared with 3D-CRT and IMRT.

Accelerated partial breast irradiation for early breast cancer / 国际肿瘤学杂志

With a view to patterns of local recurrence after breast conserving surgery, whole breast irradiation(WBI) after surgery is controversial and partial-breast irradiation(PBI) came up. Many clinical trials related with accelerated partial-breast irradiation using a variety of radiotherapeutic techniques such as interstitial brachytherapy (IBT), MammoSite Radiation Therapy System, intraoperative radiotherapy(IORT), threedimensional conformal radiotherapy(3-DCRT)and intensity modulated radiation therapy(IMRT) in selected patients have been carried out. Accelerated partial-breast irradiation that provides faster, more convenient treat-ment demonstrates local control rate and safety comparable to that of whole breast irradiation. Partial breast irradiation may be an alternative way to whole breast radiotherapy and will be one of the standard treatments in women with early breast cancer seeking breast conservation.

Comparative study of the displacement of the selected clips in the cavity measured by orthogonal kilovoltage X-ray film in conditions of free breath and active breathing control for patients treated by external-beam partial breast irradiation / 中华放射肿瘤学杂志

Objective To compare the displacements of the clips in the cavity measured with orthagonal kilovoltage (KV) X-my plain film in conditions of moderate deep inspiration breathing hold(mDIBH) and free breath (FB), and compare the margins from clinical target volume (CTV) to planning target volume (PTV) based on the displacements. Methods Before radiotherapy, 2 and 5 sets of orthogonal KV plain film were respectively collected in mDIBH and FB group, then the automatic registration of the reconstructed KV plain film and DRR derived from the planning OF images was finished. In conditions of mDIBH and FB, the displacements of the selected clip at the same location in the different directions and of the different selected clips in the same direction were compared. The margins in three dimensional directions were calculated and compared in conditions of mDIBH and FB . Results In FB hold group, the difference of displacement in left-right (LR), cranial-caudal (CC) and anterior-posterior (AP) directions were statistically significant between the clips at the cranial and caudal border of the cavity (9. 7 mm and 10. 6 nun (Z = -2. 12,P =0. 037) ,7. 3 mm and 8. 3 mm (Z = -2. 31 ,P=0. 041) ,15.5 mm and 16. 1 nun (Z = -2. 32,P = 0. 041)), but not statistically significant for the clips at the bottom and lateral P=0.814),15.7 mm and 16.5 mm (Z=-0.26,P=0.856)). The corresponding differences in the different directions were statistically significant (5.0 mm and 7. 8 mm(Z = -2. 31, P =0. 036), 5.0 mm and 9. 3 nun (Z= -2. 21,P=0. 021),7. 8 mm and9.3 mm (Z= -2. 11,P=0.041)). In FB group, the differences of the displacements of the four selected clips were statistically significant in CC and AP directions (7.3 mm and 8.4 mm (Z= -2.45,P=0.021), 15.5 mm and 16.5 mm (Z= -2.41,P= 0.043)), but not in LF direction (10.6 nun and 10.6 mm (Z= -0.24,P=0. 815)). In mDIBH group, the displacements in LF direction were statistically significant (4. 4 mm and 5.4 mm (Z = -2. 31, P = O. 031)), but not in CC and AP directions (8. 6 mm and 8.6 mm (Z =-0. 21, P = 0. 815), 10. 5 mm and 10. 8 mm (Z = -0. 27 ,P =0. 754)). There were statistically significant difference of the margins in LF and AP directions (9.7 mm and 5.0 mm (Z= -2.34,P=0.029),15.5 mm and 9.3 mm (Z= -2. 31,P= 0.021)), but not in CC direction (7.3 mm and 7. 8 mm (Z= -0.29,P =0.770)) between mDIBH and FB conditions. Conclusions The margins extended from CTV to PTV for EBPBI should be determined based on the respiratory status, border location and border direction.