Radiotherapy to the Left Breast with 3DCRT, IMRT or VMAT: International Medical Center Experience

Radiation therapy after conservative breast surgery is an integral part of the treatment of early breast cancer. The aim of radiotherapy is to achieve the best coverage of the Planning Target Volume (PTV), while reducing the dose to the Organs at Risk (OAR). Such goals are not always achievable with the conformal three dimensions plans (3DCRT). Recently, radiation oncologist uses Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast. In this study, we compared 3DCRT, IMRT and VMAT for left breast cancer patients in terms of PTV coverage, OAR. We also revised the different dose distribution in 1) different breast volume categories, 2) nodal irradiation versus breast only, and 3) boost versus no boost. Results: The routinely reported dose constrains for the ipsilateral lung and for the heart were not significantly different on comparing the three techniques. While for the contralateral lung, the difference in mean dose was in favor of 3DCRT. In large breast volume, 3DCRT provided a lower Max dose to the contralateral lung and the lowest mean dose to the contralateral breast when compared to IMRT p < 0. 046. In case of no nodal irradiation, the contralateral breast mean dose was lower in 3DCRT in comparison to IMRT and VMAT p < 0.037. When boost dose was given, 3DCRT plans had produced a lower Max dose to the contralateral lung p < 0.017. Conclusion: The three techniques (3DCRT, IMRT, and VMAT) can meet the clinical dosimetry demands of radiotherapy for left breast cancer after conservative surgery, as long as the routinely OARs only (heart and ipsilateral lung) are reported. Our study showed that 3CDRT can provide a lower dose to the contralateral organs (breast and lung), specially, in case of large breast volumes, no nodal irradiation and when a boost is given.

Helical tomotherapy and volumetric modulated arc therapy:New therapeutic arms in the breast cancer radiotherapy

AIM To analyse clinical and dosimetric results of helical tomotherapy(HT) and volumetric modulated arc therapy(VMAT) in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT). Dose were 63.8 Gy(HT) and 63.2 Gy(VMAT) in the tumour bed, 52.2 Gy in the breast, 50.4 Gy in supraclavicular nodes(SCN) and internal mammary chain(IMC) with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions. Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort, the coverage of clinical target volumes was as follows: Tumour bed: 99.4% ± 2.4%; breast: 98.4% ± 4.3%; SCN: 99.5% ± 1.2%; IMC:96.5% ± 13.9%. For the VMAT cohort, the coverage was as follows: Tumour bed: 99.7% ± 0.5%, breast: 99.3% ± 0.7%; SCN: 99.6% ± 1.4%; IMC: 99.3% ± 3%. For ipsilateral lung, Dmean and V20 were 13.6 ± 1.2 Gy, 21.1% ± 5%(HT) and 13.6 ± 1.4 Gy, 20.1% ± 3.2%(VMAT). Dmean and V30 of the heart were 7.4 ± 1.4 Gy, 1% ± 1%(HT) and 10.3 ± 4.2 Gy, 2.5% ± 3.9%(VMAT). For controlateral breast Dmean was 3.6 ± 0.2 Gy(HT) and 4.6 ± 0.9 Gy(VMAT). Acute skin toxicity grade 3 was 5% in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance. A longer follow-up is needed to assess the impact of low doses to healthy tissues.

Effects of postmastectomy radiotherapy on prognosis in different tumor stages of breast cancer patients with positive axillary lymph nodes

Objective: To explore the effects of postmastectomy radiotherapy(PMRT) on the locoregional failure-free survival(LRFFS) and overall survival(OS) of breast cancer patients under different tumor stages and with one to three positive axillary lymph nodes(ALNs). Methods: We conducted a retrospective review of 527 patients with one to three positive lymph nodes who underwent modified radical or partial mastectomy and axillary dissection from January 2000 to December 2002. The patients were divided into the T1-T2 N1 and T3-T4 N1 groups. The effects of PMRT on the LRFFS and OS of these two patient groups were analyzed using SPSS 19.0, Pearson's χ2-test, Kaplan-Meier method, and Cox proportional hazard model. Results: For T1-T2 N1 patients, no statistical significance was observed in the effects of PMRT on LRFFS [hazard ratio(HR)=0.726; 95% confidence interval(CI): 0.233-2.265; P=0.582] and OS(HR=0.914; 95% CI: 0.478-1.745; P=0.784) of the general patients. Extracapsular extension(ECE) and high histological grade were the risk factors for LRFFS and OS with statistical significance in multivariate analysis. Stratification analysis showed that PMRT statistically improved the clinical outcomes in high-risk patients [ECE(+), LRFFS: P=0.026, OS: P=0.007; histological grade III, LRFFS: P<0.001, OS: P=0.007] but not in low-risk patients [ECE(–), LRFFS: P=0.987, OS: P=0.502; histological grade I-II, LRFFS: P=0.816, OS: P=0.296]. For T3-T4 N1 patients, PMRT effectively improved the local control(HR=0.089; 95% CI: 0.210-0.378; P=0.001) of the general patients, whereas no statistical effect was observed on OS(HR=1.251; 95% CI: 0.597-2.622; P=0.552). Absence of estrogen receptors and progesterone receptors(ER/PR)(–) was an independent risk factor. Further stratification analysis indicated a statistical difference in LRFFS and OS between the high-risk patients with ER/PR(–) receiving PMRT and not receiving PMRT [ER/PR(–), LRFFS: P=0.046, OS: P=0.039]. However, PMRT had a beneficial effect on the reduction of locoregional recurrence(LRR) but not in total mortality [ER/PR(+), LRFFS: P<0.001, OS: P= 0.695] in T3-T4 N1 patients with ER/PR(+) who received endocrine therapy. Conclusion: PMRT could reduce ECE(+), histological grade III-related LRR, and total mortality of T1-T2 N1 patients. T3-T4 N1 patients with ER/PR(–) could benefit from PMRT by improving LRFFS and OS. However, PMRT could only reduce LRR but failed to improve OS for T3-T4 N1 patients with ER/PR(+) who received endocrine therapy.

Survey on physicians' opinions of post-mastectomy radiotherapy for breast cancer in Guangdong province

Objective:The aim of our study was to comprehensively access current status of radiotherapy physicians' opinions in post-mastectomy radiotherapy(PMRT) for breast cancer in Guangdong province.Methods:From June 2007 to June 2008,questionnaires on the clinical value,sequencing with chemotherapy and endocrine therapy,indications and irradiated targets for PMRT were sent to physicians of all radiotherapy departments registering at Radiotherapy Professional Committee of Guangdong Anti-cancer Association.Results:There were 126 physicians joining this investigation.Proportions of physicians who accepted the views that PMRT could merely improve local control or can improve both local control and overall survival were 100% and 25.2%.The most common sequences of PMRT and chemotherapy or endocrine therapy were "sandwich" and sequential modes,performed 46.9% and 59.5% respectively.The median interval of surgery and PMRT was 8 weeks.Proportions of physicians who accepted T3-4 diseases,or four or more axillary lymph nodes metastasis,or T1-2 with 1-3 positive lymph nodes,or T1-2N0 with primary tumor located in the center or inner quadrant as the indications of PMRT were 97.6%,100%,46.8%,13.5%,respectively.Proportions of physicians who accepted chest wall,supraclavicular region,internal mammary chain or axilla as irradiated targets were 86.5%,100%,49.2% and 38.9% respectively.Conclusion:For Radiotherapy physicians of Guangdong Province,there is still lacking of consensus in the opinions of whether PMRT can improve survival,and optimal sequencing with chemotherapy or endocrine therapy,and how to make decision for patients with T1-2 with 1-3 positive lymph nodes,and rational irradiated targets,which requires advanced professional training for physicians and further prospective clinical trial evidences to guide clinical practice.

Experience with intraoperative radiotherapy for breast cancer: the Geneva University Hospital's experience

Background Breast conserving surgery along with adjuvant radiotherapy is effective in terms of local control and survival for early- stage breast cancer （1）. External beam radiotherapy （EBRT） following breast conserving surgery has been shown to improve survival by preventing local recurrence, in the Early Breast Cancer Trialists＇ Collaborative Group meta-analysis （2）. Standard radiotherapy typically requires numerous fractions over a 3-5 week period and is performed weeks or months after surgery or chemotherapy.

Comparison of dosimetry with magnetic resonance and computed tomography imaging delineation of surgical bed volume in breast cancer irradiation

Background Postoperative radiotherapy after conservative surgery for patients with breast cancer usually includes focal over-irradiation(boost)to the surgical bed(SB).Irradiation planning using computed tomography(CT)is difficult in many cases because of insufficient intrinsic soft tissue contrast.To ensure appropriate radiation to the tumor,large boost volumes are delineated,resulting in a higher dose to the normal tissue.Magnetic resonance imaging(MRI)provides superior soft tissue contrast than CT and can better differentiate between normal tissue and the SB.However,for SB delineation CT images alone remain the pathway followed in patients undergoing breast irradiation.This study aimed to evaluate the potential advantages in boost dosimetry by using MRI and CT as pre-treatment imaging.Methods Eighteen boost volumes were drawn on CT and MRI and elastically co-registered using commercial image registration software.The radiotherapy treatment plan was optimized using the CT volumes as the baseline.The dose distributions of the target volumes on CT and MRI were compared using dose-volume histogram cutoff points.Results The radiation volumes to the SB varied considerably between CT and MRI(conformity index between 0.24 and 0.67).The differences between the MRI and CT boost doses in terms of the volume receiving 98%of the prescribed dose(V98%)varied between 10%and 30%.Smaller differences in the V98%were observed when the boost volumes were delineated using MRI.Conclusion Using MRI to delineate the volume of the SB may increase the accuracy of boost dosimetry.