Randomized controlled trial of intensity-modulated radiotherapy for early breast cancer: 5-year results confirm superior overall cosmesis

Radiation Doses Received by Major Organs at Risk in Children and Young Adolescents Treated for Cancer with External Beam Radiation Therapy: A Large-scale Study from 12 European Countries

PURPOSE

Childhood cancer survivors, in particular those treated with radiation therapy, are at high risk of long-term iatrogenic events. The prediction of risk of such events is mainly based on the knowledge of the radiation dose received to healthy organs and tissues during treatment of childhood cancer diagnosed decades ago. We aimed to set up a standardized organ dose table to help former patients and clinicians in charge of long-term follow-up clinics.

METHODS AND MATERIALS

We performed whole body dosimetric reconstruction for 2646 patients from 12 European countries treated between 1941 and 2006 (median, 1976). Most plannings were 2- or 3-dimensional. A total of 46% of patients were treated using Cobalt 60, and 41%, using a linear accelerator. The median prescribed dose was 27.2 Gy (IQ1-IQ3, 17.6-40.0 Gy). A patient-specific voxel-based anthropomorphic phantom with more than 200 anatomic structures or substructures delineated as a surrogate of each subject's anatomy was used. The radiation therapy was simulated with a treatment planning system based on available treatment information. The radiation dose received by any organ of the body was estimated by extending the treatment planning system dose calculation to the whole body, by type and localization of childhood cancer.

RESULTS

The integral dose and normal tissue doses to most of the 23 considered organs increased between the 1950s and 1970s and decreased or plateaued thereafter. Whatever the organ considered, the type of childhood cancer explained most of the variability in organ dose. The country of treatment explained only a small part of the variability.

CONCLUSIONS

The detailed dose estimates provide very useful information for former patients or clinicians who have only limited knowledge about radiation therapy protocols or techniques, but who know the type and site of childhood cancer, sex, age, and year of treatment. This will allow better prediction of the long-term risk of iatrogenic events and better referral to long-term follow-up clinics.

Hypofractionated whole breast IMRT with HDR brachytherapy boost in early-stage breast cancer: Long-term results from a single-center

INTRODUCTION/OBJECTIVES

The addition of a boost to the lumpectomy bed after whole-breast (WB) radiotherapy plays a key role in the treatment of patients with breast cancer (BC). The clinical benefits of a boost with high-dose-rate brachytherapy (HDR-BT) after conventional fractionation is supported by a large body of evidence. However, few studies have described its outcomes after a hypofractionated scheme.

MATERIALS AND METHODS

We included all patients treated with adjuvant WB-IMRT in 15 sessions followed by a single-session HDR-BT boost with local anesthesia on an outpatient basis.

RESULTS

Between 2009 and 2017, 638 patients with early-stage BC were treated according to the aforementioned protocol after breast-conserving surgery. Median follow-up was 6 years (4-11). Despite the low incidence of side effects and their slightness, we did identify an impact of breast volume on the risk of acute radiodermatitis, fibrosis, pain and edema. However, we did not identify any relationship between the volume in cubic centimeters of the BT-implant with acute or long-term side effects. 2.2% patients had an actual local relapse, 2.4% a 2nd primary in the same breast and 2.39% were diagnosed with contralateral BC. Event-free survival at 11 years was 85.5% with an overall survival of 95.7%.

CONCLUSION

Adjuvant hypofractionated whole-breast IMRT followed by a single dose HDR-BT boost has a low incidence of acute and chronic toxicity and excellent oncological outcomes. However, it may be worthwhile to intensify self-care protocols and surveillance in women with large breasts who may be at increased risk of side effects.

Modifiable Postmastectomy Radiation Therapy Factors and Impact on Implant-Based Breast Reconstruction Outcomes

BACKGROUND

Intensity-modulated radiation therapy and other modifiable radiation factors have been associated with decreased radiation toxicity. These factors could allow for improved reconstructive outcomes in patients requiring postmastectomy radiation therapy (PMRT). However, they have not yet been well studied in implant-based breast reconstruction.

METHODS

The authors performed a retrospective chart review of patients who underwent mastectomy with immediate tissue expander placement followed by PMRT. Radiation characteristics were collected, including radiation technique, bolus regimen, x-ray energy, fractionation, maximum radiation hot spot, and tissue volume receiving more than 105% or more than 107% of the prescription dose. Reconstructive complications occurring after initiation of PMRT were analyzed with respect to these radiation characteristics.

RESULTS

Sixty-eight patients (70 breasts) were included in this study. The overall complication rate was 28.6%, with infection being the most common complication (24.3%), requiring removal of the tissue expander or implant in greater than half of infections (15.7%). Maximum radiation hot spot was greater in patients who required explantation after PMRT, and this approached statistical significance (114.5% ± 7.2% versus 111.4% ± 4.4%; P = 0.059). Tissue volume receiving more than 105% and 107% were also greater in patients who required explantation after PMRT (42.1% ± 17.1% versus 33.0% ± 20.9% and 16.4% ± 14.5% versus 11.3% ± 14.6%, respectively); however, this was not statistically significant ( P = 0.176 and P = 0.313, respectively). There were no significant differences in complication rates between patients with respect to radiation technique or other radiation characteristics studied.

CONCLUSION

Minimizing the radiation hot spots and volumes of tissue receiving greater than the prescription dose of radiation may improve reconstructive outcomes in patients undergoing implant-based breast reconstruction followed by PMRT.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

A Beam Angle Selection Method to Improve Plan Robustness Against Position Error in Intensity-Modulated Radiotherapy for Left-Sided Breast Cancer

PURPOSE

We report a dosimetric study in whole breast irradiation (WBI) of plan robustness evaluation against position error with two radiation techniques: tangential intensity-modulated radiotherapy (T-IMRT) and multi-angle IMRT (M-IMRT).

METHODS

Ten left-sided patients underwent WBI were selected. The dosimetric characteristics, biological evaluation and plan robustness were evaluated. The plan robustness quantification was performed by calculating the dose differences (Δ) of the original plan and perturbed plans, which were recalculated by introducing a 3-, 5-, and 10-mm shift in 18 directions.

RESULTS

M-IMRT showed better sparing of high-dose volume of organs at risk (OARs), but performed a larger low-dose irradiation volume of normal tissue. The greater shift worsened plan robustness. For a 10-mm perturbation, greater dose differences were observed in T-IMRT plans in nearly all directions, with higher ΔD98%, ΔD95%, and ΔDmean of CTV Boost and CTV. A 10-mm shift in inferior (I) direction induced CTV Boost in T-IMRT plans a 1.1 (ΔD98%), 1.1 (ΔD95%), and 1.7 (ΔDmean) times dose differences greater than dose differences in M-IMRT plans. For CTV Boost, shifts in the right (R) and I directions generated greater dose differences in T-IMRT plans, while shifts in left (L) and superior (S) directions generated larger dose differences in M-IMRT plans. For CTV, T-IMRT plans showed higher sensitivity to a shift in the R direction. M-IMRT plans showed higher sensitivity to shifts in L, S, and I directions. For OARs, negligible dose differences were found in V20 of the lungs and heart. Greater ΔDmax of the left anterior descending artery (LAD) was seen in M-IMRT plans.

CONCLUSION

We proposed a plan robustness evaluation method to determine the beam angle against position uncertainty accompanied by optimal dose distribution and OAR sparing.

Noninferiority of Local Control and Comparable Toxicity of Intensity Modulated Radiation Therapy With Simultaneous Integrated Boost in Breast Cancer: 5-Year Results of the IMRT-MC2 Phase III Trial

PURPOSE

The IMRT-MC2 trial was conducted to demonstrate the noninferiority of conventionally fractionated intensity modulated radiation therapy with a simultaneous integrated boost to 3-dimensional conformal radiation therapy with a sequential boost for adjuvant breast radiation therapy.

METHODS AND MATERIALS

A total of 502 patients were randomized between 2011 and 2015 for the prospective, multicenter, phase III trial (NCT01322854). Five-year results of late toxicity (late effects normal tissue task force-subjective, objective, management, and analytical), overall survival, disease-free survival, distant disease-free survival, cosmesis (Harvard scale), and local control (noninferiority margin at hazard ratio [HR] of 3.5) were analyzed after a median follow-up of 62 months.

RESULTS

The 5-year local control rate for the intensity modulated radiation therapy with simultaneous integrated boost arm was non-inferior to the control arm (98.7% vs 98.3%, respectively; HR, 0.582; 95% CI, 0.119-2.375; P = .4595). Furthermore, there was no significant difference in overall survival (97.1% vs 98.3%, respectively; HR, 1.235; 95% CI, 0.472-3.413; P = .6697), disease-free survival (95.8% vs 96.1%, respectively; HR, 1.130; 95% CI, 0.487-2.679; P = .7758), and distant disease-free survival (97.0% vs 97.8%, respectively; HR, 1.667; 95% CI, 0.575-5.434; P = .3601). After 5 years, late toxicity evaluation and cosmetic assessment further showed no significant differences between treatment arms.

CONCLUSIONS

The 5-year results of the IMRT-MC2 trial provide strong evidence that the application of conventionally fractionated simultaneous integrated boost irradiation for patients with breast cancer is both safe and effective, with noninferior local control compared with 3-dimensional conformal radiation therapy with sequential boost.

Risk evaluation of secondary malignancies after radiotherapy of breast cancer in light of the continuous development of planning techniques

Secondary cancer risk is a significant concern for women treated with breast radiation therapy due to improved long-term survival rates. We evaluated the potential of new advanced automated planning algorithms together with hybrid techniques to minimize the excess absolute risk (EAR) for secondary cancer in various organs after radiation treatment for early staged breast cancer. Using CT data set of 25 patients, we generated 4 different radiation treatment plans of different complexity, including 3-dimensional conformal radiotherapy (3D-CRT), field-in-field (FinF), hybrid-IMRT (HMRT) and automated hybrid-VMAT (HVMAT) techniques. The organ-equivalent dose (OED) was calculated from differential dose-volume histograms on the basis of the "linear-exponential," "plateau," and "full mechanistic" dose-response models and was used to evaluate the EAR for secondary cancer in the contralateral breast (CB), contralateral lung (CL), and ipsilateral lung (IL). Statistical comparisons of data were performed by a Kruskal-Wallis analysis of variance. The planning objectives were fulfilled with all the planning techniques for both target coverage and organs-at-risk sparing. The differences in EAR for CB, CL and IL secondary tumor induction were not significant among the 4 techniques. For the CB and CL, the mean absolute difference did not reach 1 case of 10000 patient-years. For the IL, the mean absolute difference was up to 5 cases of 10,000 patient-years. In conclusion, the automated HVMAT technique allows an EAR reduction at the level of well-consolidated tangential 3D-CRT or FinF techniques, keeping all the HVMAT dosimetric improvements unchanged. On the basis of this analysis, the adoption of the HVMAT technique poses no increase in EAR and could be considered safe also for younger patients.

Beyond the heart in hypofractionated radiotherapy and in the transition from 3D to IMRT/VMAT

Background

The knowledge of the risks induced by radiation with hypofractionation regimens has only recently been estimated together with its implementation as a management standard. However, the dose to other risk organs with intensity-modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) is not clear, that is why this is only a reference study of radiation doses to organs at risk in hypofractionation in our center.

Materials and methods

We completed a retrospective and observational analysis of 1398 patients treated with adjuvant hypofractionated radiotherapy from 2015 to 2018, using the clinical records and dose-volume histogram of patients treated with moderate hypofractionated adjuvant radiotherapy. To analyze the institutional experience on the dosimetry of the esophagus and liver as risk organs in the use of moderate adjuvant hypofractionated radiotherapy in breast cancer.

Results

The dosimetry of the esophagus was 3271 cGy DMax, 177 cGy DMed, 68 cGy D50%, 500 cGy DcMAX with 3D RT and 4124 cGy DMax, 1242 cGy DMed, 934.50 cGy D50%, 3213 cGy DcMAX with IMRT/VMAT and the dosimetry for the liver was for right breast cancer 466 cGy DMed, 102 cGy D50% and 8% V20, for left breast cancer 22 cGy DMed, 6.10 cGy D50% and 0.3% V20.

Conclusion

The statistically significant differences in irradiation show the lack of consensus on the optimal restrictions in hypofractionation regimens to reduce clinical sequela; consequently, the variability in the specification of each radiation oncologist is observed; standardization in our center can lead to improvement in the quality of treatments.

Evaluation of Cardiac Substructures Exposure of DIBH-3DCRT, FB-HT, and FB-3DCRT in Hypofractionated Radiotherapy for Left-Sided Breast Cancer after Breast-Conserving Surgery: An In Silico Planning Study

Left-sided breast cancer radiotherapy can lead to late cardiovascular complications, including ischemic events. To mitigate these risks, cardiac-sparing techniques such as deep-inspiration breath-hold (DIBH) and intensity-modulated radiotherapy (IMRT) have been developed. However, recent studies have shown that mean heart dose is not a sufficient dosimetric parameter for assessing cardiac exposure. In this study, we aimed to compare the radiation exposure to cardiac substructures for ten patients who underwent hypofractionated radiotherapy using DIBH three-dimensional conformal radiation therapy (3DCRT), free-breathing (FB)-3DCRT, and FB helical tomotherapy (HT). Dosimetric parameters of cardiac substructures were analyzed, and the results were statistically compared using the Wilcoxon signed-rank test. This study found a significant reduction in the dose to the heart, left anterior descending coronary artery, and ventricles with DIBH-3DCRT and FB-HT compared to FB-3DCRT. While DIBH-3DCRT was very effective in sparing the heart, in some cases, it provided little or no cardiac sparing. FB-HT can be an interesting treatment modality to reduce the dose to major coronary vessels and ventricles and may be of interest for patients with cardiovascular risks who do not benefit from or cannot perform DIBH. These findings highlight the importance of cardiac-sparing techniques for precise delivery of radiation therapy.

Evaluation of the ESMO-Magnitude of Clinical Benefit Scale version 1.1 (ESMO-MCBS v1.1) for adjuvant radiotherapy in breast cancer

BACKGROUND

The European Society of Medical Oncology (ESMO) has suggested using the ESMO-Magnitude of Clinical Benefit Scale (MCBS) to grade the magnitude of clinical benefit of cancer therapies. This approach has not been applied to radiation therapy (RT) yet. We applied the ESMO-MCBS to experiences describing the use of RT to assess (1) the 'scoreability' of the data, (2) evaluate the reasonableness of the grades for clinical benefit and (3) identify potential shortcomings in the current version of the ESMO-MCBS in its applicability to RT.

MATERIALS AND METHODS

We applied the ESMO-MCBS v1.1 to a selection of studies in radiotherapy that had been identified as references in the development of American Society for Radiation Oncology (ASTRO) evidence-based guidelines on whole breast radiation. Of the 112 cited references, we identified a subset of 16 studies that are amenable to grading using the ESMO-MCBS.

RESULTS

Of the 16 studies reviewed, 3/16 were scoreable with the ESMO tool. Six of 16 studies could not be scored because of shortcomings in the ESMO-MCBS v1.1: (1) in 'non-inferiority studies', there is no credit for improved patient convenience, reduced patient burden or improved cosmesis; (2) in 'superiority studies' evaluating local control as a primary endpoint, there is no credit for the clinical benefit such as reduced need for further interventions. In 7/16 studies, methodological deficiencies in the conduct and reporting were identified.

CONCLUSIONS

This study represents a first step in determining the utility of the ESMO-MCBS in the evaluation of clinical benefit in radiotherapy. Important shortcomings were identified that would need to be addressed in developing a version of the ESMO-MCBS that can be robustly applied to radiotherapy treatments. Optimization of the ESMO-MCBS instrument will proceed to enable assessment of value in radiotherapy.

Analytical models for external photon beam radiotherapy out-of-field dose calculation: a scoping review

A growing body of scientific evidence indicates that exposure to low dose ionizing radiation (< 2 Gy) is associated with a higher risk of developing radio-induced cancer. Additionally, it has been shown to have significant impacts on both innate and adaptive immune responses. As a result, the evaluation of the low doses inevitably delivered outside the treatment fields (out-of-field dose) in photon radiotherapy is a topic that is regaining interest at a pivotal moment in radiotherapy. In this work, we proposed a scoping review in order to identify evidence of strengths and limitations of available analytical models for out-of-field dose calculation in external photon beam radiotherapy for the purpose of implementation in clinical routine. Papers published between 1988 and 2022 proposing a novel analytical model that estimated at least one component of the out-of-field dose for photon external radiotherapy were included. Models focusing on electrons, protons and Monte-Carlo methods were excluded. The methodological quality and potential limitations of each model were analyzed to assess their generalizability. Twenty-one published papers were selected for analysis, of which 14 proposed multi-compartment models, demonstrating that research efforts are directed towards an increasingly detailed description of the underlying physical phenomena. Our synthesis revealed great inhomogeneities in practices, in particular in the acquisition of experimental data and the standardization of measurements, in the choice of metrics used for the evaluation of model performance and even in the definition of regions considered out-of-the-field, which makes quantitative comparisons impossible. We therefore propose to clarify some key concepts. The analytical methods do not seem to be easily suitable for massive use in clinical routine, due to the inevitable cumbersome nature of their implementation. Currently, there is no consensus on a mathematical formalism that comprehensively describes the out-of-field dose in external photon radiotherapy, partly due to the complex interactions between a large number of influencing factors. Out-of-field dose calculation models based on neural networks could be promising tools to overcome these limitations and thus favor a transfer to the clinic, but the lack of sufficiently large and heterogeneous data sets is the main obstacle.

Quantifying the value of older adult-specific clinical trials: Post-lumpectomy irradiation among older adults with early-stage breast cancer

INTRODUCTION

Although there is increasing interest in conducting cancer clinical trials in older adults, the benefit of such trials is unclear. We aimed to quantify the real-world clinical and economic effects of two phase 3 trials (CALGB 9343 and PRIME II) which showed that post-lumpectomy radiation therapy (RT) improves loco-regional recurrence but makes no improvement in overall survival among older women with early-stage breast cancer (ESBC).

MATERIALS AND METHODS

We developed a health-transition model to quantify the incremental clinical and economic outcomes between scenarios with vs. without older adult-specific trial results from a societal perspective between 2004 and 2018. The transition probabilities in the model were mainly derived from the 10-year results of CALGB 9343. The total number of the affected patient population in the US and the change in the probability of omitting post-lumpectomy RT due to the CALGB 9343 and PRIME II results were derived from a retrospective analysis of the SEER registry data for patients with ESBC. Sensitivity analyses were conducted to calculate the 95% credible interval (CR) of the incremental clinical and economic outcomes between the two scenarios.

RESULTS

Between 2004 and 2018, 32,936 (95% CR: 31,512, 34,357) fewer patients received post-lumpectomy RT among those aged 70 years or older diagnosed with ESBC in the US and there was a decrease cost of $419 M USD (95% CR: -$238 M, -$689 M) in scenarios with vs. without older adult-specific trial results. The difference in projected life years (1083 years, 95% CI: -2542, 7985) and QALYs (866 years, 95% CI: -2561, 7780) were not significant. At a willingness-to-pay threshold of $100 k/QALY, the probability of older adult-specific trial results generating a positive net monetary benefit was 98%.

DISCUSSION

The CALGB 9343 and PRIME II trial results were associated with a substantial cost-saving in the US society. Our results suggest that older adult-specific clinical trials that demonstrate no survival benefit of an intervention in older adults could be correlated with a significant monetary benefit. Further case studies are needed for different types of older adult-specific trials to understand the value of older adult-specific trials comprehensively.

Helical tomotherapy experience in breast cancer adjuvant radiotherapy and acute toxicity results

Background

This study aimed to evaluate acute toxicity and oncological outcomes of breast cancer patients who underwent adjuvant radiotherapy (RT) with tomotherapy.

Materials and methods

The results of 114 patients who underwent adjuvant RT with Tomotherapy device between 17.08.10-12.06.2021 in Ankara Atatürk Training and Research Hospital and Ankara City Hospital were evaluated retrospectively. The primary endpoint of the study was acute adverse events, and the secondary endpoints were overall survival (OS) and disease-free survival (DFS).

Results

The results of 103 patients who met the inclusion criteria were analyzed. The median follow-up was 21 (range 1-125.8) months. Grade +3 esophagitis was not observed in any patient; no esophagitis was observed in 60 (58.3%) patients. Grade 3 dermatitis was observed in 3 (2.9%) patients. In addition, dermatitis was not observed in 47 (45.6%) patients. The relationship between chest wall volume and esophagitis development was statistically significant (p = 0.006; Z score: -2769). The median OS was 24.1 (range 1-128.5) and median disease-free survival was 21.1 (range 1-125.8) months. Five patients (4.9%) died and 9 patients (8.7%) relapsed. Local recurrence was observed in only 1 (1%) patient. There was a statistically significant correlation between OS and contralateral lung V20 dose [p < 0.001; Spearman Correlation Coefficient (SCC) -406) and heart mean dose (p < 0.001; SCC -370)]. There was a statically significant correlation between DFS and cN (p < 0.001); pN (p < 0.001); heart mean dose (p < 0.001; SCC -351); contralateral lung V5 dose (p = 0.041; SCC -213); contralateral lung V20 dose (p < 0.001; SCC -434).

Conclusion

Acute toxicity results show improvement in breast cancer adjuvant radiotherapy with helical tomotherapy.

On the feasibility of improved target coverage without compromising organs at risk using online adaptive stereotactic partial breast irradiation (A-SPBI)

PURPOSE

Describe an early-adopting institution's experience with online adaptive radiation for stereotactic partial breast irradiation.

METHODS AND MATERIALS

Retrospective review of 22 women treated between May 2021 and March 2022 with adaptive stereotactic partial breast irradiation. A total of 106 of 110 fractions were evaluated for dosimetric changes in target coverage and organ-at-risk (OAR) dose. Patient set up with stereotactic wooden frame and adapted per fraction. Treatment and planning times were collected prospectively by radiation therapists.

RESULTS

Scheduled PTV_30 Gy was <95% in 72.1% and <90% in 38.5% of fractions, and both PTV and CTV coverage were improved significantly after adaption, and 83.7% of fractions were delivered as adapted per physician choice. There was no difference in OAR coverage. Average adaptive treatment planning took 15 min and average time-on-couch was 34.4 min.

CONCLUSIONS

Adaptive stereotactic breast irradiation resulted in improved target coverage with equivalent dosing to OARs in an efficient and tolerated treatment time. Improved target coverage allowed for decreased PTV margins compared to prior trial protocols that may improve acute and late toxicities.

Cost-effectiveness of Post-Mastectomy Radiotherapy (PMRT) for breast cancer in India: An economic modelling study

Background

The role of post-mastectomy radiotherapy (PMRT) for breast cancer is controversial when 3-or-less lymph nodes are metastatic. Apart from local control, survival and toxicity, cost also plays an important role in decision-making.

Methods

A Markov model was designed to assess cost, health outcomes and cost-effectiveness of different radiotherapy techniques for management of PMRT patients. Thirty-nine scenarios were modelled based on type of radiotherapy, laterality, pathologic nodal burden, and dose fractionation. We considered a societal perspective, lifetime horizon and a 3% discount rate. The data on quality of life (QoL) was derived using the cancer database on cost and QoL. Published data on cost of services delivered in India were used.

Findings

Post-mastectomy radiotherapy results in incremental quality adjusted life years (QALYs) that ranged from -0.1 to 0.38 across different scenarios. The change in cost ranged from estimated median savings of USD 62 (95% confidence intervals: -168 to -47) to incurring an incremental cost of USD 728 (650-811) across different levels of nodal burden, breast laterality and dose fractionation. For women with node-negative disease, disease-specific systemic therapy remains to be the preferred strategy. For women with node-positive disease, two-dimensional radiotherapy (2DRT) with hypofractionation is the most cost-effective strategy. However, a CT based planning is preferred when maximum heart distance (MHD) >1cm, irregular chest wall contour and inter-field separation >18cm.

Interpretation

PMRT is cost-effective for all node-positive patients. With similar toxicity and effectiveness profile compared with conventional fractionation, moderate hypofractionation significantly reduces the cost of treatment and should be the standard of care. Conventional techniques for PMRT are cost-effective over newer modalities which provide minimal additional benefit, at high cost.

Funding

The funding to collect primary data for study was provided by Department of Health Research, Ministry of Health and Family Welfare, New Delhi, wide letter number F. No. T.11011/02/2017-HR/3100291.

Radiotherapy of Breast Cancer-Professional Guideline 1st Central-Eastern European Professional Consensus Statement on Breast Cancer

The international radiotherapy (RT) expert panel has revised and updated the RT guidelines that were accepted in 2020 at the 4th Hungarian Breast Cancer Consensus Conference, based on new scientific evidence. Radiotherapy after breast-conserving surgery (BCS) is indicated in ductal carcinoma in situ (stage 0), as RT decreases the risk of local recurrence (LR) by 50-60%. In early stage (stage I-II) invasive breast cancer RT remains a standard treatment following BCS. However, in elderly (≥70 years) patients with stage I, hormone receptor-positive tumour, hormonal therapy without RT can be considered. Hypofractionated whole breast irradiation (WBI) and for selected cases accelerated partial breast irradiation are validated treatment alternatives to conventional WBI administered for 5 weeks. Following mastectomy, RT significantly decreases the risk of LR and improves overall survival of patients who have 1 to 3 or ≥4 positive axillary lymph nodes. In selected cases of patients with 1 to 2 positive sentinel lymph nodes axillary dissection can be substituted with axillary RT. After neoadjuvant systemic treatment (NST) followed by BCS, WBI is mandatory, while after NST followed by mastectomy, locoregional RT should be given in cases of initial stage III-IV and ypN1 axillary status.

Breast Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The therapeutic options for patients with noninvasive or invasive breast cancer are complex and varied. These NCCN Clinical Practice Guidelines for Breast Cancer include recommendations for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, and management of breast cancer during pregnancy. The content featured in this issue focuses on the recommendations for overall management of ductal carcinoma in situ and the workup and locoregional management of early stage invasive breast cancer. For the full version of the NCCN Guidelines for Breast Cancer, visit NCCN.org.

New fractionations in breast cancer: a dosimetric study of 3D-CRT versus VMAT

INTRODUCTION

Adjuvant radiation therapy (RT) following primary surgery in women affected by early breast cancer (EBC) plays a central role in reducing local recurrences and overall mortality. The FAST-FORWARD trial recently demonstrated that 1-week hypofractionated adjuvant RT is not inferior to the standard schedule in terms of local relapse, cosmetic outcomes and toxicity. The aim of this in silico study was to evaluate the dosimetric aspects of a 1-week RT course, administered through volumetric modulated arc therapy (VMAT), compared with traditional three-dimensional conformal radiation therapy (3D-CRT) with tangential fields.

METHODS

Patients affected by left-side EBC undergoing adjuvant RT were selected. ESTRO guidelines for the clinical target volume (CTV) delineation and FAST-FORWARD protocol for CTV to planning target volume (PTV) margin definition were followed. Total prescribed dose was 26 Gy in five fractions. The homogeneity index (HI) and the global conformity index (GCI) were taken into account for planning and dose distribution optimisation purposes. Both 3D-CRT tangential fields and VMAT plans were generated for each patient.

RESULTS

The analysis included 21 patients. PTV coverage comparison between 3D-CRT and VMAT plans showed significant increases for GCI (P < 0.05) in VMAT technique; no statistically significant differences were observed regarding HI. For organs at risks (OAR), statistically significant increases were observed in terms of skin V103% (P < 0.002) and ipsilateral lung V30% (P < 0.05) with 3D-CRT and of heart V5% (P < 0.05) with VMAT technique.

CONCLUSIONS

This in silico study showed that both 3D-CRT and VMAT are dosimetrically feasible techniques in the framework of 1-week hypofractionated treatments for left EBC.

Factors Associated with Late Local Radiation Toxicity after Post-Operative Breast Irradiation

Purpose. To assess determinants associated with late local radiation toxicity in patients treated for breast cancer. Methods. A systematic review was performed. All studies reporting ≥2 variables associated with late local radiation toxicity after treatment with postoperative whole breast irradiation were included. Cohort studies, randomized controlled trials, and cross-sectional studies were eligible designs. Study characteristics and definitions of determinants and outcome measures were extracted. If possible, the measure of association was extracted. Results. Twenty-one studies were included in this review. Six out of seven studies focused on the association between radiotherapy (boost) dose or irradiated breast volume and late radiation toxicity found significant results. Tumor bed boost was associated with late radiation toxicity, fibrosis, and/or edema in six out of twelve studies. Lower age was associated with late breast toxicity in one study, while in another study, higher age was significantly associated with breast fibrosis. Also, no association between age and late radiation toxicity was found in eight out of twelve studies. Similar inconsistent results were found in the association between late radiation toxicity and other patient-related factors (i.e., breast size, diabetes mellitus) and surgical and systemic treatment-related factors (i.e., complications after surgery, chemotherapy, and time between surgery and radiotherapy). Conclusion. In modern 3D radiotherapy, radiotherapy (boost) dose and volume are—like in 2D radiotherapy—associated with late local radiation toxicity, such as breast fibrosis and edema. Treatment de-escalation, for example, partial breast irradiation in selected patients might be important to decrease late local toxicity without compromising locoregional control and survival.

Comparative Effectiveness Analysis of 3D-Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy (IMRT) in a Prospective Multicenter Cohort of Patients With Breast Cancer

PURPOSE

Simple intensity modulation of radiation therapy reduces acute toxicity compared with 2-dimensional techniques in adjuvant breast cancer treatment, but it remains unknown whether more complex or inverse-planned intensity modulated radiation therapy (IMRT) offers an advantage over forward-planned, 3-dimensional conformal radiation therapy (3DCRT).

METHODS AND MATERIALS

Using prospective data regarding patients receiving adjuvant whole breast radiation therapy without nodal irradiation at 23 institutions from 2011 to 2018, we compared the incidence of acute toxicity (moderate-severe pain or moist desquamation) in patients receiving 3DCRT versus IMRT (either inverse planned or, if forward-planned, using ≥5 segments per gantry angle). We evaluated associations between technique and toxicity using multivariable models with inverse-probability-of-treatment weighting, adjusting for treatment facility as a random effect.

RESULTS

Of 1185 patients treated with 3DCRT and conventional fractionation, 650 (54.9%) experienced acute toxicity; of 774 treated with highly segmented forward-planned IMRT, 458 (59.2%) did; and of 580 treated with inverse-planned IMRT, 245 (42.2%) did. Of 1296 patients treated with hypofractionation and 3DCRT, 432 (33.3%) experienced acute toxicity; of 709 treated with highly segmented forward-planned IMRT, 227 (32.0%) did; and of 623 treated with inverse-planned IMRT, 164 (26.3%) did. On multivariable analysis with inverse-probability-of-treatment weighting, the odds ratio for acute toxicity after inverse-planned IMRT versus 3DCRT was 0.64 (95% confidence interval, 0.45-0.91) with conventional fractionation and 0.41 (95% confidence interval, 0.26-0.65) with hypofractionation.

CONCLUSIONS

This large, prospective, multicenter comparative effectiveness study found a significant benefit from inverse-planned IMRT compared with 3DCRT in reducing acute toxicity of breast radiation therapy. Future research should identify the dosimetric differences that mediate this association and evaluate cost-effectiveness.

Potential gains: Comparison of a mono-isocentric three-dimensional conformal radiotherapy (3D-CRT) planning technique to hybrid intensity-modulated radiotherapy (hIMRT) to the whole breast and supraclavicular fossa (SCF) region

INTRODUCTION

Until late 2018, standard of practice at the Northern Sydney Cancer Centre (NSCC) for breast and nodal treatment was a conformal mono-isocentric technique. A planning study comparing an existing mono-isocentric three-dimensional conformal radiotherapy (3D-CRT) planning technique to a hybrid intensity-modulated radiotherapy (hIMRT) approach for the whole breast and supraclavicular fossa (SCF) region was undertaken with the aim to improve plan quality by improving dose conformity/homogeneity across target volumes and reducing hotspots outside the target.

METHODS

A cohort of 17 patients was retrospectively planned using the proposed hIMRT technique, keeping the same planning constraints as the original treated breast and SCF 3D-CRT plan and normalising the 3D-CRT plans to achieve minimum breast/SCF target coverage to compare organs at risk (OARs). Normal tissue index (NTI) and homogeneity index (HI) were compared for plan quality as well as for evaluating OARs.

RESULTS

The hIMRT technique showed statistically significant improvements in NTI and HI, as well as improvement in maximum brachial plexus and thyroid doses. There was a negligible increase in maximum oesophagus dose which could be improved if used in optimisation. Other OAR doses in the irradiated region were comparable to the 3D-CRT plans, however maximum doses were reduced overall.

CONCLUSION

The hIMRT planning technique maintained clinically acceptable doses to OARs and reduced normal tissue dose while maintaining equivalent dose coverage to breast and SCF planning target volumes with improved conformity and homogeneity. The reduction in maximum doses promotes a favourable toxicity profile, with potential benefit of improved long-term cosmesis.

The Impact of an Incidental Dose on Axillary Tumor Control and Toxicity in Localized Breast Cancer: A Retrospective Analysis

Simple Summary

The incidental axillary dose varies according to the whole breast irradiation technique. However, this dose has not been shown to be a prognostic factor for locoregional recurrence. The objectives of our retrospective study are to dosimetrically evaluate the incidental axillary dose according to the different irradiation techniques and the risk factors of axillary recurrence. We confirmed that the irradiation technique has an influence on the incidental dose delivered to the axillary area, but has no influence on the risk of axillary recurrence. The risk of lymphoedema could be related to the use of high tangential beams and the mean dose delivered at level II.

Abstract

Purpose: The dosimetric analysis of the incidental axillary dose delivered to axillary lymph node levels I–III by different techniques of whole breast irradiation and the analysis of prognostic factors of axillary recurrence of breast cancer. Methods: We perform a retrospective analysis that includes 171 patients with localized breast carcinoma irradiated at Centre Paul Strauss. To be included in the study, patients had to have a histological confirmation of breast cancer diagnosis, surgical treatment without axillary lymph node dissection (ALND), whole breast irradiation without axillary irradiation by a specific field, and a treatment plan available. Results: Three patients had lymph node recurrence. There was no significant correlation between the maximal or mean dose delivered at the three axillary levels and the risk of axillary lymph node recurrence. There was no significant correlation between the irradiation technique and the risk of axillary lymph node recurrence. Two patients, both in the HT group, had lymphoedema. There was significantly more lymphoedema in the HT group than in the ST and IMRT groups (p < 0.048). The mean dose in level II was significantly higher in the group of patients with lymphoedema (3.45 Gy (1.08; 9.62) vs. 23.4 Gy (23.1; 23.6)) (p < 0.02). Conclusion: The irradiation technique has an influence on the incidental dose delivered to the axillary area, but has no influence on the risk of axillary recurrence. The risk of lymphoedema could be related to the use of HT and the mean dose delivered at level II.

Evaluation of robustness in hybrid intensity-modulated radiation therapy plans generated by commercial software for automated breast planning

This study aimed to evaluate the robustness against geometric uncertainties in the hybrid intensity-modulated radiation therapy (IMRT) plans generated by commercially available software for automated breast planning (ABP). The ABP plans were compared with commonly used forward-planned field-in-field (FIF) technique plans. The planning computed tomography datasets of 20 patients who received left-sided breast-conserving surgery were used for both the ABP and FIF plans. Geometric uncertainties were simulated by shifting beam isocenters by 2, 3, 5, and 10 mm in the six directions: anterior/posterior, left/right, and superior/inferior. A total of 500 plans (20 patients and 25 scenarios, including the original plan) were created for each of the ABP and FIF plans. The homogeneity index of the target volume in the ABP plans was significantly better (p < 0.001) than the value in the FIF plans in the scenarios of shifting beam isocenters by 2, 3, and 5 mm. Mean heart dose and percentage volume of lungs receiving a dose more than 20 Gy were clinically acceptable in all scenarios. The hybrid IMRT plans generated by commercially available ABP software provided better robustness against geometric uncertainties than forward-planned FIF plans.

Tangential Volumetric Modulated Arc Therapy for Locally Advanced Breast Cancer

Cardiovascular toxicity from breast radiotherapy is a concern to patients and providers. Here we present a cardiac-sparing strategy utilizing tangential VMAT (tVMAT) in comparison to standard 3DCRT. Ten patients with left-sided breast cancer previously treated with adjuvant RT covering breast, axillary, and supraclavicular nodal regions were selected for the study. For each patient two plans were created: 1) a dual-isocenter three-field 3DCRT plan and 2) a monoisocentric tVMAT plan. The prescription for both techniques was 50 Gy in 25 fractions to the breast and nodal target volumes. Compared to 3DCRT, tVMAT provided more uniform coverage to breast and regional lymph nodes (mean conformity index was 1.42 for tVMAT versus 2.42 for 3DCRT, p<0.01) and the max point dose for tVMAT was lower on average (112.8% for tVMAT versus 121.5% for 3DCRT, p<0.001). Coverage to lymph nodes was superior for tVMAT (average minimum-coverage to 95% of entire nodal target volumes was 99.5% of the prescribed dose for tVMAT versus 94.9% for 3DCRT, p <0.001). OAR sparing was improved with tVMAT, with a lower average V20_Gy for the left lung (15.0% for tVMAT versus 24.6% for 3DCRT, p<0.01), and lower mean heart dose (156 cGy for tVMAT versus 200 cGy for 3DCRT, p<0.01). In conclusion, tangential VMAT is a promising technique for the treatment of intact breast and regional lymphatics and may improve target coverage and OAR avoidance compared to 3D conformal techniques.

Variations in Head and Neck Treatment Plan Quality Assessment Among Radiation Oncologists and Medical Physicists in a Single Radiotherapy Department

Background

Agreement between planners and treating radiation oncologists (ROs) on plan quality criteria is essential for consistent planning. Differences between ROs and planning medical physicists (MPs) in perceived quality of head and neck cancer plans were assessed.

Materials and Methods

Five ROs and four MPs scored 65 plans for in total 15 patients. For each patient, the clinical (CLIN) plan and two or four alternative plans, generated with automated multi-criteria optimization (MCO), were included. There was always one MCO plan aiming at maximally adhering to clinical plan requirements, while the other MCO plans had a lower aimed quality. Scores were given as follows: 1-7 and 1-2, not acceptable; 3-5, acceptable if further planning would not resolve perceived weaknesses; and 6-7, straightway acceptable. One MP and one RO repeated plan scoring for intra-observer variation assessment.

Results

For the 36 unique observer pairs, the median percentage of plans for which the two observers agreed on a plan score (100% = 65 plans) was 27.7% [6.2, 40.0]. In the repeat scoring, agreements between first and second scoring were 52.3% and 40.0%, respectively. With a binary division between unacceptable (scores 1 and 2) and acceptable (3-7) plans, the median inter-observer agreement percentage was 78.5% [63.1, 86.2], while intra-observer agreements were 96.9% and 86.2%. There were no differences in observed agreements between RO-RO, MP-MP, and RO-MP pairs. Agreements for the highest-quality, automatically generated MCO plans were higher than for the CLIN plans.

Conclusions

Inter-observer differences in plan quality scores were substantial and could result in inconsistencies in generated treatment plans. Agreements among ROs were not better than between ROs and MPs, despite large differences in training and clinical role. High-quality automatically generated plans showed the best score agreements.

Comparison of volumetric modulated arc therapy and intensity-modulated radiotherapy for left-sided whole-breast irradiation using automated planning

Background

Published treatment technique comparisons for postoperative left-sided whole breast irradiation (WBI) with deep-inspiration breath-hold (DIBH) are scarce, small, and inconclusive. In this study, fully automated multi-criterial plan optimization, generating a single high-quality, Pareto-optimal plan per patient and treatment technique, was used to compare for a large patient cohort 1) intensity modulated radiotherapy (IMRT) with two tangential fields and 2) volumetric modulated arc therapy (VMAT) with two small tangential subarcs.

Materials and methods

Forty-eight randomly selected patients recently treated with DIBH and 16 × 2.66 Gy were included. The optimizer was configured for the clinical planning protocol. Comparisons between IMRT and VMAT included dosimetric plan parameters, estimated excess relative risks (ERR) for toxicities, delivery times, MUs, and deliverability accuracy at a linac.

Results

The automatically generated IMRT and VMAT plans applied in this study were similar or higher in quality than the manually generated clinical plans. For equal PTVin V95% (98.4 ± 0.9%), VMAT had significant advantages compared to IMRT regarding breast dose homogeneity and doses in heart and ipsilateral lung, at the cost of some minor deteriorations for contralateral breast (few cases with larger deteriorations) and lung. Conformality improved from 1.38 to 1.18 (p < 0.001). With VMAT, ERR for major coronary events and ipsilateral lung tumors were reduced by 3% (range: −1–12%) and 16% (range: −3–38%), respectively. MUs and delivery times were higher for VMAT. There were no statistical differences in γ passing rates.

Conclusion

For WBI in conservative therapy of left-sided breast patients treated with DIBH, VMAT with two tangential subarcs was generally dosimetrically superior to IMRT with two tangential static fields. Results need confirmation by robustness analyses.

Association of Breast Cancer Irradiation With Cardiac Toxic Effects: A Narrative Review

IMPORTANCE

To promptly recognize and manage cardiovascular (CV) risk factors before, during, and after cancer treatment, decreasing the risk of cancer therapy-related cardiac dysfunction is crucial. After recent advances in breast cancer treatment, mortality rates from cancer have decreased, and the prevalence of survivors with a potentially higher CV disease risk has increased. Cardiovascular risks might be associated with the multimodal approach, including systemic therapies and breast radiotherapy (RT).

OBSERVATIONS

The heart disease risk seems to be higher in patients with tumors in the left breast, when other classic CV risk factors are present, and when adjunctive anthracycline-based chemotherapy is administered, suggesting a synergistic association. Respiratory control as well as modern RT techniques and their possible further refinement may decrease the prevalence and severity of radiation-induced heart disease. Several pharmacological cardioprevention strategies for decreasing cardiac toxic effects have been identified in several guidelines. However, further research is needed to ascertain the feasibility of these strategies in routine practice.

CONCLUSIONS AND RELEVANCE

This review found that evidence-based recommendations are lacking on the modalities for and intensity of heart disease screening, surveillance of patients after RT, and treatment of these patients. A multidisciplinary and multimodal approach is crucial to guide optimal management.

Two-year toxicity of simultaneous integrated boost in hypofractionated prone breast cancer irradiation: Comparison with sequential boost in a randomized trial

INTRODUCTION

A simultaneous integrated boost (SIB) leads to less acute toxicity. Less is known for late toxicity due to SIB. In this first and only randomized trial, two-years toxicity is analysed.

MATERIALS AND METHODS

Physician-assessed toxicity, using the LENT SOMA scale, and photographs, analysed with the BCCT.core software, was examined for 150 patients, randomized between SIB and sequential boost (SEB).

RESULTS

Differences in physician-assessed two-years toxicity and photographic analysis between SIB and SEB are very small and not significant.

CONCLUSION

There is no indication that a SIB leads to an excess in toxicity or worse cosmetic outcome at 2 years.

[Diffusion prophylactic axillary irradiation in breast cancer - Literature review]

PURPOSE

In breast cancer, radiotherapy is an essential component of the treatment. However, indications of irradiation of the internal mammary chain and axillary area are debatables. Axillary recurrence in patients with invasive breast carcinoma remains an issue. Currently, the substitution of axillary lymph node dissection by sentinel node biopsy leads to revisit the role of axillary irradiation. Breast irradiation including level I, II and III might decrease the risk of axillary recurrence.

MATERIAL AND METHODS

A literature search was performed in PubMed and the Cochrane library to identify articles publishing data regarding dose-volume analysis of axillary levels in breast irradiation aiming to determine the potential therapeutic implications.

RESULTS

Eleven articles were retained. A total of 375 treatment plans were analyzed. The results concerning the irradiation technique, initial dose prescribed to breast, delineated volumes and dose received at axillary levels were heterogeneous. The average dose delivered to axilla levels I-III with 3D-conformal radiotherapy using standard fields were between 24Gy and 43.5Gy, 3Gy and 32.5Gy and between 1.0Gy and 20.5Gy respectively. The average doses delivered to axilla levels I-III with 3D-conformal radiotherapy using high tangential fields were between 38Gy and 49.7Gy, 11Gy and 47.1Gy and 5Gy 38.7Gy, 32.1Gy and 5Gy (result available for only one study) respectively. Finally, the average doses delivered to axilla levels I-III with intensity modulated radiation therapy were between 14.5Gy and 42.6Gy, 3.4Gy and 35Gy and between 1.2Gy and 25.5Gy respectively.

CONCLUSIONS

Incidental axillary dose seems insufficient to be therapeutic regardless of the irradiation technique. There are meaningful differences between intensity modulated radiation therapy and 3D-conformal radiotherapy.

Breast cancer radiotherapy: What physicians need to know in the era of the precision medicine

Breast cancer is the most common cancer in women worldwide and encompasses a broad spectrum of diseases in one with significant epidemiological, clinical, and biological heterogeneity, which determines a different natural history and prognostic profile. Although classical tumour staging (TNM) still provides valuable information, the current reality is that the clinicians must consider other biological and molecular factors that directly influence treatment decision-making. The management of breast cancer has changed radically in the last 15 years due to significant advances in our understanding of these tumours. This knowledge has brought with it a major impact regarding surgical and systemic management and has been practice-changing, but it has also created significant uncertainties regarding how best integrate the radiotherapy treatment into the therapeutic scheme. In parallel, radiotherapy itself has also experienced major advances, new radiobiological concepts have emerged, and genomic data and other patient-specific factors must now be integrated into individualised treatment approaches. In this context, "precision medicine" seeks to provide an answer to these open questions and uncertainties. The aim of the present review is to clarify the meaning of this term and to critically evaluate its role and impact on contemporary breast cancer radiotherapy.

Insights into the theranostic value of precision medicine on advanced radiotherapy to breast cancer

Breast cancer is the most common cancer in women worldwide. "Breast cancer" encompasses a broad spectrum of diseases (i.e., subtypes) with significant epidemiological, clinical, and biological heterogeneity. Each of these subtypes has a different natural history and prognostic profile. Although tumour staging (TNM classification) still provides valuable information in the overall management of breast cancer, the current reality is that clinicians must consider other biological and molecular factors that directly influence treatment decision-making, including extent of surgery, indication for chemotherapy, hormonal therapy, and even radiotherapy (and treatment volumes). The management of breast cancer has changed radically in the last 15 years due to significant advances in our understanding of these tumours. While these changes have been extremely positive in terms of surgical and systemic management, they have also created significant uncertainties concerning integration of local and locoregional radiotherapy into the therapeutic scheme. In parallel, radiotherapy itself has also experienced major advances. Beyond the evident technological advances, new radiobiological concepts have emerged, and genomic data and other patient-specific factors must now be integrated into individualized treatment approaches. In this context, "precision medicine" seeks to provide an answer to these open questions and uncertainties. Although precision medicine has been much discussed in the last five years or so, the concept remains somewhat ambiguous, and it often appear to be used as a "catch-all" term. The present review aims to clarify the meaning of this term and, more importantly, to critically evaluate the role and impact of precision medicine on breast cancer radiotherapy. Finally, we will discuss the current and future of precision medicine in radiotherapy.

Dosimetric comparison of left sided whole breast irradiation with Tangential wedge beam, electron boosted Tangential wedged beam and asymmetric technique

Background:

Irradiation of the adjacent critical structures is inevitable in breast cancer radiotherapy (RT). Our purpose is to assess the dose distribution across the breast tissue and adjacent organs with our institutional asymmetric technique for left-sided breast cancer compared to the standard tangential wedged beam (TWB) and electron-boosted TWB techniques.

Materials and Methods:

The three RT planning were created for 30 consecutive patients with a focus on proper coverage of the planning target volume (PTV). The irritated doses into the heart, ipsilateral lung, and left anterior descending artery (LAD) were evaluated.

Results:

No significant difference was found in the mean values of relative PTV irradiated to 47.5 Gy, PTV dose and the volume of PTV, and critical organs between the treatments. The mean dose (Dmean) irradiated to the heart and LAD was lowest with the electron-boosted TWB. The Dmean to the heart was comparable between the TWB and asymmetric RT techniques, while the Dmean to LAD was significantly reduced with asymmetric technique versus TWB. The heart volume receiving ≥25 Gy and the Dmean to the left lung were significantly decreased with the asymmetric technique compared with TWB. The mean relative lung volume irradiated to ≥20 Gy was comparable between all techniques. The mean central lung distance was also significantly increased from 18.03 ± 4.5 cm with asymmetric RT to 37.47 ± 5.6 cm with TWB and to 27.67 ± 3.8 cm with electron-boosted TWB techniques.

Conclusion:

The asymmetric technique is useful for patients with breast cancer on the left side, having acceptable PTV coverage and considerably reduced cardiopulmonary doses.

Can the Choice of Radiotherapy Delivery Technique Influence Which Target Delineation Protocol to Use? A Plan-Quality-Based Analysis in Left Breast Cancer

Introduction This study investigates the optimal target delineation protocol stratified by treatment planning technique in patients undergoing whole breast radiotherapy after breast conservation surgery.

Materials and Methods Target delineation using Tangent (RTOG 0413 Whole Breast Irradiation Protocol), European SocieTy for Radiotherapy and Oncology (ESTRO), and Radiation Therapy & Oncology Group (RTOG) guidelines was performed on 10 randomly selected treatment planning computed tomography datasets of patients with left-sided breast cancer. An objective plan quality metric (PQM) scoring schema was defined and communicated to the medical physicist prior to commencement of treatment planning. Treatment planning was performed using field-in-field (FiF) intensity modulated radiotherapy technique (IMRT), inverse IMRT, and volumetric modulated arc therapy (VMAT), for each type of target. Two-way repeated measures, analysis of variance was utilized to compare the total PQM scores and dosimetric variables, stratified by treatment planning method.

Results Total PQM score of plans for FiF, IMRT, and VMAT revealed that Tangent and ESTRO delineations were equivalent regardless of planning technique (Tangent vs. ESTRO for FiF, p = 0.099; Tangent vs. ESTRO for IMRT, p = 0.029; Tangent vs. ESTRO for VMAT, p = 0.438). Both delineation protocols were significantly superior to RTOG for all treatment planning techniques.

Conclusion For all treatment planning techniques, ESTRO and Tangent delineation were equivalent and both achieved significantly higher scores than RTOG delineation.

Prospective Study of Intensity-Modulated Radiation Therapy for Locally Advanced Breast Cancer

Simple Summary

Tomotherapy is a modern intensity-modulated radiotherapy technique, whose aim is to reduce the high doses delivered to organs at risk. Thus, we conducted a prospective study evaluating the early and medium-term toxicities, the patient’s quality of life, and the aesthetic outcomes (evaluated by both physicians and patients) of tomotherapy for breast cancer. We wanted to show that this treatment is very well tolerated, with low-grade acute toxicities, and has only a moderate impact on patients’ quality of life and aesthetic outcome, in order to support its larger use in this very frequent situation.

Abstract

The objective of this study was to evaluate the acute and medium-term toxicities, the quality of life, and aesthetic results of patients with breast cancer (BC) treated with tomotherapy. This was a prospective study, including patients with BC treated by tomotherapy. Radiation therapy delivered 50 Gy in 25 fractions to the breast or chest wall and to lymph node areas, with a simultaneous integrated boost at a dose of 60 Gy at the tumor bed in cases of breast conservative surgery. We included 288 patients, 168 and 120 treated with breast-conserving surgery and mastectomy respectively. Two hundred sixty patients (90.3%) received lymph node irradiation. Median follow-up was 25 months (6–48). Acute dermatitis was observed in 278 patients (96.5%), mostly grade 1 (59.7%). The aesthetic aspect of the breast at one year was reported as “good” or “excellent” in 84.6% of patients. The patients’ quality of life improved over time, especially those treated with chemotherapy. The two-year overall survival and disease-free survival were 97.8% (95% confidence interval (CI): 94.1–99.2%), and 93.4% (95% CI: 89.2–96.0%) respectively. Tomotherapy for locally advanced BC has acceptable toxicity, supporting its use in this indication; however, longer follow-up is needed to assess long-term outcomes.

Intensity Modulated Radiation Therapy (IMRT) With Simultaneously Integrated Boost Shortens Treatment Time and Is Noninferior to Conventional Radiation Therapy Followed by Sequential Boost in Adjuvant Breast Cancer Treatment: Results of a Large Randomized Phase III Trial (IMRT-MC2 Trial)

PURPOSE

In the modern era, improvements in radiation therapy techniques have paved the way for simultaneous integrated boost irradiation in adjuvant breast radiation therapy after breast conservation surgery. Nevertheless, randomized trials supporting the noninferiority of this treatment to historical standards of care approach are lacking.

METHODS

A prospective, multicenter, randomized phase 3 trial (NCT01322854) was performed to analyze noninferiority of conventional fractionated intensity modulated radiation therapy with simultaneous integrated boost (IMRT-SIB) to 3-D conformal radiation therapy with sequential boost (3-D-CRT-seqB) for breast cancer patients. Primary outcomes were local control (LC) rates at 2 and 5 years (noninferiority margin at hazard ratio [HR] of 3.5) as well as cosmetic results 6 weeks and 2 years after radiation therapy (evaluated via photo documentation calculating the relative breast retraction assessment [pBRA] score [noninferiority margin of 1.25]).

RESULTS

A total of 502 patients were randomly assigned from 2011 to 2015. After a median follow-up of 5.1 years, the 2-year LC for the IMRT-SIB arm was noninferior to the 3-D-CRT-seqB arm (99.6% vs 99.6%, respectively; HR, 0.602; 95% CI, 0.123-2.452; P = .487). In addition, noninferiority was also shown for cosmesis after IMRT-SIB and 3-D-CRT-seqB at both 6 weeks (median pBRA, 9.1% vs 9.1%) and 2 years (median pBRA, 10.4% vs 9.8%) after radiation therapy (95% CI, -0.317 to 0.107 %; P = .332). Cosmetic assessment according to the Harvard scale by both the patient and the treating physician as well as late-toxicity evaluation with the late effects normal tissues- subjective, objective, management, analytic criteria, a score for the evaluation of long-term adverse effects in normal tissue, revealed no significant differences between treatment arms. In addition, there was no difference in overall survival rates (99.6% vs 99.6%; HR, 3.281; 95% CI: -0.748 to 22.585; P = .148) for IMRT-SIB and 3-D-CRT-seqB, respectively.

CONCLUSIONS

To our knowledge, this is the first prospective trial reporting the noninferiority of IMRT-SIB versus 3-D-CRT-seqB with respect to cosmesis and LC at 2 years of follow-up. This treatment regimen considerably shortens adjuvant radiation therapy times without compromising clinical outcomes.

Accelerated partial breast irradiation with 3-dimensional conformal and image-guided intensity-modulated radiotherapy following breast conserving surgery - 7-Year results of a phase II trial

Purpose

To present the 7-year results of accelerated partial breast irradiation (APBI) using three-dimensional conformal (3D-CRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS).

Patients and methods

Between 2006 and 2014, 104 patients were treated with APBI given by means of 3D-CRT using 3–5 non-coplanar, isocentric wedged fields, or IG-IMRT using kV-CBCT. The total dose of APBI was 36.9 Gy (9 × 4.1 Gy) using twice-a-day fractionation. Survival results, side effects and cosmetic results were assessed.

Results

At a median follow-up of 90 months three (2.9%) local recurrences, one (0.9%) regional recurrence and two (1.9%) distant metastases were observed. The 7-year local (LRFS), recurrence free survival was 98.9%. The 7-year disease-free (DFS), metastases free (MFS) and overall survival (OS) was 94.8%, 97.9% and 94.8%, respectively. Late side effects included G1 skin toxicity in 15 (14.4%), G1, G2, and G3 fibrosis in 26 (25%), 3 (2.9%) and 1 (0.9%) patients respectively. Asymptomatic (G1) fat necrosis occurred in 10 (9.6%) patients. No ≥ G2 or higher late side effects occurred with IMRT. The rate of excellent/good and fair/poor cosmetic results was 93.2% and 6.8%, respectively.

Conclusion

7-year results of APBI with 3D-CRT and IG-IMRT are encouraging. Toxicity profile and local tumor control are comparable to other series using multicatheter interstitial brachytherapy. Therefore, these external beam APBI techniques are valid alternatives to whole breast irradiation and brachytherapy based APBI.

•

Phase II APBI trial using 3D-CRT or IG-IMRT.

•

Twice-a-day fractionation, with a total dose of 36.9 Gy (9 × 4.1Gy).

•

No Grade 2 or worst late side effects with IG-IMRT at median follow up of 90 months.

•

These APBI techniques are valid alternatives to WBI or brachytherapy based APBI.

Hypofractionated radiation therapy for breast cancer: Preferences amongst radiation oncologists in Europe - Results from an international survey

BACKGROUND AND PURPOSE

We aimed to assess the prescription preference about hypofractionated radiation therapy (HFRT) for breast cancer (BC) patients amongst radiation oncologists (ROs) practicing in Europe and to identify restraints on HFRT utilisation.

MATERIALS AND METHODS

An online survey was circulated amongst ROs in Europe through personal, RO and BC societies' networks, from October 2019 to March 2020. The statistical analyses included descriptive statistics, chi-squared testing, and logistic regression analysis.

RESULTS

We received 412 responses from 44 countries. HFRT was chosen as the preferred schedule for whole breast irradiation (WBI) by 54.7% and for WBI with regional nodes irradiation (RNI) by 28.7% of the responding ROs. In the case of postmastectomy RT with or without reconstruction, HFRT was preferred by 21.1% and 29.6%, respectively. Overall, 69.2% of the responding ROs selected at least one factor influencing the decision to utilise HFRT, the most frequent of which included age (51.4%), RNI (46.9%), internal mammary lymph nodes irradiation (39.7%), BC stage (33.5%) and implant-based breast reconstruction (31.6%). ROs working in academic centres (odds ratio, (OR), 1.7; 95% confidence interval, (CI); 1.1-2.6, p = 0.019), practicing in Western Europe (OR, 4.2; 95%CI; 2.7-6.6, p < 0.0005) and/or dedicating >50% of clinical time to BC patients (OR, 2.5; 95%CI; 1.5-4.2, p = 0.001) more likely preferred HFRT.

CONCLUSION

Although HFRT is recognised as a new standard, its implementation in routine RT clinical practice across Europe varies for numerous reasons. Better dissemination of evidence-based recommendations is advised to improve the level of awareness about this clinical indication.

Acute toxicity of normofractionated intensity modulated radiotherapy with simultaneous integrated boost compared to three-dimensional conformal radiotherapy with sequential boost in the adjuvant treatment of breast cancer

BACKGROUND

Intensity-modulated radiotherapy (IMRT) improves dose homogeneity and late toxicity compared to simple tangential techniques in adjuvant whole-breast radiotherapy for patients with breast cancer. Simultaneous-integrated boost (SIB) radiotherapy shortens the overall treatment time and improves dose homogeneity. However, prospective randomized trials regarding IMRT with SIB for adjuvant radiotherapy in breast cancer are lacking.

METHODS

The IMRT-MC2 (MINT) trial is a phase III prospective randomized controlled trial comparing IMRT with SIB (Arm A: whole breast 28 × 1.8 Gy, Boost 28 × 2.3 Gy) to 3D-conformal radiotherapy with a sequential boost (Arm B: whole breast 28 × 1.8 Gy, boost 8 × 2 Gy) in patients with breast cancer after BCS. Indication for boost radiotherapy was defined as age < 70 years or age > 70 years with presence of additional risk factors. This is a retrospective analysis of acute toxicity at one of two trial sites.

RESULTS

Five hundred two patients were randomized, of which 446 patients were eligible for this analysis. There was no statistically significant difference in terms of any grade radiation dermatitis between the two treatment arms at the end of treatment (p = 0.26). However, radiation dermatitis grade 2/3 (29.1% vs. 20.1 and 3.5% vs. 2.3%) occurred significantly more often in Arm A (p = 0.02). Breast/chest wall pain at the first follow-up visit was significantly more common in patients treated on Arm B (p = 0.02).

CONCLUSIONS

Treatment on both arms was well tolerated, however there were some differences regarding radiodermatitis and breast pain. Further analyses are ongoing.

TRIAL REGISTRATION

clinicaltrials.gov , NCT01322854 , registered 24th March 2011.

Dosimetry and Feasibility Studies of Volumetric Modulated Arc Therapy With Deep Inspiration Breath-Hold Using Optical Surface Management System for Left-Sided Breast Cancer Patients

Background

During radiotherapy (RT) procedure of breast cancer, portions of the heart and lung will receive some radiation dose, which may result in acute and late toxicities. In the current study, we report the experience of our single institution with organs at risk (OARs)–sparing RT with deep inspiration breath hold (DIBH) using an Optical Surface Management System (OSMS) and compare the dosimetric parameters with that of free breathing (FB).

Patients and Methods

Forty-eight cases diagnosed as early stage left-sided breast cancer scheduled for postoperative RT were enrolled. The OSMS was used to monitor the breathing magnitude and track the real-time respiratory status, which can control a stable lung and heart volume during RT delivery under DIBH. We did the dosimetric analysis of the heart, left anterior descending (LAD) coronary artery, lungs, and contralateral breast under FB and DIBH plans.

Results

Compared with FB–volumetric-modulated arc therapy (FB-VMAT), DIBH-VMAT resulted in significantly changed volumes to the heart and lungs receiving irradiation dose. The average mean heart dose and average D2%, V₅, and V₁₀ showed significant differences between the DIBH and FB techniques. For the LAD coronary artery, we found significantly reduced average mean dose, D2%, and V₁₀ with DIBH. Similar results were also found in the lungs and contralateral breast. The use of flattening-filter–free decreased treatment time compared with the flat beam mode in our VMAT (p < 0.05). For the 48 patients, there were no significant differences in the lateral, longitudinal, and vertical directions between OSMS and cone beam CT.

Conclusions

DIBH-VMAT with OSMS is very feasible in daily practice with excellent patient compliance in our single-center experience. Note that OSMS is an effective tool that may allow easier-to-achieve precise positioning and better and shorter position-verify time. Meanwhile, compared with FB, DIBH was characterized by lower doses to OARs, which may reduce the probability of cardiac and pulmonary complications in the future.

Postoperative radiotherapy with intensity-modulated radiation therapy versus 3-dimensional conformal radiotherapy in early breast cancer: A randomized clinical trial of KROG 15-03

PURPOSE

To investigate the safety and efficacy of intensity-modulated radiation therapy (IMRT) for early breast cancer compared with 3-dimensional conformal radiotherapy (3D-CRT) in a prospective and randomized trial.

METHODS AND MATERIALS

From March 2015 to February 2018, 693 patients with pT1-2N0M0 early breast cancer who underwent breast-conserving surgery were enrolled and randomly assigned into IMRT and 3D-CRT. The primary endpoint was 3-year locoregional recurrence-free survival (LRRFS). The secondary endpoints were recurrence-free survival, overall survival, acute toxicity, target coverage index, irradiation dose to organs at risk, and fatigue inventory. The radiation dose for the 3D-CRT arm was 59.4 Gy in 33 fractions for 6.5 weeks. It was 57.4 Gy in 28 fractions with simultaneous integrated boost for 5.5 weeks for the IMRT arm.

RESULTS

Of 693 patients, 349 and 344 patients received 3D-CRT and IMRT, respectively. There was no significant difference in LRRFS between the two arms. Conformity index of planning target volume was significantly superior in the IMRT arm than the 3D-CRT arm (p < 0.001). The mean lung dose and V₅-V₅₀ for the ipsilateral lung were significantly lower in the IMRT arm than the 3D-CRT arm (all p < 0.05). The incidence of grade 2 or higher dermatitis was significantly lower in the IMRT arm (p = 0.009).

CONCLUSION

Compared to 3D-CRT, IMRT showed similar results in locoregional tumor control but superior results in planning target volume coverage. When IMRT is used in breast cancer, the irradiation dose to an ipsilateral lung and skin toxicity can be reduced.

Hypofractionated Versus Conventional Fractionated Radiotherapy After Breast-Conserving Surgery in the Modern Treatment Era: A Multicenter, Randomized Controlled Trial From China

PURPOSE

No randomized trials have compared hypofractionated radiotherapy (HFRT) with conventional fractionated radiotherapy (CFRT) after breast-conserving surgery in the Asian population. This study aimed to determine whether a 3.5-week schedule of HFRT is noninferior to a standard 6-week schedule of CFRT in China.

PATIENTS AND METHODS

Patients from 4 Chinese institutions who had undergone breast-conserving surgery and had T1-2N0-3 invasive breast cancers participated this study. Patients were randomly assigned (1:1) using a computer-generated central randomization schedule, without stratification, to receive whole-breast irradiation with or without nodal irradiation, followed by tumor-bed boost, either at a dose of 50 Gy in 25 fractions over 5 weeks with a boost of 10 Gy in five fractions over 1 week (CFRT) or 43.5 Gy in 15 fractions over 3 weeks with a boost of 8.7 Gy in three daily fractions (HFRT). The primary endpoint was 5-year local recurrence (LR), and a 5% margin of 5-year LR was used to establish noninferiority.

RESULTS

Between August 2010 and November 2015, 734 patients were assigned to the HFRT (n = 368) or CFRT (n = 366) group. At a median follow-up of 73.5 months (interquartile range, 60.5-91.4 months), the 5-year cumulative incidence of LR was 1.2% in the HFRT group and 2.0% in the CFRT group (hazard ratio, 0.62; 95% CI, 0.20 to 1.88; P = .017 for noninferiority). There were no significant differences in acute and late toxicities, except that the HFRT group had less grade 2-3 acute skin toxicity than the CFRT group (P = .019).

CONCLUSION

CFRT and HFRT with a tumor-bed boost may have similar low LR and toxicity.

Skin Toxicity in Early Breast Cancer Patients Treated with Field-In-Field Breast Intensity-Modulated Radiotherapy versus Helical Inverse Breast Intensity-Modulated Radiotherapy: Results of a Phase III Randomised Controlled Trial

AIMS

Skin toxicity is a common adverse effect of breast radiotherapy. We investigated whether inverse-planned intensity-modulated radiotherapy (IMRT) would reduce the incidence of skin toxicity compared with forward field-in-field breast IMRT (FiF-IMRT) in early stage breast cancer.

MATERIALS AND METHODS

This phase III randomised controlled trial compared whole-breast irradiation with either FiF-IMRT or helical tomotherapy IMRT (HT-IMRT), with skin toxicity as the primary end point. Patients received 50 Gy in 25 fractions and were assessed to compare skin toxicity between treatment arms.

RESULTS

In total, 177 patients were available for assessment and the median follow-up was 73.1 months. Inverse IMRT achieved more homogeneous coverage than FiF-IMRT; erythema and moist desquamation were higher with FiF-IMRT compared with HT-IMRT (61% versus 34%; P < 0.001; 33% versus 11%; P < 0.001, respectively). Multivariate analysis showed large breast volume, FiF-IMRT and chemotherapy were independent factors associated with worse acute toxicity. There was no difference between treatment arms in the incidence of late toxicities. The 5-year recurrence-free survival was 96.3% for both FiF-IMRT and HT-IMRT and the 5-year overall survival was 96.3% for FiF-IMRT and 97.4% for HT-IMRT.

CONCLUSIONS

Our study showed significant reduction in acute skin toxicity using HT-IMRT compared with FiF-IMRT, without significant reduction in late skin toxicities. On the basis of these findings, inverse-planned IMRT could be used in routine practice for whole-breast irradiation with careful plan optimisation to achieve the required dose constraints for organs at risk.

Health-related quality of life after accelerated breast irradiation in five fractions: A comparison with fifteen fractions

INTRODUCTION

In breast cancer patients, duration of illness and treatment have a negative impact on the quality of life. The duration of radiotherapy can be shortened by reducing the number of treatment fractions. In this study, the impact of an accelerated breast irradiation schedule in 5 fractions over 10 to 12 days on health-related quality of life (HRQoL) was investigated and compared to a standard hypofractionation schedule of 15 fractions.

METHODOLOGY

The study population was composed of 530 patients treated in 15 fractions and 196 patients treated in 5 fractions. Patients were included in different trials evaluating HRQoL. Radiotherapy-related items of the EORTC QLQ-C30 and BR23 and Breast-Q questionnaires were evaluated by comparing baseline scores to scores at 2-4 weeks and 1 year after radiotherapy. Clinically important improvements and deteriorations of HRQoL were compared between the 2 radiation schedules.

RESULTS

Patients treated in 5 fractions show less deterioration of physical well-being 2-4 weeks after radiotherapy. One year after radiotherapy, the 5 fractions schedule results in more patients reporting a clinically important improvement in pain, arm and breast symptoms and future perspective.

CONCLUSION

Radiotherapy in 5 fractions over 10-12 days results in more improvement and less deterioration of HRQoL than a 15 fractions schedule over 3 weeks.