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

Patient-Reported Outcomes Between Whole-Breast Plus Regional Irradiation and Whole-Breast Irradiation Only in pN1 Breast Cancer After Breast-Conserving Surgery and Taxane-Based Chemotherapy: A Randomized Phase 3 Clinical Trial (KROG 17-01)

PURPOSE

The role of regional node irradiation (RNI) with whole-breast irradiation (WBI) in patients with pN1 breast cancer receiving taxane-based adjuvant chemotherapy is not well defined. The KROG 1701 trial, a phase 3, multicenter, noninferiority study, aimed to compare the disease-free survival between WBI+RNI and WBI alone in this patient cohort. Comprehensive patient-reported outcomes (PROs) collected at multiple timepoints are reported.

METHODS AND MATERIALS

The trial (NCT03269981) enrolled patients with pN1 breast cancer after breast-conserving surgery and taxane-based adjuvant chemotherapy, allocating them to receive either WBI+RNI or WBI only. PROs were assessed using European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaires Core 30and breast cancer-specific module 23 modules at baseline, during radiation therapy, and at subsequent follow-up intervals of 3 to 6 months, and annually up to 4 years.

RESULTS

From April 2017 to December 2021, 840 patients were enrolled; 777 received intervention as assigned, and 750 completed baseline PRO questionnaires (387 in WBI+RNI, 363 in WBI only). All PRO domains showed improvements over time (P < .001). During radiation therapy, the WBI+RNI group reported greater fatigue and nausea. Higher arm symptom scores were observed in the WBI+RNI group 3 months post-treatment (P = .030). No other significant PRO domain differences, including arm/breast symptoms, were observed between the 2 groups.

CONCLUSIONS

In patients with pN1 breast cancer treated with taxane-based chemotherapy, adding RNI to WBI resulted in minor, temporary declines in specific PRO domains, but these differences were not clinically significant. This indicates that overall patient experience between WBI+RNI and WBI is comparable, supporting the safety and patient tolerability of both treatments.

Selection criteria and method for deep inspiration breath-hold in patients with left breast cancer undergoing PMRT/IMRT

Purpose

This study explored whether a free-breathing mean heart dose (FB-MHD) of 4 Gy is a reliable dose threshold for selecting left breast cancer patients after modified radical mastectomy suitable for deep inspiration breath-hold (DIBH) and developed anatomical indicators to predict FB-MHD for rapid selection.

Materials and methods

Twenty-three patients with left breast cancer treated with DIBH were included to compare FB and DIBH plans. The patients were divided into the high-risk (FB-MHD ≥ 4 Gy) and low-risk (FB-MHD < 4 Gy) groups to compare dose difference, normal tissue complication probability (NTCP) and the DIBH benefits. Another 30 patients with FB only were included to analyze the capacity of distinguishing high-risk heart doses patients according to anatomical metrics, such as cardiac-to-chest Euclidean distance (CCED), cardiac-to-chest gap (CCG), and cardiac-to-chest combination (CCC).

Results

All heart doses were significantly lower in patients with DIBH plans than in those with FB plans. Based on FB-MHD of 4 Gy cutoff, the heart dose, NTCP for cardiac death, and benefits from DIBH were significantly higher in the high-risk group than in the low-risk group. The CCED was a valid anatomical indicator with the largest area under the curve (AUC) of 0.83 and maintained 95 % sensitivity and 70 % specificity at the optimal cutoff value of 2.5 mm.

Conclusions

An FB-MHD of 4 Gy could be used as an efficient dose threshold for selecting patients suitable for DIBH. The CCED may allow a reliable prediction of FB-MHD in left breast cancer patients at CT simulation.

Post-mastectomy radiation therapy after breast reconstruction: from historic dogmas to practical expert agreements based on a large literature review of surgical and radiation therapy considerations

Breast reconstruction (BR) after mastectomy is important to consider for a woman's body image enhancement and psychological well-being. Although post-mastectomy radiation (PMRT) significantly improves the outcome of patients with high-risk breast cancer (BC), PMRT after BR may affect cosmetic outcomes and may compromise the original goal of improving quality of life (QoL). With the lack of practical guidelines, it seems essential to work on a consensus and provide some "expert agreements" to offer patients the best option for PMRT after BR. We report a global "expert agreement" that results from a critical review of the literature on BR and PMRT during the 6th international multidisciplinary breast conference in March 2023.

Are We Missing Acute Toxicities Associated With Hypofractionated Breast Irradiation? A Report From a Large Multicenter Cohort Study

PURPOSE

The efficacy and long-term safety of hypofractionated whole breast irradiation (HF-WBI) have been established through multiple randomized trials, yet data about acute toxicities remain more limited. Since 2013, our group has prospectively collected acute toxicity data from weekly treatment evaluations and additional assessment after completion. In 2016, we intentionally shifted the posttreatment assessment follow-up visit from 1 month to 2 weeks to evaluate for missed acute toxicity occurring in that immediate posttreatment window. Here, we report whether 2-week follow-up has resulted in increased detection of acute toxicities compared with 4-week follow-up.

METHODS AND MATERIALS

We prospectively compared acute toxicity for patients treated with HF-WBI between January 1, 2013, and August 31, 2015 (4 week follow-up cohort) to patients treated between January 1, 2016, and August 31, 2018 (2 week follow-up cohort). Analyses included a multivariable model that adjusted for other factors known to correlate with toxicity. We prospectively defined acute toxicity as maximum breast pain (moderate or severe rating) and/or occurrence of moist desquamation reported 7 days before the completion of radiation therapy (RT) until 42 days after completion.

RESULTS

A total of 2689 patients who received postlumpectomy radiation and boost were analyzed; 1862 patients in the 2-week follow-up cohort and 827 in the 4-week follow-up cohort. All acute toxicity measures assessed were statistically similar between follow-up cohorts when compared in an unadjusted fashion. Overall acute composite toxicity was 26.4% and 27.7% for patients in the 4-week follow-up and 2-week follow-up cohorts, respectively. Overall acute composite toxicity remained similar between follow-up cohorts in a multivariable, adjusted model and was significantly related to patient's age, body mass index, smoking status, and treatment technique (intensity-modulated RT vs 3-dimensional conformal radiation therapy) but not follow-up cohort.

CONCLUSIONS

An earlier posttreatment follow-up for HF-WBI patients did not reveal a significant increased incidence of acute toxicities at 2 weeks compared with 4 weeks. This study provides physicians and patients with additional data on the safety and tolerability of HF-WBI for early stage breast cancer.

Master Breast Radiation Planning: Simple Guide for Radiation Oncology Residents

This article focuses on various aspects of breast radiation treatment planning, from simulation to field design. It covers the most common techniques including tangents, mono isocentric, dual isocentric, electron-photon match, and VMAT. This can serve as a guide for radiation oncology residents and medical students to advance their understanding of key aspects of breast radiation treatment and planning processes.

An IMRT planning technique for treating whole breast or chest wall with regional lymph nodes on Halcyon and Ethos

PURPOSE/OBJECTIVE

Field size limitations on Halcyon and Ethos treatment machines largely preclude use of the conventional monoisocentric three-field technique for breast/chest wall and regional lymph nodes. We present an alternative, IMRT-based planning approach that facilitates treatment on Halcyon and Ethos while preserving plan quality.

MATERIALS/METHODS

Eight breast and regional node cases (four left-sided, four right-sided) were planned for an Ethos machine using a 15-17 field IMRT technique. Institutional plan quality metrics for CTV and PTV coverage and OAR sparing were assessed. Five plans (four right-sided, one left-sided) were also planned using a hybrid 3D multisocenter technique. CTV coverage and OAR sparing were compared to the IMRT plans. Eclipse scripting tools were developed to aid in beam placement and plan evaluation through a set of dosimetric scorecards, and both are shared publicly.

RESULTS

On average, the IMRT plans achieved breast CTV and PTV coverage at 50 Gy of 97.9% and 95.7%, respectively. Supraclavicular CTV and PTV coverages at 45 Gy were 100% and 95.5%. Axillary lymph node CTV and PTV coverages at 45 Gy were 100% and 97.1%, and IMN CTV coverage at 45 Gy was 99.2%. Mean ipsilateral lung V20 Gy was 19.3%, and average mean heart dose was 1.6 Gy for right-sided cases and 3.0 Gy for left-sided. In comparison to the hybrid 3D plans, IMRT plans achieved higher breast and supraclavicular CTV coverage (99.9% vs. 98.6% and 99.9% vs. 93.4%), higher IMN coverage (99.6% vs. 78.2%), and lower ipsilateral lung V20 Gy (19.6% vs. 28.2%).

CONCLUSION

Institutional plan quality benchmarks were achieved for all eight cases using the IMRT-based planning approach. The IMRT-based planning approach offered superior conformity and OAR sparing than a competing hybrid 3D approach.

Factors Associated With Cardiac Radiation Dose Reduction After Hypofractionated Radiation Therapy for Localized, Left-Sided Breast Cancer in a Large Statewide Quality Consortium

PURPOSE

Limiting cardiac radiation dose is important for minimizing long-term cardiac toxicity in patients with left-sided early-stage breast cancer.

METHODS AND MATERIALS

Prospectively collected dosimetric data were analyzed for patients undergoing moderately hypofractionated radiation therapy to the left breast within the Michigan Radiation Oncology Quality Consortium from 2016 to 2022. The mean heart dose (MHD) goal was progressively tightened from ≤2 Gy in 2016 to MHD ≤ 1.2 Gy in 2018. In 2021, a planning target volume (PTV) coverage goal was added, and the goal MHD was reduced to ≤1 Gy. Multivariate logistic regression models were developed to assess for covariates associated with meeting the MHD goals in 2016 to 2020 and the combined MHD/PTV coverage goal in 2021 to 2022.

RESULTS

In total, 4165 patients were analyzed with a median age of 64 years. Overall average cardiac metric compliance was 91.7%. Utilization of motion management increased from 41.8% in 2016 to 2020 to 46.5% in 2021 to 2022. Similarly, use of prone positioning increased from 12.2% to 22.2% in these periods. On multivariate analysis in the 2016 to 2020 cohort, treatment with motion management (odds ratio [OR], 5.20; 95% CI, 3.59-7.54; P < .0001) or prone positioning (OR, 3.21; 95% CI, 1.85-5.57; P < .0001) was associated with meeting the MHD goal, while receipt of boost (OR, 0.25; 95% CI, 0.17-0.39; P < .0001) and omission of hormone therapy (OR, 0.65; 95% CI, 0.49-0.88; P = .0047) were associated with not meeting the MHD goal. From 2021 to 2022, treatment with motion management (OR, 1.89; 95% CI, 1.12-3.21; P = .018) or prone positioning (OR, 3.71; 95% CI, 1.73-7.95; P = .0008) was associated with meeting the combined MHD/PTV goal, while larger breast volume (≥1440 cc; OR, 0.34; 95% CI, 0.13-0.91; P = .031) was associated with not meeting the combined goal.

CONCLUSIONS

In our statewide consortium, high rates of compliance with aggressive targets for limiting cardiac dose were achievable without sacrificing target coverage.

Implementation and evaluation of an iterative-based algorithm for automatic beam angle optimization in breast cancer treatment planning

INTRODUCTION

A beam angle optimization (BAO) algorithm was developed to evaluate its clinical feasibility and investigate the impact of varying BAO constraints on breast cancer treatment plans.

MATERIALS AND METHODS

A two-part study was designed. In part 1, we retrospectively selected 20 patients treated with radiotherapy after breast-conserving surgery. For each patient, BAO plans were designed using beam angles optimized by the BAO algorithm and the same optimization constraints as manual plans. Dosimetric indices were compared between BAO and manual plans. In part 2, fifteen patients with left breast cancer were included. For each patient, three distinct cardiac constraints (mean heart dose < 5 Gy, 3 Gy or 1 Gy) were established during the BAO process to obtain three optimized beam sets which were marked as BAO_H1, BAO_H3, BAO_H5, respectively. These sets of beams were then utilized under identical IMRT constraints for planning. Comparative analysis was conducted among the three groups of plans.

RESULTS

For part 1, no significant differences were observed between BAO plans and manual plans in all dosimetric indices, except for ipsilateral lung V5, where BAO plans performed slightly better than manual plans (35.5% ± 5.6% vs 36.9% ± 4.3%, p = 0.034). For part 2, Stricter BAO heart constraints resulted in more perpendicular beams. However, there was no significant difference between BAO_H1, BAO_H3 and BAO_H5 with the same IMRT constraint in the heart dose. Meanwhile, the left lung dose was increased while the right breast and lung doses were decreased with stricter heart constraints in BAO. When mean heart dose < 5 Gy in IMRT constraint, the mean dose to the right lung was decreased from 0.46 Gy for BAO_H5 to 0.33 Gy for BAO_H1 (p = 0.027).

CONCLUSIONS

The BAO algorithm can achieve quality plans comparable to manual plans. IMRT constraints dominate the final plan dose, while varying BAO constraints alter the trade-off among structures, providing an additional degree of freedom in planning design.

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.

Safety of hypofractionated volumetric modulated arc therapy for early breast cancer: A preliminary report

The present study attempts to evaluate the acute and subacute toxicities of hypofractionated volumetric modulated arc therapy (HFX-VMAT) in patients with early breast cancer (EBC). It is a retrospective analysis of 23 patients treated with HFX-VMAT after breast-conserving surgery between September 2021 and February 2022. A total dose of 50.05 to 52.55 Gy was delivered, consisting of 40.05 Gy to the ipsilateral whole breast in 15 fractions of 2.67 Gy and a tumor bed boost dose of 10-12.5 Gy in 4-5 fractions. The primary endpoint was acute/subacute radiation pneumonitis (RP). The secondary endpoint was poor cosmesis, indicating acute/subacute radiation dermatitis. Chest computed tomography (CT) and the Common Terminology Criteria for Adverse Events v.5.0 were used to assess acute and subacute RP and dermatitis, respectively, during radiotherapy (RT) and at 3- and 6-months post-RT. The median follow-up duration was 3.8 months (range, 2.3-4.2). A total of seven patients developed RP. None of these patients presented RP-related symptoms; the diagnosis was based on radiologic findings observed on follow-up chest CT. Among the seven patients with RP, five had right-sided, and two had left-sided breast tumors (71.4 vs. 28.6%; P=0.026). Grade 1 erythema was observed in 19 patients (82.6%) and grade 2 erythema in four (17.4%). The mean target dose, D_105% (the dose received by 105% of the target volume), homogeneity index, mean lung dose, ipsilateral lung V₂₀ (the percentage volume receiving 20 Gy), and V₃₀ (the percentage volume receiving 30 Gy) for ipsilateral whole breast RT were significantly associated with RP (P=0.039, 0.047, 0.018, 0.015, 0.018 and 0.003, respectively.). HFX-VMAT showed tolerable acute/subacute toxicities. Therefore, HFX-VMAT is an effective and safe treatment option for EBC.

Histology Specific Molecular Biomarkers: Ushering in a New Era of Precision Radiation Oncology

Histopathology and clinical staging have historically formed the backbone for allocation of treatment decisions in oncology. Although this has provided an extremely practical and fruitful approach for decades, it has long been evident that these data alone do not adequately capture the heterogeneity and breadth of disease trajectories experienced by patients. As efficient and affordable DNA and RNA sequencing have become available, the ability to provide precision therapy has become within grasp. This has been realized with systemic oncologic therapy, as targeted therapies have demonstrated immense promise for subsets of patients with oncogene-driver mutations. Further, several studies have evaluated predictive biomarkers for response to systemic therapy within a variety of malignancies. Within radiation oncology, the use of genomics/transcriptomics to guide the use, dose, and fractionation of radiation therapy is rapidly evolving but still in its infancy. The genomic adjusted radiation dose/radiation sensitivity index is one such early and exciting effort to provide genomically guided radiation dosing with a pan-cancer approach. In addition to this broad method, a histology specific approach to precision radiation therapy is also underway. Herein we review select literature surrounding the use of histology specific, molecular biomarkers to allow for precision radiotherapy with the greatest emphasis on commercially available and prospectively validated biomarkers.

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.

Decreases in Radiation Oncology Medicare Reimbursement over time: Analysis by Billing Code

PURPOSE

Radiation oncology (RO) has seen declines in Medicare reimbursement (MCR). However, there are no recent studies analyzing the contributions of specific billing codes to overall RO reimbursement. We compared total MCR for specific Healthcare Common Procedure Coding System (HCPCS) codes in 2019 with MCR for those codes in 2010 and 2015, corrected for inflation, to see how the same basket of RO services in 2019 would have been reimbursed in 2010 and 2015 (adjusted MCR).

METHODS AND MATERIALS

The Centers for Medicare & Medicaid Services Physician/Supplier Procedure Summary database was used to obtain MCR data for RO HCPCS codes in 2010, 2015, and 2019. For each code, the total allowed charge was divided by the number of submitted claims to calculate the average MCR per claim in 2010, 2015, and 2019. The 2019 billing frequency for each code was then multiplied by the inflation-adjusted average MCR for those codes in 2010 and 2015 to determine what the MCR would have been in 2010 and 2015 using 2019 dollars and utilization rates. Results were compared with actual 2019 MCR to calculate the projected difference.

RESULTS

Total inflation-adjusted RO MCR was $2281 million (M), $1991 M, and $1848 M in 2010, 2015, and 2019 respectively. This represents a cut of $433 M (19%) and $143 M (7%) from 2010 and 2015, respectively, to 2019. After utilization adjustment, total reimbursement was $2534 M, $2034 M, and $1848 M for 2010, 2015, and 2019, respectively, representing a cut of $686 M (27%) and $186 M (9%) from 2010 and 2015, respectively, to 2019. Intensity modulated radiation therapy (IMRT) treatment delivery and planning accounted for $917 M (36%), $670 M (33%), and $573 M (31%) of the adjusted MCR in 2010, 2015, and 2019, respectively.

CONCLUSIONS

Medicare reimbursement decreased substantially from 2010 to 2019. A decline in IMRT treatment reimbursement was the primary driver of MCR decline. When considering further cuts, policymakers should consider these trends and their consequences for health care quality and access.

Toxicity of Hypofractionated Whole Breast Radiotherapy Without Boost and Timescale of Late Skin Responses in a Large Cohort of Early-Stage Breast Cancer Patients

AIM

To report toxicity of hypofractionated whole-breast radiotherapy in a large cohort of early-stage breast cancer (BCaients.

MATERIALS AND METHODS

From 02/2009-05/2017, 1325 consecutive BCa patients were treated with 40.05 Gy/15 fractions, without boost. Median age was 62 (IQR:51.1-70.5) years. Chemotherapy was prescribed for 28% of patients, hormonal therapy for 80.3%, monoclonal antibodies for 8.2%.

RESULTS

Median follow-up was 72.4 (IQR: 44.6-104.1) months. Acute RTOG toxicity was: 69.8% Grade (G) 1, 14.3% G2 and 1.7% G3. Late SOMA-LENT toxicities were: edema-hyperpigmentation (E-H): G1 28.67%, G2 4.41%, G3 0.15%; fibrosis-atrophy-telangiectasia-pain (F-A-T-P): G1 14.6%, G2 3.2%, G3 0.8%, G4 0.1%. Median time to first occurrence was 6 and 18 months, respectively. Aesthetic result after surgery was excellent in 28.7%, good in 41.5%, acceptable in 20.3% and poor in 9.5% of patients. Change in breast appearance after radiotherapy was mild in 6.9%, moderate in 2.3% and marked in 1.3% of patients. Concomitant chemotherapy, obesity, smoking, use of bolus and planning target volume (PTV) were associated with higher acute toxicity. Patients ≥55 years old were less likely to experience acute toxicity. PTV and acute G2 toxicity were associated with ≥G2 E-H. PTV, concomitant chemotherapy, hypertension and ≥G2 acute toxicity were associated with increased risk of F-A-T-P.

CONCLUSION

Hypofractionated whole-breast radiotherapy without boost demonstrated mild acute and late toxicity in a large cohort of consecutive patients. Moderate and marked changes in breast appearance were registered for 3.6% of patients and occurred between 18 to 42 months.