Radiation Therapy Field Design and Lymphedema Risk After Regional Nodal Irradiation for Breast Cancer

Optimizing posterior neck coverage in regional nodal irradiation for breast cancer

Patterns-of-failure studies suggest the posterior neck (PN) may harbor microscopic disease in patients with locally advanced breast cancer. We compared target coverage, lung dosimetry, and toxicity in patients treated with either an anterior oblique field (AO) or opposed oblique fields (OO) to address the superior axillary and supraclavicular (SCV) nodal regions. We identified 109 patients treated at a single institution with regional nodal irradiation utilizing a mono-isocentric technique with a "third field" for superior axillary and SCV coverage. SCV and PN clinical target volume (CTV) coverage was determined based on the delivered treatment plan. CTV coverage, lung dosimetry, and toxicity differences between AO and OO treatment groups were evaluated using Wilcoxon rank-sum and Fisher's exact tests. The AO group had 29 patients, and the OO group had 80. Both groups had similar body mass indices and anterior-posterior separations at the match line. The median V90% of the PN was significantly improved in the OO group (100%) compared to 30% in the AO group (p < 0.001). The median V90% in the axillary levels I to III were similarly improved in the OO group compared to the OA group (p < 0.001). The maximum dose, heterogeneity and V90% of the SCV, as well as the lung dosimetry were similar in both groups. Rates of toxicities including ipsilateral upper extremity lymphedema and pneumonitis (all grade 1), and moist desquamation were low and similar across groups. Compared to a single anterior field, opposed oblique fields provide superior axillary and posterior neck coverage without increasing toxicity.

Excluding Upper Axillary Level 1 in Regional Nodal Irradiation Does Not Increase Axillary Recurrence Risk in Patients With Breast Cancer

PURPOSE

The optimal extent of regional nodal irradiation (RNI) in postoperative radiation therapy for breast cancer, particularly regarding axillary level 1 (AXL1), remains uncertain. This study aimed to compare clinical outcomes between extensive RNI including the entire axilla and limited RNI excluding the upper AXL1 in patients with breast cancer.

METHODS AND MATERIALS

A retrospective analysis included 1780 women with nonmetastatic unilateral breast cancer who underwent RNI during postoperative radiation therapy between 2007 and 2018. Patients were classified into extensive and limited RNI groups based on the upper AXL1 inclusion in the radiation field. Propensity-score matching yielded a cohort of 1020 patients. Noninferiority of limited RNI compared with extensive RNI was assessed with a defined margin of ≤2% in the 5-year axillary recurrence rate.

RESULTS

After a median follow-up of 67.9 months, the 5-year axillary recurrence rates were similar between extensive and limited RNI groups (1.2% vs 1.6%; Plog-rank= .790). Limited RNI demonstrated noninferiority with a 0.4% difference (95% confidence interval, -1.1% to 1.9%; Pnoninferiority= .019). Disease-free survival (87.9% vs 91.5%; Plog-rank= .122) and overall survival (94.1% vs 96.9%; Plog-rank= .260) at 5 years were not significantly different between extensive and limited RNI groups. Multivariable analysis revealed that lymphovascular invasion (hazard ratio [HR], 5.17; P = .02) and negative hormone receptor status (HR, 11.73; P = .002) were associated with a higher risk of axillary recurrence, whereas limited RNI showed no significant association (HR, 1.35; P = .652). Subgroup analysis demonstrated that extensive RNI did not improve axillary control in patients with lymphovascular invasion, hormone receptor negativity, positive lymph node metastasis, or a small number of nodes removed.

CONCLUSIONS

Limited RNI, excluding the upper AXL1 from the radiation field, demonstrated axillary recurrence rates comparable with those of extensive RNI in patients with breast cancer. The study suggests that extensive RNI may not provide additional therapeutic benefits, whereas limited RNI appears to be a valid option for regional control.

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.

Hypofractionation for Regional Nodal Irradiation in Breast Cancer: Best of Both the Worlds

Locoregional radiotherapy play an important role in controlling the disease after surgery in patients with breast cancer. Radiotherapy schedules vary from conventional fraction to hypofractionation. The purpose of this review is to get an insight into the data on regional nodal irradiation (RNI) with hypofractionation in patients with breast cancer. This systematic review was constructed in accordance with Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) framework. Electronic databases such as PubMed, Cochrane and EMBASE were searched from January 1, 2023 to March 31, 2023 to identify studies published in English language on hypofractionated RNI in post mastectomy patients. The search was carried out with the National Library of Medicine's Medical Subject Heading (MeSH) terms like "regional nodal irradiation," "hypofractionated" and "hypofractionation in breast cancer" with different Boolean operators (and/or). A manual search of reference lists of included articles was also performed to make sure there were no additional cases unidentified from the primary search. Studies deemed potentially eligible were identified and assessed by same independent reviewers to confirm eligibility. RNI data are mainly from a randomized study from Beijing and pooled data from START trials. There are also data from retrospective and single institutional studies and a few phase II studies with limited number of patients using different dose fractionations and techniques of radiotherapy. Doses used in these trials ranged from 26-47.7 Gy in 5-19 fractions over 1-4 weeks. Grade ≥ 2 pulmonary fibrosis and lymphedema rate ranged from 2%-7.9% and 3%-19.8% respectively. Grade ≥ 2 shoulder dysfunction and brachial plexopathy ranged from 0.2%-28% and 0%-< 1%, respectively. Late effects with a dose range of 26-40 Gy delivered in 5 to 15 fractions over 1-3 weeks were less/similar to conventional fraction. Current data showed lower/similar rates of toxicity with hypofractionated RNI compared with conventional fractionation RNI. Doses of 26 Gy to 40 Gy delivered in 5 to 15 fractions over 1-3 weeks are safe for RNI. With limited data, ultra-hypofractionation 26 Gy/5 fractions/1 week also seems to be safe. However, long-term outcome is awaited and many trials are going on to address its efficacy and safety.

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.

Multinational Association of Supportive Care in Cancer (MASCC) clinical practice guidance for the prevention of breast cancer-related arm lymphoedema (BCRAL): international Delphi consensus-based recommendations

Background

Developing strategies to prevent breast cancer-related arm lymphoedema (BCRAL) is a critical unmet need because there are no effective interventions to eradicate it once it reaches a chronic state. Certain strategies such as prospective surveillance programs and prophylactic lymphatic reconstruction have been reported to be effective in clinical trials. However, a large variation exists in practice based on clinician preference, organizational standards, and local resources.

Methods

A two-round international Delphi consensus process was performed from February 27, 2023 to May 25, 2023 to compile opinions of 55 experts involved in the care and research of breast cancer and lymphoedema on such interventions.

Findings

Axillary lymph node dissection, use of post-operative radiotherapy, relative within-arm volume increase one month after surgery, greater number of lymph nodes dissected, and high body mass index were recommended as the most important risk factors to guide selection of patients for interventions to prevent BCRAL. The panel recommended that prospective surveillance programs should be implemented to screen for and reduce risks of BCRAL where feasible and resources allow. Prophylactic compression sleeves, axillary reverse mapping and prophylactic lymphatic reconstruction should be offered for patients who are at risk for developing BCRAL as options where expertise is available and resources allow. Recommendations on axillary management in clinical T1-2, node negative breast cancer patients with 1-2 positive sentinel lymph nodes were also provided by the expert panel. Routine axillary lymph node dissection should not be offered in these patients who receive breast conservation therapy. Axillary radiation instead of axillary lymph node dissection should be considered in the same group of patients undergoing mastectomy.

Interpretation

An individualised approach based on patients' preferences, risk factors for BCRAL, availability of treatment options and expertise of the healthcare team is paramount to ensure patients at risk receive preventive interventions for BCRAL, regardless of where they are receiving care.

Funding

This study was not supported by any funding. RJC received investigator grant support from the Australian National Health and Medical Research Council (APP1194051).

Incidence of and Influencing Factors for Arm Lymphedema After Salvage Treatment for an Isolated Locoregional Recurrence of Breast Cancer

PURPOSE

Data on subsequent arm lymphedema (SAL) after salvage treatment for locoregional recurrence (LRR) of breast cancer are limited. We conducted a study to evaluate the risk of SAL in patients with LRR.

METHODS

We reviewed the data of patients with breast cancer who had LRR and were initially diagnosed between January 2003 and December 2017. Among the 214 patients who received curative salvage treatment, most had local (n = 125, 57.9%), followed by regional (n = 73, 34.1%), and locoregional (n = 16, 7.9%) recurrences. A competing risk analysis considering the factors of death and a second LRR were performed to exclude potential malignant lymphedema. We used the Fine-Gray subdistribution hazards model to estimate the hazard ratio (HR) for comparing the risk of SAL.

RESULTS

With a median follow-up duration of 41.4 months (interquartile range, 25.6-65.1), 51 patients (23.8%) experienced SAL with a median interval of 9.9 months after treatment. The two-year cumulative incidence of SAL was 12.7%. Among the 18 patients with initial lymphedema, nine (50.0%) developed SAL. Multivariate analysis revealed that a history of lymphedema (HR, 4.61; p < 0.001) and taxane-based salvage chemotherapy (HR, 2.38; p = 0.009) were significantly associated with SAL development.

CONCLUSION

Salvage treatment for LRR-induced SAL was performed in 24% of the patients. A history of initial lymphedema and salvage taxane-based chemotherapy increases the risk of developing SAL. Therefore, close surveillance for the incidence of SAL is required in patients opting for salvage treatment for LRR.

The Role of Post-Mastectomy Radiotherapy in T1-2N1 Breast Cancer Patients: Propensity Score Matched Analysis

This study aimed to evaluate the role of post-mastectomy radiotherapy (PMRT) in T1-2N1 breast cancer. Between 2006 and 2014, a total of 504 patients with T1-2N1 breast cancer were analyzed. PMRT was administered to 71 patients, and 1:2 propensity score matching (PSM) was performed between the PMRT and non-PMRT groups. Loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates were compared according to PMRT status. Thirteen and one loco-regional recurrences were observed in the PMRT and non-PMRT groups, respectively. Before PSM, the 8-year LRC, DFS, and OS rates in the non-PMRT and PMRT groups were 98.5% and 96.5% (p = 0.426), 89.7% and 91.2% (p = 0.700), and 91.5% and 92.1% (p = 0.679), respectively. Corresponding rates were 95.6% and 96.5% (p = 0.365), 84.1% and 91.2% (p = 0.185), and 88.4% and 92.1% (p = 0.276), respectively, after PSM. Multivariate analysis showed that three lymph node metastases were prognostic for LRC and DFS rates and LVI for OS rate. Arm lymphedema developed in 32.4% of patients who received PMRT, which was significantly higher than the non-PMRT group (p < 0.001). Contributions of PMRT for improvement of treatments outcomes in T1-2N1 breast cancer patients were not evident, while the incidence of arm lymphedema significantly increased after PMRT. Further prospective trials are required to re-evaluate the role of PMRT.

A Prospective Study of Radiation Therapy After Immediate Lymphatic Reconstruction: Analysis of the Dosimetric Implications

PURPOSE

Axillary lymph node dissection (ALND) and regional nodal irradiation (RNI) are the primary causes of breast cancer-related lymphedema (BCRL). Immediate lymphatic reconstruction (ILR) is a novel surgical procedure that reduces the incidence of BCRL after ALND. The ILR anastomosis is placed in a location thought to be outside the standard radiation therapy fields to prevent radiation-induced fibrosis of the reconstructed vessels; however, there is excess risk of BCRL from RNI even after ILR. The purpose of this study was to understand the radiation dose distribution in relation to the ILR anastomosis.

METHODS AND MATERIALS

This prospective study included 13 patients treated with ALND/ILR from October 2020 to June 2022. A twirl clip deployed during surgery was used to identify the ILR anastomosis site during radiation treatment planning. All cases were planned using a 3D-conformal technique with opposed tangents and an obliqued supraclavicular (SCV) field.

RESULTS

RNI deliberately targeted axillary Levels 1 to 3 and the SCV nodal region in 4 patients and was limited to Level 3 and SCV nodes in 9 patients. The ILR clip was located in Level 1 in 12 patients and Level 2 in 1 patient. In patients with radiation directed at only Level 3 and SCV, the ILR clip was still within the radiation field in 5 of these patients and received a median dose of 3939 cGy (range, 2025-4961 cGy). The median dose to the ILR clip was 3939 cGy (range, 139-4961 cGy) for the entire cohort. The median dose was 4275 cGy (range, 2025-4961 cGy) when the ILR clip was within any radiation field and 233 cGy (range, 139-280 cGy) when the clip was outside all fields.

CONCLUSION

The ILR anastomosis was often directly irradiated with 3D-conformal techniques and received substantial radiation dose, even when the site was not deliberately targeted. Long-term analysis will help determine whether minimizing radiation dose to the anastomosis will decrease BCRL rates.

Incorporating axillary-lateral thoracic vessel juncture dosimetric variables improves model for predicting lymphedema in patients with breast cancer: A validation analysis

Background

A relationship between the axillary-lateral thoracic vessel juncture (ALTJ) dose and lymphedema rate has been reported in patients with breast cancer. The purpose of this study was to validate this relationship and explore whether incorporation of the ALTJ dose-distribution parameters improves the prediction model's accuracy.

Methods

A total of 1,449 women with breast cancer who were treated with multimodal therapies from two institutions were analyzed. We categorized regional nodal irradiation (RNI) as limited RNI, which excluded level I/II, vs extensive RNI, which included level I/II. The ALTJ was delineated retrospectively, and dosimetric and clinical parameters were analyzed to determine the accuracy of predicting the development of lymphedema. Decision tree and random forest algorithms were used to construct the prediction models of the obtained dataset. We used Harrell's C-index to assess discrimination.

Results

The median follow-up time was 77.3 months, and the 5-year lymphedema rate was 6.8 %. According to the decision tree analysis, the lowest lymphedema rate (5-year, 1.2 %) was observed in patients with ≤ six removed lymph nodes and ≤ 66 % ALTJ V_35Gy. The highest lymphedema rate was observed in patients with > 15 removed lymph nodes and an ALTJ maximum dose (D_max) of > 53 Gy (5-year, 71.4 %). Patients with > 15 removed lymph nodes and an ALTJ D_max ≤ 53 Gy had the second highest rate (5-year, 21.5 %). All other patients had relatively minor differences, with a rate of 9.5 % at 5 years. Random forest analysis revealed that the model's C-index increased from 0.84 to 0.90 if dosimetric parameters were included instead of RNI (P <.001).

Conclusion

The prognostic value of ALTJ for lymphedema was externally validated. The estimation of lymphedema risk based on individual dose-distribution parameters of the ALTJ seemed more reliable than that based on the conventional RNI field design.

Quantifying radiation in the axillary bed at the site of lymphedema surgical prevention

PURPOSE

Immediate lymphatic reconstruction (ILR) is a procedure known to reduce the risk of lymphedema in patients undergoing axillary lymph node dissection (ALND). However, patients who receive adjuvant radiotherapy are at increased risk of lymphedema. The aim of this study was to quantify the extent of radiation at the site of surgical prevention.

METHODS

We recently began deploying clips at the site of ILR to identify the site during radiation planning. A retrospective review was performed to identify breast cancer patients who underwent ILR with clip deployment and adjuvant radiation therapy from October 2020 to April 2022. Patients were excluded if they had not completed radiotherapy. The exposure and dose of radiation received by the site was determined and recorded.

RESULTS

In a cohort of 11 patients, the site fell within the radiation field in 7 patients (64%) and received a median dose of 4280 cGy. Among these 7 patients, 3 had sites located within tissue considered at risk of oncologic recurrence and the remaining 4 sites received radiation from a tangential field treating the breast or chest wall. The median dose to the ILR site for the 4 patients whose sites were outside the radiation fields was 233 cGy.

CONCLUSION

Our findings suggest that even when the site of surgical prevention was not within the targeted radiation field during treatment planning, it remains susceptible to radiation. Strategies for limiting radiation at this site are needed.

A comparison of acute patient-reported outcomes in breast cancer patients with and without regional nodal irradiation using the ESAS and PRFS tool

BACKGROUND AND PURPOSE

Regional nodal irradiation (RNI) is commonly administered in patients with breast cancer with node-positive disease to prevent cancer recurrence. The purpose of this study is to identify whether RNI is associated with greater acute symptom burden from baseline to 1 to 3 months post completion of radiotherapy (RT) when compared to localized RT.

MATERIALS AND METHODS

Patient and treatment characteristics were collected prospectively for breast cancer patients with and without RNI from February 2018 to September 2020. The Edmonton Symptom Assessment System (ESAS) and Patient-Reported Functional Status (PRFS) tool were completed by patients at baseline, weekly during RT, and at a 1- to 3-month follow-up visit. The Wilcoxon rank-sum or Fisher exact tests were used to compare variables between patients with or without RNI.

RESULTS

A total of 781 patients were included in the analysis. Baseline symptom reporting was similar between cohorts, with the exception of PRFS scores (p = 0.0023), which were worse in patients receiving RNI. Across all time points, differences in outcomes between cohorts were minimal, except for lack of appetite (p = 0.03) and PRFS scores (p = 0.049), which were significantly aggravated in patients treated with RNI.

CONCLUSION

There is insufficient evidence to suggest that RNI is associated with greater symptom burden as assessed with the ESAS. Further research should be conducted over a longer time period to determine the impact of late effects of RNI on patient-reported symptoms.

The influence of axillary surgery and radiotherapeutic strategy on the risk of lymphedema and upper extremity dysfunction in early breast cancer patients

PURPOSE

To explore the risk factors for breast cancer-related lymphedema (BCRL) and upper extremity dysfunction (UED) in patients with early breast cancer after modern comprehensive treatment and to compare the toxicity of different treatment strategies.

METHODS

From 2017 to 2020, a total of 1369 female patients with pT1-3N0-1M0 breast cancer who underwent adjuvant radiotherapy in our centre were retrospectively reviewed. BCRL and UED were identified by the Norman and QuickDASH questionnaires. The incidence, severity and risk factors for BCRL and UED were evaluated.

RESULTS

After a median follow-up of 25 months, a total of 249 patients developed BCRL; axillary lymph node dissection (ALND), increased number of dissected nodes, right-sided and hypofractionated radiotherapy containing RNI were found to be significant risk factors (all p values < 0.05). The sentinel lymph node biopsy (SLNB)+ regional nodal irradiation (RNI) group had a significantly lower BCRL risk than the ALND + RNI group (10.8% vs. 32.5%, HR = 0.426, p = 0.020), while there was no significant difference between ALND vs. ALND + RNI or SLNB vs. SLNB + RNI. A total of 193 patients developed UED, and ALND (p = 0.02) was the only significant risk factor. The SLNB + RNI group had a significantly decreased risk of UED compared with the ALND + RNI group (7.5% vs. 23.9%, HR = 0.260, p = 0.001), and there was no significant difference between SLNB vs. SLNB + RNI or ALND vs. ALND + RNI.

CONCLUSION

Aggressive ALND remains the primary risk factor for BCRL and UED while RNI does not. Thus, replacing ALND with tailored radiotherapy would be an effective preventive strategy in early breast cancer patients.

Early Disturbance of Lymphatic Transport as a Risk Factor for the Development of Breast-Cancer-Related Lymphedema

Introduction: Breast-cancer-related lymphedema (BCRL) is a frequently occurring and debilitating condition. When lymphedema is diagnosed late, treatment can be expected to be less effective. Lymphofluoroscopy can provide details about the superficial lymphatic architecture and can detect an early disturbance of lymphatic transport (i.e., dermal backflow) before the lymphedema is clinically visible. The main objective of this study is to investigate whether this early disturbance of lymphatic transport visualized by lymphofluoroscopy is a risk factor for the development of BCRL. Methodology: All patients scheduled for unilateral breast cancer surgery with axillary lymph node dissection or sentinel node biopsy were considered. Patients were assessed at baseline and 1, 3, 6, 9, 12, 18, 24 and 36 months postoperatively. During each visit, a clinical assessment was performed to determine the volume difference between both arms and hands (through circumference measurements and water displacement). Clinical BCRL was defined as a ≥5% increase in relative arm volume difference compared to the baseline value. Variables related to (1) the disturbance of lymphatic transport (through lymphofluoroscopy), (2) the demographics and general health of the patient and (3) the breast cancer and treatment of the patient were collected. Results: We included data of 118 patients in the present study. Thirty-eight patients (39.8%) developed BCRL. Early disturbance of lymphatic transport was identified as a risk factor for the development of clinical BCRL (HR 2.808). Breast-cancer- and treatment-related variables such as axillary lymph node dissection (ALND) (HR 15.127), tumor stage (HR 1.745), mastectomy (HR 0.186), number of positive lymph nodes (HR 1.121), number of removed lymph nodes (HR 1.055), radiotherapy of the axilla (HR 2.715), adjuvant taxanes (HR 3.220) and postsurgical complications (HR 2.590) were identified as significant risk factors for the development of BCRL. In the multivariate analysis, age and ALND were withheld as independent risk factors for the development of BCRL. Conclusion: Lymphofluoroscopy can identify an early disturbance of lymphatic transport after breast cancer treatment. Patients with an early disturbance of lymphatic transport are considered to be a high-risk group for the development of BCRL. This study also confirms that age and ALND are predictors for the development of BCRL. Therefore, a surveillance program of these patients with lymphofluoroscopy could be useful to identify lymphedema in subclinical stages.

Association between Immediate Breast Reconstruction and the Development of Breast Cancer-Related Lymphedema

BACKGROUND

With the increasing number of patients undergoing immediate breast reconstruction after mastectomy, the impact of immediate breast reconstruction on the risk of breast cancer-related lymphedema has become an emerging area of interest. This study aimed to identify the association between immediate breast reconstruction and postoperative lymphedema.

METHODS

A retrospective cohort study was conducted from 2006 to 2016 with 5900 consecutive patients who underwent mastectomy for primary breast cancer with or without immediate breast reconstruction. After excluding patients with synchronous contralateral breast cancer, lymphedema before mastectomy, history of procedures performed in the axillary region, and follow-up data of less than 1 year, the cumulative incidence of lymphedema after immediate breast reconstruction and after no reconstruction was calculated and compared using multivariate Cox regression analysis.

RESULTS

Overall, 5497 patients (mean age, 51.7 years) were included, and 630 developed lymphedema. The 5-year cumulative incidence rate of lymphedema was significantly reduced in patients who underwent immediate breast reconstruction versus control patients (9.6% versus 12.2%; P = 0.02). In the multivariate analysis, immediate breast reconstruction status (hazard ratio, 0.75; 95% confidence interval, 0.56 to 0.99; P = 0.042) was an independent predictor for lymphedema. Similar significant associations were observed in the subgroup analyses of patients with a body mass index less than 30 kg/m2 (P = 0.024), in those with fewer than 10 dissected lymph nodes (P = 0.042), or in those with adjuvant radiotherapy (P = 0.048).

CONCLUSIONS

Immediate breast reconstruction was associated with a reduced risk of lymphedema. These results may be used for predicting the development of lymphedema following breast reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Patterns of regional recurrence according to molecular subtype in patients with pN2 breast cancer treated with limited field regional irradiation

OBJECTIVE

There is little evidence regarding the radiotherapy modification based on molecular subtypes in breast cancer. This study aimed to identify the risk and patterns of regional recurrence according to molecular subtype in patients with pN2 breast cancer.

METHODS

We identified 454 patients who underwent radical surgery for breast cancer with 4-9 axillary lymph node metastases. All patients underwent axillary lymph node dissection, adjuvant chemotherapy and limited-field regional nodal irradiation. The rates and patterns of regional recurrence were compared between the following three subgroups: luminal type (estrogen receptor- and/or progesterone receptor-positive), HER2-type (estrogen receptor- and progesterone receptor-negative and HER2-positive) and triple-negative type (estrogen receptor-, progesterone receptor- and HER2-negative).

RESULTS

Regional recurrence occurred in 18/454 patients (4%). The risk of regional recurrence was higher in the triple-negative (hazard ratio 7.641) and HER2-type (hazard ratio 4.032) subtypes than in the luminal subtype. The predominant pattern of regional recurrence was inside the radiotherapy field in triple-negative breast cancer and outside the radiotherapy field in HER2-type and luminal-type cancers.

CONCLUSIONS

In patients with pN2 breast cancer, the risk of regional recurrence was higher in the triple-negative and HER2-type than in the luminal type. In-field recurrence was predominant in triple-negative cancer, while out-field recurrence was frequent in luminal and HER2-type breast cancers.

The Lymphatic Endothelium in the Context of Radioimmuno-Oncology

The study of lymphatic tumor vasculature has been gaining interest in the context of cancer immunotherapy. These vessels constitute conduits for immune cells' transit toward the lymph nodes, and they endow tumors with routes to metastasize to the lymph nodes and, from them, toward distant sites. In addition, this vasculature participates in the modulation of the immune response directly through the interaction with tumor-infiltrating leukocytes and indirectly through the secretion of cytokines and chemokines that attract leukocytes and tumor cells. Radiotherapy constitutes the therapeutic option for more than 50% of solid tumors. Besides impacting transformed cells, RT affects stromal cells such as endothelial and immune cells. Mature lymphatic endothelial cells are resistant to RT, but we do not know to what extent RT may affect tumor-aberrant lymphatics. RT compromises lymphatic integrity and functionality, and it is a risk factor to the onset of lymphedema, a condition characterized by deficient lymphatic drainage and compromised tissue homeostasis. This review aims to provide evidence of RT's effects on tumor vessels, particularly on lymphatic endothelial cell physiology and immune properties. We will also explore the therapeutic options available so far to modulate signaling through lymphatic endothelial cell receptors and their repercussions on tumor immune cells in the context of cancer. There is a need for careful consideration of the RT dosage to come to terms with the participation of the lymphatic vasculature in anti-tumor response. Here, we provide new approaches to enhance the contribution of the lymphatic endothelium to radioimmuno-oncology.

Risk factors of unilateral breast cancer-related lymphedema: an updated systematic review and meta-analysis of 84 cohort studies

PURPOSE

To review and update the incidence and risk factors for breast cancer-related lymphedema based on cohort studies.

METHODS

The study was guided by the Joanna Briggs Institute methodology and the Cochrane handbook for systematic reviews. PubMed, EMBASE, CINAHL, Scopus, Web of Science, The Cochrane Library, CNKI, SinoMed, and Wan Fang Database were searched from inception to November 15, 2021. Cohort studies reported adjusted risk factors were selected. PRISMA guideline was followed. Study quality were evaluated using the Newcastle-Ottawa scale. Random-effects models were adopted. The robustness of pooled estimates was validated by meta-regression and subgroup analysis. Lymphedema incidence and adjusted risk factors in the multivariable analyses with hazard / odds ratios and 95% CIs were recorded.

RESULTS

Eighty-four cohort studies involving 58,358 breast cancer patients were included. The pooled incidence of lymphedema was 21.9% (95% CI, 19.8-24.0%). Fourteen factors were identified including ethnicity (black vs. white), higher body mass index, higher weight increase, hypertension, higher cancer stage (III vs. I-II), larger tumor size, mastectomy (vs. breast conservation surgery), axillary lymph nodes dissection, more lymph nodes dissected, higher level of lymph nodes dissection, chemotherapy, radiotherapy, surgery complications, and higher relative volume increase postoperatively. Additionally, breast reconstruction surgery, and adequate finance were found to play a protective role. However, other variables such as age, number of positive lymph nodes, and exercise were not correlated with risk of lymphedema.

CONCLUSION

Treatment-related factors still leading the development of breast cancer-related lymphedema. Other factors such as postoperative weight increase and finance status also play a part. Our findings suggest the need to shift the focus from treatment-related factors to modifiable psycho-social-behavioral factors.

Prediction of breast cancer-related lymphedema risk after postoperative radiotherapy via multivariable logistic regression analysis

PURPOSE

We identified novel clinical and dosimetric prognostic factors affecting breast cancer-related lymphedema after postoperative radiotherapy (RT) and developed a multivariable logistic regression model to predict lymphedema in these patients.

METHODS AND MATERIALS

In total, 580 patients with unilateral breast cancer were retrospectively reviewed. All patients underwent breast surgery and postoperative RT with or without systemic treatment in 2015. Among the 580 patients, 532 with available RT plan data were randomly divided into training (n=372) and test (n=160) cohorts at a 7:3 ratio to generate and validate the lymphedema prediction models, respectively. An area under the curve (AUC) value was estimated to compare models.

RESULTS

The median follow-up duration was 5.4 years. In total, 104 (17.9%) patients experienced lymphedema with a cumulative incidence as follows: 1 year, 10.5%; 3 years, 16.4%; and 5 years, 17.6%. Multivariate analysis showed that body mass index ≥25 kg/m2 (hazard ratio [HR] 1.845), dissected lymph nodes ≥7 (HR 1.789), and taxane-base chemotherapy (HR 4.200) were significantly associated with increased lymphedema risk. Conversely, receipt of RT at least 1 month after surgery reduced the risk of lymphedema (HR 0.638). A multivariable logistic regression model using the above factors, as well as the minimum dose of axillary level I and supraclavicular lymph node, was created with an AUC of 0.761 and 0.794 in the training and test cohorts, respectively.

CONCLUSIONS

Our study demonstrated that a shorter interval from surgery to RT and other established clinical factors were associated with increased lymphedema risk. By combining these factors with two dosimetric parameters, we propose a multivariable logistic regression model for breast cancer-related lymphedema prediction after RT.

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.

Axilla versus Wrist as the Recipient Site in Vascularized Lymph Node Transfer for Breast Cancer-Related Lymphedema: A Systematic Review and Meta-Analysis

BACKGROUND

 Vascularized lymph node transfers (VLNT) are being used with increasing frequency for the treatment of breast cancer-related lymphedema (BCRL). However, there is a lack of consensus in the surgical field as to which recipient site should be utilized. We, therefore, aim to assess the evidence comparing the wrist and axilla as recipient sites for VLNT in BCRL.

METHODS

 We conducted a systematic literature review to compare the wrist and axilla as recipient sites for VLNT in BCRL. Demographic data, as well as circumference reduction rate (CRR), excess volume reduction (EVR), postoperative decrease in infections per year, postoperative discontinuation of compression garments, and overall pooled complication rate were extracted from included studies. These were compared through a meta-analysis.

RESULTS

 A total of 37 studies met the inclusion criteria for a total of 689 patients. VLNTs to the wrist and axilla resulted in a decrease in CRR of 42.1 and 51.5%, and a decrease in EVR of 35.6 and 48.8%, respectively. However, our meta-analysis showed no significant differences between CRR or EVR and between wrist and axilla as recipient sites. Similarly, we found no differences in postoperative decrease in infections per year, postoperative discontinuation of compression garments, and overall pooled complication rate.

CONCLUSION

 These data suggest noninferiority between the wrist and axilla as recipient sites for VLNT in the context of BCRL. In the absence of randomized, prospective data, we hope these results can be used as an evidence-based reference and facilitate future studies.

Radiation therapy-associated toxicity: Etiology, management, and prevention

Radiation therapy (RT) is a curative treatment for many malignancies and provides effective palliation in patients with tumor-related symptoms. However, the biophysical effects of RT are not specific to tumor cells and may produce toxicity due to exposure of surrounding organs and tissues. In this article, the authors review the clinical context, pathophysiology, risk factors, presentation, and management of RT side effects in each human organ system. Ionizing radiation works by producing DNA damage leading to tumor death, but effects on normal tissue may result in acute and/or late toxicity. The manifestation of toxicity depends on both cellular characteristics and affected organs' anatomy and physiology. There is usually a direct relationship between the radiation dose and volume to normal tissues and the risk of toxicity, which has led to guidelines and recommended dose limits for most tissues. Side effects are multifactorial, with contributions from baseline patient characteristics and other oncologic treatments. Technological advances in recent decades have decreased RT toxicity by dramatically improving the ability to deliver RT that maximizes tumor dose and minimizes organ dose. Thus the study of RT-associated toxicity is a complex, core component of radiation oncology training that continues to evolve alongside advances in cancer management. Because RT is used in up to one-half of all patients with cancer, an understanding of its acute and late effects in different organ systems is clinically pertinent to both oncologists and nononcologists.

A historical literature review on the role of posterior axillary boost field in the axillary lymph node coverage and development of lymphedema following regional nodal irradiation in breast cancer

To elucidate whether (1) a posterior axillary boost (PAB) field is an optimal method to target axillary lymph nodes (LNs); and (2) the addition of a PAB increases the incidence of lymphedema, a systematic review was undertaken. A literature search was performed in the PubMed database. A total of 16 studies were evaluated. There were no randomized studies. Seven articles have investigated dosimetric aspects of a PAB. The remaining 9 articles have determined the effect of a PAB field on the risk of lymphedema. Only 2 of 9 articles have prospectively reported the impact of a PAB on the risk of lymphedema development. There are conflicting reports on the necessity of a PAB. The PAB field provides a good coverage of level I/II axillary LNs because these nodes are usually at a greater depth. The main concern regarding a PAB is that it produces a hot spot in the anterior region of the axilla. Planning studies optimized a traditional PAB field. Prospective studies and the vast majority of retrospective studies have reported the use of a PAB field does not result in increasing the risk of lymphedema development over supraclavicular-only field. The controversies in the incidence of lymphedema suggest that field design may be more important than field arrangement. A key factor regarding the use of a PAB is the depth of axillary LNs. The PAB field should not be used unless there is an absolute indication for its application. Clinicians should weigh lymphedema risk in individual patients against the limited benefit of a PAB, in particular after axillary dissection. The testing of the inclusion of upper arm lymphatics in the regional LN irradiation target volume, and universal methodology measuring lymphedema are all areas for possible future studies.

Feasibility of arm-draining lymph node-sparing radiotherapy of breast cancer: A pilot planning study

INTRODUCTION

Lymphoedema following axillary radiotherapy for breast cancer causes significant morbidity. Our goal was to evaluate the feasibility of sparing the lymph node that drains the arm's lymphatics (ARM node) while achieving standard dose constraints for whole breast and comprehensive lymph node irradiation.

METHODS

Six patients underwent lymphoscintigraphy and SPECT CT to identify the breast sentinel node (SN) and ARM node. The ARM node was contoured on the SPECT CT and deformably registered to the radiotherapy treatment planning CT. Radiotherapy plans (50 Gy in 25 fractions) with VMAT technique were generated, with the aim to spare the ARM node (Mean dose <25 Gy) and achieve adequate coverage to the remaining axilla. The plan required the breast SN site (clip + 10 mm surrounding the clip) to achieve D98% > 47.5 Gy, and axillary nodal CTV excluding ARM node to achieve D90% > 45 Gy.

RESULTS

In one patient, the ARM node was within the volume of breast SN site and sparing was not possible. For the remaining 5 patients, an ARM node-sparing plan could be successfully generated; the mean dose to the ARM node ranged from 11.2 to 23.1 Gy (median 13.8 Gy). In these 5 subjects, D90% > 45 Gy of axillary nodal CTV (range, 44.9-48.5 Gy, median 46.2 Gy) and D98% > 47.5 Gy of breast SN site were achieved.

CONCLUSION

In this planning study, ARM node-sparing VMAT of the breast and lymph nodes was feasible, while maintaining adequate dosimetric coverage. However, in some individuals, localization of the ARM node in close proximity to breast SN site precluded the generation of an ARM node-sparing treatment plan.

Discordance in clinical versus pathological staging in breast cancer: Are we undermining the significance of accurate preoperative staging in the present era?

BACKGROUND

The present era of individualized treatment for breast cancer is influenced by the initial disease status including the anatomical extent, grade, and receptor status. An accurate preoperative staging is the basis of treatment planning and prognostication. Our study aims to determine the discordance between the preoperative clinical and the postoperative pathological stages of breast cancer patients.

METHODOLOGY

The medical records of all non-metastatic breast cancer patients from January 2017 to December 2018 who underwent upfront surgery were reviewed. They were staged as per the eighth AJCC and the concordance between the clinical (c) and pathological T (tumor), N (nodal), and final AJCC stage was studied. A Chi-square test was used to determine factors that significantly correlate with disease discordance.

RESULTS

A total of 307 breast cancer patients were analyzed. Among these, 43.3% were hormone receptor-positive, 30.6% were Her2 positive and 26% were triple-negative. Overall stage discordance was seen in 48.5% (n = 149) patients (upstaging in 22.1%, downstaging in 26.4%). The discordance rate was 48.9% for T stage (cT versus pT) and 57.4% for N stage (cN versus pN). Among patients with clinically node-negative disease, 53.4% were found to have positive nodes on histopathology, while 27.2% had vice versa. Overall, the factors associated with upstaging were ER-positive, Her2 positive and triple-negative status (all p < 0.05), while none of the factors showed significant association with downstaging.

CONCLUSIONS

About half of breast cancer patients had discordance between clinical and pathological staging with higher discordance in the nodal stage. This changes the disease prognosis, and may also affect the offered surgical treatment and radiotherapy. Thus highlighting the need for a precise pre-operative staging. Also, this information will aid clinicians in discussions with patients, keeping in mind the likelihood of change in disease staging and management.

A National Survey of Breast Surgeons and Radiation Oncologists on Contemporary Axillary Management in Mastectomy Patients

BACKGROUND

Management of axillary lymph nodes in breast cancer has undergone significant change over the past decade through landmark clinical trials. This study aimed to assess national practice patterns in axillary management in patients undergoing upfront mastectomy and examines what guides provider recommendations.

METHODS

A national case-based survey study was performed of surgeons and radiation oncologists from July to August 2020. Surgeons were identified through the American Society of Breast Surgeons (ASBrS) after review and approval by the ASBrS Research Committee, and radiation oncologists were identified through an institutional database. Both descriptive and comparative statistical analyses were performed.

RESULTS

Overall, 994 providers responded-680 surgeons and 314 radiation oncologists. Surgeons were older and in practice longer (p < 0.05) and treated a higher percentage of breast patients (81% vs. 40%, p < 0.001). Most surgeons were hospital-employed (43%), whereas most radiation oncologists were in private practice (40%; p < 0.001). Fifty-two percent of surgeons routinely send sentinel lymph nodes (SLNs) for frozen section (52%) during mastectomy, of which 78% proceed directly to axillary lymph node dissection (ALND) if positive. There was significant variability in treatment recommendations between the two groups among the hypothetical cases (p < 0.001). In the setting of low disease burden in the SLNs, > 30% of surgeons recommended ALND, while radiation oncologists recommend axillary radiotherapy over axillary clearance (p < 0.001).

CONCLUSION

There is significant heterogeneity in the management of the axilla in mastectomy patients with pathologically positive SLNs, both between and among surgeons and radiation oncologists. Efforts should be made to assist both groups in identifying de-escalation opportunities to ensure that mastectomy patients with positive SLNs are treated appropriately.

Auxiliary Structures-Assisted Radiotherapy Improvement for Advanced Left Breast Cancer

Background

To improve the quality of plan for the radiation treatment of advanced left breast cancer by introducing the auxiliary structures (ASs) which are used to spare the regions with no intact delineated structures adjacent to the target volume.

Methods

CT data from 20 patients with left-sided advanced breast cancer were selected. An AS designated as A1 was created to spare the regions of the aorta, pulmonary artery, superior vena ava, and contralateral tissue of the upper chest and neck, and another, designated as A2, was created in the regions of the cardia and fundus of the stomach, left liver lobe, and splenic flexure of the colon. IMRT and VMAT plans were created for cases with and without the use of the AS dose constraints in plan optimization. Dosimetric parameters of the target and organs at risk (OARs) were compared between the separated groups.

Results

With the use of AS dose constraints, both the IMRT and VMAT plans were clinically acceptable and deliverable, even showing a slight improvement in dose distribution of both the target and OARs compared with the AS-unused plans. The ASs significantly realized the dose sparing for the regions and brought a better conformity index (p < 0.05) and homogeneity index (p < 0.05) in VMAT plans. In addition, the volume receiving at least 20 Gy (V₂₀) for the heart (p < 0.05), V₄₀ for the left lung (p < 0.05), and V₄₀ for the axillary-lateral thoracic vessel juncture region (p < 0.05) were all lower in VMAT plans.

Conclusion

The use of the defined AS dose constraints in plan optimization was effective in sparing the indicated regions, improving the target dose distribution, and sparing OARs for advanced left breast cancer radiotherapy, especially those that utilize VMAT plans.

Risk of Lymphedema Following Contemporary Treatment for Breast Cancer: An Analysis of 7617 Consecutive Patients From a Multidisciplinary Perspective

OBJECTIVE

The aim of this study was to identify the comprehensive risk factors for lymphedema, thereby enabling a more informed multidisciplinary treatment decision-making.

SUMMARY BACKGROUND DATA

Lymphedema is a serious long-term complication in breast cancer patients post-surgery; however, the influence of multimodal therapy on its occurrence remains unclear.

METHODS

We retrospectively collected treatment-related data from 5549 breast cancer patients who underwent surgery between 2007 and 2015 at our institution. Individual radiotherapy plans were reviewed for regional nodal irradiation (RNI) field design and fractionation type. We identified lymphedema risk factors and used them to construct nomograms to predict individual risk of lymphedema. Nomograms were validated internally using 100 bootstrap samples and externally using 2 separate datasets of 1877 Asian and 191 Western patients.

RESULTS

Six hundred thirty-nine patients developed lymphedema during a median follow-up of 60 months. The 3-year lymphedema incidence was 10.5%; this rate increased with larger irradiation volumes (no RNI vs RNI excluding axilla I-II vs RNI including axilla I-II: 5.7% vs 16.8% vs 24.1%) and when using conventional fractionation instead of hypofractionation (13.5% vs 6.8%). On multivariate analysis, higher body mass index, larger number of dissected nodes, taxane-based regimen, total mastectomy, larger irradiation field, and conventional fractionation were strongly associated with lymphedema (all P < 0.001). Nomograms constructed based on these variables showed good calibration and discrimination internally (concordance index: 0.774) and externally (0.832 for Asian and 0.820 for Western patients).

CONCLUSIONS

Trimodality breast cancer treatment factors interact to promote lymphedema. Lymphedema risk can be decreased by deintensifying node dissection, chemotherapy regimen, and field and dose of radiotherapy. Deescalation strategies on a multidisciplinary basis might minimize lymphedema risk.

Loco-regional therapy and the risk of breast cancer-related lymphedema: a systematic review and meta-analysis

BACKGROUND

This meta-analysis was designed to assess the association between two loco-regional therapies, regional nodal irradiation (RNI) and axillary lymph node dissection (ALND), and breast cancer-related lymphoedema (BCRL).

METHODS

We searched PubMed, Science Direct, Embase, and BMJ databases for clinical studies published between January 1, 2010 and January 1, 2020, which assessed risk factors and incidence/prevalence of BCRL. Two investigators independently selected articles to extract relative data and calculate corresponding exact binomial 95% confidence intervals (CIs). In total, 93 articles were reviewed, from which 19 studies were selected. The extracted data were pooled using a random-effects mixed model.

RESULTS

The incidence of lymphedema in the selected studies ranged from 3% to 36.7%, with a pooled incidence of 14.29% (95% CI 13.79-14.79). The summary odds ratio/risk ratio (OR/RR) of ALND vs. no-ALND was 3.67 (95% CI 2.25-5.98) with a heterogeneity (I²) of 81% (P < 0.00001). After excluding the studies with an abnormally high risk of lymphedema from self-reporting, the summary hazard ratio (HR) was 2.99 (95% CI 2.44-3.66) with no heterogeneity (I² = 0%, P = 0.83). The summary OR/RR of patients with vs. without radiotherapy (RT) was 1.82 (95% CI 0.92-3.59), but the RR of RT to breast/chest vs. both axillary and supraclavicular areas was 2.66 (95% CI 0.73-9.70).

CONCLUSION

Regional nodal irradiation has a significantly higher risk for developing lymphedema than irradiation of the breast/chest wall. Axillary dissection and axillary RT have a similar risk for early-onset of breast cancer-related lymphoedema, although the risk trends higher for axillary dissection.

Prevention of Breast Cancer-Related Lymphedema

Tremendous progress has been made over the past several decades in the treatment of breast cancer. Mortality and recurrence rates continue to decline. Our ability to tailor patient- and tumor-specific treatments has rapidly advanced. The vast majority of our patients can safely have breast conservation. Unfortunately, for many patients, survivorship is burdened by ongoing quality-of-life issues. Most breast cancer patients are asymptomatic at presentation, and the onus is on us to preserve this. Surgery, radiation, and systemic therapy can result in long-term toxicities that can be amplified with multimodality approaches. We must strive to apply minimally effective therapies rather than a maximally tolerated approach. Breast cancer-related lymphedema (BCRL) is a particularly dreaded chronic complication. This review strives to give the reader a better understanding of BCRL and shed light on wisely choosing an integration of treatment modalities that minimizes BCRL risk. Key literature on emerging concepts is highlighted.

The Risk of Subclinical Breast Cancer-Related Lymphedema by the Extent of Axillary Surgery and Regional Node Irradiation: A Randomized Controlled Trial

PURPOSE

To compare the risk of subclinical breast cancer-related lymphedema (sBCRL) using bioimpedance spectroscopy (BIS) or tape measure (TM) by the extent of axillary surgery and regional nodal irradiation (RNI).

METHODS AND MATERIALS

Patients were randomized to surveillance with TM or BIS. A BIS ≥6.5 L-Dex units or TM volume change ≥5 and <10% above presurgical baselines "triggered" sBCRL. The incidence of sBCRL by sentinel node biopsy or axillary lymph node dissection (ALND) with or without RNI was examined for 484 patients. Radiation was categorized as "limited RNI" (axilla level I/II only) or "extensive RNI" (axilla level III or supraclavicular fossa with or without level I/II).

RESULTS

At a median follow-up of 20.5 months, 109 of 498 patients (21.9%) triggered sBCRL (BIS 13.5% vs TM 25.6%; P <.001). In patients not receiving RNI, BIS triggered 12.9% of patients undergoing SNB and 25.0% undergoing ALND (P = .18). Extensive RNI significantly increased triggering with BIS versus no RNI after sentinel node biopsy (SNB; 33.3% vs 12.9%; P = .03) but not ALND (30.8% vs 25.0%; P = .69). Triggering by TM was greater than 25% for most subgroups and was inferior to BIS in discriminating the risk of sBCRL by utilization of RNI or axillary surgery.

CONCLUSIONS

The lower triggering rates with BIS and its better discrimination of the risk of sBCRL by receipt and type of RNI compared with TM support its use for posttreatment surveillance to detect sBCRL and to initiate early intervention. The risk of sBCRL increased with more extensive axillary treatment. Patients having ALND or extensive RNI require close surveillance for BCRL. Longer follow-up is required to determine rates of progression to clinical lymphedema.

Longitudinal impact of postmastectomy radiotherapy on arm lymphedema in patients with breast cancer: An analysis of serial changes in arm volume measured by infrared optoelectronic volumetry

BACKGROUND AND PURPOSE

This study was conducted to evaluate the longitudinal impact of postmastectomy radiation therapy (PMRT) on persistent severe lymphedema (PSL) using arm volume measurements by an infrared optoelectronic volumetry.

MATERIALS AND METHODS

Of the patients who underwent mastectomy between 2008 and 2016, we included 330 patients with secondary arm lymphedema. Percentage of excessive volume (PEV) of the arm were serially assessed using an optoelectronic volumetry 1, 3, 6, 12, 18, 24, 36, and 48 months after the lymphedema diagnosis (T_{lymh_Dx}). We defined PSL as 2 or more episodes of PEV ≥ 20%. Risk factors for PSL were evaluated using stepwise regression analyses.

RESULTS

Patients who received PMRT (n = 202, 61.2%) were more likely to have larger extent of axillary node dissection (AND), and frequent stage II/III lymphedema at T_{lymh_Dx} than those who did not receive PMRT (p < 0.001). With a median follow-up of 72.5 months, PSL occurred in 71 (21.5%) patients. Patients with PSL were more frequently treated with AND of ≥ 20 nodes without reconstruction, had advanced lymphedema stage and higher PEV at T_{lymh_Dx}, and more frequent events of cellulitis compared to those without PSL. The risk of developing PSL was significantly associated with PMRT with regional node irradiation (RNI), AND of ≥20 nodes, lymphedema stage, and PEV at T_{lymh_Dx}, cellulitis, and compliance with physical therapy.

CONCLUSION

PMRT, especially RNI, was associated with a consistent increase in PEV in patients with arm lymphedema. Therefore, timely physical therapy is necessary for this patient population.

Clinical evaluation of atlas- and deep learning-based automatic segmentation of multiple organs and clinical target volumes for breast cancer

Manual segmentation is the gold standard method for radiation therapy planning; however, it is time-consuming and prone to inter- and intra-observer variation, giving rise to interests in auto-segmentation methods. We evaluated the feasibility of deep learning-based auto-segmentation (DLBAS) in comparison to commercially available atlas-based segmentation solutions (ABAS) for breast cancer radiation therapy. This study used contrast-enhanced planning computed tomography scans from 62 patients with breast cancer who underwent breast-conservation surgery. Contours of target volumes (CTVs), organs, and heart substructures were generated using two commercial ABAS solutions and DLBAS using fully convolutional DenseNet. The accuracy of the segmentation was assessed using 14 test patients using the Dice Similarity Coefficient and Hausdorff Distance referencing the expert contours. A sensitivity analysis was performed using non-contrast planning CT from 14 additional patients. Compared to ABAS, the proposed DLBAS model yielded more consistent results and the highest average Dice Similarity Coefficient values and lowest Hausdorff Distances, especially for CTVs and the substructures of the heart. ABAS showed limited performance in soft-tissue-based regions, such as the esophagus, cardiac arteries, and smaller CTVs. The results of sensitivity analysis between contrast and non-contrast CT test sets showed little difference in the performance of DLBAS and conversely, a large discrepancy for ABAS. The proposed DLBAS algorithm was more consistent and robust in its performance than ABAS across the majority of structures when examining both CTVs and normal organs. DLBAS has great potential to aid a key process in the radiation therapy workflow, helping optimise and reduce the clinical workload.

Quantifying the Impact of Axillary Surgery and Nodal Irradiation on Breast Cancer-Related Lymphedema and Local Tumor Control: Long-Term Results From a Prospective Screening Trial

PURPOSE

To independently evaluate the impact of axillary surgery type and regional lymph node radiation (RLNR) on breast cancer-related lymphedema (BCRL) rates in patients with breast cancer.

PATIENTS AND METHODS

From 2005 to 2018, 1,815 patients with invasive breast cancer were enrolled in a lymphedema screening trial. Patients were divided into the following 4 groups according to axillary surgery approach: sentinel lymph node biopsy (SLNB) alone, SLNB+RLNR, axillary lymph node dissection (ALND) alone, and ALND+RLNR. A perometer was used to objectively assess limb volume. All patients received baseline preoperative and follow-up measurements after treatment. Lymphedema was defined as a ≥ 10% relative increase in arm volume arising > 3 months postoperatively. The primary end point was the BCRL rate across the groups. Secondary end points were 5-year locoregional control and disease-free-survival.

RESULTS

The cohort included 1,340 patients with SLNB alone, 121 with SLNB+RLNR, 91 with ALND alone, and 263 with ALND+RLNR. The overall median follow-up time after diagnosis was 52.7 months for the entire cohort. The 5-year cumulative incidence rates of BCRL were 30.1%, 24.9%, 10.7%, and 8.0% for ALND+RLNR, ALND alone, SLNB+RLNR, and SLNB alone, respectively. Multivariable Cox models adjusted for age, body mass index, surgery, and reconstruction type showed that the ALND-alone group had a significantly higher BCRL risk (hazard ratio [HR], 2.66; P = .02) compared with the SLNB+RLNR group. There was no significant difference in BCRL risk between the ALND+RLNR and ALND-alone groups (HR, 1.20; P = .49) and between the SLNB-alone and SLNB+RLNR groups (HR, 1.33; P = .44). The 5-year locoregional control rates were similar for the ALND+RLNR, ALND-alone, SLNB+RLNR, and SLNB-alone groups (2.8%, 3.8%, 0%, and 2.3%, respectively).

CONCLUSION

Although RLNR adds to the risk of lymphedema, the main risk factor is the type of axillary surgery used.

Dosimetric comparison of incidental axillary irradiation between three-dimensional conformal and volumetric modulated arc techniques for breast cancer

Radiotherapy techniques for breast cancer have evolved with efforts to reduce treatment-related side effects. In the present study, we conducted dosimetric analysis of incidental axillary irradiation between volumetric modulated arc therapy (VMAT) and three-dimensional conformal radiotherapy (3D-CRT). A total of 20 patients with early stage left breast cancer who underwent breast-conserving surgery followed by postoperative radiotherapy were analyzed. For VMAT plans, dose-volume constraints were not imposed on the axilla, as with 3D-CRT. We compared the dosimetric parameters of the planning target volumes, organs at risk and axillary level I-III of the two plans. VMAT showed better target coverage and a normal organ-sparing effect compared with 3D-CRT. The incidental axillary irradiation of VMAT was lower; the mean dose and the V40Gy were significantly reduced at all axillary levels, with the exception of no difference in the maximum dose to axillary level I. In conclusion, VMAT decreased incidental axillary irradiation, even in the absence of a dose-volume constraint on the axilla, and can, therefore, decrease the risk of radiotherapy-related lymphedema. However, caution is also required because it is unclear whether this incidental axillary irradiation is beneficial for reducing recurrence on the axilla.

Comparison of Nodal Target Volume Definition in Breast Cancer Radiation Therapy According to RTOG Versus ESTRO Atlases: A Practical Review From the TransAtlantic Radiation Oncology Network (TRONE)

Regional nodal irradiation has gained interest in recent years with the publication of several important randomized trials and the availability of more conformal techniques. Target volume delineation represents a critical step in the radiation planning process. Adequate coverage of the microscopic tumor spread to regional lymph nodes must be weighed against exposure of critical structures such as the heart and lungs. Among available guidelines for delineating the clinical target volume for the breast/chest wall and regional nodes, the Radiation Therapy Oncology Group and European Society for Radiotherapy and Oncology guidelines are the most widely used internationally. These guidelines have been formulated based on anatomic boundaries of areas historically covered in 2-dimensional field-based radiation therapy but have not been validated by patterns-of-failure studies. In recent years, an important body of data has emerged from mapping studies documenting patterns of local and regional recurrence. We aim to review, discuss, and compare contouring guidelines for breast cancer radiation therapy in the context of contemporary data on locoregional relapse to improve their implementation in modern practice.

The impact of radiation on lymphedema: a review of the literature

Radiation therapy (RT) is a common adjunct therapy in oncology. However, it carries a significant risk of lymphedema when utilized in some anatomic locations. Recent studies have provided insight into lymphedema pathophysiology, diagnostic techniques, and RT. This review will examine the role of RT in upper and lower extremity lymphedema. Radiation's role in increasing the risk of lymphedema through decreased lymphatic proliferation potential, interstitial fibrosis compressing lymphatic vessels, and mechanical insufficiency of the lymphatic system will be reviewed.

Mapping of Metastatic Level I Axillary Lymph Nodes in Patients with Newly Diagnosed Breast Cancer

PURPOSE

We examined the distribution of pretreatment nodal metastases to the level I axilla (Ax-L1) to assess the appropriateness of current breast atlases and provide guidelines in relationship to easily identifiable anatomic landmarks for accurate delineation of this lymph node (LN) basin.

METHODS AND MATERIALS

Patients with newly diagnosed breast cancer and biopsy-proven metastatic Ax-L1 LNs were identified. We related the location of each LN to its most adjacent rib and its distance from the bottom of the humeral head, axillary vessels, and a line connecting the anterior aspects of the pectoralis and latissimus dorsi muscles (P-L line). LNs were mapped onto a representative planning computed tomography scan, and their distribution was used to validate the current Radiation Therapy Oncology Group, European Society for Radiotherapy and Oncology, and Radiotherapy Comparative Effectiveness breast atlases. Furthermore, we examined metastases to a subregion encompassing the superolateral Ax-L1, irradiation of which correlates highly with lymphedema.

RESULTS

We identified 106 eligible patients with 107 biopsied LNs. All LNs fell between the second and fifth ribs (mean, 3.8 ± 0.56). Mean distance from the inferior aspect of the humeral head was 4.3 ± 1.6 cm (range, 0.3-8.4). Mean distance from the inferior aspect of the axillary vessels was 2.9 ± 1.5 cm (range, -0.6 to 5.4). Mean distance from the P-L line was 0.01 ± 1.9 cm (range, -2.2 to 2.4); negative and positive values denote medial or lateral to the P-L line. A Radiation Therapy Oncology Group-compliant Ax-L1 consensus contour, created from contours by 4 attending breast radiation oncologists, partially or fully missed 45% of mapped LNs. European Society for Radiotherapy and Oncology- and Radiotherapy Comparative Effectiveness-compliant Ax-L1 similarly missed 46% and 34% of mapped LNs, respectively. LNs were most frequently missed in the lateral direction. The superolateral Ax-L1 encompassed 9.3% of the mapped LNs.

CONCLUSIONS

A significant percentage of at-risk Ax-L1 tissue falls outside current contouring atlases. We propose expansion of the recommended Ax-L1 borders, most notably in the lateral direction.

Development and Validation of a Nomogram to Predict Lymphedema After Axillary Surgery and Radiation Therapy in Women With Breast Cancer From the NCIC CTG MA.20 Randomized Trial

PURPOSE

Regional nodal irradiation for women with breast cancer is known to be an important risk factor for the development of upper extremity lymphedema, but tools to accurately predict lymphedema risks for individual patients are lacking. This study sought to develop and validate a nomogram to predict lymphedema risk after axillary surgery and radiation therapy in women with breast cancer.

METHODS AND MATERIALS

Data from 1832 women accrued on the MA.20 trial between March 2000 and February 2007 were used to create a prognostic model with National Cancer Institute Common Toxicity Criteria Version 2.0 grade 2 or higher lymphedema as the primary endpoint. Multivariable logistic regression estimated model performance. External validation was performed on data from a single large academic cancer center (N = 785).

RESULTS

In the MA.20 trial cohort, 3 risk factors were predictive of lymphedema risk: body mass index (adjusted odds ratio, 1.05 per unit body mass index; 95% confidence interval [CI], 1.03-1.08, P < .001), extent of axillary surgery (adjusted odds radio for 8-11 lymph nodes removed, 3.28 [95% CI, 1.53-7.89] P = .004; 12-15 lymph nodes, 4.04 [95% CI, 1.76-10.26] P = .002; ≥16 nodes, 5.08 [95% CI, 2.26-12.70] P < .001), and extent of nodal irradiation (adjusted odds radio for limited, 1.66 [95% CI, 1.08-2.56] P = .02; for extensive, 2.31 [95% CI, 1.28-4.10] P = .004). A nomogram was created from these data that predicted lymphedema risk with reasonable accuracy confirmed by both internal (concordance index, 0.69; 95% CI, 0.64-0.74) and external validation (concordance index, 0.71; 95% CI, 0.66-0.76).

CONCLUSIONS

The nomogram created from the MA.20 randomized trial data using clinical information may be useful for lymphedema screening and risk stratification for therapeutic intervention trials.