Coverage Of Axillary Lymph Nodes Research Articles

Axillary Lymph Node Coverage in Breast Cancer Patients Treated with Adjuvant Radiation Using High Tangent Fields Technique: A Single Institution’s Experience

Background: The high tangent field (HTF) technique is used to provide radiation coverage of the inferior axillary nodal levels for breast cancer patients when the lower axilla is at risk for micrometastatic disease. Despite its use in clinical practice, there is concern about whether HTF provide sufficient coverage of level I and II axillary nodal regions. The purpose of this study is to quantify and evaluate the coverage of HTF at our institution. Methods: Patients diagnosed with early invasive breast carcinoma (pT1-2 pN0-1a) who received HTF radiation between January 1st, 2012 and December 31st, 2016 were retrospectively reviewed. Level I and II axillary nodal regions were contoured on each patient’s simulation CT. Dosimetric parameters were re-calculated to evaluate coverage. Statistical analysis was conducted using Mann-Whitney-U method. Results: Thirty-seven patients with low-risk breast adenocarcinoma were included. For level I and II, the mean V90% was 94.63% ± 7.60% and 73.33% ± 21.83% respectively. Twenty-nine patients received adequate V90% coverage of level I and had a mean level II V90% of 76% ± 18.71% while eight patients who did not receive adequate V90% level I coverage had a mean level II V90% of 63.64% ± 30.22%. The median level II V90% of patients receiving adequate and inadequate level I V90% was 77.74% and 71.11% respectively; the difference was not statistically significant (P = 0.33). Conclusion: HTF provides adequate coverage for level I nodes, but inadequate coverage for level II. Contouring nodal volumes may assist field placement and improve nodal volume coverage.

Dosimetric Analysis of Axillary Lymph Node Coverage Using High Tangents in the Prone Position for Left-Sided Breast Cancers.

Aim/Objective: Prone positioning is often used to reduce the dose to organs at risk during adjuvant breast irradiation. High tangents are used with supine treatments in patients with the low-volume nodal disease to increase nodal coverage while minimizing toxicities. Our study aims to evaluate nodal coverage for patients treated in the prone position with high tangents.Materials and Methods: Our study analyzed the plans for 20 patients with early-stage, left-sided breast cancers treated at our institution from 2018 to 2019. All patients were treated in the prone position. Axillary nodal levels I-III were contoured, and treatment plans were generated using high tangents. The heart, bilateral lungs, and breast tissue were retrospectively contoured. All plans were evaluated to a dose of 42.4 Gy in 16 fractions.Results: Level I lymph node levels had a mean coverage of 99% of the prescription dose (range: 98-100%). Similarly, level II coverage was approximately 88% (range: 65-100%). The mean coverage for level III was approximately 25% (range: 0-52%). The mean heart dose, mean lung volume receiving ≥20 Gy (V20) for the bilateral lungs, and ipsilateral V20 were 1.69 Gy, 1.64%, and 3.56%, respectively.Conclusion:Treating patients in the prone position with high tangents provides excellent coverage of axillary levels I and II, although there is minimal coverage of axillary level III. Prospective trials are needed to evaluate the clinical outcomes when treating patients with high tangents in the prone position.

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.

Axillary Lymph Node Coverage in Breast Cancer Patients Treated with Adjuvant Radiation Using High Tangent Technique: A Single Institution Experience

Axillary Lymph Node Coverage in Breast Cancer Patients Treated with Adjuvant Radiation Using High Tangent Technique: A Single Institution Experience

A Dosimetric Analysis of Axillary Lymph Node Coverage Using High Tangents in the Prone Position for Left-Sided Breast Cancers

A Dosimetric Analysis of Axillary Lymph Node Coverage Using High Tangents in the Prone Position for Left-Sided Breast Cancers

49: Axillary Lymph Node Coverage in Breast Cancer Patients Treated with Adjuvant Radiation Using High Tangent Technique: Bc Cancer Kelowna Experience

49: Axillary Lymph Node Coverage in Breast Cancer Patients Treated with Adjuvant Radiation Using High Tangent Technique: Bc Cancer Kelowna Experience

Coverage of Axillary Lymph Nodes with High Tangents in the Prone Position

Coverage of Axillary Lymph Nodes with High Tangents in the Prone Position

Contralateral tissue sparing in lymph node-positive breast cancer radiotherapy with VMAT technique

The objective of this study was to modify volumetric modulated arc therapy (VMAT) design for breast irradiation with axillary lymph node involvement to enhance normal tissue sparing while maintaining good planning target volume (PTV) coverage. Four VMAT plans were generated retrospectively for 10 patients with breast cancer for comparison. First, 2 partial arcs with an avoidance sector (Pavoid) for the lung and the heart were created. Second, a split-arc design with 2 partial arcs was used, changing the collimator angle by splitting the arcs in the middle, resulting in 4 partial arcs (Psplit). Third, the arc angles in the Psplit were modified to emphasize tangential directions, corresponding to the avoidance sector in Pavoid, resulting in 2 lateral and 2 anterior partial arcs. Furthermore, a fifth arc was added to ensure the coverage of axillary lymph nodes (Ptang). Fourth, one of the anterior arcs was removed to limit the number of arcs during treatment (Ptang-1). PTV coverage was the highest in Psplit with a V90%(PTV) of 98.4 ± 0.6%. Also the dose homogeneity and conformity were the best (p < 0.02) in Psplit, and a smaller high-dose volume was distributed to the ipsilateral lung, heart, and humeral head, than in the other designs. In Ptang and Ptang-1, the PTV coverage was acceptable with V90%(PTV) of 97.9 ± 0.8% and 98.0 ± 0.8%, respectively, and low-dose volumes in normal tissue were smaller compared with Psplit. The removal of 1 partial arc from Ptang (Ptang-1) did not have a significant effect on dose parameters. In Pavoid, the contralateral breast and lung volumes of low-dose level were the smallest. However, the PTV coverage was reduced (V90% = 97.0 ± 1.6%), and the heart, ipsilateral lung, and humeral head received significantly higher doses than in other designs. The modified split-arc methods Ptang and Ptang-1, emphasizing tangential directions, were close to the original split-arc method in PTV coverage while reducing the dose to the healthy tissues distant from the PTV. Ptang-1 is seen as a favorable treatment option over Ptang with less treatment time.

Axillary lymph node coverage with 3-dimensional tangential field irradiation and correlation with heart and lung dose

PurposeThe American College of Surgeons Oncology Group Z0011 trial indicated no benefit from axillary lymph node (LN) dissection after a positive sentinel LN biopsy in patients receiving breast irradiation, suggesting that level I-II LNs were covered in tangential fields. Methods and materialsWe evaluated 50 computed tomography–based tangential breast plans and contoured level I-III axillary LNs using the Radiation Therapy Oncology Group guidelines. The volumes of level I-III LN regions covered by 90% and 95% of the prescription dose (PD) were calculated and correlated with the V20 ipsilateral lung and mean heart dose. We calculated field length, distance from the humeral head, and separation. The Pearson correlation method and linear models were used in the correlative study. ResultsLevel I LN mean and median volume (MMV) covered by 90% of the PD were 46.8% and 47.2%, respectively. MMV covered by 95% of the PD was 30.8% and 29.62%. Mean and median dose to level I LNs were 29.03 Gy and 30.13 Gy, respectively. The MMV of level II LNs covered by 90% of the PD was 2.49% and 0%. The mean and median dose to level II LNs were 6.09 Gy and 2.12 Gy, respectively. The MMV of level III LNs was 0% with a mean and median dose of 1.04 Gy and 0.92 Gy, respectively. There was a moderate correlation between the 95% prescription coverage of level I LNs and V20 ipsilateral lung and a smaller correlation between 95% prescription coverage of level I LNs and mean heart dose. Distance from the humeral head was inversely correlated with coverage of level I and II LNs and positively correlated with V20 lung. ConclusionIn most patients, <50% of the level I LN volume was covered by 90% of the PD and <30% was covered by 95%; <5% of the level II nodes were covered by 90% of the PD; and coverage was 0% for level III LNs.

Coverage of Axillary Lymph Nodes with Tangential Breast Irradiation in Korea: A Multi-Institutional Comparison Study.

Introduction. To evaluate the dose distribution and coverage of axilla using only tangential field for whole breast radiotherapy (RT) at three institutions in Korea. Methods. We used computed tomography (CT) images of nine consecutive 1-2 sentinel lymph node-positive patients who underwent breast conserving surgery and whole breast RT without axillary lymph node (ALN) dissection for clinical T1-2N0 breast cancer. The CT data were transferred to three radiation oncologists in 3 institutions and each radiation oncologist created treatment plans for all nine patients; a total of 27 treatment plans were analyzed. Results. The mean doses delivered to levels I and II were 31.9 Gy (9.9–47.9 Gy) and 22.3 Gy (3.4–47.7 Gy). Ninety-five percent of levels I and II received a mean dose of 11.8 Gy (0.4–43.0 Gy) and 3.0 Gy (0.3–40.0 Gy). The percent volumes of levels I and II covered by 95% of the prescribed dose were only 29.0% (0.2–74.1%) and 11.5% (0.0–70.1%). The dose distribution and coverage of axilla were significantly different between three institutions (p = 0.001). Conclusion. There were discrepancies in ALN coverage between three institutions. A standardization of whole breast RT technique through further research with a nationwide scale is needed.

Virtual lymph node analysis to evaluate axillary lymph node coverage provided by tangential breast irradiation.

PurposeTo investigate the coverage of axillary lymph node with tangential breast irradiation fields by using virtual lymph node (LN) analysis.Materials and MethodsForty-eight women who were treated with whole breast irradiation after breast-conserving surgery were analyzed. The axillary and breast volumes were delineated according to the Radiation Therapy Oncology Group (RTOG) contouring atlas. To generate virtual LN contours, preoperative fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scans with identifiable LN were fused with the CT scans, and the virtual LN contour were delineated on the CT.ResultsThe median level I and II axillary volume coverage percentages at the VD95% line were 33.5% (range, 5.3% to 90.4%) and 0.6% (range, 0.0% to 14.6%), respectively. Thirty-one LNs in 18 patients were delineated (26 in level I and 5 in level II). In the level I axilla, 84.6% of virtual LNs were encompassed by the 95% isodose line. In the level II axilla, by contrast, none of the virtual LNs were encompassed by the 95% isodose volumes. There was a substantial discrepancy between the RTOG contouring atlas-based axillary volume analysis and the virtual LN analysis, especially for the level I axillary coverage. The axillary volume coverage was associated with the body mass index (BMI) and breast volume.ConclusionThe tangential breast irradiation did not deliver adequate therapeutic doses to the axillary region, particularly those in the level II axilla. Patients with small breast volumes or lower BMI showed reduced axillary coverage from the tangential breast fields. For axillary LN irradiation, individualized anatomy-based radiation fields for patients would be necessary.

Abstract P4-16-13: Relationship between coverage of axillary lymph nodes, with tangential breast irradiation, and body mass index

Abstract Background: The ACOSOG Z0011 trial confirmed axillary clearance is not necessary in select, clinically lymph node-negative women with positive sentinel lymph node biopsies (SLNBs) who undergo breast-conserving surgery(BCS) or receive whole-breast radiotherapy(RT) and systemic therapy. The results suggested that the receipt of adjuvant breast RT and systemic therapy is adequate for loco-regional control. But it was unknown whether the low regional recurrence rates in these patients were caused by the treatment of a portion of the axilla with the tangent fields. In any case, axillary lymph node dose with tangential breast irradiation differs for each patient. It could depend on the proportions or body mass index(BMI) of each patient. If the difference of BMI impacts axillary coverage in breast RT, it could also influence loco-regional control. The purpose of this study was the dosimetric analyses of the axillary coverage with standard breast tangential irradiation, by BMI categories. Methods and materials: Between April 2007 and September 2011, 256 breast cancer patients were treated with breast tangential irradiation after BCS. They were classified using BMI categories as follows: underweight (&amp;lt;18.5), normal weight (18.5–24.9), overweight (25.0–29.9) and obese (≥30). From all the patients, 35 patients (10 in each category, but only 5 in obese due to the small-number) were randomly selected. In these 35 cases, after contouring the level of the axillary lymph nodes (Level Ior II) on CT images, the irradiation mean dose to the axillary level I/II and the percentage of axillary volumes that received at least 95% of the prescribed dose (VD95) were analyzed using the dose-volume histograms for each patient. Results: The median patient age at diagnosis was 54 years (range, 32–77 years). All the patients had undergone BCS without axillary clearance. Mean doses to level I were 39 Gy (77% of prescribed dose) for obese, 37 Gy (74%) for overweight, 32 Gy (65%) for normal-weight, and 29 Gy (58%) for underweight, respectively. Whereas the mean VD95% of axillary level I were 55% for obese, 47% for overweight, 31% for normal-weight, and 19% for underweight, respectively. No patient had adequate coverage of level II regardless of BMI category. Although the irradiation doses to axillary lymph node were relatively high for the high BMI groups, the tangential field designed to treat only the breast did not adequately cover the axillary region and, therefore, cannot be relied upon for prophylactic therapy of the axilla. In this study, BMI among 256 Japanese women ranged from 15.8 to 34.2 (mean, 22.3). Only 19% of the women were overweight or obese, with only 3% classified as obese. Whereas, in the NSABP B-14 trial, BMI among American women ranged from 13.8 to 55.2 (mean, 26.2). Approximately 50% of the women were overweight or obese, with 20% classified as obese. Conclusion: Standard tangential breast irradiation, especially for patient of low BMI, results in substantially reduced dose to the level I axilla. Further specific treatment planning and beam arrangement are required to irradiate axillary lymph node with the therapeutic dose. The difference in BMI by regional physical characteristics may impact on axillary coverage in breast RT. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-16-13.

Axillary lymph node coverage of tangent radiotherapy: Comparison of supine versus prone positioning.

200 Background: Recent randomized evidence has demonstrated low rates of axillary nodal failure in patients with one to two positive lymph nodes who receive local therapy with sentinel lymph node biopsy and simple tangential radiotherapy alone. Decreasing utilization of complete axillary nodal dissections has potential implications for radiotherapy treatment delivery design. We sought to compare the inadvertent coverage of the axillary lymph nodal regions between supine versus prone position for whole breast radiotherapy using simple tangent fields. Methods: Twenty patients with breast cancer who had previously received whole breast radiotherapy with simple tangent fields were randomly selected. Patients were selected such that 10 patients had received treatment in the supine position and 10 patients in the prone position. Axillary lymph node levels I-III were contoured by a single physician according to the RTOG breast contouring atlas. The previously generated radiotherapy plans, each to deliver a prescribed dose between 42.56 and 50Gy, were dosimetrically compared to assess differences in coverage of the nodal volumes. Results: In both positions, dose to each of the axillary nodal regions was low. For level I, the volume receiving 95% of the prescribed dose (V95) was 34.7% for supine positioning and 1.6% for prone positioning. All other analyzed volumes, specifically V25 (71.5% vs 32.6%), V50 (63.3% vs 28.2%), and V75 (57.6% vs 24.1%), were 50% greater for supine compared to prone positioning. Level II coverage was less with V95 of 6% and 0.1% respectively. Similarly V25 (32.8% vs 5.7%), V50 (25.7% vs 3.8%), and V75 (20.3% vs 2.1%) were less compared to level one and greater in the supine position. Level III coverage was less than 10% for both positions at all measured volumes of V95, V75, V50, and V25. Conclusions: Delivery of radiotherapy using simple tangents inadequately covers all axillary nodal levels. Coverage is greater in the supine position with very little inadvertent coverage in the prone position. The risk of nodal recurrence should be carefully considered when deciding to use a simple tangential field design. Additional factors such as dose to the lung and heart should also be considered for positioning.

Coverage of axillary lymph nodes with high tangential fields in breast radiotherapy

Coverage of axillary lymph nodes with high tangential fields in breast radiotherapy

Coverage of axillary lymph nodes with high tangential fields in breast radiotherapy

The aim of this study is to evaluate the coverage of axillary nodal volumes with high tangent fields (HTF) in breast radiotherapy and to determine the utility of customised blocking. The treatment plans of 30 consecutive patients with early breast cancer were evaluated. The prescription dose was 50 Gy to the whole breast. Axillary level I-II lymph node volumes were delineated and the cranial border of the tangential fields was set just below the humeral head to create HTF. Dose-volume histograms (DVH) were used to calculate the doses received by axillary nodal volumes. In a second planning set, HTF were modified with multileaf collimators (MLC-HTF) to obtain an adequate dose coverage of axillary nodes. The mean doses of the axillary nodes, the ipsilateral lung and heart were compared between the two plans (HTF vs MLC-HTF) using a paired sample t-test. The doses received by 95% of the breast volumes were not significantly different for the two plans. The doses received by 95% of the level I and II axillary volumes were 16.79 Gy and 11.59 Gy, respectively, for HTF, increasing to 47.2 Gy and 45.03 Gy, respectively, for MLC-HTF. Mean lung doses and per cent volume of the ipsilateral lung receiving 20 Gy (V20) were also increased from 6.47 Gy and 10.47%, respectively, for HTF, to 9.56 Gy and 16.77%, respectively, for MLC-HTF. Our results suggest that HTF do not adequately cover the level I and II axillary lymph node regions. Modification of HTF with MLC is necessary to obtain an adequate coverage of axillary levels without compromising healthy tissue in the majority of the patients.

Coverage of Axillary Lymph Nodes in Supine vs. Prone Breast Radiotherapy

To compare the dosimetry of target and normal tissue when tangents with the breast tissue were applied in a subset of breast cancer patients who had undergone computed tomography (CT) planning both supine and prone. The CT images of 20 patients who had undergone simulation in supine and prone positions were used for planning. The axillary lymph node regions (level I-III), breast tissue, tumor bed, heart, and bilateral lungs were manually contoured. Standard tangent fields were designed for the whole breast to deliver a prescribed dose of 50 Gy. Dose-volume histograms were compared between the two sets. In each patient, coverage of breast tissue and tumor bed was readily achieved by either technique. In either position, treatment of the nodal regions was inadequate. On average, the mean dose to the nodal regions for levels I-III was approximately 50% less in the prone as compared with the supine position. The mean ipsilateral lung volume receiving 95% of the prescribed dose was 6.3% in the supine position compared to 0.43% in the prone position. When planned supine, the mean heart volume receiving 30 Gy was 0.56% compared with 0.30% in the prone position. Planning in either position was found to achieve adequate coverage of the breast tissue and tumor bed for all patients. Lung was better spared prone. Coverage of axillary nodes was inadequate in either position, but further reduced in the prone vs. supine position. The choice of optimal setup should take into considerations stage and risk of nodal recurrence.