Supraclavicular Field Research Articles

SU-E-T-389: Effect of Interfractional Shoulder Motion On Low Neck Nodal Targets for Patients Treated Using Volume Modulated Arc Therapy (VMAT)

Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT). Methods: Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs. A second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient's treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the low neck contours. Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan) and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan) for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3. Conclusion: Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT.

Effect of interfractional shoulder motion on low neck nodal targets for patients treated using volume modulated arc therapy (VMAT)

Purpose: To quantify the dosimetric impact of interfractional shoulder motion on targets in the low neck for head and neck patients treated with volume modulated arc therapy (VMAT). Methods : Three patients with head and neck cancer were selected. All three required treatment to nodal regions in the low neck in addition to the primary tumor site. The patients were immobilized during simulation and treatment with a custom thermoplastic mask covering the head and shoulders. One VMAT plan was created for each patient utilizing two full 360° arcs and a second plan was created consisting of two superior VMAT arcs matched to an inferior static AP supraclavicular field. A CT-on-rails alignment verification was performed weekly during each patient’s treatment course. The weekly CT images were registered to the simulation CT and the target contours were deformed and applied to the weekly CT. The two VMAT plans were copied to the weekly CT datasets and recalculated to obtain the dose to the deformed low neck contours. Results: The average observed shoulder position shift in any single dimension relative to simulation was 2.5 mm. The maximum shoulder shift observed in a single dimension was 25.7 mm. Low neck target mean doses, normalized to simulation and averaged across all weekly recalculations were 0.996, 0.991, and 1.033 (Full VMAT plan) and 0.986, 0.995, and 0.990 (Half-Beam VMAT plan) for the three patients, respectively. The maximum observed deviation in target mean dose for any individual weekly recalculation was 6.5%, occurring with the Full VMAT plan for Patient 3. Conclusion : Interfractional variation in dose to low neck nodal regions was quantified for three head and neck patients treated with VMAT. Mean dose was 3.3% higher than planned for one patient using a Full VMAT plan. A Half-Beam technique is likely a safer choice when treating the supraclavicular region with VMAT. ------------------------------------------- Cite this article as: Casey K, Wang P, Tung S, Rosenthal D. Effect of interfractional shoulder motion on low neck nodal targets for patients treated using volume modulated arc therapy (VMAT). Int J Cancer Ther Oncol 2014; 2 (2):020218. DOI : 10.14319/ijcto.0202.18

Bilateral implant reconstruction does not affect the quality of postmastectomy radiation therapy

To determine if the presence of bilateral implants, in addition to other anatomic and treatment-related variables, affects coverage of the target volume and dose to the heart and lung in patients receiving postmastectomy radiation therapy (PMRT). A total of 197 consecutive women with breast cancer underwent mastectomy and immediate tissue expander (TE) placement, with or without exchange for a permanent implant (PI) before radiation therapy at our center. PMRT was delivered with 2 tangential beams + supraclavicular lymph node field (50Gy). Patients were grouped by implant number: 51% unilateral (100) and 49% bilateral (97). The planning target volume (PTV) (defined as implant + chest wall + nodes), heart, and ipsilateral lung were contoured and the following parameters were abstracted from dose-volume histogram (DVH) data: PTV D95% > 98%, Lung V20Gy > 30%, and Heart V25Gy > 5%. Univariate (UVA) and multivariate analyses (MVA) were performed to determine the association of variables with these parameters. The 2 groups were well balanced for implant type and volume, internal mammary node (IMN) treatment, and laterality. In the entire cohort, 90% had PTV D95% > 98%, indicating excellent coverage of the chest wall. Of the patients, 27% had high lung doses (V20Gy > 30%) and 16% had high heart doses (V25Gy > 5%). No significant factors were associated with suboptimal PTV coverage. On MVA, IMN treatment was found to be highly associated with high lung and heart doses (both p < 0.0001), but implant number was not (p = 0.54). In patients with bilateral implants, IMN treatment was the only predictor of dose to the contralateral implant (p = 0.001). In conclusion, bilateral implants do not compromise coverage of the target volume or increase lung and heart dose in patients receiving PMRT. The most important predictor of high lung and heart doses in patients with implant-based reconstruction, whether unilateral or bilateral, is treatment of the IMNs. Refinement of radiation techniques in reconstructed patients who require comprehensive nodal irradiation is warranted.

Novel Method of Cardiac Sparing With Deep-Inspiration Breath-Hold Utilizing Surface Electromagnetic Transponders in Women With Left-Sided Breast Cancer

Purpose/Objective(s): Deep-inspiration breath hold (DIBH) for radiation therapy of the breast is an established technique that has been shown to minimize heart dose. A method for intrafraction motion management with DIBH technique was developed utilizing electromagnetic transponders placed on the skin. This retrospective study is the first report on the pilot experience of this novel method. Materials/Methods: Between January 1 and October 1, 2012, 40 patients with left-sided breast cancer underwent CT simulation and were treated with DIBH using surface electromagnetic transponders. Simulation CT scans were obtained in both free-breathing (FB) and DIBH positions in all patients. Treatment planning was performed on the DIBH CT scan with fusion of the FB scan. The heart was contoured and dose volume histograms computed. To reproduce the DIBH from the simulation and for intrafraction motion management, two methods of monitoring were simultaneously employed in all patients: 1) surface electromagnetic transponder system with real-time tracking and 2) lasers aligned to DIBH skin marks with continuous video surveillance during entire beam-on time. Results: Median age was 50 years (range, 31-70), 27.5% (11/40) DCIS, 45% (18/40) stage I, 20% (8/40) stage II, 7.5% (3/40) stage III. Eighty percent (32/40) of patients received 45-50.4 Gy in standard fractionation and 20% (8/40) received 42.5 Gy in 16 fractions to the left whole breast. Seventy-five percent (30/40) were treated to the left breast, one patient to the chest wall, one patient to a chest wall with tissue expander, three patients to the breast and supraclavicular field (SCF) and five patients to the chest wall with tissue expander plus SCF. The average mean heart dose was 78.9 c Gy with DIBH compared with 290.2 c Gy in FB (p-value < 0.0001). The mean heart V5 was 0.96% with DIBH and 12.7% with FB, mean V10 was 0.28% with DIBH versus 7.5% with FB, mean heart V15 was 0.014% with DIBH versus 5.2% with FB (p-value < 0.0001). The average transponder to laser difference for the first consecutive 535 fractions was 0.09 cm in the superior-inferior direction (SD 0.23), 0.09 cm in the anterior-posterior direction (SD 0.32) and 0.03 cm in the right-left direction (SD 0.29). Conclusions: An initial cohort of women with left-sided breast cancer has been successfully treated with DIBH technique using a novel method of skin surface electromagnetic transponders. This method was found to be feasible, accurate and well-tolerated by patients. There was a significant reduction in cardiac dose with DIBH. A prospective registry trial using the surface electromagnetic transponder system with DIBH is being initiated to confirm these findings. Author Disclosure: L. Fang: None. J. Kim: F. Honoraria; Varian. D. Kaurin: G. Consultant; Varian. K. Holloway: None. M. Lavilla: None. L. Sweeney: G. Consultant; Varian.

SU‐C‐137‐07: A Comprehensive Investigation of Dosimetric Uncertainties in Junction Region of Breast Superclavicular and Tangential Fields

Purpose: The dosimetric uncertainties in junction regions are one of the major concerns in treatments involving field‐junctions, especially tangential breast and supraclavicular fossa radiotherapy fields. The uncertainties are linked to dose calculation algorithms, set‐up, jaw/couch position uncertainties, and choice of mono‐versus multiple‐isocentric techniques. The purpose of this study was to comprehensively investigate the effects of these common variants to understand dose non‐uniformity in junction regions. Methods: To understand the effects from dose algorithms and setup uncertainties, a typical tangential/superclav field combination was planned to an anthropomorphic Rando phantom using the Pinnacle‐9.0 treatment‐planning system and delivered 6 times on different days. 3 films (EBT2) were placed in coronal plane across the field‐junction. Pinnacle CCC‐9.0, Eclipse AAA‐10.0 and AcurosXB‐11.0 were used for calculation. To understand the effects from the linac's mechanical uncertainties, junctions were generated with two open fields using both mono‐isocentric and two‐isocentric techniques. Junction‐fields were delivered on 6 different linacs to EBT2 in a solid water phantom. Impacts of couch position accuracy/reproducibility, and jaw‐position accuracy/reproducibility were analyzed. Results: In general, the major contributor to the dose uncertainties in junction region is the jaw position accuracy. Among the 6 linacs investigated in this study, the uncertainty of jaw position can be up to ±3mm, subsequently leading to about 25% hot/cold of dose distributions in junction region. The impact of mono versus two‐isocentric technique is relatively small (within 5%), because the patient‐couch positioning was found to have good accuracy and reproducibility. All dose algorithms are found to be in close mutual agreement (within 5%) for most regions of the junction. Jaw positioning has good short‐term reproducibility, but might change over months. Conclusion: Dose inhomogeneities at field‐junctions are more strongly dependent on jaw‐positioning accuracy compared to setup, dose‐calculation, and other source of errors.Impact:Guidance to improve dose uniformity in field‐junction. This work was funded by National Institutes of Health grants 2R44CA105806‐02, CA010953

SU-E-P-26: 3-D Treatment Planning Of Chest Wall/Breast, Using Monoisocentric Technique

Purpose: The purpose of this study is to describe the monoisocentric technique followed in Shifa International Hospital. Methods: More than 30 consecutive patients have been treated from Oct 2011 to May 2012 with monoisocentric technique. Methods for treatment planning and irradiation, the methodology for making the isocenter and fields. With precise treatment planning system, linear accelerator — asymmetric four collimator jaws, the longitudinal(Y) jaws beam-split at the match line namely upper and lower border of fields, transverse (X) jaws defined lateral border of the fields. All patients underwent CT planning in the supine position with the ipsilateral arm overhead. The chest wall/breast was treated with a pair of opposing half beam tangential fields with the blockage of upper half of the field and the upper axillary and supraclavicular nodal region were treated with an anterior photon field with the blockage of lower half of the field. A monoisocentric technique was used to match the tangential fields with the anterior field at the isocentre. Multi-leaf collimators were utilized for shielding of normal structures. Results: Various techniques using a half-blocked supraclavicular field with special tangential fields have been introduced to eliminate the junction problem. These are, however complicated involving couch motion & machine isocentre repositioning when changing from the supraclavicular to the tangential fields. Monoisocentric technique is simple and easy to setup; since the same machine's isocentre is used for all treatment fields and no couch movements or patient reposition is required. Another use/advantage of monoisocentric technique is a reduction of treatment time. Conclusion: Treatment technique takes full advantage of dual asymmetric jaws to achieve a perfect match-line, necessitates only one isocenter and setup point. In monoisocentric technique reproducibility of positioning is simple and precise. This setup is technician friendly and the match-line is perfect without overdose and underdose at the junction.

Optimizing of the Tangential Technique and Supraclavicular Fields in 3 Dimensional Conformal Radiation Therapy for Breast Cancer

Radiotherapy plays an essential role in the management of breast cancer. Three-dimensional conformal radiation therapy (3D-CRT) is applied based on 3D image information of anatomy of patients. In 3D-CRT for breast cancer one of the common techniques is tangential technique. In this project, various parameters of tangential and supraclavicular fields are optimized. This project has been done on computed tomography images of 100 patients in Isfahan Milad Hospital. All patients have been simulated and all the important organs have been contoured by radiation oncologist. Two techniques in supraclavicular region are evaluated including: 1-A single field (Anterior Posterior [AP]) with a dose of 200 cGy per fraction with 6 MV energy. This is a common technique. 2-Two parallel opposed fields (AP-Posterior Anterior [PA]). The dose of AP was 150 cGy with 6 MV energy and PA 50 cGy with 18 MV. In the second part of the project, the tangential fields has been optimized with change of normalization point in five points: (1) Isocenter (Confluence of rotation gantry axis and collimator axis) (2) Middle of thickest part of breast or middle of inter field distance (IFD) (3) Border between the lung and chest wall (4) Physician's choice (5) Between IFD and isocenter. Dose distributions have been compared for all patients in different methods of supraclavicular and tangential field. In parallel opposed fields average lung dose was 4% more than a single field and the maximum received heart dose was 21.5% less than a single field. The average dose of planning tumor volume (PTV) in method 2 is 2% more than method 1. In general AP-PA method because of a better coverage of PTV is suggested. In optimization of the tangential field all methods have similar coverage of PTV. Each method has spatial advantages and disadvantages. If it is important for the physician to reduce the dose received by the lung and heart, fifth method is suggested since in this method average and maximum received dose to heart and lung have been reduced few percent in comparison to other methods. If a better coverage of PTV is important for the physician second method can be an optimized method. In this method, average and maximum received dose to PTV have been increased few percent in comparisons of physician's choice method and three other methods. In optimizing of supraclavicular field AP-PA method due to better coverage of PTV is suggested. In optimizing of tangential all methods are similar. Each method has special advantages and disadvantages. The physicians can change the depth of the normalization point in the breast to get the desired average dose.

Optimization of three dimensional planning dosimetric in breast phantom for match region of supraclavicular and tangential fields

Complex geometry of breast tissue causes perturbation in dose distribution. This problem can beget overdose or under-dose points in match region of three fields. The aim of this study is to create dose homogeneity distribution in match region between tangential and supraclavicular fields (SCF) with Gafchromic external beam therapy (EBT) film. In this study, an anatomical slab phantom was designed with cork lung inhomogeneity and plexiy colored heart part. Conventional and three dimensional (3D) methods were utilized along with Gafchromic EBT film. In asymmetric fields (3D method) much better results in match region were observed (i.e., maximum amount overlap area of 0.43 cm(2), overlap depth of 3.55 cm and an average overlap width of 0.75 cm). This study revealed that EBT film is a proper tool for two dimensional (2D) relative-dose measurements. The study showed difficulties in achieving homogenous dose distribution in match region of tangential and supraclavicular.

Radiation Oncology Self-Directed Dosimetry Workshops: AP/PA Spine, 3-Field Breast, and IMRT

OPEN ACCESSDecember 17, 2012Radiation Oncology Self-Directed Dosimetry Workshops: AP/PA Spine, 3-Field Breast, and IMRT Daniel William Golden, MD, Christopher John Stepaniak, PhD, Steven J. Chmura, MD, PhD Daniel William Golden, MD University of Chicago Google Scholar More articles by this author , Christopher John Stepaniak, PhD University of Chicago Google Scholar More articles by this author , Steven J. Chmura, MD, PhD University of Chicago Division of the Biological Sciences The Pritzker School of Medicine Google Scholar More articles by this author https://doi.org/10.15766/mep_2374-8265.9297 SectionsAbout ToolsDownload Citations ShareFacebookTwitterEmail AbstractThese self-directed dosimetry modules were developed to teach key radiation treatment planning concepts in a self-directed, interactive, and hands-on format. Because the modules are self-directed, learners can complete them when they have available time in the clinic. Since these workshops teach basic planning concepts and skills, they should be completed in order: first AP/PA spine, then three-field breast, and finally IMRT (intensity-modulated radiation therapy). Learners do not need to complete a dosimetry rotation to learn conceptual and practical aspects of radiation treatment planning. The modules can be repeated to ensure that the concepts and practical aspects covered are fully understood. These modules have been completed by multiple radiation oncology residents and have received positive reviews. It takes approximately 1 hour to complete each module. Residents have consistently rated their comfort level and understanding of treatment planning as improved after completion of the modules. Educational Objectives By the end of the AP/PA spine module, learners will be able to: Open a treatment plan.Contour a target.Create a planning target volume (PTV) using an expansion.Set a treatment isocenter.Create a treatment field.Set beam borders.Prescribe a dose and number of fractions.Turn on isodose lines.Evaluate a basic dose-volume histogram.Change a beam energy.Copy and oppose a treatment field.Understand the concept of depth-dose curves.Understand dose volume histograms.Understand different beam energy and the effect on maximum dose.Understand gross tumor volume to PTV expansion and the significant increase in volume with a small PTV expansion.Understand single versus opposed beams and the effect on maximum dose. By the end of the three-field breast module, learners will be able to: Set two isocenters for the tangent fields and supraclavicular fields.Select tangent beam angles.Set the jaws for tangent and supraclavicular beams.Match the tangent beams and supraclavicular fields in a two-isocenter plan.Create a second treatment planning trial.Set the isocenter for a monoisocentric treatment plan.Compare two planning trials. By the end of the intensity-modulated radiation therapy (IMRT) module, learners will be able to: Set IMRT optimization parameters.Set planning objectives for the target volume and organs at risk.Use a ring structure to constrain the high dose region of an IMRT plan.Compare two IMRT trials.Understand targets and organs at risk. Sign up for the latest publications from MedEdPORTAL Add your email below FILES INCLUDEDReferencesRelatedDetails FILES INCLUDED Included in this publication: General Instructor Guide.docx Spine Instructor Guide.docx Spine Module.docx Spine Folder Spine evaluation.docx Breast Instructor Guide.docx Breast Folder Breast Module.docx Breast evaluation form.docx IMRT Instructor Guide.docx IMRT Folder IMRT Module.docx IMRT evaluation form.docx To view all publication components, extract (i.e., unzip) them from the downloaded .zip file. Download editor’s noteThis publication may contain technology or a display format that is no longer in use. CitationGolden DW, Stepaniak CJ, Chmura SJ. Radiation Oncology Self-Directed Dosimetry Workshops: AP/PA Spine, 3-Field Breast, and IMRT. MedEdPORTAL. 2012;8:9297. https://doi.org/10.15766/mep_2374-8265.9297 Copyright & Permissions© 2012 Golden et al. This is an open-access article distributed under the terms of the Creative Commons Attribution license.KeywordsBreast CancerDosimetryNeoplasm MetastasisRadiometryIMRT Disclosures None to report. Funding/Support None to report. Loading ...

Rethinking the Supraclavicular Field: Anterior Wedged Pair 3D Conformal Radiation Therapy Versus Single Anterior Oblique Field as Treatment of the Axillary Apex and Supraclavicular Fossa in Node Positive Breast Cancer

Rethinking the Supraclavicular Field: Anterior Wedged Pair 3D Conformal Radiation Therapy Versus Single Anterior Oblique Field as Treatment of the Axillary Apex and Supraclavicular Fossa in Node Positive Breast Cancer

Failure Rate and Cosmesis of Immediate Tissue Expander/Implant Breast Reconstruction After Postmastectomy Irradiation

BackgroundThis study reports the rate of breast reconstruction failure and cosmetic outcomes after postmastectomy radiation therapy (PMRT) with temporary tissue expanders (TEs) or implants in place. Patients and MethodsNinety-four patients underwent mastectomy (93 unilateral, 1 bilateral; 95 cases total) and immediate TE reconstruction followed by PMRT. Ninety TEs and 5 permanent implants were irradiated. All patients received a dose of 5400 cGy given in 180-cGy fractions to the reconstructed breast. Twenty-one patients (22%) received tangents alone and 74 patients (78%) were treated with tangents and a supraclavicular field using a monoisocentric technique. Bolus was used in 91 patients (96%). Eighty-eight patients (93%) received chemotherapy and 78 patients (82%) received endocrine therapy. ResultsWith a median follow-up of 24.1 months, 19 patients (20%) experienced failure of reconstruction. The 1-, 2-, and 3-year actuarial rate of reconstruction failure was 9.7%, 19.3%, and 25.5%, respectively. Infection was the most common cause of failure. Of the 19 failures, 8 patients underwent salvage procedures with flap reconstruction. Univariate analysis was performed examining age, chemotherapy use, hormone therapy use, use of a supraclavicular field, smoking status, diabetes, hypertension, and menopausal status. No risk factors were found to be associated with reconstruction failure. In patients who did not experience reconstruction failure, good/excellent cosmesis was observed in 75% of patients. ConclusionIn the current series of women with a high risk of locoregional recurrence, PMRT with a TE/implant in place provides good cosmesis in the majority of women, with an acceptable risk of expander or implant loss.

Predictors of locoregional outcome in patients receiving neoadjuvant therapy and postmastectomy radiation

The objective of this study was to identify predictors of locoregional recurrence (LRR) after neoadjuvant therapy (NAT) and postmastectomy radiation (PMRT) in a cohort of patients with stage II through III breast cancer and to determine whether omission of the supraclavicular field had an impact on the risk of LRR. The authors reviewed records from 464 patients who received NAT and PMRT from January 1999 to December 2009. The median patient age was 50 years (range, 25-81 years). Clinical disease stage was stage II in 29% of patients, stage III in 71%, and inflammatory in 14%. Receptor status was estrogen receptor (ER)-positive in 54% of patients, progesterone receptor (PR)-positive in 39%, human epidermal growth factor receptor 2 (HER2)-positive in 24%, and negative for all 3 receptors (triple negative) in 32%. All patients received NAT and underwent mastectomy, and 19.6% had a complete pathologic response in the breast and axilla, 17.5% received radiation to the chest wall only, and 82.5% received radiation to the chest wall and the supraclavicular field; omission of the supraclavicular field was more common in patients with lower clinical and pathologic lymph node status. The median follow-up was 50.5 months, and the 5-year cumulative incidence of LRR was 6% (95% confidence interval, 3.9%-8.6%). Predictors of LRR were clinical stage III (P = .038), higher clinical lymph node status (P = .025), higher pathologic lymph node status (P = .003), the combination of clinically and pathologically positive lymph nodes (P < .001), inflammatory presentation (P = .037), negative ER status (P = .006), negative PR status (P = .015), triple-negative status (P < .001), and pathologic tumor size >2 cm (P = .045). On univariate analysis, omission of the supraclavicular field was not associated significantly with LRR (hazard ratio, 0.89; P = .833); however, on multivariate analyses, omission of the supraclavicular field was associated significantly with LRR (hazard ratio, 3.39; P = .024). Presenting stage, receptor status, pathologic response to neoadjuvant therapy, and omission the supraclavicular field were identified as risk factors for LRR after neoadjuvant therapy and PMRT.

P3-13-04: Functional and Cosmetic Outcomes Following Post-Mastectomy Irradiation with Tissue Expander/Implant Reconstruction.

Abstract Purpose: To examine the rate of breast reconstruction failure and cosmetic outcomes following post-mastectomy radiation therapy (PMRT) with temporary tissue expander or implant in place. Methods and Materials: Ninety-four patients with 95 primary breast malignancies underwent mastectomy and immediate tissue expander reconstruction followed by PMRT. Ninety tissue expanders and five implants were irradiated. All patients received a dose of 5,400 cGy given in 180 cGy fractions. Twenty-one patients (22%) received tangents alone and seventy-four patients (78%) were treated with tangents and a supraclavicular field via a mono-isocentric technique. Bolus was used in 91 patients (96%). Eighty-eight patients (93%) received chemotherapy and 78 patients (82%) received endocrine therapy. Results: With a median follow up of 22.4 months, nineteen patients (20%) developed a reconstruction failure. Ten patients lost their tissue expanders with a median time to reconstruction failure of 7 months (range 3–9 months) while ten patients lost their permanent implant with a median time to loss of 19 months (range 9–31 months) following PMRT. The one and two-year actuarial rate of reconstruction failure was 11.2% and 24.9%, respectively. The most common cause of failure was infection (37%), followed by skin break down (21%), extrusion of expander or implant (16%), fibrosis/eschar (11%), trauma (11%) and pain (5%). Out of the 19 failures, eight patients were salvaged with an autologous flap reconstruction. Univariate analysis was performed to examine the association between age, chemotherapy, hormonal therapy, smoking status, hypertension, diabetes, menopause status, weight and the use of a third supraclavicular RT field on reconstruction failure. However no risk factors were found to be associated with reconstruction failure. In patients who did not have reconstruction failure, good/excellent cosmesis was observed in 79% of patients and fair/poor cosmesis was observed in 21% of patients. Conclusions: In our series of women with a high risk of recurrence, PMRT with a tissue expander in place followed by a prosthetic implant provides good cosmesis in the majority of women with an acceptable risk of expander or implant loss. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-13-04.

Factors Associated With the Development of Breast Cancer–Related Lymphedema After Whole-Breast Irradiation

To determine the rates of breast cancer-related lymphedema (BCRL) in patients undergoing whole-breast irradiation as part of breast-conserving therapy (BCT) and to identify clinical, pathologic, and treatment factors associated with its development. A total of 1,861 patients with breast cancer were treated at William Beaumont Hospital with whole-breast irradiation as part of their BCT from January 1980 to February 2006, with 1,497 patients available for analysis. Determination of BCRL was based on clinical assessment. Differences in clinical, pathologic, and treatment characteristics between patients with BCRL and those without BCRL were evaluated, and the actuarial rates of BCRL by regional irradiation technique were determined. The actuarial rate of any BCRL was 7.4% for the entire cohort and 9.9%, 14.7%, and 8.3% for patients receiving a supraclavicular field, posterior axillary boost, and internal mammary irradiation, respectively. BCRL was more likely to develop in patients with advanced nodal status (11.4% vs. 6.3%, p = 0.001), those who had a greater number of lymph nodes removed (14 nodes) (9.5% vs. 6.0%, p = 0.01), those who had extracapsular extension (13.4% vs. 6.9%, p = 0.009), those with Grade II/III disease (10.8% vs. 2.9%, p < 0.001), and those who received adjuvant chemotherapy (10.5% vs. 6.7%, p = 0.02). Regional irradiation showed small increases in the rates of BCRL (p = not significant). These results suggest that clinically detectable BCRL will develop after traditional BCT in up to 10% of patients. High-risk subgroups include patients with advanced nodal status, those with more nodes removed, and those who receive chemotherapy, with patients receiving regional irradiation showing a trend toward increased rates.

Excellent Local Control in an Updated Analysis of Concurrent Chemoradiation for Node-positive Breast Cancer Treated with Breast Conserving Surgery

Materials/Methods:Weenrolled patients in a prospective, single-armstudyofwomenwithnode-positiveStage II/III breast cancers who underwent BCS and adjuvant therapy consisting of 4 cycles of doxorubicin (60 mg/m2) and cyclophosphamide (600 mg/m2) followed by 4 cycles of paclitaxel (175 mg/m2) given every 3 weeks. Radiotherapy was delivered concurrently with the first two cycles of paclitaxel and consisted of 39.6 Gy/22 fxs to thewhole breast with a 14 Gy/7 fxs tumor bed boost. A supraclavicular field was added in patients with 4 or more positive axillary lymph nodes (LN) or extracapsular extension. Axillary fields were treated in patients with inadequate dissections or gross nodal disease. Breast cosmesis was scored prior to radiation and at follow-up using the Harvard criteria and pulmonary toxicity was monitored by the carbon monoxide diffusing capacity and available imaging.

Addition of a third field significantly increases dose to the brachial plexus for patients undergoing tangential whole-breast therapy after lumpectomy

Our goal was to evaluate brachial plexus (BP) dose with and without the use of supraclavicular (SCL) irradiation in patients undergoing breast-conserving therapy with whole-breast radiation therapy (RT) after lumpectomy. Using the standardized Radiation Therapy Oncology Group (RTOG)–endorsed guidelines delineation, we contoured the BP for 10 postlumpectomy breast cancer patients. The radiation dose to the whole breast was 50.4 Gy using tangential fields in 1.8-Gy fractions, followed by a conedown to the operative bed using electrons (10 Gy). The prescription dose to the SCL field was 50.4 Gy, delivered to 3-cm depth. The mean BP volume was 14.5 ± 1.5 cm3. With tangential fields alone, the median mean dose to the BP was 0.57 Gy, the median maximum dose was 1.93 Gy, and the irradiated volume of the BP receiving 40, 45, and 50 Gy was 0%. When the third (SCL field) was added, the dose to the BP was significantly increased (P = .01): the median mean dose to the BP was 40.60 Gy, and the median maximum dose was 52.22 Gy. With 3-field RT, the median irradiated volume of the BP receiving 40, 45, and 50 Gy was 83.5%, 68.5%, and 24.6%, respectively. The addition of the SCL field significantly increases dose to the BP. The possibility of increasing the risk of BP morbidity should be considered in the context of clinical decision making.

Optimization of 3D Planning Dosimetry in a Breast Phantom for the Match Region of Supraclavicular and Tangential Fields

Introduction: The complex geometry of breast and also lung and heart inhomogeneities near the planning target volume (PTV) result in perturbations in dose distribution. This problem can result in overdosage or underdosage in the match region of the three treatment fields. The purpose of this study is to create a homogeneous dose distribution in the match region between the supraclavicular and tangential fields, utilizing Gafchromic EBT film for dosimetry. Material and Methods: In this study, a slab phantom was designed with lung- and heart-equivalent inhomogetenities. Our measurements were carried out using Gafchromic EBT film. Irradiations were performed using the 6 MV photon beam of a Varian 2100 Clinac linear accelerator. Three-dimensional treatment planning and dose calculations were carried out using the RT Dose Plan software. The conventional method with source-to-skin distance match and a 3D method with source-to-axis distance match under different combinations of parameters such as gantry, collimator and couch rotations as well as asymmetric fields were utilized. Results: The results demonstrated differences between the 3D and conventional techniques. The best results in the match region were observed using the 3D method with asymmetric technique (maximum area of overlap = 0.43 cm2, depth of overlap = 3.55 cm, and average width of overlap = 0.75 cm). Discussion and Conclusion: This study shows that the EBT film is a suitable tool for two-dimensional distribution dosimetry and relative dose measurements. The study shows difficulties in achieving a homogenous dose distribution in the match region of supraclavicular and tangential fields and also demonstrates the effects of setup parameters on matching of treatment fields.

Predicting lymphatic drainage patterns and primary tumour location in patients with breast cancer

Detailed knowledge of the lymphatic drainage of the breast is limited. Lymphoscintigraphy is a technique used during breast cancer treatment to accurately map patterns of lymphatic drainage from the primary tumour to the draining lymph nodes. This study aimed to create a statistical model to analyse the spread of breast cancer and primary tumour location using a large lymphoscintigraphy database, and visualise the results with a novel computational model. This study was based on lymphoscintigraphy data from 2,304 breast cancer patients treated at the Royal Prince Alfred Hospital Medical Centre in Sydney, Australia. Bayesian inferential techniques were implemented to estimate the probabilities of lymphatic drainage from each region of the breast to each draining node field, to multiple node fields, and to determine probabilities of tumour prevalence in each breast region. A finite element model of the torso and discrete model of the draining node fields were created to visualise these data and a software tool was developed to display the results ( www.abi.auckland.ac.nz/breast-cancer ). Results confirmed that lymphatic drainage is most likely to occur to the axillary node field, and that there is significant likelihood of drainage to the internal mammary node field. The likelihood of lymphatic drainage from the whole breast to the axillary, internal mammary, infraclavicular, supraclavicular and interpectoral node fields were 98.2, 35.3, 1.7, 3.1, and 0.7%, respectively; whilst the probability of lymphatic drainage to multiple node fields was estimated to be 36.4%. Additionally, primary tumours are most likely to develop in the upper regions of the breast. The models developed provide quantitative estimates of lymphatic drainage of the breast, giving important insights into understanding breast cancer metastasis and have the potential to benefit both clinicians and patients during breast cancer diagnosis and treatment.

Using Nodal Ratios to Predict Risk of Regional Recurrences in Patients Treated with Breast Conservation Therapy with 4 or More Positive Lymph Nodes

Purpose. The value of nodal ratios (NRs) as a prognostic variable in breast cancer is continually being demonstrated. The purpose of this study was to use NR in patients with ≥4+ nodes to assess a correlation of NR with regional (lymph node) recurrence. Methods. Inclusion criteria was ≥8 nodes dissected with ≥4+ nodes after breast conservation therapy. Of 1060 patients treated from 1975 to 2003 who had a minimum of 8 nodes dissected, 273 were node+; 56 patients had ≥4+ involved nodes and were the focus of this study. Nodal ratios were calculated for each patient and grouped into 3 categories: high (≥70%), intermediate (40%–69%) and low (<40%). Each nodal ratio was correlated with patterns of local, regional, and distant failures and OS. Results. Outcomes for the entire cohort were BRFS-83%, NRFS-93%, DMFS-61%, and OS 63% at 10 yrs. The OS, DMFS, and NRFS correlated with N2 (4–9 nodes+) versus N3 (≥10+) status but did not correlate with BRFS, as expected. When evaluating NR, 18 pts had high NR (>70%). Only 3 patients experienced nodal recurrences, all within previously radiated supraclavicular fields. All 3 in-field regional failures occurred in the N3 group of patients with NR >70%. All were treated with a single AP field prescribed to a dose of 46 Gy at a standard depth of 3 cm. Conclusions. In this group of N2/N3 patients treated with BCT, we were able to identify patients at high risk for regional failures as those with high NR of >70% and ≥10+ nodes. While these findings need to be reproduced in larger datasets, this group of patients with NR of >70% in 4 or more positive axillary lymph nodes may benefit from meticulous targeting of regional nodes, dose escalation, and/or more intensive systemic therapies.

SU‐E‐T‐416: Geometric and Dosimetric Effects of Residual Setup Error on the Cord and Larynx in Split‐Field Head and Neck Radiation Therapy

Purpose: In split‐field head and neck radiation therapy, image guided alignment of the superior IMRT field may result in large setup errors in the supraclavicular field. The goal of this study was to quantify geometric and dosimetric effects of residual setup error on the cord and larynx using the split‐field technique. Methods: Cord and larynx contours of 27 patients were propagated from a planning CT onto daily in‐room CTs using deformable registration. Cord contours were divided into superior and inferior structures at the match plane. Interfractional variations in the position of the larynx, superior cord, and inferior cord centroids were measured. Deformable registration allowed the calculation of cumulative dose delivered for each patient. The discrepancy between planned and delivered doses was compared for the maximum dose to the superior and inferior cord, mean dose to the larynx, larynx V50 and D60. Results: The group mean error, systematic error, and random error of the larynx centroid positions were 0.12cm, 0.06cm, and 0.08cm, laterally, and 0.15cm, 0.06cm, and 0.08cm in the anterior‐posterior direction. The lateral values for the superior cord were 0.04cm, 0.01cm, and 0.03cm, and for the inferior cord were 0.17cm, 0.06cm, and 0.12cm. Lateral and anterior‐posterior margins were 0.22cm and 0.20cm (larynx), 0.05cm and 0.08cm (superior cord), and 0.22cm and 0.35cm (inferior cord). Maximum cord dose was 43.8Gy. The average change in maximum dose was 0.3Gy (max=1.8Gy) for the superior cord, and −0.6Gy (max=1.2Gy) for the inferior cord. The increases in larynx mean dose, V50, and D60 averaged 1.6Gy (SD=2.5Gy), 3.24% (SD=3.52%), and 4.7Gy (SD=6.1Gy). Conclusions: While the inferior cord demonstrated the largest motion, it remained within the cord block. The increase in maximum cord dose and mean larynx dose were no more than 1.8Gy and 5.1Gy, respectively. The split‐field technique remains clinically viable.Funding provided by the University of Texas Graduate School of Biomedical Sciences at Houston.