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Breast Respiratory Motion in Free Breathing Assessed by 4-Dimensional Computed Tomography
E58
International Journal of Radiation Oncology Biology Physics
events by LN+ group. No significant P values were found at all GEE model results by LN total number group (no data). Conclusion: Positive axillary LN number removed associates with arm lymphedema among BC patients. RT does not increase BCRL over the first postoperative RT course. Long term effect of RT on BCRL needs follow-up data for evaluation. Author Disclosure: Z. Li: None. W. Geng: None. J. Zhang: None. J. Yin: None. D. Kong: None. J. Kong: None. J. Zhang: None. A. Zhang: None.
UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium, 2CHU de Martinique, Fort de France, Martinique
2139 Does Achieving Pathologic Complete Response From Neoadjuvant Chemotherapy (NAC) for Breast Cancer Lead to Higher Rates of Breast Conservation Therapy? R.L. Young, J.G. Bazan, J.L. Wobb, C. Decker, and J.R. White; The James Cancer Hospital and Solove Research Institute, Wexner Medical Center at The Ohio State University, Department of Radiation Oncology, Columbus, OH Purpose/Objective(s): Neoadjuvant chemotherapy (NAC) is more frequently used for treatment of operable breast cancer since it has the established benefits of identifying those with improved prognosis based on disease response and enabling more women to undergo lumpectomy and radiation for breast conservation therapy (BCT). With the use of new, targeted agents in combination with traditional chemotherapy, pathologic complete response (pCR) rates have dramatically increased in select groups. We hypothesized that we would see more breast conservation in those women that achieve pCR from undergoing NAC at our institution. Materials/Methods: The Institution Cancer Registry was used to identify women who had undergone NAC between 2009 and 2014, excluding women who would not qualify for BCS (T4d), cN3, or metastatic disease. Tumor characteristics (histology, grade, and receptor status), clinical (c) and pathological (yp) staging, and loco-regional management (BCT, mastectomy and RT use) were recorded. SAS was used for all statistical analyses. Results: A total of 396 women underwent NAC during the study period. Most (71%) were cStage II with 54.8% cN+, 44.7% cN0, 59.3% cT2 tumors, 55.8% Grade 1-2, and 44.2% Grade 3. Hormone receptor positive disease was noted in 54.8%, HER2 was positive in 31.1%, and 31.1% were triple negative (TN). Clinical stages I and III comprised 11.4% and 16% of the group, respectively. One third of women (33.8%) achieved a pCR (ypT0N0) with specific breast response as follows: 38% ypT0, 37% ypT1, 20% ypT2, 4% ypT3, and 1% ypT4. The rate of pCR was 42.7% for TN, 50.5% for HER2+, and 24% for hormone sensitive. Nodal response was 62% ypN0, 22% ypN1, 11% ypN2, and 5% ypN3. Mastectomy was done for 69.2% (274/396) rather than BCS (30.8%) following NAC. Of note, 15% of women (58/396) underwent b/l mastectomies (contralateral prophylactic). On Chi-square analysis, the use of BCS versus mastectomy did not correlate with achievement of pCR; BCT 38.5% versus 31.8% for mastectomy (P Z 0.1885). Specifically, BCT was performed for 36% ypT0/Tis, 36% ypT1, 21% ypT2, and 5.6% ypT3. Breast surgery type did correlate with overall downstaging (P Z 0.0002). Approximated molecular subtype was not related to usage of BCS (P Z 0.1214e0.6101). Conclusion: Despite demonstrating a pCR rate comparable to other current data, we did not find higher rates of BCT compared to mastectomy in women whose disease achieve pCR after NAC. These patterns of surgical management observed in our institution may reflect national trends in which mastectomy continues to be favored over BCT even among women with complete responses to NAC therapy. Author Disclosure: R.L. Young: None. J.G. Bazan: None. J.L. Wobb: None. C. Decker: None. J.R. White: member; National Cancer Institute Breast Cancer Steering Committee. Co-chair; NRG Oncology.
2140 Breast Respiratory Motion in Free Breathing Assessed by 4Dimensional Computed Tomography V. Vinh-Hung,1,2 T. Gevaert,1 K. Tournel,1 D. Verellen,1 N. Leduc,2 T. Reynders,1 T. Mulliez,1 and M. De Ridder1; 1Radiotherapy Department,
Purpose/Objective(s): In order to assess whether respiratory motion should be accounted for in the radiation treatment of the breast, we evaluate displacements of the breast during free breathing as measured by 4D-CT. Materials/Methods: The radiotherapy department’s records of women undergoing thoracic free breathing 4D-CT regardless of pathology were retrospectively reviewed. Mastectomy cases and repeated 4D-CT’s were excluded. Transversal and sagittal displacements of the right and left breast’s surface at different respiratory phases were measured at the nipple and on the 4 quadrants at 5.7 cm distance from the nipple. Comparisons used the 2-sided t-test. Identification of groups of patients used KMeans clustering. Results: Sixty-eight women were identified. The overall largest motion measured in any patient ranged from 1.3 to 10.4 mm, mean m Z 3.8 mm, standard deviation Z 1.7 mm. By breast location, the means of the max displacements were: upper inner quadrant right (UIQR) 2.8 mm vs. lower inner quadrant right (LIQR) 1.9 mm, P < 0.0001; upper outer right (UOQR) 3.0 mm vs. lower outer right (LOQR) 2.2 mm; upper inner left (UIQL) 2.7 mm vs. lower inner left (LIQL) 1.8 mm, P < 0.0001; upper outer left (UOQL) 2.7 mm vs. lower outer left (LOQL) 2.0 mm, P < 0.0001, nipple right 2.4 mm vs. left 2.2 mm, P Z 0.0895. KMeans identified 3 clusters: group 1 small motion, N Z 34 (50%) patients, m Z 2.7 mm, SD Z 0.9; group 2 intermediate motion, N Z 25 (36.8%), m Z 4.3 mm, SD Z 1.0; group 3 (including one outlier) large motion, N Z 9 (13.2%), m Z 6.6 mm, SD Z 1.7. Conclusion: Respiratory motion was significantly larger in the upper quadrants as compared with the lower quadrants. Stereotactic radiation techniques might be feasible in Group 1 without requiring respiratory management. The majority of patients in this study (86.8%) presented with small respiratory motion of 2.7-4.3 mm, indicating that conventional radiation treatment without breathing control appears adequate, with a caveat regarding the differences of movements according to location. Clustering indicates that 13.2% of patients might benefit from respiratory control for their radiation treatment. Author Disclosure: V. Vinh-Hung: Chairman; INRWG. Clinical research; IGRG. T. Gevaert: None. K. Tournel: None. D. Verellen: Treasurer; ESTRO. N. Leduc: None. T. Reynders: None. T. Mulliez: None. M. De Ridder: Chairman; UZ Brussel.
2141 Assessing Long-Term Complication Rates in Patients Undergoing Immediate Postmastectomy Breast Reconstruction and Adjuvant Radiation R. Sacotte,1 N. Fine,2 J.Y. Kim,2 M. Alghoul,2 K. Bethke,3 N. Hansen,3 S.A. Khan,3 S. Kulkarni,3 J.B. Strauss,4 J.P. Hayes,4 and E.D. Donnelly4; 1 Feinberg School of Medicine, Northwestern University, Chicago, IL, 2 Division of Plastic and Reconstructive Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, 3Department of Surgery, Northwestern University Robert H. Lurie Comprehensive Cancer Center, Chicago, IL, 4Department of Radiation Oncology, The Robert H. Lurie Comprehensive Cancer Center, Chicago, IL Purpose/Objective(s): Postmastectomy radiation therapy (PMRT) for breast cancer increases survival, decreases local recurrences, and is a pillar of care in locally advanced disease. While immediate postmastectomy breast reconstruction has been shown to significantly improve psychosocial outcomes, it has also been linked to increased complications when followed by PMRT. Though there are multiple studies assessing and comparing the complication rates of immediate tissue expander/implant reconstructions (TE/I) and autologous tissue reconstructions (ATR) when PMRT is utilized, there are few with long term follow up. This study aims to quantify the long term complication rates of PMRT following immediate reconstruction and timing of complications in a large patient population.
International Journal of Radiation Oncology Biology Physics
events by LN+ group. No significant P values were found at all GEE model results by LN total number group (no data). Conclusion: Positive axillary LN number removed associates with arm lymphedema among BC patients. RT does not increase BCRL over the first postoperative RT course. Long term effect of RT on BCRL needs follow-up data for evaluation. Author Disclosure: Z. Li: None. W. Geng: None. J. Zhang: None. J. Yin: None. D. Kong: None. J. Kong: None. J. Zhang: None. A. Zhang: None.
UZ Brussel, Vrije Universiteit Brussel, Brussels, Belgium, 2CHU de Martinique, Fort de France, Martinique
2139 Does Achieving Pathologic Complete Response From Neoadjuvant Chemotherapy (NAC) for Breast Cancer Lead to Higher Rates of Breast Conservation Therapy? R.L. Young, J.G. Bazan, J.L. Wobb, C. Decker, and J.R. White; The James Cancer Hospital and Solove Research Institute, Wexner Medical Center at The Ohio State University, Department of Radiation Oncology, Columbus, OH Purpose/Objective(s): Neoadjuvant chemotherapy (NAC) is more frequently used for treatment of operable breast cancer since it has the established benefits of identifying those with improved prognosis based on disease response and enabling more women to undergo lumpectomy and radiation for breast conservation therapy (BCT). With the use of new, targeted agents in combination with traditional chemotherapy, pathologic complete response (pCR) rates have dramatically increased in select groups. We hypothesized that we would see more breast conservation in those women that achieve pCR from undergoing NAC at our institution. Materials/Methods: The Institution Cancer Registry was used to identify women who had undergone NAC between 2009 and 2014, excluding women who would not qualify for BCS (T4d), cN3, or metastatic disease. Tumor characteristics (histology, grade, and receptor status), clinical (c) and pathological (yp) staging, and loco-regional management (BCT, mastectomy and RT use) were recorded. SAS was used for all statistical analyses. Results: A total of 396 women underwent NAC during the study period. Most (71%) were cStage II with 54.8% cN+, 44.7% cN0, 59.3% cT2 tumors, 55.8% Grade 1-2, and 44.2% Grade 3. Hormone receptor positive disease was noted in 54.8%, HER2 was positive in 31.1%, and 31.1% were triple negative (TN). Clinical stages I and III comprised 11.4% and 16% of the group, respectively. One third of women (33.8%) achieved a pCR (ypT0N0) with specific breast response as follows: 38% ypT0, 37% ypT1, 20% ypT2, 4% ypT3, and 1% ypT4. The rate of pCR was 42.7% for TN, 50.5% for HER2+, and 24% for hormone sensitive. Nodal response was 62% ypN0, 22% ypN1, 11% ypN2, and 5% ypN3. Mastectomy was done for 69.2% (274/396) rather than BCS (30.8%) following NAC. Of note, 15% of women (58/396) underwent b/l mastectomies (contralateral prophylactic). On Chi-square analysis, the use of BCS versus mastectomy did not correlate with achievement of pCR; BCT 38.5% versus 31.8% for mastectomy (P Z 0.1885). Specifically, BCT was performed for 36% ypT0/Tis, 36% ypT1, 21% ypT2, and 5.6% ypT3. Breast surgery type did correlate with overall downstaging (P Z 0.0002). Approximated molecular subtype was not related to usage of BCS (P Z 0.1214e0.6101). Conclusion: Despite demonstrating a pCR rate comparable to other current data, we did not find higher rates of BCT compared to mastectomy in women whose disease achieve pCR after NAC. These patterns of surgical management observed in our institution may reflect national trends in which mastectomy continues to be favored over BCT even among women with complete responses to NAC therapy. Author Disclosure: R.L. Young: None. J.G. Bazan: None. J.L. Wobb: None. C. Decker: None. J.R. White: member; National Cancer Institute Breast Cancer Steering Committee. Co-chair; NRG Oncology.
2140 Breast Respiratory Motion in Free Breathing Assessed by 4Dimensional Computed Tomography V. Vinh-Hung,1,2 T. Gevaert,1 K. Tournel,1 D. Verellen,1 N. Leduc,2 T. Reynders,1 T. Mulliez,1 and M. De Ridder1; 1Radiotherapy Department,
Purpose/Objective(s): In order to assess whether respiratory motion should be accounted for in the radiation treatment of the breast, we evaluate displacements of the breast during free breathing as measured by 4D-CT. Materials/Methods: The radiotherapy department’s records of women undergoing thoracic free breathing 4D-CT regardless of pathology were retrospectively reviewed. Mastectomy cases and repeated 4D-CT’s were excluded. Transversal and sagittal displacements of the right and left breast’s surface at different respiratory phases were measured at the nipple and on the 4 quadrants at 5.7 cm distance from the nipple. Comparisons used the 2-sided t-test. Identification of groups of patients used KMeans clustering. Results: Sixty-eight women were identified. The overall largest motion measured in any patient ranged from 1.3 to 10.4 mm, mean m Z 3.8 mm, standard deviation Z 1.7 mm. By breast location, the means of the max displacements were: upper inner quadrant right (UIQR) 2.8 mm vs. lower inner quadrant right (LIQR) 1.9 mm, P < 0.0001; upper outer right (UOQR) 3.0 mm vs. lower outer right (LOQR) 2.2 mm; upper inner left (UIQL) 2.7 mm vs. lower inner left (LIQL) 1.8 mm, P < 0.0001; upper outer left (UOQL) 2.7 mm vs. lower outer left (LOQL) 2.0 mm, P < 0.0001, nipple right 2.4 mm vs. left 2.2 mm, P Z 0.0895. KMeans identified 3 clusters: group 1 small motion, N Z 34 (50%) patients, m Z 2.7 mm, SD Z 0.9; group 2 intermediate motion, N Z 25 (36.8%), m Z 4.3 mm, SD Z 1.0; group 3 (including one outlier) large motion, N Z 9 (13.2%), m Z 6.6 mm, SD Z 1.7. Conclusion: Respiratory motion was significantly larger in the upper quadrants as compared with the lower quadrants. Stereotactic radiation techniques might be feasible in Group 1 without requiring respiratory management. The majority of patients in this study (86.8%) presented with small respiratory motion of 2.7-4.3 mm, indicating that conventional radiation treatment without breathing control appears adequate, with a caveat regarding the differences of movements according to location. Clustering indicates that 13.2% of patients might benefit from respiratory control for their radiation treatment. Author Disclosure: V. Vinh-Hung: Chairman; INRWG. Clinical research; IGRG. T. Gevaert: None. K. Tournel: None. D. Verellen: Treasurer; ESTRO. N. Leduc: None. T. Reynders: None. T. Mulliez: None. M. De Ridder: Chairman; UZ Brussel.
2141 Assessing Long-Term Complication Rates in Patients Undergoing Immediate Postmastectomy Breast Reconstruction and Adjuvant Radiation R. Sacotte,1 N. Fine,2 J.Y. Kim,2 M. Alghoul,2 K. Bethke,3 N. Hansen,3 S.A. Khan,3 S. Kulkarni,3 J.B. Strauss,4 J.P. Hayes,4 and E.D. Donnelly4; 1 Feinberg School of Medicine, Northwestern University, Chicago, IL, 2 Division of Plastic and Reconstructive Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, 3Department of Surgery, Northwestern University Robert H. Lurie Comprehensive Cancer Center, Chicago, IL, 4Department of Radiation Oncology, The Robert H. Lurie Comprehensive Cancer Center, Chicago, IL Purpose/Objective(s): Postmastectomy radiation therapy (PMRT) for breast cancer increases survival, decreases local recurrences, and is a pillar of care in locally advanced disease. While immediate postmastectomy breast reconstruction has been shown to significantly improve psychosocial outcomes, it has also been linked to increased complications when followed by PMRT. Though there are multiple studies assessing and comparing the complication rates of immediate tissue expander/implant reconstructions (TE/I) and autologous tissue reconstructions (ATR) when PMRT is utilized, there are few with long term follow up. This study aims to quantify the long term complication rates of PMRT following immediate reconstruction and timing of complications in a large patient population.