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Intensity Modulated Proton Therapy for Accelerated Partial Breast Irradiation: A Single Institution Experience
Volume 99 Number 2S Supplement 2017
Poster Viewing
Abstract 2038; Table 1 Year 2006-2010 2011-2012 2013 2014 2015
Conventional fractionation N (%)
Hypofractionation N (%)
485 (98.2%) 200 (88.5%) 76 (71.7%) 49 (46.7%) 28 (19.7%)
9 (1.8%) 26 (11.5%) 30 (28.3%) 56 (53.3%) 114 (80.3%)
Rate of HF-WBI was 2.5% prior to initiation of tumor board (2006-2011) and was 45.7% after (2012-2015, p<0.0001). Multivariable analysis identified that the factors associated with increased use of HF-WBI were later year of treatment, no chemotherapy, older age, grade I-II, and treatment at hospital A. Other factors including race, insurance type, residence in an outside county, estrogen/ progesterone receptor status, and extent of lymph node evaluation were not significant.
hypofractionated whole breast irradiation (HF-WBI) utilization remains suboptimal. Population-based analyses have demonstrated that HF-WBI is utilized in only 30-40% of eligible patients. In 2012, our community-based cancer program developed a multidisciplinary breast tumor board across three clinical sites to standardize care. Herein is the first evaluation, to our knowledge, of the impact of a multidisciplinary tumor board on HF-WBI utilization in a community-based practice. Materials/Methods: Our institutional tumor registry was queried for patients with breast cancer or ductal carcinoma in situ who were treated between January 2006 and December 2015. Eligible cases included women age 50 years with stage 0-IIA breast cancer who underwent lumpectomy and whole breast irradiation. HF-WBI courses were defined as courses in which radiation was completed in 20 fractions with daily dose of >2.0 Gy. The primary outcome was use of conventionally-fractionated vs. hypofractionated WBI. Chi-squared tests were used for categorical variables and multivariable logistic regression was used to identify factors associated with the use of HF-WBI. Results: We identified 1,067 patients who met inclusion criteria and were included in the analysis. The proportion receiving HF-WBI was strongly associated with year (Table 1, p<0.0001) and increased from 1.8% prior to 2010 to 80.3% in 2015. Conclusion: This study demonstrates that the adoption of hypofractionated whole breast irradiation for patients with early stage breast cancer strongly accelerated after the implementation of an institutional multidisciplinary breast tumor board. This locally-based mechanism may be effective for facilitating adoption of national guidelines. Community-based radiation oncology practices could consider similar measures to increase utilization for eligible patients. Author Disclosure: A.E. Garda: None. L.E. Shaffer: None. A.S. Gokhale: None. J.A. Masino: None. L.J. Rivello: None. J.E. Seavolt: None. D.W. Widman: None. S.A. Padia: None. K.D. Slam: None. J.L. Knoble: None. M.S. Rajagopalan: None.
2039 Intensity Modulated Proton Therapy for Accelerated Partial Breast Irradiation: A Single Institution Experience F. Giap,1 R. Lepage,2 L. Dong,2 and H.B. Giap2; 1University of Texas Southwestern, Dallas, TX, 2Scripps Proton Therapy Center, San Diego, CA Purpose/Objective(s): This retrospective study describes a single institution’s technique and early experience with Intensity Modulated Proton Therapy (IMPT) for accelerated partial breast irradiation over the past 3 years. Materials/Methods: All 25 patients had the diagnosis of ductal carcinoma except for 6 DCIS and one lobular carcinoma. Five patients had breast implants. All patients underwent CT based simulation and treatment planning and were set up supine on a breast board or in the prone position. Daily setup and localization were accomplished with 3-6 skin surface fiducial markers tracked with orthogonal x-ray pairs. 40 Gy and 34 Gy in 10 daily treatments was prescribed to the lumpectomy cavity (GTV) and
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GTV plus 1-1.5 cm (CTV) excluding chest wall and skin. MRI fusion was used in some patients. Treatment was delivered using IMPT with a single enface field with simultaneous integrated boost. Results: Mean total patient time in treatment room was 14 minutes. Maximum and mean doses are as follows: cardiac 5.5 Gy/ 0.05 Gy, ipsilateral lung 22 Gy/ 0.6 Gy, chest wall 35 Gy/7 Gy and skin (5mm) 40Gy/ 10 Gy. Most patients experienced grade 1 dermatitis; however, 3 patients had grade 2 dermatitis. With a mean follow up time of 19 months, 3 patients had minor dry skin in the treatment area and no other late toxicities. All patients self-reported ‘good to excellent’ cosmetic outcomes. No patients had evidence of local failure. Conclusion: Using single field IMPT is a safe, feasible, and effective approach for accelerated partial breast irradiation. Further validation with more patients and longer follow-up are needed. Author Disclosure: F. Giap: None. R. Lepage: None. L. Dong: Speaker’s Bureau; Varian Medical Systems. Advisory Board; Varian Medical Systems. Patent/License Fees/Copyright; Varian Medical System. H.B. Giap: Independent Contractor; Advanced Particle Therapy, LLC, Signet HealthCare of Asia. Stock; California Proton Therapy Center. Particle Therapy Co-Operative Group.
2040 Factors Associated With MRI Screening in Women With a Personal History of Invasive, Unilateral Breast Cancer Predominately Encompass Detectability Concerns Rather Than Future Breast Cancer Risk J.V. Hegde,1 X. Wang,2 A. Kusske,3 M.L. DiNome,3 A.C. Hoyt,4 S.A. Hurvitz,5 and S.A. McCloskey1; 1Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, 2Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 3 Department of Surgery, University of California, Los Angeles, Los Angeles, CA, 4Department of Radiology, University of California, Los Angeles, Los Angeles, CA, 5Division of Hematology and Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA Purpose/Objective(s): For women with a personal history of invasive breast cancer, no validated mechanisms exist to calculate the risk of developing a future contralateral breast cancer (CBC). Accurately predicting future CBC risk would help refine MRI surveillance screening recommendations. The Manchester risk stratification model was recently developed to evaluate CBC risk in this population, primarily for surgical decision making. We hypothesized that this model may be informative for the use of MRI surveillance screening as CBC risk is an assumed consideration for high-risk surveillance. Materials/Methods: Two hundred fifty one women with newly-diagnosed, non-metastatic, unilateral invasive breast cancer who were seen in our institutional multidisciplinary breast clinic (MDC) and underwent unilateral surgery (breast conserving surgery or mastectomy) between June 2012 and November 2015 comprise the study cohort. We calculated lifetime CBC risk using the Manchester model, which incorporates major known factors for CBC, including age, family history, genetic mutation status, estrogen receptor positivity, and endocrine therapy use. Patients were then categorized as having a low (<10%), above average (10-20%), moderate (>20-30%), or high (>30%) risk for developing a future CBC. Univariate and multivariate logistic regression analyses (UVA/MVAs) were performed to evaluate whether the CBC risk was predictive of MRI surveillance while adjusting for other factors used to support MRI surveillance. Results: For the 22% (nZ55) undergoing MRI surveillance, 66% were low-, 23% were above average-, and 11% were moderate-/high-risk. Factors associated with MRI surveillance on MVA included previous mammography-occult breast cancer (OR 18.95, p<0.0001), endocrine therapy use (OR 3.89, pZ0.009), dense breast tissue (OR 3.69, pZ0.0007), mastectomy vs. lumpectomy (OR 3.12, pZ0.0041), and CBC risk as calculated by the Manchester model (OR 3.17 for every 10% increase, pZ0.0002). No pathologic factors increasing the risk of ipsilateral breast cancer recurrence were significant on MVA. However, if CBC risk
Poster Viewing
Abstract 2038; Table 1 Year 2006-2010 2011-2012 2013 2014 2015
Conventional fractionation N (%)
Hypofractionation N (%)
485 (98.2%) 200 (88.5%) 76 (71.7%) 49 (46.7%) 28 (19.7%)
9 (1.8%) 26 (11.5%) 30 (28.3%) 56 (53.3%) 114 (80.3%)
Rate of HF-WBI was 2.5% prior to initiation of tumor board (2006-2011) and was 45.7% after (2012-2015, p<0.0001). Multivariable analysis identified that the factors associated with increased use of HF-WBI were later year of treatment, no chemotherapy, older age, grade I-II, and treatment at hospital A. Other factors including race, insurance type, residence in an outside county, estrogen/ progesterone receptor status, and extent of lymph node evaluation were not significant.
hypofractionated whole breast irradiation (HF-WBI) utilization remains suboptimal. Population-based analyses have demonstrated that HF-WBI is utilized in only 30-40% of eligible patients. In 2012, our community-based cancer program developed a multidisciplinary breast tumor board across three clinical sites to standardize care. Herein is the first evaluation, to our knowledge, of the impact of a multidisciplinary tumor board on HF-WBI utilization in a community-based practice. Materials/Methods: Our institutional tumor registry was queried for patients with breast cancer or ductal carcinoma in situ who were treated between January 2006 and December 2015. Eligible cases included women age 50 years with stage 0-IIA breast cancer who underwent lumpectomy and whole breast irradiation. HF-WBI courses were defined as courses in which radiation was completed in 20 fractions with daily dose of >2.0 Gy. The primary outcome was use of conventionally-fractionated vs. hypofractionated WBI. Chi-squared tests were used for categorical variables and multivariable logistic regression was used to identify factors associated with the use of HF-WBI. Results: We identified 1,067 patients who met inclusion criteria and were included in the analysis. The proportion receiving HF-WBI was strongly associated with year (Table 1, p<0.0001) and increased from 1.8% prior to 2010 to 80.3% in 2015. Conclusion: This study demonstrates that the adoption of hypofractionated whole breast irradiation for patients with early stage breast cancer strongly accelerated after the implementation of an institutional multidisciplinary breast tumor board. This locally-based mechanism may be effective for facilitating adoption of national guidelines. Community-based radiation oncology practices could consider similar measures to increase utilization for eligible patients. Author Disclosure: A.E. Garda: None. L.E. Shaffer: None. A.S. Gokhale: None. J.A. Masino: None. L.J. Rivello: None. J.E. Seavolt: None. D.W. Widman: None. S.A. Padia: None. K.D. Slam: None. J.L. Knoble: None. M.S. Rajagopalan: None.
2039 Intensity Modulated Proton Therapy for Accelerated Partial Breast Irradiation: A Single Institution Experience F. Giap,1 R. Lepage,2 L. Dong,2 and H.B. Giap2; 1University of Texas Southwestern, Dallas, TX, 2Scripps Proton Therapy Center, San Diego, CA Purpose/Objective(s): This retrospective study describes a single institution’s technique and early experience with Intensity Modulated Proton Therapy (IMPT) for accelerated partial breast irradiation over the past 3 years. Materials/Methods: All 25 patients had the diagnosis of ductal carcinoma except for 6 DCIS and one lobular carcinoma. Five patients had breast implants. All patients underwent CT based simulation and treatment planning and were set up supine on a breast board or in the prone position. Daily setup and localization were accomplished with 3-6 skin surface fiducial markers tracked with orthogonal x-ray pairs. 40 Gy and 34 Gy in 10 daily treatments was prescribed to the lumpectomy cavity (GTV) and
E17
GTV plus 1-1.5 cm (CTV) excluding chest wall and skin. MRI fusion was used in some patients. Treatment was delivered using IMPT with a single enface field with simultaneous integrated boost. Results: Mean total patient time in treatment room was 14 minutes. Maximum and mean doses are as follows: cardiac 5.5 Gy/ 0.05 Gy, ipsilateral lung 22 Gy/ 0.6 Gy, chest wall 35 Gy/7 Gy and skin (5mm) 40Gy/ 10 Gy. Most patients experienced grade 1 dermatitis; however, 3 patients had grade 2 dermatitis. With a mean follow up time of 19 months, 3 patients had minor dry skin in the treatment area and no other late toxicities. All patients self-reported ‘good to excellent’ cosmetic outcomes. No patients had evidence of local failure. Conclusion: Using single field IMPT is a safe, feasible, and effective approach for accelerated partial breast irradiation. Further validation with more patients and longer follow-up are needed. Author Disclosure: F. Giap: None. R. Lepage: None. L. Dong: Speaker’s Bureau; Varian Medical Systems. Advisory Board; Varian Medical Systems. Patent/License Fees/Copyright; Varian Medical System. H.B. Giap: Independent Contractor; Advanced Particle Therapy, LLC, Signet HealthCare of Asia. Stock; California Proton Therapy Center. Particle Therapy Co-Operative Group.
2040 Factors Associated With MRI Screening in Women With a Personal History of Invasive, Unilateral Breast Cancer Predominately Encompass Detectability Concerns Rather Than Future Breast Cancer Risk J.V. Hegde,1 X. Wang,2 A. Kusske,3 M.L. DiNome,3 A.C. Hoyt,4 S.A. Hurvitz,5 and S.A. McCloskey1; 1Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, 2Department of Medicine, University of California, Los Angeles, Los Angeles, CA, 3 Department of Surgery, University of California, Los Angeles, Los Angeles, CA, 4Department of Radiology, University of California, Los Angeles, Los Angeles, CA, 5Division of Hematology and Oncology, Department of Medicine, University of California, Los Angeles, Los Angeles, CA Purpose/Objective(s): For women with a personal history of invasive breast cancer, no validated mechanisms exist to calculate the risk of developing a future contralateral breast cancer (CBC). Accurately predicting future CBC risk would help refine MRI surveillance screening recommendations. The Manchester risk stratification model was recently developed to evaluate CBC risk in this population, primarily for surgical decision making. We hypothesized that this model may be informative for the use of MRI surveillance screening as CBC risk is an assumed consideration for high-risk surveillance. Materials/Methods: Two hundred fifty one women with newly-diagnosed, non-metastatic, unilateral invasive breast cancer who were seen in our institutional multidisciplinary breast clinic (MDC) and underwent unilateral surgery (breast conserving surgery or mastectomy) between June 2012 and November 2015 comprise the study cohort. We calculated lifetime CBC risk using the Manchester model, which incorporates major known factors for CBC, including age, family history, genetic mutation status, estrogen receptor positivity, and endocrine therapy use. Patients were then categorized as having a low (<10%), above average (10-20%), moderate (>20-30%), or high (>30%) risk for developing a future CBC. Univariate and multivariate logistic regression analyses (UVA/MVAs) were performed to evaluate whether the CBC risk was predictive of MRI surveillance while adjusting for other factors used to support MRI surveillance. Results: For the 22% (nZ55) undergoing MRI surveillance, 66% were low-, 23% were above average-, and 11% were moderate-/high-risk. Factors associated with MRI surveillance on MVA included previous mammography-occult breast cancer (OR 18.95, p<0.0001), endocrine therapy use (OR 3.89, pZ0.009), dense breast tissue (OR 3.69, pZ0.0007), mastectomy vs. lumpectomy (OR 3.12, pZ0.0041), and CBC risk as calculated by the Manchester model (OR 3.17 for every 10% increase, pZ0.0002). No pathologic factors increasing the risk of ipsilateral breast cancer recurrence were significant on MVA. However, if CBC risk