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Prone Versus Supine Position for Adjuvant Breast Radiation Therapy: A Comparative Planning Study
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2051 Secondary Angiosarcoma After Breast-conserving Therapy Treated With Hyperfractionated Radiation Therapy With a Median Follow-up of 6.7 Years T. Linne, C.G. Morris, and N.P. Mendenhall; University of Florida, Gainesville, FL Purpose/Objective(s): Secondary angiosarcoma is a malignant cancer that develops in approximately 1% of patients who have been treated with breast-conserving therapy (BCT) for primary breast cancer. Many treatments for secondary angiosarcoma have been unsuccessful and, to our knowledge, no consensus has been reached in the medical literature on how to treat this cancer. This study reports the long-term outcomes of patients with secondary angiosarcoma treated with hyperfractionated and accelerated radiation therapy (HART). Materials/Methods: The authors retrospectively reviewed the medical records of 14 patients with secondary angiosarcoma after BCT with axillary lymph node dissection treated with HART with or without surgery from November 1997 through March 2006. The median follow-up for these patients was 6.7 years. Results: As of the most recent follow-up, 8 of the 14 patients were alive with no evidence of disease and 2 patients died of intercurrent disease; the median survival time was 101 months or 8.4 years (range, 71-164 months). The remaining 4 patients died of metastatic disease from secondary angiosarcoma and had a median survival time of 32 months (range, 5-70 months). Most patients tolerated treatment well with no complications besides some skin changes in twice-irradiated areas. One patient developed pleural effusions. The 5- and 10-year overall survival rates were 79% and 63%, respectively. The 5- and 10-year progression-free survival rates were both 64%, and the 5- and 10-year cause-specific survival rates were 79% and 71%, respectively. Conclusions: Our study shows that patients with secondary angiosarcoma after BCT who received HART with or without surgery have the highest overall survival, progression-free survival, and causespecific survival rates compared to surgery or chemotherapy. In addition, we found that axillary lymph node dissection is a risk factor for developing secondary angiosarcoma. Early diagnosis and treatment of secondary angiosarcoma improves the chances for survival. Patients who survive 3 years after HART have a lower risk of developing metastatic angiosarcoma. Finally, HART treatment is well tolerated in patients with no major complications. Author Disclosure: T. Linne: None. C.G. Morris: None. N.P. Mendenhall: None.
2052 Local Regional Recurrence Among Patients With Pleomorphic Lobular Carcinoma In Situ: Is There a Role for Radiation Therapy? C.E. Fasola, K.C. Jensen, and K.C. Horst; Stanford Cancer Center, Stanford, CA Purpose/Objective(s): Pleomorphic lobular carcinoma in situ (PLCIS) is a subset of lobular carcinoma in situ of the breast that may behave more aggressively. As such, PLCIS may warrant distinct treatment strategies. Currently, indications for the management of PLCIS are not well defined. Materials/Methods: We performed a retrospective review of 56 women with a pathological diagnosis of PLCIS from 1998 to 2012. All patients received surgical excision following core needle biopsy. A total of 34 patients had follow up information and were included in this analysis. Patient characteristics, treatment details, and clinical outcomes were reviewed. Local regional recurrence (LRR) was defined as recurrent PLCIS, invasive ductal carcinoma (IDC) or invasive lobular carcinoma (ILC). Median follow-up time was 57 months (range, 12-163 months). All analyses were performed using SAS software, version 9.3. Results: Of the 34 patients, 13 (38%) carried a diagnosis of PLCIS alone, while 21 (62%) patients had PLCIS in the setting of invasive breast
International Journal of Radiation Oncology Biology Physics carcinoma. The median age at diagnosis was 55 (range: 41-84 years). PLCIS was found to have a high incidence of underlying ductal carcinoma in situ (n Z 9, 27%) and/or invasive breast carcinoma (n Z 21, 62%) including IDC (n Z 6, 29%) and ILC (n Z 15, 71%). Compared to patients with invasive carcinoma and PLCIS, patients with PLCIS alone were more frequently treated with lumpectomy (85% v 43%, p Z 0.03) rather than mastectomy. Following surgical excision, none of the patients with PLCIS alone received adjuvant radiation therapy; however, 9 (69%) patients did receive adjuvant hormonal therapy. In contrast, 16 (76%) patients with invasive carcinoma and PLCIS received either adjuvant radiation therapy and/or chemotherapy. Among all patients, there were a total of 3 local regional recurrences at 5 years. Patients with PLCIS alone had a higher LRR rate (n Z 2/13) compared to patients with invasive carcinoma and PLCIS (n Z 1/21), although this did not reach statistical significance (15% v 5%, p Z 0.8). Interestingly, both patients with PLCIS alone who had a LRR had evidence of PLCIS within 1 mm of the surgical margin and did not receive surgical re-excision or adjuvant radiation therapy. Conclusions: Patients with PLCIS have a high incidence of underlying invasive breast carcinoma. Patients with PLCIS alone had higher rates of LRR than patients with invasive carcinoma and PLCIS, which may be a result of less aggressive adjuvant therapy. These patients may benefit from radiation therapy, particularly in the setting of close surgical margins. Further studies with larger cohorts of patients with PLCIS are needed to define the appropriate management of this disease. Author Disclosure: C.E. Fasola: None. K.C. Jensen: None. K.C. Horst: None.
2053 Prone Versus Supine Position for Adjuvant Breast Radiation Therapy: A Comparative Planning Study M. Krengli,1,2 T. Caltavuturo,1 L. Deantonio,1 E. Negri,1 I. Manfredda,1 L. Masini,1 D. Beldı`,1 G. Apicella,1 M. Brambilla,1 and G. Gambaro1; 1 University Hospital “Maggiore della Carita`”, Novara, Italy, 2University of “Piemonte Orientale”, Novara, Italy Purpose/Objective(s): To analyze dosimetric parameters of patients candidates for adjuvant breast radiation therapy (RT) in the prone versus supine position. Materials/Methods: Thirty-nine patients candidates for adjuvant breast RT with large and pendulous breasts, 23 right and 16 left sided, were included in the present study after obtaining informed consent. Age ranged from 30 to 74 (median 55 years) and BMI from 20 to 32 (median 24.2). All patients underwent CT-simulation in both prone and supine position. Clear-Vue breast board was used for prone and the breast Posiboard for supine patient setup. Target volumes and OARs (ipsilateral lung, heart, and left anterior descending [LAD] coronary artery for left sided breast) were outlined on CT simulation slices with 5 mm thickness. CTV was defined as the gland breast tissue starting 5 mm below the skin. PTV was obtained adding 5 mm margin to the CTV posteriorly and 10 mm cranial-caudally. The prescribed dose to the ICRU point was 50 Gy. Treatment plans were developed by applying 6-15 MV tangential photon fields. Dose homogeneity within the PTV was defined by the volume receiving at least 47.5 Gy but not less than 53.5 Gy (V95%-107%). Radiation exposure of the OARs (the volume of the ipsilateral lung, heart receiving more than 5 Gy, 10 Gy, and 20 Gy [V5 Gy, V10 Gy and V20 Gy], and the mean and maximum dose to the LAD) were registered in both positions. Results: The mean CTV in prone position (468 cc) was significantly larger than that in supine position (432 cc) (p Z 0.02). PTV coverage in supine position (mean V95% Z 98.0 1.6) was significantly more homogeneous than in prone position (mean V95% Z 96.5 3.5; p Z 0.04). Dmin, Dmean, Dmax, V105%, and V107% were not significantly different between the two setup positions. The lung V5, V10, and V20 were significantly less (p < 106) in prone than in supine position. The heart V5 Gy, V10 Gy, V20 Gy, and LAD Dmean and Dmax (analyzed in 16 left sided tumor patients) were less in prone than in supine position, but the difference was not statistically significant. The heart Dmax in patients with
Volume 84 Number 3S Supplement 2012 right breast was significantly lower in prone than in supine position (p Z 0.001). Based on planning data and on patients’ compliance, 27/39 patients (70%) were treated in prone position. Conclusions: Prone position may offer an advantageous alternative for irradiation of mammary gland in patients with large and pendulous breasts in particular for lung tissue. The decreased dose in the OARs suggests that prone position could be useful also in patients with pulmonary and cardiac comorbidity. Author Disclosure: M. Krengli: None. T. Caltavuturo: None. L. Deantonio: None. E. Negri: None. I. Manfredda: None. L. Masini: None. D. Beldı`: None. G. Apicella: None. M. Brambilla: None. G. Gambaro: None.
2054 4DCT-based Target Motion and Treatment Planning Variance for Whole Breast Radiation Therapy Account for Breathing Motion W. Wang, J. Li, H. Hu, T. Fan, M. Xu, and Q. Shao; Shandong Cancer Hospital, Jinan, China Purpose/Objective(s): To explore the correlation between the respirationinduced target motion and volume variation with the dosimetric variance on breast and OAR during free breathing. Materials/Methods: Seventeen patients after breast conserving surgery underwent respiration-synchronized 4DCT simulation scans during free breathing. The treatment planning constructed using the end inspiration (EI) scan, then copied and applied to the other respiratory phases and the dose distribution was calculated separately. To evaluate the dose-volume histograms parameters for the PTV, ipsilateral lung and heart. Results: During free breathing, the CTV motion vector was 2.09 0.74 mm, and the volume variation was 3.05 0.94%. There was no correlation between the volume variation of CTV and target/OAR dosimetric variation (jrj Z 0.39 w 0.48). In anteroposterior (AP), superoinferior (SI) and vector directions, the CTV movement correlated well with the mean PTV dose, conformal index (CI), and the lung volume receiving high dose (V20, V30, V40, and V50) (jrj Z 0.651 w 0.975); in SI and vector directions, the CTV displacement only correlated with the heart volume receiving >5 Gy (V5) (r Z -0.795, 0.687). The lung volume variation and the lung volume receiving high dose correlated reasonably well (r Z 0.655 w 0.882), and the correlation only exist between the heat volume variation and the V5 of heart (r Z -0.701). Conclusions: Target movement correlated well with the target/OAR dosimetric variation in certain directions, indicating that whole breast IMRT assisted with breathing control or respiratory-adapted gated treatment will promote the accuracy of dose delivery during radiation therapy. To minimize lung irradiation, gated treatment maybe most precise if centered at end expiration. Author Disclosure: W. Wang: None. J. Li: None. H. Hu: None. T. Fan: None. M. Xu: None. Q. Shao: None.
2055 Dose Distribution Analysis in Whole Breast Intensity Modulated Radiation Therapy Based on 4DCT and 3DCT W. Wang, J. Li, H. Hu, M. Xu, T. Sun, and J. Xing; Shandong Cancer Hospital, Jinan, China Purpose/Objective(s): To explore and compare the dosimetric variance in forward intensity modulated radiation therapy (IMRT) based on 4D CT and 3D CT after breast conserving surgery. Materials/Methods: Seventeen patients after breast conserving surgery underwent the 3D CT simulation scans followed by respiration-synchronized 4D CT simulation scans on the state of free breathing. The treatment plan constructed using the end inspiration (EI) scan was then copied and applied to the end expiration (EE) and 3D scans and the dose distribution were calculated separately. Dose-volume histograms (DVHs) parameters
Poster Viewing Abstracts S239 for the CTV, PTV, ipsilateral lung (IPSL) and heart were evaluated and compared. Results: The CTV volume amplitude was 11.93 28.64 cm3, and volume of the CTV receiving 95%, 100%, and 103% prescription dose among different scans were all differed by < 0.4%. Mean PTV dose at EE was lower than EI (t Z 2.87, p Z 0.011), but there was no statistical significance between 3D CT scan and EI, EE scans (t Z 1.06, -1.59; p Z 0.304, 0.132). The homogeneity index (HI) at EI, EE, 3D plans were 0.156 0.02, 0.162 0.02, 0.161 0.02, respectively, and difference only between EI and EE (t Z -2.56, p Z 0.021). The highest conformal index (CI) was at EI phase (t Z 4.55, 2.70; p Z 0.000, 0.016), and there was no significant difference between EE and 3D (t Z 0.04, p Z 0.967). The V20, V30, V40, V50 and Dmean of IPSL at EE phase were lower than EI (t Z 2.39w5.54, p Z 0.000w0.030). There were no significant differences in all the indexes for heart (t Z -1.77w1.40, p Z 0.128w0.693). Conclusions: The breast deformation during respiration may be disregarded in whole breast IMRT; PTV dose distribution was changed significantly between EI and EE phase, and the differentiation of the lung high dose area between EI and EE phase may induced by thorax expansion. Three-dimensional treatment planning is sufficient for whole breast forward IMRT, but 4D CT scans assist with respiratory gating ensure precise delivery of radiation dose. Author Disclosure: W. Wang: None. J. Li: None. H. Hu: None. M. Xu: None. T. Sun: None. J. Xing: None.
2056 Nodal Status and Tumor Location – An Unorthodox Relationship in Breast Cancer Patients J. Hammer,1 C. Track,1 K.J. Spiegl,1 H.D. Thames,2 D.H. Seewald,3 J. Feichtinger,1 A.L. Petzer,4 D. Heck,5 M. Beheshti,6 and E. Bra¨utigam1; 1 Radiotherapy, Barmherzige Schwestern Hospital, Linz, Austria, 2 Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Radiotherapy, General Hospital, Vo¨cklabruck, Austria, 4 Internal Medicine I e Hematology and Oncology, BSH, Linz, Austria, 5 Surgery, BSH, Linz, Austria, 6Nuclear Medicine & PET Center, BSH, Linz, Austria Purpose/Objective(s): Tumor location (loc) in the breast affects outcome. Beside the common prognostic factors, we identified in a number of studies subgroups with a high risk for local recurrence (LR) and survival: high node ratio, progesterone receptor negativity, and medial tumor location. In this updated analysis we evaluated the influence of the axillary nodal status on survival parameters in reference to medially (med) and laterally (lat) located primary tumors retrospectively. Materials/Methods: From 1984-2001, 2405 patients with breast cancer (pT1-2, pN0-pos), who underwent BCS systemic treatment (ST), were referred to RT. Recursive partitioning analysis (RPA) was carried out for the endpoints LR and DFS in patients with medial (n Z 568) and lateral tumors (n Z 1578). These two groups were separated according to N0 (med n Z 446, lat n Z 1071) and N pos stages (med n Z 122, lat n Z 507); centrally located tumors were excluded. Covariates included in the analysis were age, T-size, grading, ER/PR status, menopausal status, type of systemic therapy, no. of excised nodes, no. of involved lymph nodes, and their ratio (N-ratio). The relative hazard ratio (RHR) and the 10 yr results of LR and DFS were estimated in these subgroups. Results: After a mean follow-up of 135 months, the rate of LR at 10 years was 5.99%, and the DFS was 81.39%; for medial tumors 9.81% and 76.18%; and for lateral tumors 4.93% and 82.91%, respectively. The RPA for LR for med N pos stage shows no split (p> 0.05), indicating that there is no further variable or subgroup presenting with a relevant cut-off. DFS is analog to LR, and is significantly worse in the med group compared to lat, e.g. DFS for med and N0 pat. is 80.12%, for lat and N0 88.00%, p Z 0.0002. Conclusions: We hypothesize that after BCS ST and RT, patients with medial tumor locations are at higher risk. In particular, for N0-patients
2051 Secondary Angiosarcoma After Breast-conserving Therapy Treated With Hyperfractionated Radiation Therapy With a Median Follow-up of 6.7 Years T. Linne, C.G. Morris, and N.P. Mendenhall; University of Florida, Gainesville, FL Purpose/Objective(s): Secondary angiosarcoma is a malignant cancer that develops in approximately 1% of patients who have been treated with breast-conserving therapy (BCT) for primary breast cancer. Many treatments for secondary angiosarcoma have been unsuccessful and, to our knowledge, no consensus has been reached in the medical literature on how to treat this cancer. This study reports the long-term outcomes of patients with secondary angiosarcoma treated with hyperfractionated and accelerated radiation therapy (HART). Materials/Methods: The authors retrospectively reviewed the medical records of 14 patients with secondary angiosarcoma after BCT with axillary lymph node dissection treated with HART with or without surgery from November 1997 through March 2006. The median follow-up for these patients was 6.7 years. Results: As of the most recent follow-up, 8 of the 14 patients were alive with no evidence of disease and 2 patients died of intercurrent disease; the median survival time was 101 months or 8.4 years (range, 71-164 months). The remaining 4 patients died of metastatic disease from secondary angiosarcoma and had a median survival time of 32 months (range, 5-70 months). Most patients tolerated treatment well with no complications besides some skin changes in twice-irradiated areas. One patient developed pleural effusions. The 5- and 10-year overall survival rates were 79% and 63%, respectively. The 5- and 10-year progression-free survival rates were both 64%, and the 5- and 10-year cause-specific survival rates were 79% and 71%, respectively. Conclusions: Our study shows that patients with secondary angiosarcoma after BCT who received HART with or without surgery have the highest overall survival, progression-free survival, and causespecific survival rates compared to surgery or chemotherapy. In addition, we found that axillary lymph node dissection is a risk factor for developing secondary angiosarcoma. Early diagnosis and treatment of secondary angiosarcoma improves the chances for survival. Patients who survive 3 years after HART have a lower risk of developing metastatic angiosarcoma. Finally, HART treatment is well tolerated in patients with no major complications. Author Disclosure: T. Linne: None. C.G. Morris: None. N.P. Mendenhall: None.
2052 Local Regional Recurrence Among Patients With Pleomorphic Lobular Carcinoma In Situ: Is There a Role for Radiation Therapy? C.E. Fasola, K.C. Jensen, and K.C. Horst; Stanford Cancer Center, Stanford, CA Purpose/Objective(s): Pleomorphic lobular carcinoma in situ (PLCIS) is a subset of lobular carcinoma in situ of the breast that may behave more aggressively. As such, PLCIS may warrant distinct treatment strategies. Currently, indications for the management of PLCIS are not well defined. Materials/Methods: We performed a retrospective review of 56 women with a pathological diagnosis of PLCIS from 1998 to 2012. All patients received surgical excision following core needle biopsy. A total of 34 patients had follow up information and were included in this analysis. Patient characteristics, treatment details, and clinical outcomes were reviewed. Local regional recurrence (LRR) was defined as recurrent PLCIS, invasive ductal carcinoma (IDC) or invasive lobular carcinoma (ILC). Median follow-up time was 57 months (range, 12-163 months). All analyses were performed using SAS software, version 9.3. Results: Of the 34 patients, 13 (38%) carried a diagnosis of PLCIS alone, while 21 (62%) patients had PLCIS in the setting of invasive breast
International Journal of Radiation Oncology Biology Physics carcinoma. The median age at diagnosis was 55 (range: 41-84 years). PLCIS was found to have a high incidence of underlying ductal carcinoma in situ (n Z 9, 27%) and/or invasive breast carcinoma (n Z 21, 62%) including IDC (n Z 6, 29%) and ILC (n Z 15, 71%). Compared to patients with invasive carcinoma and PLCIS, patients with PLCIS alone were more frequently treated with lumpectomy (85% v 43%, p Z 0.03) rather than mastectomy. Following surgical excision, none of the patients with PLCIS alone received adjuvant radiation therapy; however, 9 (69%) patients did receive adjuvant hormonal therapy. In contrast, 16 (76%) patients with invasive carcinoma and PLCIS received either adjuvant radiation therapy and/or chemotherapy. Among all patients, there were a total of 3 local regional recurrences at 5 years. Patients with PLCIS alone had a higher LRR rate (n Z 2/13) compared to patients with invasive carcinoma and PLCIS (n Z 1/21), although this did not reach statistical significance (15% v 5%, p Z 0.8). Interestingly, both patients with PLCIS alone who had a LRR had evidence of PLCIS within 1 mm of the surgical margin and did not receive surgical re-excision or adjuvant radiation therapy. Conclusions: Patients with PLCIS have a high incidence of underlying invasive breast carcinoma. Patients with PLCIS alone had higher rates of LRR than patients with invasive carcinoma and PLCIS, which may be a result of less aggressive adjuvant therapy. These patients may benefit from radiation therapy, particularly in the setting of close surgical margins. Further studies with larger cohorts of patients with PLCIS are needed to define the appropriate management of this disease. Author Disclosure: C.E. Fasola: None. K.C. Jensen: None. K.C. Horst: None.
2053 Prone Versus Supine Position for Adjuvant Breast Radiation Therapy: A Comparative Planning Study M. Krengli,1,2 T. Caltavuturo,1 L. Deantonio,1 E. Negri,1 I. Manfredda,1 L. Masini,1 D. Beldı`,1 G. Apicella,1 M. Brambilla,1 and G. Gambaro1; 1 University Hospital “Maggiore della Carita`”, Novara, Italy, 2University of “Piemonte Orientale”, Novara, Italy Purpose/Objective(s): To analyze dosimetric parameters of patients candidates for adjuvant breast radiation therapy (RT) in the prone versus supine position. Materials/Methods: Thirty-nine patients candidates for adjuvant breast RT with large and pendulous breasts, 23 right and 16 left sided, were included in the present study after obtaining informed consent. Age ranged from 30 to 74 (median 55 years) and BMI from 20 to 32 (median 24.2). All patients underwent CT-simulation in both prone and supine position. Clear-Vue breast board was used for prone and the breast Posiboard for supine patient setup. Target volumes and OARs (ipsilateral lung, heart, and left anterior descending [LAD] coronary artery for left sided breast) were outlined on CT simulation slices with 5 mm thickness. CTV was defined as the gland breast tissue starting 5 mm below the skin. PTV was obtained adding 5 mm margin to the CTV posteriorly and 10 mm cranial-caudally. The prescribed dose to the ICRU point was 50 Gy. Treatment plans were developed by applying 6-15 MV tangential photon fields. Dose homogeneity within the PTV was defined by the volume receiving at least 47.5 Gy but not less than 53.5 Gy (V95%-107%). Radiation exposure of the OARs (the volume of the ipsilateral lung, heart receiving more than 5 Gy, 10 Gy, and 20 Gy [V5 Gy, V10 Gy and V20 Gy], and the mean and maximum dose to the LAD) were registered in both positions. Results: The mean CTV in prone position (468 cc) was significantly larger than that in supine position (432 cc) (p Z 0.02). PTV coverage in supine position (mean V95% Z 98.0 1.6) was significantly more homogeneous than in prone position (mean V95% Z 96.5 3.5; p Z 0.04). Dmin, Dmean, Dmax, V105%, and V107% were not significantly different between the two setup positions. The lung V5, V10, and V20 were significantly less (p < 106) in prone than in supine position. The heart V5 Gy, V10 Gy, V20 Gy, and LAD Dmean and Dmax (analyzed in 16 left sided tumor patients) were less in prone than in supine position, but the difference was not statistically significant. The heart Dmax in patients with
Volume 84 Number 3S Supplement 2012 right breast was significantly lower in prone than in supine position (p Z 0.001). Based on planning data and on patients’ compliance, 27/39 patients (70%) were treated in prone position. Conclusions: Prone position may offer an advantageous alternative for irradiation of mammary gland in patients with large and pendulous breasts in particular for lung tissue. The decreased dose in the OARs suggests that prone position could be useful also in patients with pulmonary and cardiac comorbidity. Author Disclosure: M. Krengli: None. T. Caltavuturo: None. L. Deantonio: None. E. Negri: None. I. Manfredda: None. L. Masini: None. D. Beldı`: None. G. Apicella: None. M. Brambilla: None. G. Gambaro: None.
2054 4DCT-based Target Motion and Treatment Planning Variance for Whole Breast Radiation Therapy Account for Breathing Motion W. Wang, J. Li, H. Hu, T. Fan, M. Xu, and Q. Shao; Shandong Cancer Hospital, Jinan, China Purpose/Objective(s): To explore the correlation between the respirationinduced target motion and volume variation with the dosimetric variance on breast and OAR during free breathing. Materials/Methods: Seventeen patients after breast conserving surgery underwent respiration-synchronized 4DCT simulation scans during free breathing. The treatment planning constructed using the end inspiration (EI) scan, then copied and applied to the other respiratory phases and the dose distribution was calculated separately. To evaluate the dose-volume histograms parameters for the PTV, ipsilateral lung and heart. Results: During free breathing, the CTV motion vector was 2.09 0.74 mm, and the volume variation was 3.05 0.94%. There was no correlation between the volume variation of CTV and target/OAR dosimetric variation (jrj Z 0.39 w 0.48). In anteroposterior (AP), superoinferior (SI) and vector directions, the CTV movement correlated well with the mean PTV dose, conformal index (CI), and the lung volume receiving high dose (V20, V30, V40, and V50) (jrj Z 0.651 w 0.975); in SI and vector directions, the CTV displacement only correlated with the heart volume receiving >5 Gy (V5) (r Z -0.795, 0.687). The lung volume variation and the lung volume receiving high dose correlated reasonably well (r Z 0.655 w 0.882), and the correlation only exist between the heat volume variation and the V5 of heart (r Z -0.701). Conclusions: Target movement correlated well with the target/OAR dosimetric variation in certain directions, indicating that whole breast IMRT assisted with breathing control or respiratory-adapted gated treatment will promote the accuracy of dose delivery during radiation therapy. To minimize lung irradiation, gated treatment maybe most precise if centered at end expiration. Author Disclosure: W. Wang: None. J. Li: None. H. Hu: None. T. Fan: None. M. Xu: None. Q. Shao: None.
2055 Dose Distribution Analysis in Whole Breast Intensity Modulated Radiation Therapy Based on 4DCT and 3DCT W. Wang, J. Li, H. Hu, M. Xu, T. Sun, and J. Xing; Shandong Cancer Hospital, Jinan, China Purpose/Objective(s): To explore and compare the dosimetric variance in forward intensity modulated radiation therapy (IMRT) based on 4D CT and 3D CT after breast conserving surgery. Materials/Methods: Seventeen patients after breast conserving surgery underwent the 3D CT simulation scans followed by respiration-synchronized 4D CT simulation scans on the state of free breathing. The treatment plan constructed using the end inspiration (EI) scan was then copied and applied to the end expiration (EE) and 3D scans and the dose distribution were calculated separately. Dose-volume histograms (DVHs) parameters
Poster Viewing Abstracts S239 for the CTV, PTV, ipsilateral lung (IPSL) and heart were evaluated and compared. Results: The CTV volume amplitude was 11.93 28.64 cm3, and volume of the CTV receiving 95%, 100%, and 103% prescription dose among different scans were all differed by < 0.4%. Mean PTV dose at EE was lower than EI (t Z 2.87, p Z 0.011), but there was no statistical significance between 3D CT scan and EI, EE scans (t Z 1.06, -1.59; p Z 0.304, 0.132). The homogeneity index (HI) at EI, EE, 3D plans were 0.156 0.02, 0.162 0.02, 0.161 0.02, respectively, and difference only between EI and EE (t Z -2.56, p Z 0.021). The highest conformal index (CI) was at EI phase (t Z 4.55, 2.70; p Z 0.000, 0.016), and there was no significant difference between EE and 3D (t Z 0.04, p Z 0.967). The V20, V30, V40, V50 and Dmean of IPSL at EE phase were lower than EI (t Z 2.39w5.54, p Z 0.000w0.030). There were no significant differences in all the indexes for heart (t Z -1.77w1.40, p Z 0.128w0.693). Conclusions: The breast deformation during respiration may be disregarded in whole breast IMRT; PTV dose distribution was changed significantly between EI and EE phase, and the differentiation of the lung high dose area between EI and EE phase may induced by thorax expansion. Three-dimensional treatment planning is sufficient for whole breast forward IMRT, but 4D CT scans assist with respiratory gating ensure precise delivery of radiation dose. Author Disclosure: W. Wang: None. J. Li: None. H. Hu: None. M. Xu: None. T. Sun: None. J. Xing: None.
2056 Nodal Status and Tumor Location – An Unorthodox Relationship in Breast Cancer Patients J. Hammer,1 C. Track,1 K.J. Spiegl,1 H.D. Thames,2 D.H. Seewald,3 J. Feichtinger,1 A.L. Petzer,4 D. Heck,5 M. Beheshti,6 and E. Bra¨utigam1; 1 Radiotherapy, Barmherzige Schwestern Hospital, Linz, Austria, 2 Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, 3Radiotherapy, General Hospital, Vo¨cklabruck, Austria, 4 Internal Medicine I e Hematology and Oncology, BSH, Linz, Austria, 5 Surgery, BSH, Linz, Austria, 6Nuclear Medicine & PET Center, BSH, Linz, Austria Purpose/Objective(s): Tumor location (loc) in the breast affects outcome. Beside the common prognostic factors, we identified in a number of studies subgroups with a high risk for local recurrence (LR) and survival: high node ratio, progesterone receptor negativity, and medial tumor location. In this updated analysis we evaluated the influence of the axillary nodal status on survival parameters in reference to medially (med) and laterally (lat) located primary tumors retrospectively. Materials/Methods: From 1984-2001, 2405 patients with breast cancer (pT1-2, pN0-pos), who underwent BCS systemic treatment (ST), were referred to RT. Recursive partitioning analysis (RPA) was carried out for the endpoints LR and DFS in patients with medial (n Z 568) and lateral tumors (n Z 1578). These two groups were separated according to N0 (med n Z 446, lat n Z 1071) and N pos stages (med n Z 122, lat n Z 507); centrally located tumors were excluded. Covariates included in the analysis were age, T-size, grading, ER/PR status, menopausal status, type of systemic therapy, no. of excised nodes, no. of involved lymph nodes, and their ratio (N-ratio). The relative hazard ratio (RHR) and the 10 yr results of LR and DFS were estimated in these subgroups. Results: After a mean follow-up of 135 months, the rate of LR at 10 years was 5.99%, and the DFS was 81.39%; for medial tumors 9.81% and 76.18%; and for lateral tumors 4.93% and 82.91%, respectively. The RPA for LR for med N pos stage shows no split (p> 0.05), indicating that there is no further variable or subgroup presenting with a relevant cut-off. DFS is analog to LR, and is significantly worse in the med group compared to lat, e.g. DFS for med and N0 pat. is 80.12%, for lat and N0 88.00%, p Z 0.0002. Conclusions: We hypothesize that after BCS ST and RT, patients with medial tumor locations are at higher risk. In particular, for N0-patients