- Email: [email protected]
Outcomes of breast cancer patients older than 80 years treated with adjuvant radiotherapy
Poster Session, Saturday 28 January 2017 regimens incorporated Anthracycline. Chemotherapy was not indicated in rest of the patients. The mean dose to PTV V95 = 99% ±0.5 SD, V100 = 93% ±2.0 SD, V110 = 0.003 ±0.004 SD of the prescribed dose. The ipsilateral lung mean V20 = 22.1% ±7.8, V35 = 8.0% ±4.0, V5 = 79.5 ±21.3 SD and dose to contralateral lung V20 = 2.3% ±3.9 SD. The dose to heart V33 = 9.1% ±9.0 SD. All the patients tolerated the treatment well with only Grade 1 skin toxicity, which was treated symptomatically. Conclusions: Helical Tomotherapy can achieve full target coverage while protecting the heart and ipsilateral lung. This treatment was well tolerated. The effect of low dose bath needs to be evaluated based on long term follow up and in future studies. No conflict of interest. 212A POSTER IMRT vs. VMAT for breast cancer treatment using a Monte Carlo algorithm J. Sanchez Mazon1 , M.A. Mendiguren Santiago1 , F. Saez Hernandez1 , C. Arguello Rodriguez1 , A. Perez Ochoa1 , J.M. Lopez Vega1 . 1 Momp´ıa Clinic, Radiation Oncology, Mompia, Spain Background: There have been significant advances in the delivery of radiotherapy over the past few decades. Newer radiation techniques, e.g., intensity modulated radiotherapy (IMRT), have been developed. IMRT techniques employ variable intensity across multiple radiation beams. More recently, there has been some interest in arc-based or rotational therapies to overcome some of the limitations associated with fixed field IMRT, e.g., volumetric modulated arc therapy (VMAT). VMAT is a radiation technique that can achieve highly conformal dose distributions with improved target volume coverage and sparing of normal tissues compared with conventional radiotherapy techniques. The main aim of this work is to comparer two different VMAT techniques with the IMRT technique in breast cancer. Material and Methods: We have calculated three different treatment techniques in 10 patients with breast cancer: IMRT, VMAT1 and VMAT2. We have used Monaco Treatment Planning System from Elekta and Monte Carlo algorithm. VMAT1 is a VMAT technique describing two half arcs (180º each) around the breast, one of them clockwise direction and the other one counterclockwise direction. VMAT2 consists of two partial arcs, starting in the same point as VMAT1 but 40 degrees of amplitude each. The IMRT technique has been calculated with 4 step and shoot static fields. All techniques were calculated to deliver 50 Gy (2 Gy per day) to the whole breast. In the three cases, we have compared the PTV coverage (V95), PTV high doses (V107) and the OAR sparing (ipsilateral lung, contralateral lung, heart and contralateral breast). Results: PTV coverage, V95, were similar between the three plans and no statistically significant discrepancies were found, although dose conformity and homogeneity are better using VMAT. Significant differences were found in PTV high doses (V107), with IMRT delivering about 4% more dosage than VMAT techniques. In terms of OAR sparing, doses in lung (both ipsilateral and contralateral) and in contralateral breast were similar in the three plans. However, differences in heart dose were statistically significant between IMRT and VMAT1, with an increase of about 3% using VMAT1 technique. Comparing both VMAT technics, we find similar PTV coverage. However, statistically significant differences were found in the heart and contralateral breast doses. VMAT1 increases the dose in about 6% in contralateral breast and 3% in heart, compared to VMAT2. Conclusions: The data suggests that VMAT and fixed field IMRT will produce largely equivalent target volume coverage. However, dose conformity and homogeneity are better using VMAT. The absolute difference in dosimetric parameters reported as statistically significant is relatively small and may not be clinically significant. So, we cannot assure that VMAT is better than IMRT in the case of breast cancer. No conflict of interest. 213 POSTER Magnetic resonance imaging in the evaluation of tumor node in breast cancer after neoadjuvant treatment A. Komiakhov1 , A. Mischenko2 , V. Semiglazov1 , P. Krivorotko1 , O. Ivanova1 , A. Petrova2 . 1 Federal State Budget Institution “Oncology Scientific-research Institute named after N.N. Petrov”- of Ministry of Public Health of the Russian, breast cancer, Saint Petersburg, Russian Federation; 2 Federal State Budget Institution “Oncology Scientific-research Institute named after N.N. Petrov”- of Ministry of Public Health of the Russian, X-ray diagnostics, Saint Petersburg, Russian Federation Breast cancer (BC) is still one of the leading oncology problems. Incidence rates are still at a high level. We estimated the effectiveness of neoadjuvant treatment of 263 patients and performed MRI for them − before treatment and during the process. In the first stage before the appointment of a
Abstracts
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system of treatment according to MRI malignancy in the mammary gland was found in 97.8% of cases, 3 cases were found in patients with occult breast cancer. After chemotherapy, the residual node on MRI was found in 52 patients, that is, in 81.2% cases. The comparison of findings on MRI and pathologic size of the remaining (residual) tumor was performed on the basis of post-operative study medication data. Separately the behavior of the kinetic curves in the preoperative treatment was analyzed. Changing the size of the tumor was predominantly direct correlation with the change in the kinetic curve type (Pearson = 0.6, p < 0.0001), that is, when you change the curve from the 3rd to the 1st type, also noted a decrease in the size of the formation. It should be noted that the third type of kinetic curves before the start of chemotherapy from 64 surveys was in the majority of women (90.6% of cases), type 2 in 6.2%, type 1 in 3.1%. After 2−3 cycles of chemotherapy third type of kinetic curves was at 31.2%. After 4−6 neoadjuvant chemotherapy 2nd and 1st type of kinetic curves correspond to the majority of patients − 84.3% (54 cases). It has been found that V-degree therapeutic pathomorphism mainly corresponded with tumor type 1st kinetic curves. I and II degree of therapeutic pathomorphism corresponded to the 3rd type of kinetic curves. The third type of kinetic curves prevailed in patients with progression and stabilization of the tumor site during the treatment, the second type of kinetic curves − with the process of stabilization and partial regression. The first type of kinetic curves is observed at partial and complete tumor regression in response to treatment. Thus, the change in the type of kinetic curves correlate with therapeutic pathomorphism (criterion Pearson −0.562, p > 0.0001). After the final analysis of the nature of the change in tumor size and the type of kinetic curves obtained data on the correlation of clinical and pathological responses (i.e., the ratio pR/cR correlation). The high degree of correlation between a full medical pathomorphosis and full clinical effect on MRI. pCR/cCR ratio stood at 0.79, indicating a high accuracy of MRI in predicting pathologic complete response to treatment. Maximum descriptiveness of MRI is noted after 4−6 cycles of chemotherapy. Therefore, there is no need to apply it after 2−3 courses. Inclusion in the diagnostic algorithm of MRI can improve the accuracy of clinical diagnostic evaluation of tumor response to neoadjuvant treatment until the prediction of pathologic complete regression (pCR). No conflict of interest. 213A POSTER Outcomes of breast cancer patients older than 80 years treated with adjuvant radiotherapy R. Barrientos1 , M. Frelinghuysen2 , M. Burotto3 . 1 Clinica IRAM, Radioterapia, Santiago, Chile; 2 Hospital Clinico Regional de Concepcion, Radiation Oncology, Concepcion, Chile; 3 Clinica Alemana de Santiago, Medical Oncology, Santiago, Chile Background: The main purpose was to estimate the overall survival of patients older than 80 years, diagnosed by Stage I−III breast cancer that were treated by surgery and adjuvant radiotherapy with curative intent. Clinical and pathologic factors that influence survival were estimated. Material and Methods: We analyzed 85 breast cancer patients older than 80 years that received surgery and adjuvant radiotherapy with curative intent. Overall survival was defined as the time from the date histopathological diagnosis until the last date of follow-up (official death certificate). Survival was analyzed by Kaplan–Meier method. A log rank test was used to compare survival of different clinical and pathological factors. Signficance level was determined at p-value <0.05. Table 1. Significant clinical/pathological factors for survival
Clinical tumor stage cT1 cT2 cT3 cT4b cT4d Overall Clinical Nodes Positive Negative Overall Regional lymph node irradiation Local irradiation Locoregional irradiation Overall Pathologic tumor stage pT1 pT2 pT3 pT4b pT4d Overall
Number of patients
Percentage (%)
Number of events
5-year survival
Log rank test (p-value)
8 8 36 28 5 85
9 9 42 33 7 100
1 4 6 4 2 19
80 90 68 NR NR
56 29 85
66 34 100
11 8 19
80 75
0.006
53 32 84
62 38 100
7 12 19
74 56
0.02
40 31 8 2 3 83
48 37 9 2 3 98
7 5 4 2 1 19
77 76 38 NR NR
0.003
0.001
Survival estimated by Kaplan–Meier. Comparison between subset of factors by Log-Rank (Mantel–Cox) test. NR, not reached.
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Abstracts
Results: The median age at the time of diagnosis was 82.7 (range 77 to 88). The median follow up was 42 months. Fifty five patients (65%) received partial mastectomy and 30 patients (35%) total mastectomy (MT). Fifty four patients (63%) received whole breast or chest wall irradiation, while 31 patients (37%) received locorregional irradiation. Five patients presented cutaneous toxicity grade 3. Overall survival was 70% at 5 years and breast cancer specific survival (BCSS) was 94% at 5 years. Four patients (4.2%) died of cardiovascular disease. In the univariate analysis clinical preoperative nodal stage, clinical and pathological tumour size, locorregional irradiation and pathologic tumor stage were significant variables for worst overall survival (Table 1). No other examined factor was significantly related. Conclusion: Patients older than 80 treated by Stage I−III breast cancer have long survival after treatment. OS and BCSS is high at five years. Patients with locally advanced preoperative disease, pathologic tumor size and locorregional irradiation contributed negatively to survival. No conflict of interest. 214 POSTER The role of post-mastectomy radiotherapy (PMRT) and prognostic factors of locoregional recurrence D. Delishaj1 , S. Ursino1 , V. Mazzotti1 , S. Spagnesi1 , L.R. Fatigante1 , B. Manfredi1 , A. Cristaudo1 , F. Pasqualetti1 , F. Orlandi1 , R. Morganti2 , L. Concetta1 , M. Roncella3 , M. Cantarella1 , E. Lombardo1 , A. Fontana4 , F. Matteucci1 , A. Michelotti4 , M.G. Fabrini1 , A. Falcone4 , F. Paiar1 . 1 Department of Experimental and Clinical Medicine, Division of Radiation Oncology-University of Pisa, Pisa, Italy; 2 Department of Experimental and Clinical Medicine, Section of Statistics, University of Pisa, Pisa, Italy; 3 Department of Experimental and Clinical Medicine, Breast Surgery-University of Pisa, Pisa, Italy; 4 Department of Experimental and Clinical Medicine, Division of Oncology-University of Pisa, Pisa, Italy Background: The purpose of the study was to evaluate the outcome of patients (pts) undergone to mastectomy followed or not by postmastectomy radiotherapy (PMRT) and to investigate the clinicopathological prognostic factors of locoregional recurrence (LRR). Methods and Materials: We retrospectively reviewed data of patients underwent total mastectomy and sentinel lymph node examination +/− axillary dissection. Patients were staged according to AJCCU/UICC 7º Edition. According to consensus in literature PMRT was limited to the chest wall (CW-PMRT) in stage pT3 N1 or extended to the lymphatic drainages of apex axilla and supraclavicular nodes (CWLD-PMRT) in stage pT4 N2−3. Patients underwent salvage mastectomy after a previous conservative surgery and RT or with of systemic disease at diagnosis were excluded from the study. Radiotherapy treatment was performed with linear accelerator and 3DCRT technique using X photons of 6 and/or 15 MV energy. Two tangential beam technique was used for CW-PMRT whereas an half beam technique with the addiction of 1−2 anterior-posterior (AP-PA) beam was used for CWLDPMRT. The prescribed dose was 50 Gy delivered in 25 fractions adding a boost of 20 Gy and 14−16 Gy for positive and close (<2 mm) surgical margins, respectively. Neoadjuvant chemotherapy (CT), adjuvant CT, Trastuzumab, Tamoxifen and systemic endocrine therapy were prescribed according to international guidelines. Radiotherapy was deferred after the completion of adjuvant CT. Univariate and multivariate analyses were performed using SPSS 22 (SPSS Inc., Chicago, IL, USA) technology. Results: Between January 2004 and June 2013 a total of 912 patients underwent total mastectomy; of whom 269 (29.5%) underwent PMRT and 643 (70.5%) did not. Among PMRT group 77 underwent CW and 202 CWLD irradiation. The median follow up was 40 months (range, 3– 118). No significant difference in terms of LRR was found between the noPMRT and PMRT groups (p = 0.175; HR = 1.613; 95% CI = 0.808−3.219). The uni- and multivariate analysis of LRR for patients not undergone to PMRT showed a significant correlation with the presence of ECE (p = 0.049), Mib-1 >30% (p = 0.048) and triple negative status (p = 0.001). On the contrary, the triple negative status resulted as the only variable significantly correlated to LRR (p < 0.0001) in the PMRT group whereas ECE and Mib-1 >30% lost the significance. Finally, no significant difference was shown between CWLD and CW-PMRT (p = 0.078; HR = 0.375; 95% CI = 0.126−1.116). Conclusions: Based on our data, we strongly confirm the positive impact of PMRT in local advance disease and recommend to carefully consider it in presence of ECE and Mib-1 >30% regardless T and N stage. CW irradiation might be a valid option in selected intermediate disease (i.e. less than 3 positive lymph nodes). Future “well designed” prospective studies are needed to properly validate our results. No conflict of interest.
Poster Session, Saturday 28 January 2017 214A POSTER Breast irradiation using personalised thermoplastic mask for immobilisation: Pros and cons A. Dinu1 , T. Flonta1 , V. Virag1 , L. Marcu2 . 1 Gavril Curteanu Municipal Hospital, Radiotherapy department, Oradea, Romania; 2 University of Oradea, Faculty of Science, Oradea, Romania Background: The goal of radiotherapy is to achieve a high therapeutic ratio by increasing tumour control via adequate CTV dosimetry and decreasing normal tissue toxicity through better protection of the organs at risk. To attain this goal, solutions are often required for treatment optimisation, such as the use of immobilising devices for setup error reduction. There is a scarcity of literature data regarding thermoplastic masks for breast immobilisation when no prone breast board is available. Thus, the aim of the current study was to assess the advantages and drawbacks of thermoplastic masks used for patients with large breasts undergoing radiotherapy. Materials and Methods: Patients with large breasts presenting with invasive left-sided breast carcinomas were treated post-segmentectomy in our radiotherapy department. Personalised thermoplastic masks were prepared to assist with immobilisation during fractionated radiotherapy. In order to evaluate the pros and cons of thermoplastic mask for breast immobilisation, 7 patients have been irradiated with the mask while other 7 were used as control. Dose prescriptions were identical for the two patient groups: 50 Gy in 25 fractions to the whole breast CTV and boost dose to the tumour bed of 60 Gy in 25 fractions. The two main aspects assessed in the study were: (1) the reduction of setup errors with the immobilising mask; (2) the acute effects with/without the mask. Results: For an accurate determination of the setup errors, EPID images were fused with the DRR images for each patient. Weekly positioning errors were determined for the two patient groups along the X and Y axes. The results indicated a clear advantage of the thermoplastic mask, which has reduced the errors to one third of the no-mask scenario. Furthermore, while the setup errors over the first two treatment weeks in both groups ranged between 1 and 2 mm, after the third week of treatment the errors in the no-mask group started to increase up to 4 mm. The immobilised group presented no changes. These errors could pose long-term risks to the heart. A shortcoming of the thermoplastic mask is the increase in the skin dose which resulted in grade 3 radiodermatitis, which however, resolved in 3 months post-irradiation. Conclusions: The use of breast masks considerably increases the reproducibility of patient positioning and limits the setup errors. This is an important outcome, since positioning errors are often a challenge when treating large-breasted patients, given the fact that after 15−20 dose fractions the inflammatory processes can change the shape and the volume of the breast. The error reductions allowed an accurate D95% dose delivery, while the heart was adequately protected. A drawback of this irradiation technique is the increase in the skin dose, a consequence that can be managed with suitable medical care. No conflict of interest. 215 POSTER Hypofractionated radiotherapy after conservative surgery in breast cancer patients: a phase I-II trial (MARA-1) M. Pieri1 , R. Frakulli1 , G. Macchia2 , A. Farioli3 , S. Cilla4 , F. Deodato2 , I. Ammendolia1 , G. Tolento1 , S. Cammelli1 , L. Di Lullo5 , M. Taffurelli3 , C. Zamagni6 , D. Smaniotto7 , F. Marazzi7 , V. Valentini7 , G. Ferrandina8 , A.G. Morganti1 . 1 S. Orsola-Malpighi Hospital-University of Bologna, Radiation Oncology Center- Department of Experimental- Diagnostic and Specialty Medicine- DIMES, Bologna, Italy; 2 Fondazione Giovanni Paolo II, Radiation Oncology Unit, Campobasso, Italy; 3 S. Orsola-Malpighi Hospital-University of Bologna, Department of Medical and Surgical Sciences DIMEC, Bologna, Italy; 4 Fondazione Giovanni Paolo II, Medical Physic Unit, Campobasso, Italy; 5 General Hospital, Department of Oncology, Isernia, Italy; 6 S. Orsola-Malpighi Hospital-University of Bologna, Medical Oncology Unit, Bologna, Italy; 7 Catholic University of the Sacred Heart, Radiation Oncology Department, Rome, Italy; 8 Catholic University of the Sacred Heart, Gynecologic Oncology Unit, Rome, Italy Background: The aim of this study is to evaluate late toxicity after hypofractionated radiotherapy (MARA-1 protocol) in early stage breast carcinoma as compared to a control group (CG) treated with standard fractionation. Material and Methods: MARA-1 is a prospective phase I-II study on accelerated IMRT. In the CG the whole breast received 50.4 Gy in 28 fractions (fx) with a sequential boost on the tumour bed of 10 Gy in 4 fx with 3D technique. In MARA-1 an IMRT technique was used and prescribed dose to the breast was 40 Gy in 16 fx with a concomitant boost of 4 Gy.
Abstracts
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system of treatment according to MRI malignancy in the mammary gland was found in 97.8% of cases, 3 cases were found in patients with occult breast cancer. After chemotherapy, the residual node on MRI was found in 52 patients, that is, in 81.2% cases. The comparison of findings on MRI and pathologic size of the remaining (residual) tumor was performed on the basis of post-operative study medication data. Separately the behavior of the kinetic curves in the preoperative treatment was analyzed. Changing the size of the tumor was predominantly direct correlation with the change in the kinetic curve type (Pearson = 0.6, p < 0.0001), that is, when you change the curve from the 3rd to the 1st type, also noted a decrease in the size of the formation. It should be noted that the third type of kinetic curves before the start of chemotherapy from 64 surveys was in the majority of women (90.6% of cases), type 2 in 6.2%, type 1 in 3.1%. After 2−3 cycles of chemotherapy third type of kinetic curves was at 31.2%. After 4−6 neoadjuvant chemotherapy 2nd and 1st type of kinetic curves correspond to the majority of patients − 84.3% (54 cases). It has been found that V-degree therapeutic pathomorphism mainly corresponded with tumor type 1st kinetic curves. I and II degree of therapeutic pathomorphism corresponded to the 3rd type of kinetic curves. The third type of kinetic curves prevailed in patients with progression and stabilization of the tumor site during the treatment, the second type of kinetic curves − with the process of stabilization and partial regression. The first type of kinetic curves is observed at partial and complete tumor regression in response to treatment. Thus, the change in the type of kinetic curves correlate with therapeutic pathomorphism (criterion Pearson −0.562, p > 0.0001). After the final analysis of the nature of the change in tumor size and the type of kinetic curves obtained data on the correlation of clinical and pathological responses (i.e., the ratio pR/cR correlation). The high degree of correlation between a full medical pathomorphosis and full clinical effect on MRI. pCR/cCR ratio stood at 0.79, indicating a high accuracy of MRI in predicting pathologic complete response to treatment. Maximum descriptiveness of MRI is noted after 4−6 cycles of chemotherapy. Therefore, there is no need to apply it after 2−3 courses. Inclusion in the diagnostic algorithm of MRI can improve the accuracy of clinical diagnostic evaluation of tumor response to neoadjuvant treatment until the prediction of pathologic complete regression (pCR). No conflict of interest. 213A POSTER Outcomes of breast cancer patients older than 80 years treated with adjuvant radiotherapy R. Barrientos1 , M. Frelinghuysen2 , M. Burotto3 . 1 Clinica IRAM, Radioterapia, Santiago, Chile; 2 Hospital Clinico Regional de Concepcion, Radiation Oncology, Concepcion, Chile; 3 Clinica Alemana de Santiago, Medical Oncology, Santiago, Chile Background: The main purpose was to estimate the overall survival of patients older than 80 years, diagnosed by Stage I−III breast cancer that were treated by surgery and adjuvant radiotherapy with curative intent. Clinical and pathologic factors that influence survival were estimated. Material and Methods: We analyzed 85 breast cancer patients older than 80 years that received surgery and adjuvant radiotherapy with curative intent. Overall survival was defined as the time from the date histopathological diagnosis until the last date of follow-up (official death certificate). Survival was analyzed by Kaplan–Meier method. A log rank test was used to compare survival of different clinical and pathological factors. Signficance level was determined at p-value <0.05. Table 1. Significant clinical/pathological factors for survival
Clinical tumor stage cT1 cT2 cT3 cT4b cT4d Overall Clinical Nodes Positive Negative Overall Regional lymph node irradiation Local irradiation Locoregional irradiation Overall Pathologic tumor stage pT1 pT2 pT3 pT4b pT4d Overall
Number of patients
Percentage (%)
Number of events
5-year survival
Log rank test (p-value)
8 8 36 28 5 85
9 9 42 33 7 100
1 4 6 4 2 19
80 90 68 NR NR
56 29 85
66 34 100
11 8 19
80 75
0.006
53 32 84
62 38 100
7 12 19
74 56
0.02
40 31 8 2 3 83
48 37 9 2 3 98
7 5 4 2 1 19
77 76 38 NR NR
0.003
0.001
Survival estimated by Kaplan–Meier. Comparison between subset of factors by Log-Rank (Mantel–Cox) test. NR, not reached.
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Abstracts
Results: The median age at the time of diagnosis was 82.7 (range 77 to 88). The median follow up was 42 months. Fifty five patients (65%) received partial mastectomy and 30 patients (35%) total mastectomy (MT). Fifty four patients (63%) received whole breast or chest wall irradiation, while 31 patients (37%) received locorregional irradiation. Five patients presented cutaneous toxicity grade 3. Overall survival was 70% at 5 years and breast cancer specific survival (BCSS) was 94% at 5 years. Four patients (4.2%) died of cardiovascular disease. In the univariate analysis clinical preoperative nodal stage, clinical and pathological tumour size, locorregional irradiation and pathologic tumor stage were significant variables for worst overall survival (Table 1). No other examined factor was significantly related. Conclusion: Patients older than 80 treated by Stage I−III breast cancer have long survival after treatment. OS and BCSS is high at five years. Patients with locally advanced preoperative disease, pathologic tumor size and locorregional irradiation contributed negatively to survival. No conflict of interest. 214 POSTER The role of post-mastectomy radiotherapy (PMRT) and prognostic factors of locoregional recurrence D. Delishaj1 , S. Ursino1 , V. Mazzotti1 , S. Spagnesi1 , L.R. Fatigante1 , B. Manfredi1 , A. Cristaudo1 , F. Pasqualetti1 , F. Orlandi1 , R. Morganti2 , L. Concetta1 , M. Roncella3 , M. Cantarella1 , E. Lombardo1 , A. Fontana4 , F. Matteucci1 , A. Michelotti4 , M.G. Fabrini1 , A. Falcone4 , F. Paiar1 . 1 Department of Experimental and Clinical Medicine, Division of Radiation Oncology-University of Pisa, Pisa, Italy; 2 Department of Experimental and Clinical Medicine, Section of Statistics, University of Pisa, Pisa, Italy; 3 Department of Experimental and Clinical Medicine, Breast Surgery-University of Pisa, Pisa, Italy; 4 Department of Experimental and Clinical Medicine, Division of Oncology-University of Pisa, Pisa, Italy Background: The purpose of the study was to evaluate the outcome of patients (pts) undergone to mastectomy followed or not by postmastectomy radiotherapy (PMRT) and to investigate the clinicopathological prognostic factors of locoregional recurrence (LRR). Methods and Materials: We retrospectively reviewed data of patients underwent total mastectomy and sentinel lymph node examination +/− axillary dissection. Patients were staged according to AJCCU/UICC 7º Edition. According to consensus in literature PMRT was limited to the chest wall (CW-PMRT) in stage pT3 N1 or extended to the lymphatic drainages of apex axilla and supraclavicular nodes (CWLD-PMRT) in stage pT4 N2−3. Patients underwent salvage mastectomy after a previous conservative surgery and RT or with of systemic disease at diagnosis were excluded from the study. Radiotherapy treatment was performed with linear accelerator and 3DCRT technique using X photons of 6 and/or 15 MV energy. Two tangential beam technique was used for CW-PMRT whereas an half beam technique with the addiction of 1−2 anterior-posterior (AP-PA) beam was used for CWLDPMRT. The prescribed dose was 50 Gy delivered in 25 fractions adding a boost of 20 Gy and 14−16 Gy for positive and close (<2 mm) surgical margins, respectively. Neoadjuvant chemotherapy (CT), adjuvant CT, Trastuzumab, Tamoxifen and systemic endocrine therapy were prescribed according to international guidelines. Radiotherapy was deferred after the completion of adjuvant CT. Univariate and multivariate analyses were performed using SPSS 22 (SPSS Inc., Chicago, IL, USA) technology. Results: Between January 2004 and June 2013 a total of 912 patients underwent total mastectomy; of whom 269 (29.5%) underwent PMRT and 643 (70.5%) did not. Among PMRT group 77 underwent CW and 202 CWLD irradiation. The median follow up was 40 months (range, 3– 118). No significant difference in terms of LRR was found between the noPMRT and PMRT groups (p = 0.175; HR = 1.613; 95% CI = 0.808−3.219). The uni- and multivariate analysis of LRR for patients not undergone to PMRT showed a significant correlation with the presence of ECE (p = 0.049), Mib-1 >30% (p = 0.048) and triple negative status (p = 0.001). On the contrary, the triple negative status resulted as the only variable significantly correlated to LRR (p < 0.0001) in the PMRT group whereas ECE and Mib-1 >30% lost the significance. Finally, no significant difference was shown between CWLD and CW-PMRT (p = 0.078; HR = 0.375; 95% CI = 0.126−1.116). Conclusions: Based on our data, we strongly confirm the positive impact of PMRT in local advance disease and recommend to carefully consider it in presence of ECE and Mib-1 >30% regardless T and N stage. CW irradiation might be a valid option in selected intermediate disease (i.e. less than 3 positive lymph nodes). Future “well designed” prospective studies are needed to properly validate our results. No conflict of interest.
Poster Session, Saturday 28 January 2017 214A POSTER Breast irradiation using personalised thermoplastic mask for immobilisation: Pros and cons A. Dinu1 , T. Flonta1 , V. Virag1 , L. Marcu2 . 1 Gavril Curteanu Municipal Hospital, Radiotherapy department, Oradea, Romania; 2 University of Oradea, Faculty of Science, Oradea, Romania Background: The goal of radiotherapy is to achieve a high therapeutic ratio by increasing tumour control via adequate CTV dosimetry and decreasing normal tissue toxicity through better protection of the organs at risk. To attain this goal, solutions are often required for treatment optimisation, such as the use of immobilising devices for setup error reduction. There is a scarcity of literature data regarding thermoplastic masks for breast immobilisation when no prone breast board is available. Thus, the aim of the current study was to assess the advantages and drawbacks of thermoplastic masks used for patients with large breasts undergoing radiotherapy. Materials and Methods: Patients with large breasts presenting with invasive left-sided breast carcinomas were treated post-segmentectomy in our radiotherapy department. Personalised thermoplastic masks were prepared to assist with immobilisation during fractionated radiotherapy. In order to evaluate the pros and cons of thermoplastic mask for breast immobilisation, 7 patients have been irradiated with the mask while other 7 were used as control. Dose prescriptions were identical for the two patient groups: 50 Gy in 25 fractions to the whole breast CTV and boost dose to the tumour bed of 60 Gy in 25 fractions. The two main aspects assessed in the study were: (1) the reduction of setup errors with the immobilising mask; (2) the acute effects with/without the mask. Results: For an accurate determination of the setup errors, EPID images were fused with the DRR images for each patient. Weekly positioning errors were determined for the two patient groups along the X and Y axes. The results indicated a clear advantage of the thermoplastic mask, which has reduced the errors to one third of the no-mask scenario. Furthermore, while the setup errors over the first two treatment weeks in both groups ranged between 1 and 2 mm, after the third week of treatment the errors in the no-mask group started to increase up to 4 mm. The immobilised group presented no changes. These errors could pose long-term risks to the heart. A shortcoming of the thermoplastic mask is the increase in the skin dose which resulted in grade 3 radiodermatitis, which however, resolved in 3 months post-irradiation. Conclusions: The use of breast masks considerably increases the reproducibility of patient positioning and limits the setup errors. This is an important outcome, since positioning errors are often a challenge when treating large-breasted patients, given the fact that after 15−20 dose fractions the inflammatory processes can change the shape and the volume of the breast. The error reductions allowed an accurate D95% dose delivery, while the heart was adequately protected. A drawback of this irradiation technique is the increase in the skin dose, a consequence that can be managed with suitable medical care. No conflict of interest. 215 POSTER Hypofractionated radiotherapy after conservative surgery in breast cancer patients: a phase I-II trial (MARA-1) M. Pieri1 , R. Frakulli1 , G. Macchia2 , A. Farioli3 , S. Cilla4 , F. Deodato2 , I. Ammendolia1 , G. Tolento1 , S. Cammelli1 , L. Di Lullo5 , M. Taffurelli3 , C. Zamagni6 , D. Smaniotto7 , F. Marazzi7 , V. Valentini7 , G. Ferrandina8 , A.G. Morganti1 . 1 S. Orsola-Malpighi Hospital-University of Bologna, Radiation Oncology Center- Department of Experimental- Diagnostic and Specialty Medicine- DIMES, Bologna, Italy; 2 Fondazione Giovanni Paolo II, Radiation Oncology Unit, Campobasso, Italy; 3 S. Orsola-Malpighi Hospital-University of Bologna, Department of Medical and Surgical Sciences DIMEC, Bologna, Italy; 4 Fondazione Giovanni Paolo II, Medical Physic Unit, Campobasso, Italy; 5 General Hospital, Department of Oncology, Isernia, Italy; 6 S. Orsola-Malpighi Hospital-University of Bologna, Medical Oncology Unit, Bologna, Italy; 7 Catholic University of the Sacred Heart, Radiation Oncology Department, Rome, Italy; 8 Catholic University of the Sacred Heart, Gynecologic Oncology Unit, Rome, Italy Background: The aim of this study is to evaluate late toxicity after hypofractionated radiotherapy (MARA-1 protocol) in early stage breast carcinoma as compared to a control group (CG) treated with standard fractionation. Material and Methods: MARA-1 is a prospective phase I-II study on accelerated IMRT. In the CG the whole breast received 50.4 Gy in 28 fractions (fx) with a sequential boost on the tumour bed of 10 Gy in 4 fx with 3D technique. In MARA-1 an IMRT technique was used and prescribed dose to the breast was 40 Gy in 16 fx with a concomitant boost of 4 Gy.