- Email: [email protected]
PO-0636 WHOLE BREAST IRRADIATION USING THE RPM SYSTEM – THE BENEFIT OF A NEW TECHNIQUE
ESTRO 31
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more patients (28%) received adjuvant chemotherapy as compared to the EBRT-Group (24%). Secondary resections due to positive resection margins was necessary in 15.7% of patients in the EBRT-group but only in 9.7% in the IORT-group. Cutaneous side effects were significantly reduced (p: 0.0466) in the group of patients receiving IORT as compared to the group receiving the EBRT boost. Whereas mastitis (0.7% vs. 2%) and seroma needing at least one aspiration (7.8% vs. 9.2%) occurred slightly less frequent in the IORT-group, fat tissue necrosis was more common in the IORT-group (7.9% vs. 3.9%, p: 0.1706). We did not observe any difference in the frequency of hematoma (1.3%) and local infections (3.2% vs. 3.9%). Conclusions: Tumor bed boost using IORT in women with early breast cancer treated with breast conserving surgery and WBI was feasible. The incidence of acute side effects was scarce; most patients tolerated the IORT very well. Of importance, impaired healing was not more frequent after IORT. The study shows the potential advantage of IORT in reducing cutaneous side effects of adjuvant radiotherapy after BCS. PO-0634 PREDICTIVE FACTORS FOR LUNG INJURY AFTER INTENSITY-MODULATED RADIOTHERAPY IN WHOLE BREAST IRRADIATION H. Kim1, H.S. Bae1, M.Y. Lee1, K.H. Cheong1, K.J. Kim2, T.J. Han2, S.K. Kang2, S. Park2, T. Hwang3 1 Hallym University Sacred Heart Hospital, Department of Radiation Oncology, Anyang-City Kyungki-do, Korea Republic of 2 Hallym University Sacred Heart Hospital, Department of Radiation Oncology, Seoul, Korea Republic of 3 Hallym University Sacred Heart Hospital, Department of Radiation Oncology, Chuncheon-si Gangwon-do, Korea Republic of Purpose/Objective: To assess frequency, timings of occurrence, and predictors of radiologic lung damage after forward-planned intensitymodulated radiotherapy (FIMRT) for whole breast irradiation. Materials and Methods: We retrospectively reviewed medical records of 157 breast cancer patients and each of their serial chest computed tomography (CT) taken 4, 10, 16, and 22 months after completion of breast RT. FIMRT was administered to whole breast only (n=152), or whole breast and supraclavicular regions (n=5). Dosimetric parameters, such as mean lung dose (MLD) and lung volume receiving more than 10-50 Gy (V10-V50), and clinical parameters were analyzed in relation to radiologic lung damage. Results: In total, 104 patients (66.2%) developed radiologic lung change after whole breast FIMRT. Among the cases of radiographic lung change, 84.7% were detected at 4 months, and 15.3% at 10 months after completion of RT. More patients of 44 or younger were found to have lung damage at 10 months after RT than patients older than the age (16.3% vs. 5.8%, p=0.01). In univariate and multivariate analyses, age ≤ 44 and V40 ≤ 7.2% were significantpredictors for lower risk of radiologic lung injury. Univariate
Factors
Multivariate
OR (95% CI)
p-value OR (95% CI)
Age ≤ 44 vs. > 44
2.31 4.61)
(1.16-
0.01
3.10 6.73)
Use of No vs. Yes
taxane 0.69 1.40)
(0.34-
0.31
-
-
0.91
-
-
0.27
-
-
< 0.01
7.40 13.76)
Tamoxifen No vs. Yes
during
RT 1.04 2.35)
Interval between CTx and 0.65 RT 1.40) ≤ 21 days vs. > 21 days V40 ≤ 7.2 vs. > 7.2
(%) 7.6 11.21)
(0.46(0.30(2.34-
(1.33-
(2.92-
p-value 0.01
< 0.01
Abbreviations: OR = odds ratio; CI = confidence interval; RT = radiotherapy; CTx = chemotherapy; V40 = percent of lung volume receiving more than 40 Gy * By logistic regression analysis Conclusions: It is not uncommon to detect radiologic lung change in follow-up CT after whole breast FIMRT. More detected cases of lung change among younger patients are believed to have developed at later points after RT than those of older patients. Age and V40 were significant predictors for lung injury after whole breast IMRT.
PO-0635 DISCORDANCE IN ER/PR AND HER2 TESTING BETWEEN BIOPSY AND SURGICAL SPECIMENS IN BREAST CANCER G.K. Azad1, J.M. Singer1, S. Jader1 1 Princess Alexandra Hospital, Clinical Oncology, London, United Kingdom Purpose/Objective: Studies have shown substantial survival benefit from endocrine treatment in patients with ER positive tumours. This emphasizes the need for accurate and reliable testing. We present an audit of current practice at our institute. A prospective evaluation of all triple negative breast cancer patients was carried out over a period of 15 months. Patients had initially been tested for ER/PR and Her2 on the diagnostic core biopsy specimens using validated immunohistochemical (IHC) and fluorescent in situ hybridization (FISH) techniques. This was then repeated on the final surgical specimens to assess any discrepancies between the samples. Our institute is a participant of the United Kingdom national external quality assessment scheme for immunohistochemistry (UK NEQAS-ICC). Materials and Methods: Eligible patients were identified in the breast multidisciplinary team meetings and on the pathology electronic system. The audit period was between January 2008 and June 2009. ER and PR were repeated on the surgical specimens and reported using the 'quick score'. A score of 0-2 was considered negative and a score of ≥3 was considered positive. Her2 was retested in patients with invasive cancers using IHC and FISH. If the tumours were IHC 3+ they were considered Her2 positive. Samples with an equivocal IHC 2+ score were routinely tested using FISH. If tumours illustrated Her2 gene amplification, they were considered Her2 positive. Results: The ER/PR status changed from negative to positive in 33% of patients. 76% had invasive cancers and 23% of these had high risk node positive disease. No correlation was noted between ER/PR positivity and the grade or type of tumour. Only 1 patient was retested positive for Her2. Conclusions: There are several reasons which may contribute to the discordance in receptor testing. Tumour heterogeneity, variable specimen fixation and intra observer variability are amongst many causes. Evidently, this will have therapeutic implications. This was a prospective analysis, so none of our patient’s treatment was compromised. Tumours showing ER and PR negativity should be approached with great caution given the false negative rates highlighted by our audit. The sample size was small and larger studies are recommended, however the discordant results are a concern. We therefore propose that all patients who are ER/PR/Her2 negative should have their samples retested. PO-0636 WHOLE BREAST IRRADIATION USING THE RPM SYSTEM - THE BENEFIT OF A NEW TECHNIQUE M. Ben-David1, H. Granot1, M. Ben-Ayun1, D. Elezra1, R.M. Pfeffer1, Z. Symon1, V. Pyatigorskaya1 1 Sheba Medical Center, Radiation Oncology, Ramat-Gan, Israel Purpose/Objective: Adjuvant RT for breast cancer (BC) reduces localrecurrence and improves survival. Anterior position of the heart and baseline small lung-volume may compromise radiation homogeneity and adequate dose coverage of the breast or nodes. Deep inspiration is used to remove the heart from its anterior position and create higher lung-volume. The RPM (Real-Time Position) system is a respiratory-gating device (Varian). Using an infrared tracking-camera and a reflective marker, the system measures the patient's respiratory pattern and displays them as a waveform. In 80% inhale, the patient holds her breath and radiation is delivered for 20 seconds repeatedly to the end of that fraction. Materials and Methods: Between 5.2010-10.2011, 70 women with BC were treated using the RPM system at the Sheba Medical center. Median age was 48 years (range 30-65). All women had normalbreathing CT-simulation (NBCT) and controlled-breathing simulation with the RPM system. Treatment planning was optimized for both sets, considering breast or chest-wall coverage, ipsilateral lung V20<32%, and avoidance of the heart. 45 patients were treated to lymphatic areas, including IMN. However, for the purpose of this study, only breast and chest-wall were considered a target. Following IRB approval, data were collected and analyzed to compare best treatment-planning of NBCT and RPM. This cohort includes: 35 breasts, 25 reconstructions, 10 chest-walls). Results: All patients in this analysis had anterior heart position with compromised breast coverage for protecting the heart. For each
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ESTRO 31
patient, at least 3 cm of medial left breast area were not covered appropriately with regular 3D techniqie. Mean lung-volume was 1754cml (range 2980-1136) in the RPM group vs. 1104cml (2362-711) in the NBCT, p=0.013. Maximal heart dose (measured for 2cml) was 1.7 and 1.5Gy, respectively, p=0.28. There was no difference in V20, V10 and V5, maximal and mean lung-dose between the groups (p=NS). Mean contralateral lung-dose was similar. Maximal side effects: gradeI in 55 (78%) and -II in 7 (21%). Conclusions: For women with left-sided BC, using the RPM gating system enabled adequate breast coverage without excess lung or heart dose. Lung volume and heart dose were comparable between the techniques. This technique is now incorporated in the treatment options for women with left-sided BC who have anterior heart position. PO-0637 HOW FEASIBLE IS NODAL IRRADIATION WITH TANGENTIAL FIELDS IN BREAST CANCER? A COMPARATIVE TECHNIQUE STUDY J. Sanz1, E. Fernández-Velilla1, N. Rodríguez1, M. Prieto1, N. Anton1, P. Foro1, J. Flores1, O. Pera1, A. Reig1, M. Algara1 1 Hospital de la Esperança, Radiation Oncology, Barcelona, Spain Purpose/Objective: When 1 or 2 nodes are involved after selective node biopsy, the need of a lymphadenectomy is under discussion. So, several authors are extending the irradiation criteria in order to treat axillary levels I and II. A single modification in size of tangential fields has been proposed. Our objective is to evaluate if such a modification is enough or a more complex technical approach is required. Materials and Methods: In 10 breast cancer patients treated without lymphadenectomy, axillary levels I, II, III and supraclavicular were separately delineated. Planning was performed in 3 different ways: a) standard plan to breast with tangential fields using wedges and field segments; b) a second plan intended to reach axillary levels I and II by means of a single extension of tangential fields; and c) personalized planning directed to breast, axillary levels I, II, III and supraclavicular adding suplementary oblique fields. All plans were compared according to dosimetric parameters: Dmin, Dmax, Dmean fot PTV's and V95% and V50% for lung. Results: In 6 cases of 10 a single extension of tangential fields achieves an optimal irradiation of axillary levels I and II, but not level III and supraclavicular. Level II was not completely irradiated in 4 patients and in one of these neither level I nor II were fully treated. Doses at lung do not show a clear relationship with the irradiation technique, but in the most patients (6) the use of complex techniques shows an increase in irradiated lung volume. Results are shown in table 1. Plan
Level I Level II Min Max Mean Min Max Mean Standard 29.93 98.98 67.13 36.42 82.14 69.02 Extended 89.86 100.08 95.99 73.14 96.18 91.88 Personalized 92.56 104.57 99.80 95.54 105.37 99.76
Acceptable (%) I II II SC 0 0 0 0 90 60 0 0 100 100 100 100
Lung doses V95 V50 3,62 8,13 4,80 10,24 5,68 12,35
Conclusions: Extension of tangential fields to include axillary level I and II lymph nodes can not be considered as a standard technique. In many patients more complex techniques are required to irradiate those volumes.
POSTER: CLINICAL TRACK: CNS AND HAEMATOLOGY PO-0638 ROLE OF 11C-MET PET FOR RADIOTHERAPY PLANNING OF PRIMARY BRAIN TUMORS E. Lopci1, E. Clerici2, M. Catalano2, M. Rodari1, P. Navarria2, A. Chiti1, M. Scorsetti2 1 IRCCS Humanitas, Nuclear Medicine, Milano, Italy 2 IRCCS Humanitas, Radiotherapy and Radiosurgery, Milano, Italy Purpose/Objective: So far, very limited evidence concerns 11C-MET PET utilization for radiotherapy planning of primary brain tumors. Thus the aim of our study is that to investigate its role in this clinical setting. Materials and Methods: We enrolled 21pts (M:F=14:8; mean age 53.2yrs) affected by a histologically proven primary/relapsed gliomas, who were addressed to our Institution for radiotherapy. In all cases we performed dedicated MR, CT and 11C-MET PET before treatment. GTV was outlined on CT fused to MR (GTV-MRI/CT), on PET positive regions only (GTV-PET), and final volumes were calculated by using PET/CT/MRI co-registration. Optimal radiation dose was 60Gy. In 7pts
a contemporary chemo/radiotherapy regimen was administered. The mean observational period was 6months. In 14pts a postradiotherapy evaluation was performed; 3pts had progression/relapse within 7months; other 3pts died within 2months. A statistical analysis was performed on clinical and instrumental data Results: In19 out of 21pts a GTV-PET could be defined (mean 18,3cc), which in 14 cases (73,7%) determined a modification of the GTVMRI/CT (mean 58.79cc). Malignant lesions presented a SUVmax=3.37 (range 1.60-5.17) and a SUVratio (SUVmax/ SUVnormal)=2.43 (range 1.53-3.26). In 10/21 cases the tumor was multifocal, of which 3/10 bilateral. The overall volume change, according PET, was 139,58cc (mean 6,65cc), corresponding to 11,2% of total GTV. The ROCanalysis defined an optimal cut-off point for SUVmax<=2,7 (Sens.100%; Spec.90%), and SUVratio<=1,73 (Sens.100%; Spec.81,3%). Correlation versus pts outcome resulted inversely significant for SUVmax and SUVratio cut-offs (p=0,0115), but not for tumor grade, previous relapses, tumor multifocality and concomitant chemo/radiotherapy. Conclusions: Our data demonstrate that 11C-MET PET can have a significant impact on radiotherapy planning of pts presenting with primary/relapsed gliomas. Moreover, metabolic features appear better correlated to pts outcome, compared to other clinical parameters. PO-0639 EXCELLENT CLINICAL OUTCOME FOR PITUITARY ADENOMAS TREATED WITH STEREOTACTIC RADIOTHERAPY USING A NARROW MARGIN R. Tsang1, H. Pebdani1, N. Patil1, I. Edem1, A. Albert-Green2, M. van Prooijen1, M. Heydarian1, S. Ladak1, G. Zadeh3 1 Princess Margaret Hospital, Department of Radiation Oncology, Toronto, Canada 2 Princess Margaret Hospital, Department of Biostatistics, Toronto, Canada 3 Princess Margaret Hospital, Department of Neurosurgery, Toronto, Canada Purpose/Objective: To evaluate local control and toxicity for patients with pituitary adenomas treated with stereotactic radiotherapy (SRT). Materials and Methods: The SRT program to treat pituitary adenomas was initiated in 1997. The clinical outcome of all patients treated with SRT up to 2010 were retrospectively reviewed (n=116). Median age was 53 years (range: 19–78), with 50 males and 66 females. Thirty five patients (pts) had functional and 81 had nonfunctional tumors. Median follow up was 4.2 years (range: 0.1–14.6). Two pts received SRT as their primary treatment, 64 post-surgery for residual tumor, and 37 for radiological progression after surgery. Thirteen pts received SRT for persistently raised hormones despite surgery and medical management. Before SRT, hormone replacement therapy was observed in 36% (thyroid), 37% (cortisol), and 40% (testosterone) of pts. SRT dose was 50 Gy in 25 daily fractions (n=112, 4 pts had 45–48 Gy) using the GTC frame, and CT-MR fusion for planning (RadionicsTM [94%], PinnacleTM [6%]). Arcs (4-6) were used in 74% of cases, with the remainder multiple IMRT fields (4-6 fields). The GTV and sella contents were treated, with no expansion from CTV for PTV margin in 97% of cases. The prescription guideline was > 95% coverage of the CTV by a minimum dose of 47.5 Gy, and maximum dose < 52.5 Gy. Progression after SRT was defined as an increase in tumor size and/or worsening of hormone hypersecretion compared with pre-SRT assessment. Results: The 3- and 5-year progression free survival (PFS) rates were 95.7% and 92.6%. The 5-year PFS for functional and nonfunctional adenomas was 85% and 95% respectively (p=0.19). Six pts had local infield progression (3 nonfunctional and 3 functional tumors); among these, 3 also had metastatic spread (2 had Cushing’s disease and Nelson syndrome, 1 had nonfunctional tumor with high Mib-1 proliferation index). The clinical target volume (CTV) was associated with outcome, with lower 5-year PFS for larger target volumes treated (86.5% for treated volume > 13 cc [median], vs. 100% for volume ≤ 13 cc; p=0.023). Post SRT, hormone replacement was required in 50% of patients for thyroid, 46% for cortisol and 54% for testosterone. One patient had severe optic neuropathy (she had acromegaly and was also diabetic). To date there are no second cancers or strokes. Conclusions: This study suggests fractionated stereotactic radiotherapy is safe and effective for the treatment of pituitary adenomas. Achieving maximal surgical debulking whenever possible is important to obtain optimal tumor control with SRT. The results compare favorably with historical outcomes achieved with conventional 2 or 3-field techniques. The main early toxicity is newonset hypopituitarism as the most frequent complication of SRT.
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more patients (28%) received adjuvant chemotherapy as compared to the EBRT-Group (24%). Secondary resections due to positive resection margins was necessary in 15.7% of patients in the EBRT-group but only in 9.7% in the IORT-group. Cutaneous side effects were significantly reduced (p: 0.0466) in the group of patients receiving IORT as compared to the group receiving the EBRT boost. Whereas mastitis (0.7% vs. 2%) and seroma needing at least one aspiration (7.8% vs. 9.2%) occurred slightly less frequent in the IORT-group, fat tissue necrosis was more common in the IORT-group (7.9% vs. 3.9%, p: 0.1706). We did not observe any difference in the frequency of hematoma (1.3%) and local infections (3.2% vs. 3.9%). Conclusions: Tumor bed boost using IORT in women with early breast cancer treated with breast conserving surgery and WBI was feasible. The incidence of acute side effects was scarce; most patients tolerated the IORT very well. Of importance, impaired healing was not more frequent after IORT. The study shows the potential advantage of IORT in reducing cutaneous side effects of adjuvant radiotherapy after BCS. PO-0634 PREDICTIVE FACTORS FOR LUNG INJURY AFTER INTENSITY-MODULATED RADIOTHERAPY IN WHOLE BREAST IRRADIATION H. Kim1, H.S. Bae1, M.Y. Lee1, K.H. Cheong1, K.J. Kim2, T.J. Han2, S.K. Kang2, S. Park2, T. Hwang3 1 Hallym University Sacred Heart Hospital, Department of Radiation Oncology, Anyang-City Kyungki-do, Korea Republic of 2 Hallym University Sacred Heart Hospital, Department of Radiation Oncology, Seoul, Korea Republic of 3 Hallym University Sacred Heart Hospital, Department of Radiation Oncology, Chuncheon-si Gangwon-do, Korea Republic of Purpose/Objective: To assess frequency, timings of occurrence, and predictors of radiologic lung damage after forward-planned intensitymodulated radiotherapy (FIMRT) for whole breast irradiation. Materials and Methods: We retrospectively reviewed medical records of 157 breast cancer patients and each of their serial chest computed tomography (CT) taken 4, 10, 16, and 22 months after completion of breast RT. FIMRT was administered to whole breast only (n=152), or whole breast and supraclavicular regions (n=5). Dosimetric parameters, such as mean lung dose (MLD) and lung volume receiving more than 10-50 Gy (V10-V50), and clinical parameters were analyzed in relation to radiologic lung damage. Results: In total, 104 patients (66.2%) developed radiologic lung change after whole breast FIMRT. Among the cases of radiographic lung change, 84.7% were detected at 4 months, and 15.3% at 10 months after completion of RT. More patients of 44 or younger were found to have lung damage at 10 months after RT than patients older than the age (16.3% vs. 5.8%, p=0.01). In univariate and multivariate analyses, age ≤ 44 and V40 ≤ 7.2% were significantpredictors for lower risk of radiologic lung injury. Univariate
Factors
Multivariate
OR (95% CI)
p-value OR (95% CI)
Age ≤ 44 vs. > 44
2.31 4.61)
(1.16-
0.01
3.10 6.73)
Use of No vs. Yes
taxane 0.69 1.40)
(0.34-
0.31
-
-
0.91
-
-
0.27
-
-
< 0.01
7.40 13.76)
Tamoxifen No vs. Yes
during
RT 1.04 2.35)
Interval between CTx and 0.65 RT 1.40) ≤ 21 days vs. > 21 days V40 ≤ 7.2 vs. > 7.2
(%) 7.6 11.21)
(0.46(0.30(2.34-
(1.33-
(2.92-
p-value 0.01
< 0.01
Abbreviations: OR = odds ratio; CI = confidence interval; RT = radiotherapy; CTx = chemotherapy; V40 = percent of lung volume receiving more than 40 Gy * By logistic regression analysis Conclusions: It is not uncommon to detect radiologic lung change in follow-up CT after whole breast FIMRT. More detected cases of lung change among younger patients are believed to have developed at later points after RT than those of older patients. Age and V40 were significant predictors for lung injury after whole breast IMRT.
PO-0635 DISCORDANCE IN ER/PR AND HER2 TESTING BETWEEN BIOPSY AND SURGICAL SPECIMENS IN BREAST CANCER G.K. Azad1, J.M. Singer1, S. Jader1 1 Princess Alexandra Hospital, Clinical Oncology, London, United Kingdom Purpose/Objective: Studies have shown substantial survival benefit from endocrine treatment in patients with ER positive tumours. This emphasizes the need for accurate and reliable testing. We present an audit of current practice at our institute. A prospective evaluation of all triple negative breast cancer patients was carried out over a period of 15 months. Patients had initially been tested for ER/PR and Her2 on the diagnostic core biopsy specimens using validated immunohistochemical (IHC) and fluorescent in situ hybridization (FISH) techniques. This was then repeated on the final surgical specimens to assess any discrepancies between the samples. Our institute is a participant of the United Kingdom national external quality assessment scheme for immunohistochemistry (UK NEQAS-ICC). Materials and Methods: Eligible patients were identified in the breast multidisciplinary team meetings and on the pathology electronic system. The audit period was between January 2008 and June 2009. ER and PR were repeated on the surgical specimens and reported using the 'quick score'. A score of 0-2 was considered negative and a score of ≥3 was considered positive. Her2 was retested in patients with invasive cancers using IHC and FISH. If the tumours were IHC 3+ they were considered Her2 positive. Samples with an equivocal IHC 2+ score were routinely tested using FISH. If tumours illustrated Her2 gene amplification, they were considered Her2 positive. Results: The ER/PR status changed from negative to positive in 33% of patients. 76% had invasive cancers and 23% of these had high risk node positive disease. No correlation was noted between ER/PR positivity and the grade or type of tumour. Only 1 patient was retested positive for Her2. Conclusions: There are several reasons which may contribute to the discordance in receptor testing. Tumour heterogeneity, variable specimen fixation and intra observer variability are amongst many causes. Evidently, this will have therapeutic implications. This was a prospective analysis, so none of our patient’s treatment was compromised. Tumours showing ER and PR negativity should be approached with great caution given the false negative rates highlighted by our audit. The sample size was small and larger studies are recommended, however the discordant results are a concern. We therefore propose that all patients who are ER/PR/Her2 negative should have their samples retested. PO-0636 WHOLE BREAST IRRADIATION USING THE RPM SYSTEM - THE BENEFIT OF A NEW TECHNIQUE M. Ben-David1, H. Granot1, M. Ben-Ayun1, D. Elezra1, R.M. Pfeffer1, Z. Symon1, V. Pyatigorskaya1 1 Sheba Medical Center, Radiation Oncology, Ramat-Gan, Israel Purpose/Objective: Adjuvant RT for breast cancer (BC) reduces localrecurrence and improves survival. Anterior position of the heart and baseline small lung-volume may compromise radiation homogeneity and adequate dose coverage of the breast or nodes. Deep inspiration is used to remove the heart from its anterior position and create higher lung-volume. The RPM (Real-Time Position) system is a respiratory-gating device (Varian). Using an infrared tracking-camera and a reflective marker, the system measures the patient's respiratory pattern and displays them as a waveform. In 80% inhale, the patient holds her breath and radiation is delivered for 20 seconds repeatedly to the end of that fraction. Materials and Methods: Between 5.2010-10.2011, 70 women with BC were treated using the RPM system at the Sheba Medical center. Median age was 48 years (range 30-65). All women had normalbreathing CT-simulation (NBCT) and controlled-breathing simulation with the RPM system. Treatment planning was optimized for both sets, considering breast or chest-wall coverage, ipsilateral lung V20<32%, and avoidance of the heart. 45 patients were treated to lymphatic areas, including IMN. However, for the purpose of this study, only breast and chest-wall were considered a target. Following IRB approval, data were collected and analyzed to compare best treatment-planning of NBCT and RPM. This cohort includes: 35 breasts, 25 reconstructions, 10 chest-walls). Results: All patients in this analysis had anterior heart position with compromised breast coverage for protecting the heart. For each
S250
ESTRO 31
patient, at least 3 cm of medial left breast area were not covered appropriately with regular 3D techniqie. Mean lung-volume was 1754cml (range 2980-1136) in the RPM group vs. 1104cml (2362-711) in the NBCT, p=0.013. Maximal heart dose (measured for 2cml) was 1.7 and 1.5Gy, respectively, p=0.28. There was no difference in V20, V10 and V5, maximal and mean lung-dose between the groups (p=NS). Mean contralateral lung-dose was similar. Maximal side effects: gradeI in 55 (78%) and -II in 7 (21%). Conclusions: For women with left-sided BC, using the RPM gating system enabled adequate breast coverage without excess lung or heart dose. Lung volume and heart dose were comparable between the techniques. This technique is now incorporated in the treatment options for women with left-sided BC who have anterior heart position. PO-0637 HOW FEASIBLE IS NODAL IRRADIATION WITH TANGENTIAL FIELDS IN BREAST CANCER? A COMPARATIVE TECHNIQUE STUDY J. Sanz1, E. Fernández-Velilla1, N. Rodríguez1, M. Prieto1, N. Anton1, P. Foro1, J. Flores1, O. Pera1, A. Reig1, M. Algara1 1 Hospital de la Esperança, Radiation Oncology, Barcelona, Spain Purpose/Objective: When 1 or 2 nodes are involved after selective node biopsy, the need of a lymphadenectomy is under discussion. So, several authors are extending the irradiation criteria in order to treat axillary levels I and II. A single modification in size of tangential fields has been proposed. Our objective is to evaluate if such a modification is enough or a more complex technical approach is required. Materials and Methods: In 10 breast cancer patients treated without lymphadenectomy, axillary levels I, II, III and supraclavicular were separately delineated. Planning was performed in 3 different ways: a) standard plan to breast with tangential fields using wedges and field segments; b) a second plan intended to reach axillary levels I and II by means of a single extension of tangential fields; and c) personalized planning directed to breast, axillary levels I, II, III and supraclavicular adding suplementary oblique fields. All plans were compared according to dosimetric parameters: Dmin, Dmax, Dmean fot PTV's and V95% and V50% for lung. Results: In 6 cases of 10 a single extension of tangential fields achieves an optimal irradiation of axillary levels I and II, but not level III and supraclavicular. Level II was not completely irradiated in 4 patients and in one of these neither level I nor II were fully treated. Doses at lung do not show a clear relationship with the irradiation technique, but in the most patients (6) the use of complex techniques shows an increase in irradiated lung volume. Results are shown in table 1. Plan
Level I Level II Min Max Mean Min Max Mean Standard 29.93 98.98 67.13 36.42 82.14 69.02 Extended 89.86 100.08 95.99 73.14 96.18 91.88 Personalized 92.56 104.57 99.80 95.54 105.37 99.76
Acceptable (%) I II II SC 0 0 0 0 90 60 0 0 100 100 100 100
Lung doses V95 V50 3,62 8,13 4,80 10,24 5,68 12,35
Conclusions: Extension of tangential fields to include axillary level I and II lymph nodes can not be considered as a standard technique. In many patients more complex techniques are required to irradiate those volumes.
POSTER: CLINICAL TRACK: CNS AND HAEMATOLOGY PO-0638 ROLE OF 11C-MET PET FOR RADIOTHERAPY PLANNING OF PRIMARY BRAIN TUMORS E. Lopci1, E. Clerici2, M. Catalano2, M. Rodari1, P. Navarria2, A. Chiti1, M. Scorsetti2 1 IRCCS Humanitas, Nuclear Medicine, Milano, Italy 2 IRCCS Humanitas, Radiotherapy and Radiosurgery, Milano, Italy Purpose/Objective: So far, very limited evidence concerns 11C-MET PET utilization for radiotherapy planning of primary brain tumors. Thus the aim of our study is that to investigate its role in this clinical setting. Materials and Methods: We enrolled 21pts (M:F=14:8; mean age 53.2yrs) affected by a histologically proven primary/relapsed gliomas, who were addressed to our Institution for radiotherapy. In all cases we performed dedicated MR, CT and 11C-MET PET before treatment. GTV was outlined on CT fused to MR (GTV-MRI/CT), on PET positive regions only (GTV-PET), and final volumes were calculated by using PET/CT/MRI co-registration. Optimal radiation dose was 60Gy. In 7pts
a contemporary chemo/radiotherapy regimen was administered. The mean observational period was 6months. In 14pts a postradiotherapy evaluation was performed; 3pts had progression/relapse within 7months; other 3pts died within 2months. A statistical analysis was performed on clinical and instrumental data Results: In19 out of 21pts a GTV-PET could be defined (mean 18,3cc), which in 14 cases (73,7%) determined a modification of the GTVMRI/CT (mean 58.79cc). Malignant lesions presented a SUVmax=3.37 (range 1.60-5.17) and a SUVratio (SUVmax/ SUVnormal)=2.43 (range 1.53-3.26). In 10/21 cases the tumor was multifocal, of which 3/10 bilateral. The overall volume change, according PET, was 139,58cc (mean 6,65cc), corresponding to 11,2% of total GTV. The ROCanalysis defined an optimal cut-off point for SUVmax<=2,7 (Sens.100%; Spec.90%), and SUVratio<=1,73 (Sens.100%; Spec.81,3%). Correlation versus pts outcome resulted inversely significant for SUVmax and SUVratio cut-offs (p=0,0115), but not for tumor grade, previous relapses, tumor multifocality and concomitant chemo/radiotherapy. Conclusions: Our data demonstrate that 11C-MET PET can have a significant impact on radiotherapy planning of pts presenting with primary/relapsed gliomas. Moreover, metabolic features appear better correlated to pts outcome, compared to other clinical parameters. PO-0639 EXCELLENT CLINICAL OUTCOME FOR PITUITARY ADENOMAS TREATED WITH STEREOTACTIC RADIOTHERAPY USING A NARROW MARGIN R. Tsang1, H. Pebdani1, N. Patil1, I. Edem1, A. Albert-Green2, M. van Prooijen1, M. Heydarian1, S. Ladak1, G. Zadeh3 1 Princess Margaret Hospital, Department of Radiation Oncology, Toronto, Canada 2 Princess Margaret Hospital, Department of Biostatistics, Toronto, Canada 3 Princess Margaret Hospital, Department of Neurosurgery, Toronto, Canada Purpose/Objective: To evaluate local control and toxicity for patients with pituitary adenomas treated with stereotactic radiotherapy (SRT). Materials and Methods: The SRT program to treat pituitary adenomas was initiated in 1997. The clinical outcome of all patients treated with SRT up to 2010 were retrospectively reviewed (n=116). Median age was 53 years (range: 19–78), with 50 males and 66 females. Thirty five patients (pts) had functional and 81 had nonfunctional tumors. Median follow up was 4.2 years (range: 0.1–14.6). Two pts received SRT as their primary treatment, 64 post-surgery for residual tumor, and 37 for radiological progression after surgery. Thirteen pts received SRT for persistently raised hormones despite surgery and medical management. Before SRT, hormone replacement therapy was observed in 36% (thyroid), 37% (cortisol), and 40% (testosterone) of pts. SRT dose was 50 Gy in 25 daily fractions (n=112, 4 pts had 45–48 Gy) using the GTC frame, and CT-MR fusion for planning (RadionicsTM [94%], PinnacleTM [6%]). Arcs (4-6) were used in 74% of cases, with the remainder multiple IMRT fields (4-6 fields). The GTV and sella contents were treated, with no expansion from CTV for PTV margin in 97% of cases. The prescription guideline was > 95% coverage of the CTV by a minimum dose of 47.5 Gy, and maximum dose < 52.5 Gy. Progression after SRT was defined as an increase in tumor size and/or worsening of hormone hypersecretion compared with pre-SRT assessment. Results: The 3- and 5-year progression free survival (PFS) rates were 95.7% and 92.6%. The 5-year PFS for functional and nonfunctional adenomas was 85% and 95% respectively (p=0.19). Six pts had local infield progression (3 nonfunctional and 3 functional tumors); among these, 3 also had metastatic spread (2 had Cushing’s disease and Nelson syndrome, 1 had nonfunctional tumor with high Mib-1 proliferation index). The clinical target volume (CTV) was associated with outcome, with lower 5-year PFS for larger target volumes treated (86.5% for treated volume > 13 cc [median], vs. 100% for volume ≤ 13 cc; p=0.023). Post SRT, hormone replacement was required in 50% of patients for thyroid, 46% for cortisol and 54% for testosterone. One patient had severe optic neuropathy (she had acromegaly and was also diabetic). To date there are no second cancers or strokes. Conclusions: This study suggests fractionated stereotactic radiotherapy is safe and effective for the treatment of pituitary adenomas. Achieving maximal surgical debulking whenever possible is important to obtain optimal tumor control with SRT. The results compare favorably with historical outcomes achieved with conventional 2 or 3-field techniques. The main early toxicity is newonset hypopituitarism as the most frequent complication of SRT.