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413 Poster Accurate chest wall irradiation with MLC-shaped photon fields and block-shaped electron fields
Posters
413
Wednesday/Thursday, 18-19 September 2002 S 137
Poster
Accurate chest wall irradiation with MLC-shaped photon f i e l d s and block-shaped electron fields M. Essers, J.C. Stroom, N. Post, E. Loeff, B.J.M. Heijmen Erasmus MC -Daniel den Hoed Cancer Center, Radiotherapy, Division of Clinical Physics, Rotterdam, The Netherlands Background: In our institution, the chest walt irradiation technique consists of a medial AP electron field matched to a cranial/lateral AP photon field. Using the MM50 Racetrack Microtron, both the photon and electron fields are shaped using MLC and are delivered with full computer set-up. The photon field is given in 3 segments to effectively broaden the penumbra. The dose delivery of this technique is sufficiently homogeneous (884 09%) and reproducible (4.6%, 1 SD) in the match line of photon and electron fields. Unfortunately, the MM50 is now dismantled, Purpose: To develop an equally homogeneous, reproducible, and fast chest wall irradiation technique on Siemens units, for which the electron field cannot be shaped with an MLC, and to check the dose delivery for this technique during patient treatment using in vivo dosimetry, Materials and Methods: Using film and diode measurements, the homogeneity in dose delivery in the match line region of a technique with MLCshaped 6-MV photon fields, matched to 10 or 12-MeV electron fields, shaped with an inlay in the standard electron beam applicator, was optimized. The number of photon field segments and their positions with respect to the electron field were determined. Using dedicated linear diode arrays, the dose delivery in the cranial-caudal and medial-lateral match line of photon and electron fields was determined for 6 patients during 10 fractions each. Results: The new treatment technique consists of 4 MLC-shaped photon field segments matched to 1 block-shaped electron field. The SSD for all fields is 110 cm. Three photon field segments in medial-lateral direction, having a 6-mm gap, 1-mm overlap, and 8-mm overlap with the electron field, are combined with 2 segments in cranial-caudal direction, having a 5mm gap and 5-mm overlap with the electron field. This technique results in a dose homogeneity of 88-109% in medial-lateral direction, and 90-114% in cranial-caudal direction. The spread in dose delivery during patient treatment is 5.0% (1 SD). Conclusion: For chest wall irradiation, a technique consisting of MLCshaped AP photon beam segments, matched to an AP electron field produced with an individually shaped inlay in the standard electron beam applicator, results in a homogeneous and reproducible dose delivery during patient treatment. The workload and treatment time are kept to a minimum, while the accuracy in relative field positioning is maximised. 414
Poster
Radiotherapy for Ioco-regional recurrence of breast cancer following mastectomy : results of univariate and multivariate analysis H. Gomi. T. Abe, Y. Hoshikawa, K. Takizawa, Y. Nakajima St. Madanna University, Radiology, Kawasaki, Japan Purpose: The outcome of patients with Ioco-regional recurrence of breast cancer following mastectomy is generally poor. But the limited cases are thought to have favorable prognoses. This study was performed to evaluate prognostic factors for their influence on survival. Methods and Materials: Between 1989 and 2000, 42 patients with Iocoregional recurrence of breast cancer following mastectomy without evidence of distant metastases were treated with a course of aggressive radiation therapy at the Department of Radiology, St. Marianna University Hospital. Sites of involvement at the time of Ioco-regional recurrence included the chest wall in 30 patients and regional lymph nodes in 12 patients. Age at the time of recurrence ranged from 24 to 82 years with a median of 53 years. Median follow up for the entire group was 67months with a range of 24 to 107 months, Results: The 5-year and 7-year overall survival for the entire group were 45% and 22%, respectively. Multivariate analysis demonstrated that disease-free interval from mastectomy to recurrence correlated most strongly with overall survival (p=0.001). The 5-year overall survival was 62% for patients with a disease-free interval of at least 2 years, compared to 32% for those with a disease-free interval of less than 2 years (p<0.005). The type of chest wall recurrence was also found to be a significant prognostic factor for overall survival for patients with a chest wall recurrence (p=0.05). The 5-year overall survival was 67% for patients with an isolated type chest wall recurrence, compared to 12% for patients with a diffuse type chest wall recurrence (p<0.05). In the subsets of patients with an isolated type chest wall recurrence and a disease-free interval of at least 2 years, the 5-year overall survival was 76%.
Conclusion: These results suggest that subgroups of patients with favorable prognostic factors can survive for long periods of time. The role of radiotherapy for Ioco-regional recurrence of breast cancer following masteotomy is not always palliative. 415
Poster
Conservative treatment of breast cancer: long-term results (20-year) boosting the tumor bed by brachytherapy in stage III breast cancer B., Guix, I. Henriquez, J. Tello, A. Martinez, J. Lejarcegui, G. Zanon, H. Palombo Fundacio Imor, Institut Medic d'Onco-radioterapia, Radiation Oncology, Barcelona, Spain Background: We present the long term experience in a prospective group of patients with stage I-II breast cancer treated by conservative surgery, external beam radiotherapy (EBR) and brachtytherapy boost by LDR or HDR implants. Results were analyzed in terms of: local control, disease control, cosmesis and early and late side effects and to compare them with the results obtained without boost to the tumor bed. Methods: 992 consecutive patients (pts) with stage I (524 pts) or II (468 pts) breast carcinoma were treated between 12/1981 and 03/2001, with conservative surgery and EBR (50.4 Gy/28 fx/5.5w) followed by LDR (637 pts) or HDR (355 pts) implants. Both groups were comparable in patient's and tumor characteristics. Brachytherapy was given 2-3 w after EBR. LDR doses were 20 Gy for tumors without intraductal carcinoma and margins
Poster
Adjuvant radiotherapy after mastectomy for pTl-pT2 node negative (pNO) breast cancer: is it worth the e f f o r t ? M. Voordeckers, ,I. Van de Steene, V. Vinh-Hung, G. Storme A.Z. VUB, Radiotherapy, Brussels, Belgium Background and purpose:: Postoperative radiotherapy (RT) for pT1-2 pN0 breast cancer was the standard treatment in our department. Since only littie data on the importance of RT in this subgroup are known, we reviewed the clinical records with regard to overall survival. Material and methods: From 1984 until 2000, 1785 patient files-out of 2605were submitted to retrospective analyses. 732 of them had a pT1 (n = 428) or pT2 (n = 304) pN0 lesion. They were treated with breast conservative surgery (BCS) (279 pT1 and 65 pT2 pts resp.) or mastectomy (ME) (149 pT1 and 239 pT2 pts resp.), and axillary clearance (all pts) followed by postoperative RT of the breast or the thoracic wall. The outcome of these patients was analyzed and compared with the SEERData 1988-1997 (NCI - Surveillance, Epidemiology and End Results, release 2000). Results: The mean age of the patient group was 58.6 years (range 25 - 85 y). The actuarial overall survival (OS) at 5-and 10 years after BCS and RT was 93.4% and 84.3% for pT1 and 87.3% and 71.8% for pT2 tumors. These results are comparable with the SEER (resp. 93.9%, 84.9% for pT1, and 87.3%, 76.7% for pT2 after BCS and RT). For our ME patients the OS was resp. 92.3% and 79.5% (pT1 at resp. 5and 10 y), and 83.7% and 72% (pT2 at 5-and 10 y). In the SEER-data the
413
Wednesday/Thursday, 18-19 September 2002 S 137
Poster
Accurate chest wall irradiation with MLC-shaped photon f i e l d s and block-shaped electron fields M. Essers, J.C. Stroom, N. Post, E. Loeff, B.J.M. Heijmen Erasmus MC -Daniel den Hoed Cancer Center, Radiotherapy, Division of Clinical Physics, Rotterdam, The Netherlands Background: In our institution, the chest walt irradiation technique consists of a medial AP electron field matched to a cranial/lateral AP photon field. Using the MM50 Racetrack Microtron, both the photon and electron fields are shaped using MLC and are delivered with full computer set-up. The photon field is given in 3 segments to effectively broaden the penumbra. The dose delivery of this technique is sufficiently homogeneous (884 09%) and reproducible (4.6%, 1 SD) in the match line of photon and electron fields. Unfortunately, the MM50 is now dismantled, Purpose: To develop an equally homogeneous, reproducible, and fast chest wall irradiation technique on Siemens units, for which the electron field cannot be shaped with an MLC, and to check the dose delivery for this technique during patient treatment using in vivo dosimetry, Materials and Methods: Using film and diode measurements, the homogeneity in dose delivery in the match line region of a technique with MLCshaped 6-MV photon fields, matched to 10 or 12-MeV electron fields, shaped with an inlay in the standard electron beam applicator, was optimized. The number of photon field segments and their positions with respect to the electron field were determined. Using dedicated linear diode arrays, the dose delivery in the cranial-caudal and medial-lateral match line of photon and electron fields was determined for 6 patients during 10 fractions each. Results: The new treatment technique consists of 4 MLC-shaped photon field segments matched to 1 block-shaped electron field. The SSD for all fields is 110 cm. Three photon field segments in medial-lateral direction, having a 6-mm gap, 1-mm overlap, and 8-mm overlap with the electron field, are combined with 2 segments in cranial-caudal direction, having a 5mm gap and 5-mm overlap with the electron field. This technique results in a dose homogeneity of 88-109% in medial-lateral direction, and 90-114% in cranial-caudal direction. The spread in dose delivery during patient treatment is 5.0% (1 SD). Conclusion: For chest wall irradiation, a technique consisting of MLCshaped AP photon beam segments, matched to an AP electron field produced with an individually shaped inlay in the standard electron beam applicator, results in a homogeneous and reproducible dose delivery during patient treatment. The workload and treatment time are kept to a minimum, while the accuracy in relative field positioning is maximised. 414
Poster
Radiotherapy for Ioco-regional recurrence of breast cancer following mastectomy : results of univariate and multivariate analysis H. Gomi. T. Abe, Y. Hoshikawa, K. Takizawa, Y. Nakajima St. Madanna University, Radiology, Kawasaki, Japan Purpose: The outcome of patients with Ioco-regional recurrence of breast cancer following mastectomy is generally poor. But the limited cases are thought to have favorable prognoses. This study was performed to evaluate prognostic factors for their influence on survival. Methods and Materials: Between 1989 and 2000, 42 patients with Iocoregional recurrence of breast cancer following mastectomy without evidence of distant metastases were treated with a course of aggressive radiation therapy at the Department of Radiology, St. Marianna University Hospital. Sites of involvement at the time of Ioco-regional recurrence included the chest wall in 30 patients and regional lymph nodes in 12 patients. Age at the time of recurrence ranged from 24 to 82 years with a median of 53 years. Median follow up for the entire group was 67months with a range of 24 to 107 months, Results: The 5-year and 7-year overall survival for the entire group were 45% and 22%, respectively. Multivariate analysis demonstrated that disease-free interval from mastectomy to recurrence correlated most strongly with overall survival (p=0.001). The 5-year overall survival was 62% for patients with a disease-free interval of at least 2 years, compared to 32% for those with a disease-free interval of less than 2 years (p<0.005). The type of chest wall recurrence was also found to be a significant prognostic factor for overall survival for patients with a chest wall recurrence (p=0.05). The 5-year overall survival was 67% for patients with an isolated type chest wall recurrence, compared to 12% for patients with a diffuse type chest wall recurrence (p<0.05). In the subsets of patients with an isolated type chest wall recurrence and a disease-free interval of at least 2 years, the 5-year overall survival was 76%.
Conclusion: These results suggest that subgroups of patients with favorable prognostic factors can survive for long periods of time. The role of radiotherapy for Ioco-regional recurrence of breast cancer following masteotomy is not always palliative. 415
Poster
Conservative treatment of breast cancer: long-term results (20-year) boosting the tumor bed by brachytherapy in stage III breast cancer B., Guix, I. Henriquez, J. Tello, A. Martinez, J. Lejarcegui, G. Zanon, H. Palombo Fundacio Imor, Institut Medic d'Onco-radioterapia, Radiation Oncology, Barcelona, Spain Background: We present the long term experience in a prospective group of patients with stage I-II breast cancer treated by conservative surgery, external beam radiotherapy (EBR) and brachtytherapy boost by LDR or HDR implants. Results were analyzed in terms of: local control, disease control, cosmesis and early and late side effects and to compare them with the results obtained without boost to the tumor bed. Methods: 992 consecutive patients (pts) with stage I (524 pts) or II (468 pts) breast carcinoma were treated between 12/1981 and 03/2001, with conservative surgery and EBR (50.4 Gy/28 fx/5.5w) followed by LDR (637 pts) or HDR (355 pts) implants. Both groups were comparable in patient's and tumor characteristics. Brachytherapy was given 2-3 w after EBR. LDR doses were 20 Gy for tumors without intraductal carcinoma and margins
Poster
Adjuvant radiotherapy after mastectomy for pTl-pT2 node negative (pNO) breast cancer: is it worth the e f f o r t ? M. Voordeckers, ,I. Van de Steene, V. Vinh-Hung, G. Storme A.Z. VUB, Radiotherapy, Brussels, Belgium Background and purpose:: Postoperative radiotherapy (RT) for pT1-2 pN0 breast cancer was the standard treatment in our department. Since only littie data on the importance of RT in this subgroup are known, we reviewed the clinical records with regard to overall survival. Material and methods: From 1984 until 2000, 1785 patient files-out of 2605were submitted to retrospective analyses. 732 of them had a pT1 (n = 428) or pT2 (n = 304) pN0 lesion. They were treated with breast conservative surgery (BCS) (279 pT1 and 65 pT2 pts resp.) or mastectomy (ME) (149 pT1 and 239 pT2 pts resp.), and axillary clearance (all pts) followed by postoperative RT of the breast or the thoracic wall. The outcome of these patients was analyzed and compared with the SEERData 1988-1997 (NCI - Surveillance, Epidemiology and End Results, release 2000). Results: The mean age of the patient group was 58.6 years (range 25 - 85 y). The actuarial overall survival (OS) at 5-and 10 years after BCS and RT was 93.4% and 84.3% for pT1 and 87.3% and 71.8% for pT2 tumors. These results are comparable with the SEER (resp. 93.9%, 84.9% for pT1, and 87.3%, 76.7% for pT2 after BCS and RT). For our ME patients the OS was resp. 92.3% and 79.5% (pT1 at resp. 5and 10 y), and 83.7% and 72% (pT2 at 5-and 10 y). In the SEER-data the