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P292 Partial-breast irradiation using multicatheter brachytherapy: a 6-year experience with 252 cases
14th St.Gallen International Breast Cancer Conference / The Breast 24S1 (2015) S87–S150
P290 Postmastectomy radiation in patients with negative lymph nodes after neoadjuvant chemotherapy M. He1 *, J. Li2 , X. Ni1 , S. Chen1 , Y. Jiang1 , X. Yu2 , Z. Shao1 , G. Di1 . 1 Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China, 2 Radiotherapy, Fudan University Shanghai Cancer Center, Shanghai, China Goals: The aim of this study is to evaluate the role of postmastectomy radiotherapy (PMRT) in clinical stage II and III breast cancer patients who achieved negative node status (pN0) after neoadjuvant chemotherapy (NAC). Methods: We retrospectively analyzed the outcomes of 143 patients with pN0 after NAC and mastectomy at Fudan University Shanghai Cancer Center. In total, 103 (72%) patients received PMRT, and 40 (28%) patients did not. Univariate and multivariate survival analyses were performed to evaluate the effect of PMRT on locoregional recurrence-free survival (LRRFS) and overall survival (OS) of the two groups. Results: There were no differences between the two groups with respect to age, nuclear grade, estrogen receptor (ER) status, HER2/neu receptor status, lymphovascular space invasion (LVSI) status or pathological tumor size. However, a significantly higher proportion of patients in the irradiated group (64%) had clinical lymph node involvement than in the nonirradiated group (45%). After a median follow-up time of 49 months, 10 locoregional recurrence events occurred. For the entire cohort of patients, use of radiation therapy improved the 5-year LRRFS rate (94.5% vs. 80.2%; P = 0.032) but not the 5-year OS rate (92.2% vs. 88.7%; P = 0.617). In the subset of patients who presented with clinically stage II disease, the 5-year LRRFS and 5-year OS did not differ significantly between the PMRT and no-PMRT group (96.3% vs. 91.3%; P = 0.190 and 96.2% vs. 91.3%; P = 0.199, respectively). For patients with stage III disease at diagnosis, a trend was seen toward better local regional control with PMRT (the 5-year LRRFS rate was 92.7% vs. 64.2%; P = 0.063), although the benefit from radiation with respect to OS was not significant (5-year OS rate was 88.1% vs. 85.2%; P = 0.657). On multivariate Cox regression analyses, the clinical tumor size (hazard ratio [HR], 3.27; 95% confidence interval [CI], 1.05–10.18; P = 0.041), pathologic breast tumor response (HR, 1.82; 95% CI, 1.11– 3.77; P = 0.046) and delivery of radiation therapy (HR, 1.27; 95% CI, 1.08–9.25; P = 0.047) were independent predictors of locoregional recurrence. Conclusion: For patients who achieved pN0 after NAC, PMRT seemed to provide a clinical benefit for breast cancer patients with stage III disease. Omission of PMRT in patients with stage II disease did not increase the risk of locoregional recurrence and death. Disclosure of Interest: No significant relationships. P291 Influence of radiation boost on local control in patients with ductal carcinoma in situ J. Gugic1 *, A. Gojkovic Horvat1 , C. Grasic Kuhar2 , I. Ratosa1 , T. Marinko1 , E. Majdic1 , S.M. Paulin Kosir1 , P. Korosec1 , V. Jugovec1 , E. Matos2 . 1 Department for Radiation Oncology, Institute of Oncology, Ljubljana, Slovenia, 2 Department for Medical Oncology, Institute of Oncology, Ljubljana, Slovenia Goals: Whole breast radiotherapy (WBRT) after breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS) halves the rate of local recurrence. However, the role of radiation boost to the tumor bed is still unclear. Methods: We analysed medical charts of all women diagnosed for DCIS and treated with BCS and WBRT +/− radiation boost to the tumor bed in Department of Radiation Oncology (Institute of Oncology Ljubljana) from January 1994 till December 2009.
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Results: 217 cases of DCIS, treated with BCS and WBRT were identified, 168 (77%) of them received radiation boost. The dose of the boost varied from 7.5 Gy (in three daily fractions) to 16 Gy (in eight daily fractions), but most women (133/160, 80%) received additional 10 Gy (in four or five daily fractions) with boost. After median follow up of 88 months (6–237 months), cumulative local recurrence rate for boost and non-boost group was 8.9% and 10.2% (p = 0.105), respectively. Conclusion: According to our results, administration of radiation boost to the tumor bed after BCS and WBRT for DCIS is not associated with lower recurrence rate. Disclosure of Interest: No significant relationships. P292 Partial-breast irradiation using multicatheter brachytherapy: a 6-year experience with 252 cases K. Sato1 *, Y. Mizuno1 , H. Fuchikami1 , N. Takeda1 , T. Shimo2 , J. Kubota2 , M. Kato2 . 1 Department of Breast Oncology, Tokyo-West Tokushukai Hospital, Tokyo, Japan, 2 Department of Radiation Oncology, Tokyo-West Tokushukai Hospital, Tokyo, Japan Goals: Breast-conserving therapy (BCT) consists of breast-conserving surgery followed by adjuvant breast irradiation, and wholebreast irradiation (WBI) is generally recommended as radiation therapy. The efficacy of partial-breast irradiation (PBI) has been investigated, and we had initiated a prospective observational study on brachytherapy PBI. Here, we report a 6-year experience of PBI to compare the results of WBI with PBI. Methods: We evaluated consecutive patients with T ≤3.0 cm N0–1 breast cancer who underwent BCT between October 2008 and December 2014. PBI was considered to be an alternative to WBI in patients meeting the eligibility criteria of age ≥40 years, unifocal disease, sentinel nodes negative for metastases, and no prior treatment. WBI patients received 50 Gy in fractions of 2 Gy to the entire breast. Patients with risk factors, such as positive margins and young age (<40 years old), generally received a subsequent 10-Gy boost using electrons to the tumor bed. Regional nodal irradiation was added in patients with ≥4 positive nodes. In PBI, applicators for the introduction of iridium wires were inserted following the simulation in preoperative planning by enhanced CT. The PTV included the surgical cavity delineated by ligating clips plus a 10–20-mm margin. The maximum dose to the skin and chest wall was kept to less than 75% of the prescription dose. Dose-volume histograms were provided by postoperative CT. PBI was performed in an accelerated fashion with a dose of 32 Gy in eight fractions over 5–6 days. Results: Of 374 patients who underwent BCT, 122 received WBI and 252 received PBI. The mean age of WBI patients (51.5 years) was significantly lower than that of PBI patients (55.8 years, p < 0.005). At a median follow-up of 3.0 years, the actual rate of ipsilateral breast tumor recurrence was 2.1% and 1.0% in WBI and PBI patients, respectively (p = 0.23). There was no significant difference in the 3-year probability of disease-free survival (96.3% and 97.8%; p = 0.50), and overall survival (97.7% and 99.5%; p = 0.29). Conclusion: Although this study was based on a small number of patients with a relatively short follow-up period, the feasibility of BCT with PBI using multicatheter brachytherapy to achieve acceptable clinical outcomes in Japanese patients was demonstrated. Disclosure of Interest: No significant relationships.
P290 Postmastectomy radiation in patients with negative lymph nodes after neoadjuvant chemotherapy M. He1 *, J. Li2 , X. Ni1 , S. Chen1 , Y. Jiang1 , X. Yu2 , Z. Shao1 , G. Di1 . 1 Breast Surgery, Fudan University Shanghai Cancer Center, Shanghai, China, 2 Radiotherapy, Fudan University Shanghai Cancer Center, Shanghai, China Goals: The aim of this study is to evaluate the role of postmastectomy radiotherapy (PMRT) in clinical stage II and III breast cancer patients who achieved negative node status (pN0) after neoadjuvant chemotherapy (NAC). Methods: We retrospectively analyzed the outcomes of 143 patients with pN0 after NAC and mastectomy at Fudan University Shanghai Cancer Center. In total, 103 (72%) patients received PMRT, and 40 (28%) patients did not. Univariate and multivariate survival analyses were performed to evaluate the effect of PMRT on locoregional recurrence-free survival (LRRFS) and overall survival (OS) of the two groups. Results: There were no differences between the two groups with respect to age, nuclear grade, estrogen receptor (ER) status, HER2/neu receptor status, lymphovascular space invasion (LVSI) status or pathological tumor size. However, a significantly higher proportion of patients in the irradiated group (64%) had clinical lymph node involvement than in the nonirradiated group (45%). After a median follow-up time of 49 months, 10 locoregional recurrence events occurred. For the entire cohort of patients, use of radiation therapy improved the 5-year LRRFS rate (94.5% vs. 80.2%; P = 0.032) but not the 5-year OS rate (92.2% vs. 88.7%; P = 0.617). In the subset of patients who presented with clinically stage II disease, the 5-year LRRFS and 5-year OS did not differ significantly between the PMRT and no-PMRT group (96.3% vs. 91.3%; P = 0.190 and 96.2% vs. 91.3%; P = 0.199, respectively). For patients with stage III disease at diagnosis, a trend was seen toward better local regional control with PMRT (the 5-year LRRFS rate was 92.7% vs. 64.2%; P = 0.063), although the benefit from radiation with respect to OS was not significant (5-year OS rate was 88.1% vs. 85.2%; P = 0.657). On multivariate Cox regression analyses, the clinical tumor size (hazard ratio [HR], 3.27; 95% confidence interval [CI], 1.05–10.18; P = 0.041), pathologic breast tumor response (HR, 1.82; 95% CI, 1.11– 3.77; P = 0.046) and delivery of radiation therapy (HR, 1.27; 95% CI, 1.08–9.25; P = 0.047) were independent predictors of locoregional recurrence. Conclusion: For patients who achieved pN0 after NAC, PMRT seemed to provide a clinical benefit for breast cancer patients with stage III disease. Omission of PMRT in patients with stage II disease did not increase the risk of locoregional recurrence and death. Disclosure of Interest: No significant relationships. P291 Influence of radiation boost on local control in patients with ductal carcinoma in situ J. Gugic1 *, A. Gojkovic Horvat1 , C. Grasic Kuhar2 , I. Ratosa1 , T. Marinko1 , E. Majdic1 , S.M. Paulin Kosir1 , P. Korosec1 , V. Jugovec1 , E. Matos2 . 1 Department for Radiation Oncology, Institute of Oncology, Ljubljana, Slovenia, 2 Department for Medical Oncology, Institute of Oncology, Ljubljana, Slovenia Goals: Whole breast radiotherapy (WBRT) after breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS) halves the rate of local recurrence. However, the role of radiation boost to the tumor bed is still unclear. Methods: We analysed medical charts of all women diagnosed for DCIS and treated with BCS and WBRT +/− radiation boost to the tumor bed in Department of Radiation Oncology (Institute of Oncology Ljubljana) from January 1994 till December 2009.
S127
Results: 217 cases of DCIS, treated with BCS and WBRT were identified, 168 (77%) of them received radiation boost. The dose of the boost varied from 7.5 Gy (in three daily fractions) to 16 Gy (in eight daily fractions), but most women (133/160, 80%) received additional 10 Gy (in four or five daily fractions) with boost. After median follow up of 88 months (6–237 months), cumulative local recurrence rate for boost and non-boost group was 8.9% and 10.2% (p = 0.105), respectively. Conclusion: According to our results, administration of radiation boost to the tumor bed after BCS and WBRT for DCIS is not associated with lower recurrence rate. Disclosure of Interest: No significant relationships. P292 Partial-breast irradiation using multicatheter brachytherapy: a 6-year experience with 252 cases K. Sato1 *, Y. Mizuno1 , H. Fuchikami1 , N. Takeda1 , T. Shimo2 , J. Kubota2 , M. Kato2 . 1 Department of Breast Oncology, Tokyo-West Tokushukai Hospital, Tokyo, Japan, 2 Department of Radiation Oncology, Tokyo-West Tokushukai Hospital, Tokyo, Japan Goals: Breast-conserving therapy (BCT) consists of breast-conserving surgery followed by adjuvant breast irradiation, and wholebreast irradiation (WBI) is generally recommended as radiation therapy. The efficacy of partial-breast irradiation (PBI) has been investigated, and we had initiated a prospective observational study on brachytherapy PBI. Here, we report a 6-year experience of PBI to compare the results of WBI with PBI. Methods: We evaluated consecutive patients with T ≤3.0 cm N0–1 breast cancer who underwent BCT between October 2008 and December 2014. PBI was considered to be an alternative to WBI in patients meeting the eligibility criteria of age ≥40 years, unifocal disease, sentinel nodes negative for metastases, and no prior treatment. WBI patients received 50 Gy in fractions of 2 Gy to the entire breast. Patients with risk factors, such as positive margins and young age (<40 years old), generally received a subsequent 10-Gy boost using electrons to the tumor bed. Regional nodal irradiation was added in patients with ≥4 positive nodes. In PBI, applicators for the introduction of iridium wires were inserted following the simulation in preoperative planning by enhanced CT. The PTV included the surgical cavity delineated by ligating clips plus a 10–20-mm margin. The maximum dose to the skin and chest wall was kept to less than 75% of the prescription dose. Dose-volume histograms were provided by postoperative CT. PBI was performed in an accelerated fashion with a dose of 32 Gy in eight fractions over 5–6 days. Results: Of 374 patients who underwent BCT, 122 received WBI and 252 received PBI. The mean age of WBI patients (51.5 years) was significantly lower than that of PBI patients (55.8 years, p < 0.005). At a median follow-up of 3.0 years, the actual rate of ipsilateral breast tumor recurrence was 2.1% and 1.0% in WBI and PBI patients, respectively (p = 0.23). There was no significant difference in the 3-year probability of disease-free survival (96.3% and 97.8%; p = 0.50), and overall survival (97.7% and 99.5%; p = 0.29). Conclusion: Although this study was based on a small number of patients with a relatively short follow-up period, the feasibility of BCT with PBI using multicatheter brachytherapy to achieve acceptable clinical outcomes in Japanese patients was demonstrated. Disclosure of Interest: No significant relationships.