The Impact of Locoregional Treatment Modality on The Outcomes in Breast Cancer Patients Younger Than 40 Years of Age

Volume 96  Number 2S  Supplement 2016 Results: Of these 144 patients, 127 (88%) received PMRT. At a median follow-up of 69 months (rang: 10-111 months), 9 patients (6.3%) developed LRR and 18 patients (12.5%) developed distant metastasis. At surgery, 40 patients (27.8%) achieved pathologic complete response (pCR), while 91 patients (63.2%) achieved pN0. The 5-year LRRFS and DFS were 93.1% and 87.7%, respectively. PMRT significantly improved LRRFS and DFS rates, with a 5-year LRRFS of 95% versus 72.7% (P Z 0.012) and a 5-year DFS of 91% versus 61.6% (P Z 0.002). By univariate analysis, PMRT was the only significantly prognostic factor for LRRFS, while PMRT, pathologic T stage, pCR, molecular subtypes, and adjuvant chemotherapy significantly affected DFS. By multivariate analysis, PMRT was the only significant prognostic factors affecting LRRFS (hazard ratio [HR] 6.647, 95% confidence interval [CI] 1.45-30.39, P Z 0.015) and DFS (HR 3.457, 95% CI 1.3-9.21, P Z 0.013). For patients who achieved pCR, PMRT still significantly improved LRRFS and DFS (both P < 0.05). Conclusion: In patients with clinical stage II-III breast cancer and pN0 or pN1 after NAC, PMRT significantly improved LRRFS and DFS, even in patients achieved pCR. Author Disclosure: L. Cao: None. J. Chen: None. C. Xu: None.

2099 Is Individualized Dose Intensification Appropriate for Inflammatory Breast Cancer? D. Zaenger,1 B.M. Rabatic,1 N.A. Madden,1 J.A. Marascio,1 E.M. Marchan,1 A. Amoush,1 A. Al-Basheer,1 A. Green,1 F.M. Kong,2 B.G. Dasher,1 M. Aletan,1 J.G. Stewart,1 M.F. Ziauddin,1 M. Pishgou,1 J. Howington,1 D. Martin,1 S. Shaaban,1 K. Huang,1 C.L. Ferguson,1 and W.F. Mourad1; 1Augusta University, Augusta, GA, 2Department of Radiation Oncology, Augusta University, Augusta, GA Purpose/Objective(s): Inflammatory breast cancer (IBC) is an uncommon but aggressive variant. The current treatment paradigm is trimodality therapy with neoadjuvant chemotherapy, modified radical mastectomy (MRM), and post-mastectomy radiation therapy (PMRT). As systemic therapy decreases rates of distant metastatic disease and improves survival, the need for long-term locoregional control has become more essential. We hypothesize select subgroups benefit relatively less from conventional PMRT. We report the benefit of RT on oncologic outcomes of IBC by subgroup to identify patients that may be suitable for individualized treatment intensification. Materials/Methods: We searched the Surveillance, Epidemiology, and End Results (SEER) database for women with breast cancer. This cohort was narrowed to women with non-metastatic [Adjusted AJCC 6th M (1988+) M0] IBC [Adjusted AJCC 6th T (1988+) T4d] with MRM [(1998+) Breast] with or without external beam PMRT. To be included, patients were treated with either ipsilateral MRM with or without reconstruction with the specified race, age, hormone receptor [ER/PR Status], grade, nodal stage [Adjusted AJCC 6th N (1988+)], and radiation data. Our primary endpoint was actuarial 5-year cause-specific survival (CSS). Results: We identified a cohort of 4841 women treated between 1998 and 2007. The median age of diagnosis was 55. Black and white women comprised 13% and 81% of the cohort respectively. The actuarial 5-year CSS for the whole cohort was 56%. PMRT (n Z 2903) was utilized in 67% of patients while 33% received no RT. There was a significant benefit of PMRT compared to no RT with 5-year CSS of 59% and 50% respectively (Table 1). The benefit was not statistically significant (SS) in black women, but was in white women. N0, N1, N2, and N3 patients comprised 12%, 33%, 27%, and 28% of the cohort respectively. Node negative women had no CSS benefit at 5 years, but node positive women had a significant benefit of RT regardless of nodal stage. Low, intermediate, and high-grade tumors made up 2%, 27%, and 71% of the group. PMRT provided a significant CSS benefit in high-grade tumors with a trend in benefit in the intermediate group. Women over 70 years of age had a significantly lower CSS compared to women between 50-69, but not when compared to ages 20-49. A SS benefit of PMRT was seen regardless of age, but the greatest benefit was seen in the 20-49 group (59% v 47%).

Poster Viewing

E41

Conclusion: Our study suggests select subgroups have worse survival and may benefit relatively less from conventional PMRT. As such, select patients may benefit from individualized treatment intensification including dose escalated PMRT and/or additional adjuvant systemic therapy. Further prospective data, if feasible, is needed to confirm our findings and conclusions.

Abstract 2099; Table 1. Subgroup

PMRT

n[

Whole Cohort

Patients

n/a

Race

Black

All PMRT No PMRT No PMRT No

4841 2903 1439 360 202 2362 1143

White

5-year CSS (95% CI) 56% 59% 50% 46% 35% 61% 52%

(54.0-57.2) (57.3-61.3) (46.7-52.4) (39.4-51.3) (27.6-42.1) (59.0-63.5) (48.2-54.7)

Author Disclosure: D. Zaenger: None. B.M. Rabatic: None. N.A. Madden: None. J.A. Marascio: None. E.M. Marchan: None. A. Amoush: None. A. Al-Basheer: None. A. Green: None. F. Kong: None. B.G. Dasher: None. M. Aletan: None. J.G. Stewart: None. M.F. Ziauddin: None. M. Pishgou: None. J. Howington: None. D. Martin: None. S. Shaaban: None. K. Huang: None. C.L. Ferguson: None. W.F. Mourad: None.

2100 The Impact of Locoregional Treatment Modality on The Outcomes in Breast Cancer Patients Younger Than 40 Years of Age R.R.A. Boutrus,1 M. Hassan,1 A.A. Khalil,1 R. Abdel Maksoud,1 M. Bayomy,2 S. Naguib,3 A. Farahat,3 H. El Zawahry,4 A. Gaber,4 and M. El-Sebaie1; 1Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt, 2Biostatistics department, Zagazig University, Zagazig, Egypt, 3Surgical Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt, 4Medical Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt Purpose/Objective(s): To determine the impact of the loco-regional treatment modality, breast conserving therapy (BCT), modified radical mastectomy (M), mastectomy followed by radiation therapy (MRX), on the loco-regional recurrence (LRR) rates in breast cancer patients younger than 40 years. Materials/Methods: The data of 617 breast cancer patients younger than 40 years of age were retrospectively reviewed. Results: Median follow-up was 62 months, 213 patients were treated with BCT, 89 with M and 315 with MRX. The 10 year actuarial LRR rates according to treatment modality were: 8.9% for BCT, 11.2% for M and 5.7% for MRX (P Z 0.15). For stage I patients, LRR rates were 18% for BCT, 25% for M (P Z 0.11). Patients with stage II had LRR rates of 9.4% for BCT, 8% for M and 5.6% for MRX (P Z 0.59). Patients with stage III had LRR rates of 5.2% for BCT, 8.7% for MRM and 6.3% for MRX (P Z 0.81). On multivariate analysis, only age (HR Z 0.9, P Z 0.05) and M (HR Z 2.3, P Z 0.004) were predictors for increased LRR. In the hormone receptor negative cohort, LRR rates were 9% for BCT, 18.8% for M and 6.6% for MRX (P Z 0.03). Conclusion: For patients younger than 40 years of age, similar LRR outcomes were achieved using BCT, M, or MRX. Patients with hormone receptor negative tumors had better loco-regional control results when treated with mastectomy followed by adjuvant radiation therapy. Author Disclosure: R.R. Boutrus: None. M. Hassan: None. A. Khalil: None. R. Abdel Maksoud: None. M. Bayomy: None. S. Naguib: None. A. Farahat: None. H. El Zawahry: None. A. Gaber: None. M. ElSebaie: None.