We highlight the need for a high index of suspicion, biopsies at staging laparoscopy and undertake a review of the literature regarding this uncommon condition.

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#3095 Introduction: Women with BRCA 1/2 mutations have a lifetime risk of approximately 45-87%1 for developing breast cancer and a 20-60% risk for ovarian cancer. The managment of these patients including prophylactic surgery is contorversial and presents difficult choices for patients. Uptake of prophylactic surgery in BRCA carriers in an Irish setting has not previously been investigated.
 Methods: St. James hospital is a tertiary referral hospital for BRCA counselling and testing. All information was gathered and analysed from the Cancer genetics department database in our institution which provides a counselling service for a number of hereditary diseases.
 Results: Deleterious BRCA 1/2 mutations have been identified in 57 families since testing began in 1992. There are a total of 109 women in this cohort.
 54% of these women were diagnosed with primary breast cancer. 23 (47.9%) women were symptomatic on presentation. Only 3 (6.3%) were detected during screening. Inital surgery and prophylactic surgery uptake in this group is displayed in table 1.
 31% (n=34) of our BRCA carrier cohort remain unaffected. Uptake of surgical prohylaxis is outlined in table 2. 17 women in this group opted for no form of prophylaxis. 88% of the women will require regular screening for breast cancer.
 Age at bilateral prophylactic masectomy was 30.5 years. Of the 39 women in both groups who elected for bilateral salpingo oophorectomy, only 28% (11) women were under the age of 40 years.
 
 CPM Contralateral Prophylactic Mastectomy
 TAH/BSO Total Abd Hysterectomy/Bilat Salpingo oopherectomy
 
 TAH/BSO Total Abd Hysterectomy/Bilat Salpingo oopherectomy
 BPM Bilateral Prophylactic Mastectomy
 Discussion: Prophylactic mastectomy offers a 95% risk reduction for breast cancer of 95%, despite this, a survival benefit has not been proven. Prophylactic oophorectomy before the age of 40 years has been associated with a reduction in breast cancer of 50% and up to 80% reduction in ovarian/peritoneal malignancy.There is also data to support that oophorectomy provides a survival benefit in BRCA carriers. The rates of uptake of prophylactic surgery in both the affected and unaffected groups in our cohort are lower than that of international standards2. The reasons for this are currently under investigation.
 References:
 1. Ford D et al. Genetic heterogeneity and penetrance analysis of the BRCA1/2 genes in breast cancer families. Am J Hum Genet 1998;62(3):676-89.
 2. Metcalfe KA, et al.International variation in rates of uptake of preventive options in BRCA1/2 mutation carriers. Int J Cancer. 2008 May 1;122(9):2017-22. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3095.

Background Pregnancy associated breast cancer (PABC) is defined as breast cancer (BC) diagnosed during the gestational period (GP) or in the first year postpartum (PP). Despite its infrequent occurrence, the incidence of PABC appears to be rising due to the increasing propensity for women to delay childbirth. We have established the first combined prospective and retrospective registry study of PABC in Ireland to examine specific clinicopathological characteristics, treatments and maternal outcomes. We present the retrospective findings to date. Methods We performed a retrospective multicentre observational study of patients (pts) with PABC treated in the eight Irish cancer centres from August 2001 to March 2017. Data extracted included information on pt demographics, tumour biology, staging, treatment administered and maternal outcomes. Standard biostatistical methods were used for analysis. Results 111 PABC patients were identified. Sixty pts (54%) were diagnosed during the GP and 51 (46%) within 1 year PP. Median age at diagnosis was 36 years (yrs). Table 1 illustrates baseline characteristics. Two thirds of pts were node positive and a similar proportion had grade 3 pathology. Seventy pts (63%) were estrogen receptor (ER) positive, 36 (32%) HER2 positive, 25 (22%) triple negative. Twenty-two pts (20%) were metastatic at presentation. Seven pts (6%) had a known BRCA 1/2 mutation. The median OS (overall survival) and DFS (disease free survival) for the entire cohort was 107.4 and 94.2 months respectively (resp). There was no survival difference between those diagnosed during the GP versus PP. 5 yr DFS and OS was 68.6% and 69.2% resp. This compares unfavourably to results reported by the National Cancer Registry of Ireland in a similar age-matched BC population between 2000-2012 where the 5 yr OS was 86.5%. Variables in our study associated with poorer outcomes included younger age, tumour size, node positivity and lack of estrogen expression. Baseline characteristics PABC patients (n=11) %(n)Diagnosed in GP (n=60) %(n)Diagnosed 1yr PP (n=51) %(n)p valueDemographic    Age at diagnosis3636(25-49)36(21-44)0.31Stage    I-II54(60)55(33)53(27)0.85III23(26)23(14)23(12)1IV20(22)18(11)22(11)0.81Unknown3(3)3(2)2(1)1Pathology    Grade 366(74)70(42)63(32)0.43Node positive66(73)68(41)63(32)0.55ER+/HER2-41(45)38(23)43(22)0.69ER+/HER2+23(25)28(17)16(8)0.17ER-/HER2+14(16)17(10)12(6)0.59Triple negative22(25)17(10)29(15)0.11Surgery    Breast conservation23(26)25(15)21(11)0.82Mastectomy56(63)57(34)59(30)0.84Adjuavnt/Neoadjuvant treatment    Chemotherapy73(81)77(46)69(35)0.39Anthracycline68(55)78(36)54(19)0.03Taxane89(72)93(43)83(29)0.16Anti HER2 agent21(23)18(11)24(12)0.63Endocrine therapy64(52)63(29)66(23)0.84Radiotherapy79(64)74(34)86(30)0.85Relapse in Stage I-III    Local relapse15(13)12(6)18(7)0.55Distant relapse24(21)22(11)25(10)0.80 Conclusions PABC patients may have a poorer outcome. Our study reported higher rates of triple negative and HER2 positive breast cancer which are associated with more aggressive biology. Prospective evaluation of clinicopathological features, pharmacokinetics of treatments selected and maternal and fetal outcomes is imperative in this distinct pt group. Citation Format: Prior L, Teo M, Greally M, Ward C, O'Leary C, Aslam R, Darwish W, Ahmed N, Watson G, Kelly D, Kiely L, Hassan A, Gleeson J, Featherstone H, Lim M, Murray H, Gallagher D, Westrup J, Hennessy B, Leonard G, Grogan L, Breathnach O, Horgan A, Coate L, O'Mahony D, Coate L, O'Reilly S, Gupta R, Keane M, Duffy K, O'Connor M, Kennedy J, McCaffrey J, Higgins M, Kelly C, Carney D, Gullo G, Crown J, Walshe J. Pregnancy associated breast cancer: Evaluating maternal outcomes. A multicentre study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-17.

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