Abstract P6-09-37: Ductal carcinoma in situ: Patient outcomes and association with hormone receptors
Authors: Chaudhary LN , Jawa Z , Hanif A , Szabo A , Chitambar CR 
Published: May 2019

Abstract
Background
Local recurrence is a major concern in patients (pts) diagnosed with ductal carcinoma in situ (DCIS). Therefore, the need to identify pts at risk for DCIS recurrence is a significant priority. In invasive breast cancers, ER+/PR- subtype is considered a more aggressive tumor phenotype with poorer prognosis as compared to ER+/PR+ tumors. It is unclear whether this molecular subtype holds the same significance in pts with DCIS.
Methods
We designed an analysis to determine if a significant difference exists in the recurrence rates in pts with ER+/PR- DCIS when compared to ER+/PR+ tumors. Six hundred and ninety three pts diagnosed and treated for DCIS at Froedtert & MCW Clinical Cancer Center from Feb 2002-March 2015 were included in our study. Recurrence was defined as either non-invasive or invasive ipsilateral, contralateral or distant disease. Probabilities of recurrences were calculated using Kaplan-Meier estimator. Cox proportional hazards model was used to evaluate the effect of prognostic factors on DCIS recurrence.
Results
Median follow up was 5.2 years. Five year recurrence free survival (RFS) was 91% (95% CI 88.2-93.3) while estimated 7 year RFS was 86% (95% CI 81.9-89.2). Patient characteristics are shown in table below. Seventy five pts were found to have a recurrence during their follow-up. Most of the grade 1 tumors were ER+/PR+ whereas almost all of the ER-/PR- subtype were high grade tumors. ER+/PR- tumors were mainly intermediate and high grade (p &lt;0.0001). Pts with ER-/PR- tumors had a significantly higher risk of recurrence (HR 3.7, 95% CI 1.9-7.2, p=0.0001) and those with ER+/PR- tumor subtype did not have a statistically significant difference in risk of recurrence when compared to ER+/PR+ tumors (HR 1.75, 95% CI 0.92-3.32, p=0.085). Pts who did not receive endocrine therapy for their ER+ DCIS had a significantly higher risk of recurrence as compared to those who received endocrine therapy (HR 2.2, 95% CI 1.23-3.92, p=0.0073). When compared to pts undergoing lumpectomy and radiation, pts undergoing lumpectomy alone had a significantly higher risk of recurrence (HR 2.5, 95% CI 1.32-4.93, p=0.005) whereas those who underwent mastectomy had a significantly lower risk of recurrence (HR 0.34, 95% CI 0.15-0.8, p=0.014).
Patient characteristicsCharacteristicsN (%)Total no. of patients693Median age53 (21-91)Median BMI27 (17-65)Post-menopausal480 (69)OCP use301 (43)HRT use201 (29)Tumor characteristics Median size0.8cm (0.2-6.5)Histology Solid349 (52)Cribriform290 (43)Papillary35 (5)Comedo necrosis423 (61)ER/PR status ER+/PR+482 (71.2)ER+/PR-77 (11.4)ER-/PR-118 (17.4)Tumor grade Low125 (18)Intermediate305 (45)High250 (37)Treatment Lumpectomy517 (75)Mastectomy169 (25)Radiation450 (66)Endocrine therapy286 (42)Patients with recurrence75 (11)Type of recurrence In-situ44 (6)Invasive31 (5)BMI=body mass index, OCP=oral contraceptive pills, HRT=hormone replacement therapy
Conclusion
ER+/PR- subtype was not a significant predictor of recurrence in DCIS patients. This finding is in contrast to the risk of recurrence and tumor aggressiveness seen in invasive breast cancers. Mastectomy and post lumpectomy radiation were associated with improved outcomes as was adjuvant endocrine therapy.
Citation Format: Chaudhary LN, Jawa Z, Hanif A, Szabo A, Chitambar CR. Ductal carcinoma in situ: Patient outcomes and association with hormone receptors [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-37.