A single institution experience of brain metastases and pancreatic adenocarcinoma: Patients' treatments and outcomes.

Abstract

e16737 Background: Brain metastases (BM) occur extremely rare in pancreatic adenocarcinoma (PDAC) and few data are available regarding those patients‘ care and outcomes. Methods: We performed a retrospective monocentric analysis of our database to identify patients (pts) diagnosed with PDAC and BM from July 1997 to December 2019. Results: 16 pts were eligible among 4900 pts diagnosed with PDAC in our institution (0.3%). Median age was 64 years (38.2-74.6) with 50% female. At diagnosis, 68.8% were metastatic including 27.3% with synchronous BM. About 1/3 pts had ≥ 2 lines of chemotherapy before BM. BM were discovered from neurological symptoms in 62% of cases and either with systematic brain CT/MRI or unknown in 19% for both. BM treatment was: surgery (25%), whole brain radiation therapy (RT) (43.8%), stereotactic RT (6.3%), radiosurgery (6.3%), best supportive care (BSC) or unknown (6.3%). At follow-up cutoff date (01/01/2020), most of pts were dead (75%), 2 were alive and 2 lost of follow-up. Mean interval between initial diagnosis and BM was 9.9 months (mths) (0-73). Median time to develop BM was different between pts with non-metastatic or metastatic disease at diagnosis: 16.3 mths (6.5-44) and 4.2 mths (0-36.1), respectively (HR = 0.43 (CI95: 0.14-1.09; p = 0.09)). Median overall survival (mOS) was 14.5 mths (1.6-80.2). Definitely, the non-metastatic group at diagnosis had better survival with mOS of 40.2 mths (24.7-80.2) compared to 6.5 mths (1.7-49.8) for the metastatic group (HR = 0.24 (CI95: 0,06-0,63; p = 0.012)). The median survival period after diagnosis of BM was only 3.4 mths (0.5-13.7). Pts who underwent BM surgery had better survival with a median survival from surgery of 5.5 months (4-13.7) compared to RT (0.8 mths (0.4-2)) or BSC (0.6 mths (0.5-5.9)). HR for surgery versus RT was 0.12 (CI95: 0.02-0.31; p = 0.003). After BM diagnosis, 43.8% of patients had a systemic chemotherapy, without objective response on BM. One interesting metastatic pt with BRCA1 mutation achieved a complete response (CR) after FOLFIRINOX. One BM occurred 2 years after diagnosis, was treated with surgery + RT but relapsed 4.5 mths later with new BM. Extra-cranial CR was persistent. This pt, still alive, had the longest survival period after diagnosis of BM (13.7 mths) and OS (49.8 months). Conclusions: To our knowledge, this is one of the largest cohort reported of BM in PDAC. Very few cases exist to guide therapy. Surgery appears to be the best treatment for BM, when feasible. Further investigations are still needed to understand the pathogenicity of BM in pancreatic cancer.