Long-Term Outcome of Mucinous Pancreatic Cystic Lesions in Cancer Survivors or Patients With Extra-Pancreatic Malignancy

Abstract

Introduction: During surveillance or staging, cancer survivors or patients with extra-pancreatic malignancy may be found to have pancreatic cysts (PCs). Clinical guidelines support decisions based on cyst features without consideration of patient characteristics, including extra-pancreatic cancer-related factors. We evaluated long-term outcomes to assess the behavior of pancreatic cysts in patients with historical or concomitant malignancies. Methods: We retrospectively identified cancer survivors or patients with an extra-pancreatic malignancy who underwent EUS-FNA for suspected PCs from 1/1/2007 to 12/31/2012 and had follow-up details up to 9/1/2017. Comorbidities were classified by Charlson Comorbidity Index (CMI). Cyst high risk features were classified using the 2017 Fukuoka consensus guidelines. Descriptive statistics were used to summarize patient and procedure characteristics and non-parametric tests were used to calculate differences between medians. Results: A total of 113 patients were identified. Median age was 69 (IQR 61-75). Median CMI was 4 (IQR 3-5). By cancer history, 53 (46.9%) were cancer survivors. Most common pre-existing malignancy was breast cancer (N=21, 18.6%). Ten (8.9%) patients had a family history of pancreatic cancer. Cytology identified a mucinous lesion in 73 (64.6%). The median size of mucinous PCs was 21 mm (IQR 14-26) compared to 20 mm (IQR 14.75-25) in other PCs. (p=0.93) Mucinous PCLs were low risk in 55/73 (75.3%) patients and 18/73 (24.7%) had at least one high risk feature on EUS-FNA. In patients with mucinous lesions (n=73), the median follow up after diagnosis was 5 (IQR 4-7) years and 17 (23.3%) patients died of non-pancreatic related causes. Stable lesions were identified in 65 (89%). Six (8.2%) patients were found to have a lesion that increased in size. Ten (13.7%) patients underwent pancreatic resection. On pathology, 7 patients had IPMN with low grade dysplasia, 2 patients high grade dysplasia and one patient had a serous cystadenoma. Conclusion: Over a median follow up of 5 years, two patients (1.8%) were found to have high grade dysplasia and had surgical resection. Patients with extra-pancreatic malignancies are likely at the same risk for malignant degeneration relative to the general population and patients with low risk mucinous lesions could be safely followed. In high-risk patients, comorbidities should be factored in with cyst features for surgical decision-making.