K. Mahendraraj1,2, J. Chabot2, M. Kluger2 1Saint Barnabas Medical Center,Department Of Surgery,Livingston, NJ, USA 2Columbia University College Of Physicians And Surgeons,Department Of Surgery,New York, NY, USA
Introduction:
Signet ring carcinoma of the pancreas (SRC) is a rare and aggressive mucin-producing exocrine pancreatic malignancy, comprising less than 1% of all pancreatic carcinoma. Clinical information relating to this disease is scant and derived primarily from several case reports. This study sexamines a large cohort of SRC in order to determine characteristic demographic and pathologic factors of SRC and compare them to the relatively more common pancreatic ductal adenocarcinoma (PDAC).
Methods:
Demographic and clinical data on 103,341 patients with pancreatic cancer was abstracted from the SEER database (1973-2010). 621 SRC and 102,720 PDAC patients formed the study groups. Data was analyzed using standard statistical methodoloy.
Results:
SRC comprised 0.6% of all pancreatic cancers identified. The mean age of the SRC and PDAC patients were similar (67.5±12 vs. 68.2±11.7). Both SRC and PDAC were more common in males (54.1% and 51.1% (PDAC), p=0.08), Caucasians (74.1% and 74.7% (PDAC), p=0.005) and in the head of the pancreas (48.8% and 50.9% (PDAC), p<0.005). SRC was more often poorly differentiated (81.3%), undifferentiated (7.1%), had more lymph node positivity (50.4%), and presented more often with metastatic disease (68.1%), p<0.001. The majority of SRC and PDAC patients were not treated at all (70% and 71.8% (PDAC)), and surgery was used more often than radiotherapy to treat SRC (14% vs. 10.4%). Mean survival for SRC was significantly lower than PDAC (0.47±0.1 years vs. 0.85±0 years; p<0.05). Furthermore, mean survival for SRC patients treated with primary surgical therapy or combination surgery and radiotherapy were also significantly inferior to PDAC despite receiving equivalent therapy, p<0.001. However, SRC patients benefited more from primary radiotherapy than PDAC patients (1.05±0.17 vs. 0.93±0.02 years, p<0.001). Multivariate analysis identified tumor size over 2 cm (OR 1.4), metastatic disease (OR 1.8), and poor or undifferentiated grade (OR 2.3) as risk factors for mortality for SRC, p<0.005. A survival advantage for SRC was seen in patients treated with surgical resection (OR 0.36), p<0.005
Conclusion:
Pancreatic SRC is a rare malignancy that presents with larger tumor size, a more undifferentiated histology, greater lymph node positivity, and a higher rate of metastatic disease than PDAC, features which were associated with increased mortality. Despite these aggressive features, surgical resection with or without radiotherapy was associated with the longest survival for SRC. Surgical resection and radiotherapy should be considered in all SRC patients with resectable disease.
