Predicting patient survival after pancreaticoduodenectomy for malignancy: histopathological criteria based on perineural infiltration and lymphovascular invasion

Background: Accurate and simple prognostic criteria based on histopathology following pancreaticoduodenectomy would be helpful in assessing prognosis and considering and evaluating adjuvant therapy. This study analysed the histological parameters influencing outcome following pancreaticoduodenectomy for periampullary malignancy. Methods: A total of 110 pancreaticoduodenectomies were performed from 1998 to 2008. The median age of patients was 69 years (range 20-89 years). The median follow-up was 4.9 years. Of the procedures, 87% (96) were performed for malignancies and the remainder (n = 14) for benign aetiologies. Of the 96 malignancies, 60 were pancreatic adenocarcinoma and the rest were ampullary (14), cholangio (9), duodenal (9) carcinomas and others. Statistical analysis was performed using log-rank and Cox regression multivariate analyses. Results: Patients who underwent resection had 1-, 3- and 5-year survival rates of 70%, 46% and 41%, respectively. The 1-, 3- and 5-year survival rates for periampullary cancers other than pancreatic adenocarcinoma were 83%, 69% and 61%, respectively; those for pancreatic adenocarcinoma were 62%, 31% and 27%, respectively (P < 0.003). Poor tumour differentiation (P < 0.02), tumour size >3 cm (P < 0.04), margin <= 2 mm (P < 0.02), nodal involvement (P < 0.003), perineural infiltration (P < 0.0001) and lymphovascular invasion (P < 0.002) were associated with poorer prognosis. In a multivariate analysis, histologically identified perineural infiltration (P < 0.03) and lymphovascular invasion (P = 0.05) were significant factors influencing outcome. Five-year survival was 77% in patients negative for both factors and 15% in patients positive for both (P < 0.0001). In the pancreatic adenocarcinoma subgroup, patients who were negative for both factors had a 5-year survival of 71%, whereas those who were positive for both had a 5-year survival of 16% (P < 0.02). Conclusions: The presence of perineural infiltration and lymphovascular invasion on histopathology is highly significant in predicting 5-year outcomes after pancreaticoduodenectomy for periampullary and pancreatic malignancies.