Reappraisal of the clinical significance of tumor size in patients with pancreatic ductal carcinoma

Abstract

Objectives: Recent advances in diagnostic modalities have made it possible to detect small pancreatic ductal carcinoma and to increase the number of resected cases. However, the postoperative prognosis remains dismal.

Methods: Prognostic factors after pancreatectomy were retrospectively examined in 173 patients with small pancreatic ductal carcinomas (<or=40 mm), and the size threshold for defining small pancreatic cancer as an early and curable disease was investigated.

Results: A Cox proportional hazard survival analysis indicated that no lymph node involvement and curative resection were important independent predictors of long-term survival. The incidence of lymph node metastasis was significantly lower in patients with tumor diameters of 20 mm or less (P <or= 0.001). Tumors with diameters of 15 mm or less were statistically associated with lower extension of local tumor spreading (P = 0.001) and less advanced stage (P = 0.011). The 5-year survival rate and the median survival term in patients with tumor diameters of 15 mm or less were 75% and 62 months, respectively, which were significantly better than those in patients with tumor diameter between 21 and 40 mm (P = 0.02).

Conclusions: A small tumor size is not always a guarantor of localized disease. However, survival after pancreatectomy is significantly favorable when the tumor diameter is 15 mm or less. A tumor diameter of 15 mm is recommended as the cutoff size as small pancreatic cancer because tumors with diameters between 16 and 20 mm should be considered comparable with tumors with diameters between 21 and 40 mm.