Pancreatic carcinoma: < or = 2 cm versus > 2 cm in size

Despite recent progress in diagnosis and therapy, the clinical course of patients with pancreatic carcinoma remains dismal. There have been several approaches to improve the clinical course of patients with pancreatic carcinoma, namely: (i) detection of small pancreatic carcinoma; (ii) radical resection with retroperitoneal clearance and portal vein resection; (iii) multidisciplinary therapy including chemoradiation; and so forth.

In this series, eight Japanese patients with small pancreatic carcinoma measuring less than 2 cm in diameter (including two with non-invasive carcinoma and one with minimally invasive carcinoma) and 53 with larger pancreatic carcinoma were reviewed to find the diagnostic and therapeutic clues to improve the clinical course of patients with pancreatic carcinoma.

Lymphatic (ly) and perineural (pn) permeation was significantly more frequent and extensive in the 53 patients with large pancreatic carcinoma than in the eight with small pancreatic carcinoma (ly 0/1/2/3:3/24/18/8 versus 5/2/1/0, P = 0.0284; pn 011/2/3:4/29/14/6 versus 3/2/3/0, P = 0.0491). The surgical margin was affected by malignant cells in 18 (34%) of the 53 patients with large carcinoma but none (0%) of the eight with small carcinoma (P = 0.0004). The comprehensive stage was significantly earlier in the eight with small carcinoma than in the 53 with large carcinoma (comprehensive stage I/II/II/IV:4/0/3/1 versus 0/3/26/24, P < 0.0001). Comprehensive curability of the eight small carcinoma cases was significantly higher than that of the 53 large carcinoma cases (comprehensive curability A/B/C:5/3/0 versus 9/5/39; P = 0.0003). 1-year and 3-year cumulative survival rates of the eight patients with small carcinoma were 100% and 82%, whereas those of the 53 with large carcinoma were 51% and 17%, respectively (P = 0.0207). However, the eight small carcinoma cases already showed frequent invasion to the vascular (v), lymphatic (ly) and perineural (pn) structure [v(+): 3/8, ly(+): 5/8, pn(+):5 /8] and lymph node metastasis (n) [n(+): 3/8]. Out of the eight small pancreatic carcinomas, one minimally invasive carcinoma and two non-invasive carcinomas showed no vascular, lymphatic or perineural invasion or lymph node metastasis. All the three patients have been doing well 19, 32 and 44 months after the operation. The diagnostic clues in the three patients were dilatation of the main pancreatic duct in one and of the branch duct in the other two.

These findings suggest that surgical resection frequently cures patients with small pancreatic carcinoma but more effective adjuvant therapy should be developed to control lymphatic permeation, venous invasion or perineural infiltration in surgical resection of large pancreatic carcinoma. The supreme goal is to detect non-invasive or minimally invasive pancreatic carcinoma with a dilatation of the main or branch pancreatic duct as a diagnostic aid.