Outcomes of nonresected main-duct intraductal papillary mucinous neoplasms of the pancreas

Abstract

Aim: To compare characteristics and outcomes of resected and nonresected main-duct and mixed intraductal papillary mucinous neoplasms of the pancreas (IPMN).

Methods: Over a 14-year period, 50 patients who did not undergo surgery for resectable main-duct or mixed IPMN, for reasons of precluding comorbidities, age and/or refusal, were compared with 74 patients who underwent resection to assess differences in rates of survival, recurrence/occurrence of malignancy, and prognostic factors. All study participants had dilatation of the main pancreatic duct by ≥ 5 mm, with or without dilatation of the branch ducts. Some of the nonsurgical patients showed evidence of mucus upon perendoscopic retrograde cholangiopancreatography or endoscopic ultrasound and/or after fine needle aspiration. For the surgical patients, pathologic analysis of resected specimens confirmed a diagnosis of IPMN with involvement of the main pancreatic duct or of both branch ducts as well as the main pancreatic duct. Clinical and biologic follow-ups were conducted for all patients at least annually, through hospitalization or consultation every six months during the first year of follow-up, together with abdominal imaging analysis (magnetic resonance cholangiopancreatography or computed tomography) and, if necessary, endoscopic ultrasound with or without fine needle aspiration.

Results: The overall five-year survival rate of patients who underwent resection was significantly greater than that for the nonsurgical patients (74% vs 58%; P = 0.019). The parameters of age (< 70 years) and absence of a nodule were associated with better survival (P < 0.05); however, the parameters of main pancreatic duct diameter > 10 mm, branch duct diameter > 30 mm, or presence of extra pancreatic cancers did not significantly influence the prognosis. In the nonsurgical patients, pancreatic malignancy occurred in 36% of cases within a mean time of 33 mo (median: 29 mo; range: 8-141 mo). Comparison of the nonsurgical patients who experienced disease progression with those who did not progress showed no significant differences in age, sex, symptoms, subtype of IPMN, or follow-up period; only the size of the main pancreatic duct was significantly different between these two sub-groups, with the nonsurgical patients who experienced progression showing a greater diameter at the time of diagnosis (> 10 mm).

Conclusion: Patients unfit for surgery have a 36% greater risk of developing pancreatic malignancy of the main-duct or mixed IPMN within a median of 2.5 years.

Keywords: Main-duct intraductal papillary mucinous neoplasms; Natural history; Pancreatic surgery; Prognosis; Risk of malignancy.

Figure 1

Kaplan-Meier analysis of overall survival times depending on treatment. Nonsurgical (nonresected; solid line) and surgical (resected; dashed line) main-pancreatic duct and mixed intraductal papillary mucinous neoplasm patients.

Figure 2

Kaplan-Meier analysis of overall survival times depending on age. A: Both nonsurgical (nonresected) and surgical (resected); B: Surgical; and C: Nonsurgical main-pancreatic duct and mixed intraductal papillary mucinous neoplasm patients (solid line: patients aged < 70 years; dashed line: patients aged > 70 years).

Figure 3

Kaplan-Meier analysis of overall survival times depending on nodules. Presence (dashed line) or absence (solid line) of tissular nodules [and/or wall thickening of main-pancreatic duct (MPD) or branch-duct cysts] at diagnosis in both nonsurgical (nonresected) and surgical (resected) MPD and mixed intraductal papillary mucinous neoplasm patients.