Based on the experience to date with IPMNs, the approach to patients remains relatively complex. A meticulous and careful approach to diagnosis, oncologic risk assessment, operative planning, and surveillance is needed to adequately address these lesions. Indications for resection in patients with IPMN are (1) cancer, (2) cancer prevention in patients at high risk for malignant transformation, and (3) management of symptoms. Differentiating patients who have IPMNs by type is an important initial step in providing optimal care (Fig. 6). In patients with MPD involvement (main- and mixed-type IPMN), the risk of malignancy at resection is too high to justify nonoperative management unless comorbidity or patient preference precludes operation. Until better preoperative biomarkers of malignancy in main duct-involved IPMNs are available, it is our recommendation that all patients who are fit should undergo resection of the entire involved segment with appropriate adjustment and extension based on intraoperative pathology. Total pancreatectomy may be indicated for diffuse main duct involvement. In the more difficult and debated cohort (ie, patients with side branch disease only), a more strategic approach to whether to resect is appropriate. Patients with malignant cytopathology, concerning radiologic features (ie, mural nodules, associated mass), or symptoms attributable to IPMNs should be offered resection. Importantly, specific symptoms have variable importance in terms of oncologic risk and are worth characterizing in individual patients. Size alone should not be the determining oncologic factor for resection, although we acknowledge that the literature is unclear in this regard. Size of IPMNs (or any other cystic lesion) may be a nononcologic indication to resect for symptom control and when size or anticipated growth may complicate the ability to safely extirpate the lesion. Other factors that should be considered in determining whether to resect are number of lesions, need for prolonged surveillance, inability to adequately perform noninvasive surveillance (eg, contraindication to MRI), difficulty in surveillance (extensive/diffuse multifocal disease), and patient tolerance of risk. The decision to resect in patients undergoing primary surveillance or secondary surveillance for IPMN should be similar to the indications for primary resection noted previously. The optimal surveillance regimen, however, is unknown. The optimal surveillance regimen depends on the timing and incidence of "recurrence" and "new metachronous IPMN development," which are not fully understood, partly because of suboptimal preoperative imaging in patients with IPMNs. To solve this mystery, surgeons and pancreatologists should be encouraged to obtain optimal and timely imaging studies before taking patients to the operating room. Patients should be followed at least annually with history and physical and optimal cross-sectional imaging. Endoscopy and cytopathologic assessment should be considered at least biannually and more often when indicated by patient symptoms or concerning radiographic features. The surveillance interval should be decreased and extent of testing increased based on patients with higher oncologic risk stratification. Although resection in patients undergoing surveillance currently follows the same algorithm as patients undergoing primary resection, assessment of the main pancreatic duct in patients undergoing secondary surveillance after segmental pancreatectomy (particularly pancreaticoduodenectomy) is complicated. Although new data continue to clarify how and when to approach IPMNs with segmental or total pancreatic resection, many questions remain unanswered. Continued efforts to uncover a more accurate natural history and behavior for IPMN continue to fill the gaps in our current understanding and practice. In the meantime, it is critical to educate and frequently restratify oncologic risk in patients based on optimal and timely data (history and physical and radiographic, endoscopic, and cytopathologic results) and rigorous follow-up to guide patients in reaching a decision of whether and when to undergo IPMN resection.
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