Disease progression of side-branch intraductal papillary mucinous neoplasms following solid organ transplant

Branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) are becoming more prevalent with advanced medical imaging and account for most of pancreatic cystic neoplasms (PCNs). Most incidental lesions should be surveyed, with resection reserved for specific, high-risk cases. Solid organ transplantation candidates may be high risk of resection before transplant and will require systemic immunosuppression after transplant, which has been theorized to alter the natural history of the IPMN. We aimed to describe the progression in surveilled cysts after solid organ transplantation.

A prospectively maintained database of PCNs was queried for patients with IPMN. Patients who had received a previous solid organ transplantation and with ≥2 imaging studies >6 months apart after transplantation were included. Clinically relevant (CR) progression was defined as symptoms, worrisome/high-risk stigmata, or invasive carcinoma (IC). Growth ≥5 mm in 2 years is considered CR progression; size ≥3 cm alone is not.

Between 1997 and 2023, 252 patients received solid organ transplantation (liver, 86; kidney, 113; and lung, 54) and were diagnosed as having an IPMN. This cohort was compared with a set of 770 patients surveilled for IPMN who did not have previous transplantation. Median follow-up period was 3.7 years (IQR, 1.6-6.8). Moreover, 2 transplant patients (0.8%) developed IC, and 4 developed (1.6%) high-grade dysplasia (HGD). Both were less common in transplant patients than the nontransplant population (IC, 3.3%; HGD, 2.9%), although this was not significant on time-to-event analysis (IC, P = .152; HGD, P = .352). The rate of CR progression was high in the transplant cohort (n = 118; 47%). Features of CR progression included size growth (n = 79; 67%), other worrisome/high-risk stigmata (n = 25; 21%), and new main duct involvement (n = 14; 12%). Compared with the nontransplant (n = 128; 17%), transplant patients had a higher rate of CR progression (P < .001), which was mostly explained by a more frequent size growth (31% vs 9%; P < .001). However, no transplant patients with size growth CR progression developed IC. Moreover, 17 (6.7%) required pancreatic surgery for CR progression after transplant vs 58 (7.5%) in the nontransplant population. Furthermore, 6 resected cysts (35%) harbored high-risk pathology after transplant (IC, 2; HGD, 4) vs 40 (69%) in the general population (P < .001; IC, 29; HGD, 11).

Malignant transformation of BD-IPMNs is rare despite systemic immunosuppression in solid organ transplant patients. This supports transplantation in patients with IPMN without fear of worsening their risk of pancreatic cancer, although it was associated with a higher risk of disease progression. Patients with IPMNs should be surveilled with yearly scans after transplant, with pancreatic resection reserved for only high-risk features as we continue to define the optimal criteria for those with CR progression.