Cancer "Avatars": Patient-Derived Xenograft Growth Correlation with Postoperative Recurrence and Survival in Pancreaticobiliary Cancer

BACKGROUND

Pancreaticobiliary (PB) cancers are a diverse group of cancers with poor prognoses and high rates of recurrence after resection. Patient-derived xenografts (PDX), created from surgical specimens, provide a reliable preclinical research platform and high-fidelity cancer model from which to study these malignancies with consistent recapitulation of their original patient tumors in vivo. However, the relationship between PDX engraftment success (growth or no growth) and patient oncologic outcomes has not been well studied. We sought to evaluate the correlation between successful PDX engraftment and survival in several PB exocrine carcinomas, including the pancreatic and biliary tract.

STUDY DESIGN

In accordance with IRB and Institutional Animal Care and Use Committee protocols and with appropriate consent and approval, excess tumor tissue obtained from surgical patients was implanted into immunocompromised mice. Mice were monitored for tumor growth to determine engraftment success. PDX tumors were verified to recapitulate their tumors of origin by a hepatobiliary pathologist. Xenograft growth was correlated with clinical recurrence and overall survival data.

RESULTS

A total of 384 PB xenografts were implanted. The successful engraftment rate was 41% (158/384). We found that successful PDX engraftment was highly associated with both recurrence-free survival (p < 0.001) and overall survival (p < 0.001) outcomes. Successful PDX tumor generation occurs significantly in advance of clinical recurrences in their corresponding patients (p < 0.001).

CONCLUSIONS

Successful PB cancer PDX models predict recurrence and survival across tumor types and may provide critical lead time to alter patients' surveillance or treatment plans before cancer recurrence.

Technical Outcomes of Porto-Mesenteric Venous Reconstruction in Pancreatic Resection Using Autologous Left Renal Vein Graft as Conduit

BACKGROUND

Portal or superior mesenteric vein (PV-SMV) resection and reconstruction is sometimes required during pancreatic tumor resection. In patients requiring segmental venous resection with interposition grafting, the left renal vein (LRV) is an accessible autologous solution. However, long-term patency outcomes of the LRV as an interposition conduit in this setting have not been analyzed.

STUDY DESIGN

We conducted a retrospective analysis of patients undergoing pancreatic resection with PV-SMV reconstruction using LRV between 2002 and 2022. The primary outcome was PV-SMV patency at last follow-up, assessed with postoperative CT scans and analyzed using Kaplan-Meier survival methods that account for variation in follow-up duration. Development of any postoperative acute kidney injury within 7 days of surgery and morbidity were secondary outcomes.

RESULTS

The study cohort includes 65 patients who underwent LRV harvest; 60 (92%) ultimately underwent successful reconstruction with harvested LRV graft. Kaplan-Meier 2-year estimated patency rate of the LRV graft was 88%, with no cases of complete occlusion. Six (10%) patients experienced graft stenosis. Nine of 61 (15%) patients experienced grade II or III acute kidney injury, 6 of 9 returning to normal renal function before discharge. No difference in median serum creatinine was observed at baseline, 6 and 12 months from surgery. LRV remnant thrombosis was seen in 7 of 65 (11%) patients. Only 3 of 61 (5%) patients had persistent acute kidney injury caused by complications unrelated to LRV harvesting.

CONCLUSIONS

Autologous LRV graft was a reliable conduit for segmental PV-SMV reconstruction, resulting in a high patency rate and marginal impact on renal function. LRV harvest is a safe and potentially ideal surgical option for PV-SMV reconstruction in pancreatic surgery.

Mixed Acinar Neuroendocrine Carcinoma of the Pancreas: Comparative Population-Based Epidemiology of a Rare and Fatal Malignancy in The United States

Mixed acinar neuroendocrine carcinoma of the pancreas (MANEC-P) is an extremely rare malignancy with a poor prognosis. However, epidemiological estimates of MANEC-P remain unknown. This study aimed to estimate and compare the incidence, prevalence, and cancer-specific survival (CSS) of MANEC-P in the United States (US). Patients with MANEC-P were identified through the Surveillance, Epidemiology, and End Results (SEER) and National Program of Cancer Registries databases between 2000-2017. The primary outcomes included age-adjusted incidence rate, limited-duration prevalence, and CSS. A total of 630 patients were identified for the incidence analysis and 149 for the prevalence and CSS analyses. The MANEC-P incidence rate was 0.011 per 100,000 individuals, which was the lowest among pancreatic cancer histologic subtypes. The incidence rate was significantly higher in men and Black races and peaked at 75-79 years of age. The incidence rate was the lowest in the midwestern region (0.009) and the highest in the northeastern US (0.013). The 17-year prevalence was 0.00005%, indicating that 189 patients were alive in the United States at the beginning of 2018. The median CSS of MANEC-P was estimated to be 41 (23, 69) months. In conclusion, MANEC-P is very rare, and its incidence rate has been steady in the US over the last two decades. MANEC-P has a poor prognosis and is the 5th leading cause of pancreatic cancer-related death in the US.