Hepatic Ablation Promotes Colon Cancer Metastases in an Immunocompetent Murine Model.

OBJECTIVE: To determine the impact of radiofrequency (RF) and microwave (MW) energy compared to direct cautery on metatstatic colon cancer growth. BACKGROUND: Hepatic ablation with MW and RF energy creates a temperature gradient around a target site with temperatures known to create tissue injury and cell death. In contrast, direct heat application (cautery) vaporizes tissue with a higher site temperature but reduced heat gradient on surrounding tissue. We hypothesize that different energy devices create variable zones of sublethal injury that may promote tumor recurrence. To test this hypothesis we applied MW, RF, and cautery to normal murine liver with a concomitant metastatic colon cancer challenge. METHODS: C57/Bl6 mice received hepatic thermal injury with MW, RF, or cautery to create a superficial 3-mm lesion immediately after intrasplenic injection of 50K MC38 colon cancer cells. Thermal imaging recorded tissue temperature during ablation and for 10 seconds after energy cessation. Hepatic tumor location and volume was determined at day 7. RESULTS: Cautery demonstrated the highest maximum tissue temperatures (129°C) with more rapid return to baseline compared to MW or RF energy. All mice had metastasis at the ablation site. Mean tumor volume was significantly greater in the MW (95.3 mm; P = 0.007) and RF (55.7 mm; P = 0.015) than cautery (7.13 mm). There was no difference in volume between MW and RF energy (P = 0.2). CONCLUSIONS: Hepatic thermal ablation promotes colon cancer metastasis at the injury site. MV and RF energy result in greater metastatic volume than cautery. These data suggest that the method of energy delivery promotes local metastasis.

Comparing Short-term and Oncologic Outcomes of Minimally Invasive Versus Open Pancreaticoduodenectomy Across Low and High Volume Centers.

OBJECTIVE: To compare short-term and oncologic outcomes of patients with cancer who underwent open pancreaticoduodenectomy (OPD) versus minimally invasive pancreaticoduodenectomy (MIPD) using the National Cancer Database. SUMMARY BACKGROUND DATA: MIPD, including laparoscopic and robotic approaches, has continued to gain acceptance despite prior reports of increased short-term mortality when compared with OPD. METHODS: Patients with pancreatic cancer diagnosed from 2010 to 2015 undergoing curative intent resection were selected from the National Cancer Database. Patients submitted to OPD were compared with those submitted to MIPD. Laparoscopic and robotic approaches were included in the MIPD cohort. The primary outcome was 90-day mortality; secondary outcomes included 30-day mortality, hospital length of stay, unplanned 30-day readmission, surgical margins, number of lymph nodes harvested, and receipt of adjuvant chemotherapy. Propensity score-weighted random effects logistic regression models were used to examine the adjusted association between surgical approach and the specified outcomes. RESULTS: Between 2010 and 2015, 22,013 patients underwent OPD or MIPD for pancreatic cancer and 3754 (17.1%) were performed minimally invasively. On multivariable analysis, there was no difference in 90-day mortality between MIPD and OPD (OR, 0.92; 95% CI, 0.75-1.14). Patients undergoing MIPD were less likely to stay in the hospital for a prolonged time (OR, 0.75; 95% CI, 0.68-0.82). 30-day mortality, unplanned readmissions, margins, lymph nodes harvested, and receipt of adjuvant chemotherapy were equivalent between groups. Regardless of surgical approach, patients operated on at high volume centers had reduced 90-day mortality. CONCLUSION: Patients selected to receive MIPD for cancer have equivalent short-term and oncologic outcomes, when compared with patients who undergo OPD.