INTRODUCTION:Advances in robotic instrumentation have facilitated minimally invasive completion of complex cancer operations. The objective of this study is to determine the feasibility of robotic approach for cytoreduction (R-CRS) for peritoneal carcinomatosis in a series of 16 consecutive cases. METHODS:Single institution retrospective study of consecutive patients with peritoneal carcinomatosis deemed appropriate for R-CRS after multidisciplinary review between 2017 and 2022. Feasibility was defined as the proportion of patients in whom complete cytoreduction was achieved without conversion to open. RESULTS:A total of 16 patients (median interquartile range [IQR]: age 60 ys [45.8-70.5], body mass index 29 [24.5-33.6], peritoneal carcinomatosis index 5 [2.8-6.3]) underwent R-CRS of which six also received hyperthermic intraperitoneal chemtotherapy. Seven patients had gastrointestinal primary cancers (3 colorectal, 3 appendiceal, 1 small bowel neuroendocrine); and nine had gynecologic cancers (7 ovarian, 2 endometrial). Median operative time was 6.0 h (IQR: 5.0-9.0), and median estimated blood loss was 87.5 mL (IQR: 30.0-262.5). Robotic procedures included: pelvic tumor debulking 12 (75%), omentectomy 8 (50%), peritonectomy 6 (38%), large bowel resection 6 (37%), retroperitoneal mass resection 4 (25%), and hepatectomy 3 (19%). Median length of stay was 3.5 ds (IQR: 1.8-5.3) for the whole cohort and only 2 ds (IQR: 1.0-5.5) for patients who did not undergo hyperthermic intraperitoneal chemotherapy. Feasibility rate was 87.5%, whereas conversion, 30-d complication, and 30-d mortality rates were 12.5%, 18.8%, and 0%, respectively. CONCLUSIONS:Our experience with R-CRS demonstrates feasibility of the approach with a potential for benefit in short-term outcomes in a carefully selected cohort of patients when performed at a high-volume robotic surgery center.

Background and Objectives: Surgical site infections (SSIs) after cytoreductive surgery (CRS) +/- hyperthermic intraperitoneal chemotherapy (HIPEC) are a major cause of potentially avoidable morbidity. We explored the association of negative pressure wound therapy (NPWT) with SSI in patients undergoing CRS/HIPEC. Methods: Retrospective analysis of consecutive patients undergoing CRS/HIPEC for non-gynecologic cancers. Exposure was the receipt of NPWT versus traditional skin closure. Primary outcome was SSI within 90 days of surgery. We performed multivariable logistic regression (before and after entropy balancing) to evaluate the association of exposure with outcomes. Results: A total of 251 patients were included, of which 43 (17%) received NPWT and 26 (10.4%) developed SSIs. Baseline demographics and clinicopathologic characteristics were similar between the two groups with some exceptions: Patients who received NPWT had a higher Peritoneal Carcinomatosis Index (median 19 vs. 11, p = 0.002) and operative time (10 vs. 8.2 h, p = 0.003) but were less likely to undergo HIPEC (84% vs. 95%, p < 0.05). After entropy balancing, on multivariable logistic regression, NPWT was not associated with 90-day SSI (odds ratio = 0.90; 95% confidence interval = 0.21-3.80; p = 0.89). Conclusion: NPWT was not associated with a reduction in SSIs. These findings prompt a reevaluation of the routine use of NPWT in CRS/HIPEC.

Background In the current era of effective adjuvant therapies and de-escalation of surgery, distinguishing which patients with high-risk stage II melanoma are at increased risk of recurrence after excision of the primary lesion is essential to determining appropriate treatment and surveillance plans. Methods A single-center retrospective study analyzed patients with stage IIB or IIC melanoma. Demographic and tumor data were collected, and genomic analysis of formalin-fixed, paraffin-embedded tissue samples was performed via an internal next-generation sequencing (NGS) platform (SNaPshot). The end points examined were relapse-free survival (RFS), distant metastasis-free survival (DMFS), overall survival (OS), and melanoma-specific survival (MSS). Uni- and multivariable Cox regressions were performed to calculate the hazard ratios. Results The study included 92 patients with a median age of 69 years and a male/female ratio of 2:1. A Breslow depth greater than 4 mm, a higher mitotic rate, an advanced T stage, and a KIT mutation had a negative impact on RFS. A primary lesion in the head and neck, a mitotic rate exceeding 10 mitoses per mm 2 , a CDH1 mutation, or a KIT mutation was significantly associated with a shorter DMFS. Overall survival was significantly lower with older age at diagnosis and a higher mitotic rate. An older age at diagnosis also had a negative impact on MSS. Conclusion Traditional histopathologic factors and specific tumor mutations displayed a significant correlation with disease recurrence and survival for patients with high-risk stage II melanoma. This study supported the use of genomic testing of high-risk stage II melanomas for prognostic prediction and risk stratification.

BACKGROUND:There is variation in the probability of nodal metastases from low-grade appendiceal adenocarcinomas, and the role of right colectomy is unclear. We aimed to define the prevalence and utility of lymphovascular invasion in predicting the risk of nodal metastases to help stratify patients who may benefit from right hemicolectomy. METHODS:Patients with nonmetastatic low-grade appendiceal adenocarcinomas were identified from the National Cancer Database (2010-2017). The primary outcome was probability of nodal metastases. Logistic regression was used to identify independent predictors of nodal metastases. A 4-tier risk model-the COH Composite Score-was calculated by assigning 1 point each for a high-risk feature (lymphovascular invasion, T3/T4 T stage, or nonmucinous histology). Survival analysis was performed using the Kaplan-Meier method. Multivariate Cox regression analysis was used to identify independent predictors of survival. RESULTS:A total of 1,303 patients with nonmetastatic low-grade appendiceal adenocarcinomas (64.2% mucinous) were identified. Of the 1,133 patients with known lymphovascular invasion status, 78 (6.9%) were lymphovascular invasion positive. In multivariate analysis, lymphovascular invasion was independently associated with nodal metastases (odds ratio, 8.68; P < .001). Overall accuracy of lymphovascular invasion in predicting nodal metastases was 86%. The COH Composite Score stratified patients in 4 categories with increasing risk of nodal metastases and incrementally worse survival. For patients with the COH Composite Score of 0 (12%), the nodal metastasis rate was 3.1%, and a right hemicolectomy in this group did not improve survival. CONCLUSION:The presence of lymphovascular invasion is strongly predictive of nodal metastases. Lymphovascular invasion as part of the COH Composite Score may help guide the extent of surgery in low-grade appendiceal adenocarcinomas.

The role of surgery for patients with stage IV melanoma is rapidly evolving. In the past, limited treatment options were available and surgery was offered to carefully selected patients. Currently, in the era of effective immunotherapy, the role of surgery is still being defined. The present study examines outcomes for patients with stage IV melanoma receiving immunotherapy and surgery. Future studies will help to better identify which patients should receive surgery and when it should be performed in the setting of increasingly available therapeutic modalities for patients with stage IV melanoma.

Abstract Introduction: Delineation of tumor margins is critical in oncologic surgery, particularly in resection of pancreatic cancer. Surgeons are limited in visualization with bright light surgery. Fluorescence guided surgery (FGS) can help surgeons better visualize all potential cancer cells during the operation. In the present study, we show that the use of an anti-CEA antibody conjugated to an 800nm NIR fluorescent dye can selectively label pancreatic cancer in both pancreatic cancer cell lines and patient derived xenograft mouse models (PDOX). Materials/Methods: BxPC3-GFP cells or pancreatic cancer tissue specimens were grafted into flanks of nude mice. Both types of tumors were allowed to grow until 1 cm. Fragments tumors (2 mm3) were grafted onto the pancreatic tail of recipient mice to create PDOX models. After tumors reached 7-10mm in size, 75 ug of Anti-CEA-800 dye was injected into the tail-vein (LI-COR 800 CW IRDye®, Lincoln, NE). Mice were imaged via the Maestro CRI imaging system (Perkin Elmer, Waltham, MA) 24 hours after injection. Results: Images obtained after fluorescent antibody injection showed that anti-CEA-800 specifically labeled both the cell-line-derived tumors and patient-derived tumors with an adequate tumor to background contrast at 24 hours. The dye co-localized with GFP in tagged tumor cells lines. GFP fluorescence had poor penetration if covered by overlying tissue, which was not an issue with the anti-CEA-800 dye. The dye allowed clear identification of the tumor and tumor margin. In the BxPC-3 based tumor, the dye allowed identification of a small 1mm satellite lesion in the spleen that would otherwise have been missed. Conclusions: Fluorescent humanized anti-CEA-800 antibody specifically labeled orthotopically implanted pancreatic cancer xenografts from cell lines and patient derived tissue. Tumor-specific fluorescence imaging clearly identified the primary tumor and satellite lesion. The 800nm wavelength allowed deeper tissue penetration, particularly in areas of tumor covered by normal pancreatic parenchyma. Humanized anti-CEA antibodies conjugated to a radio-labeling agent and LI-COR 800 dye is already in Phase I/II trials. Humanized anti-CEA conjugated with the IR-800 dye is a promising agent for future clinical FGS applications. Citation Format: Thinzar Lwin, Takashi Murakami, Robert M. Hoffman, Paul J. Yazaki, Michael Bouvet. Tumor-specific antibody labeling of pancreatic cancer in a patient-derived orthotopic xenograft (PDOX) mouse model using a fluorescent humanized anti-CEA antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3729. doi:10.1158/1538-7445.AM2017-3729