Defining the learning curve for robotic pancreaticoduodenectomy for a single surgeon following experience with laparoscopic pancreaticoduodenectomy.

Robotic pancreaticoduodenectomy (RPD) has a learning curve of approximately 30-250 cases to reach proficiency. The learning curve for laparoscopic pancreaticoduodenectomy (LPD) at Duke University was previously defined as 50 cases. This study describes the RPD learning curve for a single surgeon following experience with LPD. LPD and RPD were retrospectively analyzed. Continuous pathologic and perioperative metrics were compared and learning curve were defined with respect to operative time using CUSUM analysis. Seventeen LPD and 69 RPD were analyzed LPD had an inverted learning curve possibly accounting for proficiency attained during the surgeon's fellowship and acquisition of new skills coinciding with more complex patient selection. The learning curve for RPD had three phases: accelerated early experience (cases 1-10), skill consolidation (cases 11-40), and improvement (cases 41-69), marked by reduction in operative time. Compared to LPD, RPD had shorter operative time (379 vs 479 min, p < 0.005), less EBL (250 vs 500, p < 0.02), and similar R0 resection. RPD also had improved LOS (7 vs 10 days, p < 0.007), and lower rates of surgical site infection (10% vs 47%, p < 0.002), DGE (19% vs 47%, p < 0.03), and readmission (13% vs 41%, p < 0.02). Experience in LPD may shorten the learning curve for RPD. The gap in surgical quality and perioperative outcomes between LPD and RPD will likely widen as exposure to robotics in General Surgery, Hepatopancreaticobiliary, and Surgical Oncology training programs increase.

Preoperative CT and survival data for patients undergoing resection of colorectal liver metastases.

The liver is a common site for the development of metastases in colorectal cancer. Treatment selection for patients with colorectal liver metastases (CRLM) is difficult; although hepatic resection will cure a minority of CRLM patients, recurrence is common. Reliable preoperative prediction of recurrence could therefore be a valuable tool for physicians in selecting the best candidates for hepatic resection in the treatment of CRLM. It has been hypothesized that evidence for recurrence could be found via quantitative image analysis on preoperative CT imaging of the future liver remnant before resection. To investigate this hypothesis, we have collected preoperative hepatic CT scans, clinicopathologic data, and recurrence/survival data, from a large, single-institution series of patients (n = 197) who underwent hepatic resection of CRLM. For each patient, we also created segmentations of the liver, vessels, tumors, and future liver remnant. The largest of its kind, this dataset is a resource that may aid in the development of quantitative imaging biomarkers and machine learning models for the prediction of post-resection hepatic recurrence of CRLM.

Computerized Diagnosis of Liver Tumors From CT Scans Using a Deep Neural Network Approach.

The liver is a frequent site of benign and malignant, primary and metastatic tumors. Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are the most common primary liver cancers, and colorectal liver metastasis (CRLM) is the most common secondary liver cancer. Although the imaging characteristic of these tumors is central to optimal clinical management, it relies on imaging features that are often non-specific, overlap, and are subject to inter-observer variability. Thus, in this study, we aimed to categorize liver tumors automatically from CT scans using a deep learning approach that objectively extracts discriminating features not visible to the naked eye. Specifically, we used a modified Inception v3 network-based classification model to classify HCC, ICC, CRLM, and benign tumors from pretreatment portal venous phase computed tomography (CT) scans. Using a multi-institutional dataset of 814 patients, this method achieved an overall accuracy rate of 96%, with sensitivity rates of 96%, 94%, 99%, and 86% for HCC, ICC, CRLM, and benign tumors, respectively, using an independent dataset. These results demonstrate the feasibility of the proposed computer-assisted system as a novel non-invasive diagnostic tool to classify the most common liver tumors objectively.

Hepatic Artery Infusion Pumps: A Surgical Toolkit for Intraoperative Decision-Making and Management of Hepatic Artery Infusion-Specific Complications.

BACKGROUND: Hepatic artery infusion (HAI) is a liver-directed therapy that delivers high-dose chemotherapy to the liver through the hepatic arterial system for colorectal liver metastases and intrahepatic cholangiocarcinoma. Utilization of HAI is rapidly expanding worldwide. OBJECTIVE AND METHODS: This review describes the conduct of HAI pump implantation, with focus on common technical pitfalls and their associated solutions. Perioperative identification and management of common postoperative complications is also described. RESULTS: HAI therapy is most commonly performed with the surgical implantation of a subcutaneous pump, and placement of its catheter into the hepatic arterial system for inline flow of pump chemotherapy directly to the liver. Intraoperative challenges and abnormal hepatic perfusion can arise due to aberrant anatomy, vascular disease, technical or patient factors. However, solutions to prevent or overcome technical pitfalls are present for the majority of cases. Postoperative HAI-specific complications arise in 22% to 28% of patients in the form of pump pocket (8%-18%), catheter (10%-26%), vascular (5%-10%), or biliary (2%-8%) complications. The majority of patients can be rescued from these complications with early identification and aggressive intervention to continue to deliver safe and effective HAI therapy. CONCLUSIONS: This HAI toolkit provides the HAI team a reference to manage commonly encountered HAI-specific perioperative obstacles and complications. Overcoming these challenges is critical to ensure safe and effective pump implantation and delivery of HAI therapy, and key to successful implementation of new programs and expansion of HAI to patients who may benefit from such a highly specialized treatment strategy.

Patterns and Impact of Fragmented Care in Stage II and III Gastric Cancer.

BACKGROUND: Optimal management of stage II/III gastric cancer requires multidisciplinary care, often necessitating treatment at more than one facility. We aimed to determine patterns of "fragmented" care and its impact on outcomes, including concordance with National Comprehensive Cancer Network (NCCN) guidelines and overall survival. METHODS: The 2006-2016 National Cancer Database was queried for patients with clinical stage II/III gastric adenocarcinoma who received preoperative therapy in addition to surgery. Patients were stratified based on whether surgery and chemotherapy/chemoradiation were performed at one versus multiple facilities (termed "coordinated" and "fragmented" care, respectively). Multivariable logistic regression was performed to identify factors associated with fragmented care. Survival was compared using Kaplan-Meier and Cox proportional hazards methods. RESULTS: Overall, 2033 patients met study criteria: 1043 (51.3%) received coordinated care and 990 (48.7%) fragmented care. There was no significant difference in time to surgery or pathologic upstaging by care structure. On adjusted analysis, factors associated with receipt of fragmented care included increasing age and distance traveled to the treating facility. Factors associated with coordinated care included metropolitan residence and treatment at academic and high-volume centers. Fragmented care was associated with a reduction in guideline-preferred perioperative chemotherapy (odds ratio [OR] 0.78, 95% confidence interval [CI] 0.63-0.97, p = 0.02) and increased mortality (HR 1.16, 95% CI 1.00-1.34, p = 0.05). CONCLUSIONS: For patients with stage II/III gastric cancer, fragmented care is associated with inferior outcomes, including a reduction in preferred perioperative treatment and survival. Further work is needed to ensure equitable outcomes among patients as complex cancer care becomes more regionalized.

Combined Primary Resection with Hepatic Artery Infusion Pump Implantation Is Safe for Unresectable Colorectal Liver Metastases.

BACKGROUND: Colorectal liver metastases (CRLM) are the most common cause of disease-specific mortality in patients with colorectal cancer. Hepatic artery infusion (HAI) combined with systemic chemotherapy improves survival for these patients. The safety of colorectal resection at the time of HAI pump placement has not been well established. METHODS: Patients with CRLM who underwent combined HAI pump placement and colorectal (primary) resection or HAI pump placement alone were evaluated for perioperative outcomes, pump-specific complications, infectious complications, and time to treatment initiation. These outcomes were compared using comparative statistics. RESULTS: Patients who underwent combined HAI pump placement and primary resection (n = 19) vs HAI pump placement alone (n = 13) had similar demographics and rates of combined hepatectomy. Combined HAI pump placement and primary resection group had similar operative time and blood loss (both p = NS), but longer length of stay (6 vs 4 days, p = 0.02) compared to pump placement alone. Overall postoperative complications (21% vs 8%) and pump-specific complications (16% vs 31%) were similar (both p = NS). Infection rates were not different between groups, nor was time to initiation of HAI therapy (19 vs 16 days p = NS), or systemic therapy (34 vs 35 days p = NS). CONCLUSION: Combining colorectal resection with HAI pump implantation is a safe surgical approach for management of unresectable CRLM. Postoperative complications, specifically infectious complications, were not increased, nor was there a delay to initiation of HAI or systemic chemotherapy. Investigation of long-term oncologic outcomes for HAI pump placement and primary tumor resection in patients with unresectable CRLM is ongoing.

Differences in Liver Parenchyma are Measurable with CT Radiomics at Initial Colon Resection in Patients that Develop Hepatic Metastases from Stage II/III Colon Cancer.

BACKGROUND: Currently, there are no methods to identify patients with an increased risk of liver metastases to guide patient selection for liver-directed therapies. We tried to determine whether quantitative image features (radiomics) of the liver obtained from preoperative staging CT scans at the time of initial colon resection differ in patients that subsequently develop liver metastases, extrahepatic metastases, or demonstrate prolonged disease-free survival. METHODS: Patients who underwent resection of stage II/III colon cancer from 2004 to 2012 with available preoperative CT scans were included in this single-institution, retrospective case-control study. Patients were grouped by initial recurrence patterns: liver recurrence, extrahepatic recurrence, or no evidence of disease at 5 years. Radiomic features of the liver parenchyma extracted from CT images were compared across groups. RESULTS: The cohort consisted of 120 patients divided evenly between three recurrence groups, with an equal number of stage II and III patients in each group. After adjusting for multiple comparisons, 44 of 254 (17%) imaging features displayed different distributions across the three patient groups (p < 0.05), with the clearest distinction between those with liver recurrence and no evidence of disease. Increased heterogeneity in the liver parenchyma by radiomic analysis was protective of liver metastases. CONCLUSIONS: CT radiomics is a promising tool to identify patients at high risk of developing liver metastases and is worthy of further investigation and validation.

Implementation of a Hepatic Artery Infusion Program: Initial Patient Selection and Perioperative Outcomes of Concurrent Hepatic Artery Infusion and Systemic Chemotherapy for Colorectal Liver Metastases.

BACKGROUND: Hepatic artery infusion (HAI) combined with systemic chemotherapy is a treatment strategy for patients with unresectable liver-only or liver-dominant colorectal liver metastases (CRLM). Although HAI has previously been performed in only a few centers, this study aimed to describe patient selection and initial perioperative outcomes during implementation of a new HAI program. METHODS: The study enrolled patients with CRLM selected for HAI after multi-disciplinary review November 2018-January 2020. Demographics, prior treatment, and perioperative outcomes were assessed. Objective hepatic response was calculated according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. RESULTS: During a 14-month period, 21 patients with CRLM underwent HAI pump placement. Of these 21 patients, 20 (95%) had unresectable disease. Most of the patients had synchronous disease (n = 18, 86%) and had received prior chemotherapy (n = 20, 95%) with extended treatment cycles (median 16; interquartile range, 8-22; range, 0-66). The median number of CRLMs was 7 (range, 2-40). Operations often were performed with combined hepatectomy (n = 4, 19%) and/or colectomy/proctectomy (n = 11, 52%). The study had no 90-day mortality. The overall surgical morbidity was 19%. The HAI-specific complications included pump pocket seroma (n = 2), hematoma (n = 1), surgical-site infection (n = 1), and extrahepatic perfusion (n = 1). HAI was initiated in 20 patients (95%). The hepatic response rates at 3 months included partial response (n = 4, 24%), stable disease (n = 9, 53%), and progression of disease (n = 4, 24%), yielding a 3-month hepatic disease control rate (DCR) of 76%. CONCLUSION: Implementation of a new HAI program is feasible, and HAI can be delivered safely to selected patients with CRLM. The initial response and DCR are promising, even for patients heavily pretreated with chemotherapy.

Histopathological growth patterns as biomarker for adjuvant systemic chemotherapy in patients with resected colorectal liver metastases.

Adjuvant systemic chemotherapy (CTx) is widely administered in patients with colorectal liver metastases (CRLM). Histopathological growth patterns (HGPs) are an independent prognostic factor for survival after complete resection. This study evaluates whether HGPs can predict the effectiveness of adjuvant CTx in patients with resected CRLM. Two main types of HGPs can be distinguished; the desmoplastic type and the non-desmoplastic type. Uni- and multivariable analyses for overall survival (OS) and disease-free survival (DFS) were performed, in both patients treated with and without preoperative chemotherapy. A total of 1236 patients from two tertiary centers (Memorial Sloan Kettering Cancer Center, New York, USA; Erasmus MC Cancer Institute, Rotterdam, The Netherlands) were included (period 2000-2016). A total of 656 patients (53.1%) patients received preoperative chemotherapy. Adjuvant CTx was only associated with a superior OS in non-desmoplastic patients that had not been pretreated (adjusted hazard ratio (HR) 0.52, 95% confidence interval (CI) 0.37-0.73, p < 0.001), and not in desmoplastic patients (adjusted HR 1.78, 95% CI 0.75-4.21, p = 0.19). In pretreated patients no significant effect of adjuvant CTx was observed, neither in the desmoplastic group (adjusted HR 0.83, 95% CI 0.49-1.42, p = 0.50) nor in the non-desmoplastic group (adjusted HR 0.96, 95% CI 0.71-1.29, p = 0.79). Similar results were found for DFS, with a superior DFS in non-desmoplastic patients treated with adjuvant CTx (HR 0.71, 95% CI 0.55-0.93, p < 0.001) that were not pretreated. Adjuvant CTx seems to improve OS and DFS after resection of non-desmoplastic CRLM. However, this effect was only observed in patients that were not treated with chemotherapy.

Radiomics-based prediction of microsatellite instability in colorectal cancer at initial computed tomography evaluation.

PURPOSE: To predict microsatellite instability (MSI) status of colon cancer on preoperative CT imaging using radiomic analysis. METHODS: This retrospective study involved radiomic analysis of preoperative CT imaging of patients who underwent resection of stage II-III colon cancer from 2004 to 2012. A radiologist blinded to MSI status manually segmented the tumor region on CT images. 254 Intensity-based radiomic features were extracted from the tumor region. Three prediction models were developed with (1) only clinical features, (2) only radiomic features, and (3) "combined" clinical and radiomic features. Patients were randomly separated into training (n = 139) and test (n = 59) sets. The model was constructed from training data only; the test set was reserved for validation only. Model performance was evaluated using AUC, sensitivity, specificity, PPV, and NPV. RESULTS: Of the total 198 patients, 134 (68%) patients had microsatellite stable tumors and 64 (32%) patients had MSI tumors. The combined model performed slightly better than the other models, predicting MSI with an AUC of 0.80 for the training set and 0.79 for the test set (specificity = 96.8% and 92.5%, respectively), whereas the model with only clinical features achieved an AUC of 0.74 and the model with only radiomic features achieved an AUC of 0.76. The model with clinical features alone had the lowest specificity (70%) compared with the model with radiomic features alone (95%) and the combined model (92.5%). CONCLUSIONS: Preoperative prediction of MSI status via radiomic analysis of preoperative CT adds specificity to clinical assessment and could contribute to personalized treatment selection.

Evolution of surgical management of gallbladder carcinoma and impact on outcome: results from two decades at a single-institution.

BACKGROUND: The surgical approach to gallbladder cancer (GBCA) has evolved in recent years, but the impact on outcomes is unknown. This study describes differences in presentation, surgery, chemotherapy strategy, and survival for patients with GBCA over two decades at a tertiary referral center. METHODS: A single-institution database was queried for patients with GBCA who underwent surgical evaluation and exploration and was studied retrospectively. Univariate logistic regression was used to assess the relationship between time and treatment. Univariate Cox proportional hazard regression assessed the association between year of diagnosis and survival. RESULTS: From 1992 to 2015, 675 patients with GBCA were evaluated and 437 underwent exploration. Complete resection rates increased over time (p < 0.001). In those submitted to complete resection (n = 255, 58.4%), more recent years were associated with lower likelihood of bile duct resection and major hepatectomy but greater odds of neoadjuvant and adjuvant chemotherapy (p < 0.05). No significant association was found between year of diagnosis and OS or RFS (p > 0.05) for patients with complete resection. CONCLUSION: Over the study period, GBCA treatment evolved to include fewer biliary and major hepatic resections with no apparent adverse impact on outcome. Further prospective trials, specifically limited to GBCA, are needed to determine the impact of adjuvant chemotherapy.

Quantitative imaging features of pretreatment CT predict volumetric response to chemotherapy in patients with colorectal liver metastases.

OBJECTIVES: This study investigates whether quantitative image analysis of pretreatment CT scans can predict volumetric response to chemotherapy for patients with colorectal liver metastases (CRLM). METHODS: Patients treated with chemotherapy for CRLM (hepatic artery infusion (HAI) combined with systemic or systemic alone) were included in the study. Patients were imaged at baseline and approximately 8 weeks after treatment. Response was measured as the percentage change in tumour volume from baseline. Quantitative imaging features were derived from the index hepatic tumour on pretreatment CT, and features statistically significant on univariate analysis were included in a linear regression model to predict volumetric response. The regression model was constructed from 70% of data, while 30% were reserved for testing. Test data were input into the trained model. Model performance was evaluated with mean absolute prediction error (MAPE) and R2. Clinicopatholologic factors were assessed for correlation with response. RESULTS: 157 patients were included, split into training (n = 110) and validation (n = 47) sets. MAPE from the multivariate linear regression model was 16.5% (R2 = 0.774) and 21.5% in the training and validation sets, respectively. Stratified by HAI utilisation, MAPE in the validation set was 19.6% for HAI and 25.1% for systemic chemotherapy alone. Clinical factors associated with differences in median tumour response were treatment strategy, systemic chemotherapy regimen, age and KRAS mutation status (p < 0.05). CONCLUSION: Quantitative imaging features extracted from pretreatment CT are promising predictors of volumetric response to chemotherapy in patients with CRLM. Pretreatment predictors of response have the potential to better select patients for specific therapies. KEY POINTS: • Colorectal liver metastases (CRLM) are downsized with chemotherapy but predicting the patients that will respond to chemotherapy is currently not possible. • Heterogeneity and enhancement patterns of CRLM can be measured with quantitative imaging. • Prediction model constructed that predicts volumetric response with 20% error suggesting that quantitative imaging holds promise to better select patients for specific treatments.

Regional differences in gallbladder cancer pathogenesis: Insights from a multi-institutional comparison of tumor mutations.

BACKGROUND: Although rare in the United States, gallbladder cancer (GBCA) is a common cause of cancer death in some parts of the world. To investigate regional differences in pathogenesis and outcomes for GBCA, tumor mutations were analyzed from a sampling of specimens. METHODS: Primary tumors from patients with GBCA who were treated in Chile, Japan, and the United States between 1999 and 2016 underwent targeted sequencing of known cancer-associated genes. Fisher exact and Kruskal-Wallis tests assessed differences in clinicopathologic and genetic factors. Kaplan-Meier methods evaluated differences in overall survival from the time of surgery between mutations. RESULTS: A total of 81 patients were included. Japanese patients (11 patients) were older (median age, 72 years [range, 54-81 years]) compared with patients from Chile (21 patients; median age, 59 years [range, 32-73 years]) and the United States (49 patients; median age, 66 years [range, 46-87 years]) (P = .002) and had more well-differentiated tumors (46% vs 0% for Chile/United States; P < .001) and fewer gallstone-associated cancers (36% vs 67% for Chile and 69% for the United States; P = .13). Japanese patients had a median mutation burden of 6 (range, 1-23) compared with Chile (median mutation burden, 7 [range, 3-20]) and the United States (median mutation burden, 4 [range, 0-27]) (P = .006). Tumors from Japanese patients lacked AT-rich interaction domain 1A (ARID1A) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutations, whereas Chilean tumors lacked Erb-B2 receptor tyrosine kinase 3 (ERBB3) and AT-rich interaction domain 2 (ARID2) mutations. SMAD family member 4 (SMAD4) was found to be mutated similarly across centers (38% in Chile, 36% in Japan, and 27% in the United States; P = .68) and was univariately associated with worse overall survival (median, 10 months vs 25 months; P = .039). At least one potentially actionable gene was found to be altered in 80% of tumors. CONCLUSIONS: Differences in clinicopathologic variables suggest the possibility of distinct GBCA pathogenesis in Japanese patients, which may be supported by differences in mutation pattern. Among all centers, SMAD4 mutations were detected in approximately one-third of patients and may represent a converging factor associated with worse survival. The majority of patients carried mutations in actionable gene targets, which may inform the design of future trials.

Actual 10-year survival after hepatic resection of colorectal liver metastases: what factors preclude cure?

BACKGROUND: Hepatic resection of colorectal liver metastases is associated with long-term survival. This study analyzes actual 10-year survivors after resection of colorectal liver metastases, reports the observed rate of cure, and identifies factors that preclude cure. METHODS: A single-institution, prospectively maintained database was queried for all initial resections for colorectal liver metastases for the years 1992-2004. Observed cure was defined as actual 10-year survival with either no recurrence or resected recurrence with at least 3 years of disease-free follow-up. Clinical risk score was dichotomized into low (0-2) and high (3-5). Semiparametric proportional hazards mixture cure model was utilized to estimate probability of cure. RESULTS: We included 1,211 patients with a median follow-up for survivors of 11 years. Median disease-specific survival was 4.9 years (95% CI: 4.4-5.3). 295 patients (24.4%) were actual 10-year survivors. The observed cure rate was 20.6% (n = 250). Among 250 cured patients, 192 (76.8%) had no recurrence and 58 (23.2%) had a resected recurrence with at least 3 years of disease-free follow-up. Extrahepatic disease (n = 88), carcinoembryonic antigen >200 ng/mL (n = 119), positive margin (n = 109), and >10 tumors (n = 31) had observed cure rates less than 10%. In cure model analysis, patients with both extrahepatic disease and high clinical risk score (n = 31) had an estimated probability of cure of 3.5%. CONCLUSION: Actual 10-year survival after resection of colorectal liver metastases is 24% with an observed 20% cure rate. Patients with both high clinical risk score and extrahepatic disease have an estimated probability of cure less than 5%. When such factors are identified, strong consideration may be given to preoperative strategies, such as neoadjuvant chemotherapy, to help select patients for surgical therapy.

The Impact of Primary Tumor Location on Long-Term Survival in Patients Undergoing Hepatic Resection for Metastatic Colon Cancer.

BACKGROUND: The impact of primary tumor location on overall survival (OS), recurrence-free survival (RFS), and long-term outcomes has not been well established in patients undergoing potentially curative resection of colorectal liver metastases (CRLM). METHODS: A single-institution database was queried for initial resections for CRLM 1992-2004. Primary tumor location determined by chart review (right = cecum to transverse; left = splenic flexure to sigmoid). Rectal cancer (distal 16 cm), multiple primaries, and unknown location were excluded. Kaplan-Meier and Cox regression methods were used. Cure was defined as actual 10-year survival with either no recurrence or resected recurrence with at least 3 years of disease-free follow-up. RESULTS: A total of 907 patients were included with a median follow-up of 11 years; 578 patients (64%) had left-sided and 329 (36%) right-sided primaries. Median OS for patients with a left-sided primary was 5.2 years (95% confidence interval [CI] 4.6-6.0) versus 3.6 years (95% CI 3.2-4.2) for right-sided (p = 0.004). On multivariable analysis, the hazard ratio for right-sided tumors was 1.22 (95% CI 1.02-1.45, p = 0.028) after adjusting for common clinicopathologic factors. Median RFS was marginally different stratified by primary location (1.3 vs. 1.7 years; p = 0.065). On multivariable analysis, location of primary was not significantly associated with RFS (p = 0.105). Observed cure rates were 22% for left-sided and 20% for right-sided tumors. CONCLUSIONS: Among patients undergoing resection of CRLM, left-sided primary tumors were associated with improved median OS. However, long-term survival and recurrence-free survival were not significantly different stratified by primary location. Patients with left-sided primary tumors displayed a prolonged clinical course suggestive of more indolent biology.

Hypophosphatemia after Hepatectomy or Pancreatectomy: Role of the Nicotinamide Phosphoribosyltransferase.

BACKGROUND: Postoperative hypophosphatemia is common and is associated with a lower risk of liver failure after hepatectomy, but higher morbidity after pancreatectomy. Whether different physiologic mechanisms underlie the hypophosphatemia associated with these very different clinical outcomes is unclear. This study aims to evaluate the underlying mechanism in postoperative hypophosphatemia. STUDY DESIGN: We prospectively enrolled 120 patients who underwent major hepatectomy (n = 30), minor hepatectomy (n = 30), pancreatectomy (n = 30), and laparotomy without resection (control group, n = 30). Preoperative and postoperative serum and urinary phosphorus, calcium, and creatinine, as well as phosphaturic factors, including serum nicotinamide phosphoribosyltransferase (NAMPT), fibroblast growth factor-23, and parathyroid hormone were measured. In addition, we evaluated urinary levels of nicotinamide catabolites, N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-3-carboxamide. RESULTS: We found that significant hypophosphatemia occurred from postoperative day (POD) 1 to POD 2 in all 4 groups and was preceded by hyperphosphaturia from preoperative day to POD 1. Phosphate level alterations were associated with a significant increase in NAMPT levels from preoperative day to POD 2 in all 3 resected groups, but not in the control group. The fibroblast growth factor-23 levels were significantly decreased postoperatively in all 4 groups, and parathyroid hormone levels did not change in any of the 4 groups. Urine levels of N-methyl-2-pyridone-5-carboxamide and N-methyl-4-pyridone-3-carboxamide decreased significantly in all 4 groups postoperatively. CONCLUSIONS: This study demonstrates that the mechanism of hypophosphatemia is the same for both liver and pancreas resections. Postoperative hypophosphatemia is associated with increased NAMPT. The mechanism that upregulates NAMPT and its role on disparate clinical outcomes in postoperative patients warrant additional investigation.

Computed Tomography Image Texture: A Noninvasive Prognostic Marker of Hepatic Recurrence After Hepatectomy for Metastatic Colorectal Cancer.

BACKGROUND: Recurrence after resection of colorectal liver metastases (CRLMs) occurs in up to 75% of patients. Preoperative prediction of hepatic recurrence may inform therapeutic strategies at the time of initial resection. Texture analysis (TA) is an established technique that quantifies pixel intensity variations (heterogeneity) on cross-sectional imaging. We hypothesized that tumoral and parenchymal changes that are predictive of overall survival (OS) and recurrence in the future liver remnant (FLR) can be detected using TA on preoperative computed tomography (CT) images. METHODS: Patients who underwent resection for CRLM between 2003 and 2007 with appropriate preoperative CT scans were included (n = 198) in this retrospective study. Texture features extracted from the tumor and FLR, and clinicopathologic variables, were incorporated into a multivariable survival model. RESULTS: Quantitative imaging features of the FLR were an independent predictor of both OS and hepatic disease-free survival (HDFS). Tumor texture showed significant association with OS. TA of the FLR allowed patient stratification into two groups, with significantly different risks of hepatic recurrence (hazard ratio 2.09, 95% confidence interval 1.33-3.28; p = 0.001). Patients with homogeneous parenchyma had approximately twice the risk of hepatic recurrence (41 vs. 20%). CONCLUSION: TA of the tumor and FLR are independently associated with OS, and TA of the FLR is independently associated with HDFS. Patients with homogeneous parenchyma had a significantly higher risk of hepatic recurrence. Preoperative TA of the liver represents a potential biomarker to identify patients at risk of liver recurrence after resection for CRLM.