Long-Duration Neoadjuvant Therapy with FOLFIRINOX Yields Favorable Outcomes for Patients Who Undergo Surgery for Pancreatic Cancer.

BACKGROUND: In 2023 alone, it's estimated that over 64,000 patients will be diagnosed with PDAC and more than 50,000 patients will die of the disease. Current guidelines recommend neoadjuvant therapy for patients with borderline resectable and locally advanced PDAC, and data is emerging on its role in resectable disease. Neoadjuvant chemotherapy may increase the number of patients able to receive complete chemotherapy regimens, increase the rate of microscopically tumor-free resection (R0) margin, and aide in identifying unfavorable tumor biology. To date, this is the largest study to examine surgical outcomes after long-duration neoadjuvant chemotherapy for PDAC. METHODS: Retrospective analysis of single-institution data. RESULTS: The routine use of long-duration therapy in our study (median cycles: FOLFIRINOX = 10; gemcitabine-based = 7) is unique. The majority (85%) of patients received FOLFIRINOX without radiation therapy; the R0 resection rate was 76%. Median OS was 41 months and did not differ significantly among patients with resectable, borderline-resectable, or locally advanced disease. CONCLUSIONS: This study demonstrates that in patients who undergo surgical resection after receipt of long-duration neoadjuvant FOLFIRINOX therapy alone, survival outcomes are similar regardless of pretreatment resectability status and that favorable surgical outcomes can be attained.

A critical appraisal of the current landscape of resectable BRAF mutated colorectal liver metastases: a systematic review.

BACKGROUND: Patients with surgically resectable BRAF-mutated colorectal liver metastases (CRLM) or limited extrahepatic disease constitute a highly selective subgroup among BRAF-mutated patients, characterized by a more indolent disease biology. This is evident in their suitability for surgical resection. However, initial studies from a decade ago presented a discouraging outlook for these patients, citing early, frequent, multifocal recurrences and a very limited median overall survival (OS) of less than two years. Our objective was to provide an updated, comprehensive, and critically assessed review of the current literature on the prognostic impact of BRAF variants in CRLM, as well as to explore optimal treatment strategies for these patients through a systematic search. METHODS: A systematic literature search of the Medline, Scopus, and CENTRAL databases for studies reporting long-term outcomes of patients with a known BRAF status was performed. RESULTS: A total of 386 unique studies were screened during the study selection process. After applying the exclusion criteria, a total of 18 studies published between 2012 and 2023 were deemed eligible for inclusion. CONCLUSIONS: In contrast to older studies, more recent studies, with larger sample sizes, have revealed that the rate of extrahepatic recurrence is comparable between BRAF-mutated and wild-type patients. Furthermore, they have reported significantly improved survival outcomes, with OS extending up to 52 months. Notably, patients with non-V600E BRAF mutations may even achieve outcomes comparable to those with wild-type BRAF CRLM. Additionally, a few recent studies have compared surgery and systemic therapies, indicating that surgery is associated with improved survival rates, even for patients with the V600E mutation. This challenges the previous belief that BRAF mutations are absolute contraindications to surgical treatment. Surgical denial for technically resectable patients may now be reserved for specific clinical scenarios, such as the presence of a BRAF V600E mutation and concurrent extrahepatic disease.

National practice patterns in the use of endoscopic ultrasound biopsy for resectable Pancreatic Neuroendocrine Tumors: Insights into the role of DOTATATE PET/CT in diagnosis.

INTRODUCTION: Pancreatic neuroendocrine tumors (PNETs) are typically diagnosed using endoscopic ultrasound-guided (EUS) biopsy, which can be associated with complications. Since 2016, DOTATATE PET/CT has emerged as an effective tool to localize and stage PNETs. METHODS: Patients with PNETs who underwent R0 resections were identified from the 2004-2019 National Cancer Database PUF. Joinpoint regression and multivariable logistic regression were used to analyze trends in the use of biopsy. RESULTS: Of 16,746 R0 resected PNET patients, 44 â€‹% underwent diagnostic biopsy. Joinpoint regression showed a significant increase in the use of biopsy from 2004 to 2019 (APC 1.80, p â€‹< â€‹0.001). A higher percentage of patients diagnosed after DOTATATE approval underwent biopsy compared to those diagnosed before (48 â€‹% vs. 42 â€‹%, p â€‹< â€‹0.001). Adjusted analysis showed diagnosis after 2016 was associated with increased odds of biopsy (OR â€‹= â€‹1.67, p â€‹< â€‹0.001). CONCLUSIONS: Despite technologic advancement with DOTATATE PET/CT, there has been a significant increase in the proportion of resectable PNETs undergoing preoperative biopsy.

A machine learning approach for predicting textbook outcome after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

INTRODUCTION: Peritoneal carcinomatosis is considered a late-stage manifestation of neoplastic diseases. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) can be an effective treatment for these patients. However, the procedure is associated with significant morbidity. Our aim was to develop a machine learning model to predict the probability of achieving textbook outcome (TO) after CRS-HIPEC using only preoperatively known variables. METHODS: Adult patients with peritoneal carcinomatosis and who underwent CRS-HIPEC were included from a large, single-center, prospectively maintained dataset (2001-2020). TO was defined as a hospital length of stay ≤14 days and no postoperative adverse events including any complications, reoperation, readmission, and mortality within 90 days. Four models (logistic regression, neural network, random forest, and XGBoost) were trained, validated, and a user-friendly risk calculator was then developed. RESULTS: A total of 1954 CRS-HIPEC procedures for peritoneal carcinomatosis were included. Overall, 13% (n = 258) achieved TO following CRS-HIPEC procedure. XGBoost and logistic regression had the highest area under the curve (AUC) (0.76) after model optimization, followed by random forest (AUC 0.75) and neural network (AUC 0.74). The top preoperative variables associated with achieving a TO were lower peritoneal cancer index scores, not undergoing proctectomy, splenectomy, or partial colectomy and being asymptomatic from peritoneal metastases prior to surgery. CONCLUSION: This is a data-driven study to predict the probability of achieving TO after CRS-HIPEC. The proposed pipeline has the potential to not only identify patients for whom surgery is not associated with prohibitive risk, but also aid surgeons in communicating this risk to patients.

Robotic-assisted endoluminal gastric leiomyoma resection: a novel surgical technique for benign gastroesophageal junction tumors.

Gastric leiomyomas are rare, benign smooth muscle tumors that arise from the muscularis propria and can be found in any part of the stomach. The American College of Gastroenterologists recommends resection only for symptomatic leiomyomas, which can often present with bleeding, abdominal pain, or dyspepsia. Notably, symptomatic leiomyomas that arise at the gastroesophageal (GE) junction, especially those that are large, pose unique challenges. Specifically, total gastrectomy with esophagojejunostomy is often necessary, which can be associated with a compromised quality of life and possible complications such as anastomotic stricture or reflux esophagitis. In this context, we present the case of a young, male patient with a large symptomatic leiomyoma at the GE junction who was offered a robotic-assisted endoluminal leiomyoma resection. By placing endoluminal trocars and utilizing the Da Vinci® robot, we were able to carefully excise the tumor without perforating the stomach or causing GE junction stenosis. This allowed the patient to preserve his stomach and avoid a high-risk anastomosis. Another notable highlight of the case included the use of the endoscope as both a bougie and a source of insufflation. The patient had an uncomplicated postoperative course and a rapid recovery, highlighting the feasibility of this approach for patients with benign GE junction tumors.

A Novel Machine Learning Approach to Predict Textbook Outcome in Colectomy.

BACKGROUND: Several calculators exist to predict risk of postoperative complications. However, in low-risk procedures such as colectomy, a tool to determine the probability of achieving the ideal outcome could better aid clinical decision-making, especially for high-risk patients. A textbook outcome is a composite measure that serves as a surrogate for the ideal surgical outcome. OBJECTIVE: To identify the most important factors for predicting textbook outcomes in patients with nonmetastatic colon cancer undergoing colectomy and to create a textbook outcome decision support tool using machine learning algorithms. DESIGN: This was a retrospective analysis study. SETTINGS: Data were collected from the American College of Surgeons National Surgical Quality Improvement Program database. PATIENTS: Adult patients undergoing elective colectomy for nonmetastatic colon cancer (2014-2020) were included. MAIN OUTCOME MEASURES: Textbook outcome was the main outcome, defined as no mortality, no 30-day readmission, no postoperative complications, no 30-day reinterventions, and a hospital length of stay of ≤5 days. Four models (logistic regression, decision tree, random forest, and eXtreme Gradient Boosting) were trained and validated. Ultimately, a web-based calculator was developed as proof of concept for clinical application. RESULTS: A total of 20,498 patients who underwent colectomy for nonmetastatic colon cancer were included. Overall, textbook outcome was achieved in 66% of patients. Textbook outcome was more frequently achieved after robotic colectomy (77%), followed by laparoscopic colectomy (68%) and open colectomy (39%, p < 0.001). eXtreme Gradient Boosting was the best performing model (area under the curve = 0.72). The top 5 preoperative variables to predict textbook outcome were surgical approach, patient age, preoperative hematocrit, preoperative oral antibiotic bowel preparation, and patient sex. LIMITATIONS: This study was limited by its retrospective nature of the analysis. CONCLUSIONS: Using textbook outcome as the preferred outcome may be a useful tool in relatively low-risk procedures such as colectomy, and the proposed web-based calculator may aid surgeons in preoperative evaluation and counseling, especially for high-risk patients. See Video Abstract . UN NUEVO ENFOQUE DE APRENDIZAJE AUTOMTICO PARA PREDECIR EL RESULTADO DE LOS LIBROS DE TEXTO EN COLECTOMA: ANTECEDENTES:Existen varias calculadoras para predecir el riesgo de complicaciones posoperatorias. Sin embargo, en procedimientos de bajo riesgo como la colectomía, una herramienta para determinar la probabilidad de lograr el resultado ideal podría ayudar mejor a la toma de decisiones clínicas, especialmente para pacientes de alto riesgo. Un resultado de libro de texto es una medida compuesta que sirve como sustituto del resultado quirúrgico ideal.OBJETIVO:Identificar los factores más importantes para predecir el resultado de los libros de texto en pacientes con cáncer de colon no metastásico sometidos a colectomía y crear una herramienta de apoyo a la toma de decisiones sobre los resultados de los libros de texto utilizando algoritmos de aprendizaje automático.DISEÑO:Este fue un estudio de análisis retrospectivo.AJUSTES:Los datos se obtuvieron de la base de datos del Programa Nacional de Mejora de la Calidad del Colegio Americano de Cirujanos.PACIENTES:Se incluyeron pacientes adultos sometidos a colectomía electiva por cáncer de colon no metastásico (2014-2020).MEDIDAS PRINCIPALES DE RESULTADO:El resultado de los libros de texto fue el resultado principal, definido como ausencia de mortalidad, reingreso a los 30 días, complicaciones posoperatorias, reintervenciones a los 30 días y una estancia hospitalaria ≤5 días. Se entrenaron y validaron cuatro modelos (regresión logística, árbol de decisión, bosque aleatorio y XGBoost). Finalmente, se desarrolló una calculadora basada en la web como prueba de concepto para su aplicación clínica.RESULTADOS:Se incluyeron un total de 20.498 pacientes sometidos a colectomía por cáncer de colon no metastásico. En general, el resultado de los libros de texto se logró en el 66% de los pacientes. Los resultados de los libros de texto se lograron con mayor frecuencia después de la colectomía robótica (77%), seguida de la colectomía laparoscópica (68%) y la colectomía abierta (39%) (p<0,001). XGBoost fue el modelo con mejor rendimiento (AUC=0,72). Los cinco principales variables preoperatorias para predecir el resultado en los libros de texto fueron el abordaje quirúrgico, la edad del paciente, el hematocrito preoperatorio, la preparación intestinal con antibióticos orales preoperatorios y el sexo femenino.LIMITACIONES:Este estudio estuvo limitado por la naturaleza retrospectiva del análisis.CONCLUSIONES:El uso de los resultados de los libros de texto como resultado preferido puede ser una herramienta útil en procedimientos de riesgo relativamente bajo, como la colectomía, y la calculadora basada en la web propuesta puede ayudar a los cirujanos en la evaluación y el asesoramiento preoperatorios, especialmente para pacientes de alto riesgo. (Traducción-Yesenia Rojas-Khalil ).

Instrument and Supply Variability: An Opportunity to Reduce the Carbon Footprint of the Operating Room.

INTRODUCTION: Reducing costs and carbon footprints are important, parallel priorities for the US health-care system. Within surgery, reducing the number of instruments that are sterilized and disposable supplies that are used for each operation may help achieve both goals. We wanted to measure the existing variability in surgical instrument and supply choices and assess whether standardization could have a meaningful cost and environmental impact. METHODS: We analyzed surgeon preference cards for common general surgery operations at our hospital to measure the number of sterilizable instrument trays and supplies used by each surgeon for each operation. From this data, we calculated supply costs, carbon footprint, and median operative time and studied the variability in each of these metrics. RESULTS: Among the ten operations studied, variability in sterilizable instrument trays requested on surgeon preference cards ranged from one to eight. Variability in disposable supplies requested ranged from 17 to 45. Variability in open supply costs ranged from $104 to $4184. Variability in carbon footprint ranged from 17 to 708 kg CO2e. If the highest-cost surgeon for each operation switched their preference card to that of the median-cost surgeon, $245,343 in open supply costs and 41,708 kg CO2e could be saved. CONCLUSIONS: There is significant variability in the instrument and supply choices of surgeons performing common general surgery operations. Standardizing this variability may lead to meaningful cost savings and carbon footprint reduction, especially if scaled across the entire health system.

A Machine Learning Approach to Predict Postoperative Pancreatic Fistula After Pancreaticoduodenectomy Using Only Preoperatively Known Data.

BACKGROUND: Clinically-relevant postoperative pancreatic fistula (CR-POPF) following pancreaticoduodenectomy (PD) is a major postoperative complication and the primary determinant of surgical outcomes. However, the majority of current risk calculators utilize intraoperative and postoperative variables, limiting their utility in the preoperative setting. Therefore, we aimed to develop a user-friendly risk calculator to predict CR-POPF following PD using state-of-the-art machine learning (ML) algorithms and only preoperatively known variables. METHODS: Adult patients undergoing elective PD for non-metastatic pancreatic cancer were identified from the ACS-NSQIP targeted pancreatectomy dataset (2014-2019). The primary endpoint was development of CR-POPF (grade B or C). Secondary endpoints included discharge to facility, 30-day mortality, and a composite of overall and significant complications. Four models (logistic regression, neural network, random forest, and XGBoost) were trained, validated and a user-friendly risk calculator was then developed. RESULTS: Of the 8666 patients who underwent elective PD, 13% (n = 1160) developed CR-POPF. XGBoost was the best performing model (AUC = 0.72), and the top five preoperative variables associated with CR-POPF were non-adenocarcinoma histology, lack of neoadjuvant chemotherapy, pancreatic duct size less than 3 mm, higher BMI, and higher preoperative serum creatinine. Model performance for 30-day mortality, discharge to a facility, and overall and significant complications ranged from AUC 0.62-0.78. CONCLUSIONS: In this study, we developed and validated an ML model using only preoperatively known variables to predict CR-POPF following PD. The risk calculator can be used in the preoperative setting to inform clinical decision-making and patient counseling.

Lymph Node Dissection in Intrahepatic Cholangiocarcinoma: a Critical and Updated Review of the Literature.

BACKGROUND: Lymphatic spread of intrahepatic cholangiocarcinoma (iCCA) is common and negatively impacts survival. However, the precise role of lymph node dissection (LND) in oncologic outcomes for patients with intrahepatic cholangiocarcinoma remains to be established. METHODS: Updated evidence on the preoperative diagnosis and prognostic value of lymph node metastasis is reviewed, as well as the potential benefit of LND in patients with iCCA. RESULTS: The ability to accurately determine nodal status for iCCA with current imaging modalities is equivocal. LND has prognostic value for both survival and disease recurrence. However, execution rates of LND are highly varied in the literature, ranging from 26.9 to 100%. At least 6 lymph nodes should be examined from nodal stations of the hepatoduodenal ligament and hepatic artery as well as based on the location of the primary tumor. Neoadjuvant therapies may be beneficial if lymph node metastases at diagnosis are suspected. Surgeons performing a minimally invasive approach should focus on increasing LND rates and harvesting ≥ 6 lymph nodes. Lymph node negativity is required in patients with iCCA being considered for liver transplantation under investigational protocols. CONCLUSION: Despite an upward trend in the LND rate, the reality is that only 10% of patients with iCCA receive an adequate LND. This review underscores the importance of routinely increasing the rate of adequate LND in these patients in order to achieve accurate staging, appropriately select patients for adjuvant therapy, and improve the prognosis of clinical outcomes. While prospective data is lacking, the therapeutic impact of LND remains unknown.

Development and Validation of Prediction Models and Risk Calculators for Posthepatectomy Liver Failure and Postoperative Complications Using a Diverse International Cohort of Major Hepatectomies.

OBJECTIVE: The study aim was to develop and validate models to predict clinically significant posthepatectomy liver failure (PHLF) and serious complications [a Comprehensive Complication Index (CCI)>40] using preoperative and intraoperative variables. BACKGROUND: PHLF is a serious complication after major hepatectomy but does not comprehensively capture a patient's postoperative course. Adding the CCI as an additional metric can account for complications unrelated to liver function. METHODS: The cohort included adult patients who underwent major hepatectomies at 12 international centers (2010-2020). After splitting the data into training and validation sets (70:30), models for PHLF and a CCI>40 were fit using logistic regression with a lasso penalty on the training cohort. The models were then evaluated on the validation data set. RESULTS: Among 2192 patients, 185 (8.4%) had clinically significant PHLF and 160 (7.3%) had a CCI>40. The PHLF model had an area under the curve (AUC) of 0.80, calibration slope of 0.95, and calibration-in-the-large of -0.09, while the CCI model had an AUC of 0.76, calibration slope of 0.88, and calibration-in-the-large of 0.02. When the models were provided only preoperative variables to predict PHLF and a CCI>40, this resulted in similar AUCs of 0.78 and 0.71, respectively. Both models were used to build 2 risk calculators with the option to include or exclude intraoperative variables ( PHLF Risk Calculator; CCI>40 Risk Calculator ). CONCLUSIONS: Using an international cohort of major hepatectomy patients, we used preoperative and intraoperative variables to develop and internally validate multivariable models to predict clinically significant PHLF and a CCI>40 with good discrimination and calibration.

Using the Comprehensive Complication Index to Rethink the ISGLS Criteria for Post-hepatectomy Liver Failure in an International Cohort of Major Hepatectomies.

OBJECTIVE: To compare different criteria for post-hepatectomy liver failure (PHLF) and evaluate the association between International Study Group of Liver Surgery (ISGLS) PHLF and the Comprehensive Complication Index (CCI)" and 90-day mortality. SUMMARY OF BACKGROUND DATA: PHLF is a serious complication following hepatic resection. Multiple criteria have been developed to characterize PHLF. METHODS: Adults who underwent major hepatectomies at twelve international centers (2010-2020) were included. We identified patients who met criteria for PHLF based on three definitions: 1) ISGLS, 2) Balzan (INR > 1.7 and bilirubin > 2.92mg/dL) or 3) Mullen (peak bilirubin >7mg/dL). We compared the 90-day mortality and major morbidity predicted by each definition. We then used logistic regression to determine the odds of CCI>40 and 90-day mortality associated with ISGLS grades. RESULTS: Among 1646 included patients, 19 (1.1%) met Balzan, 68 (4.1%) met Mullen, and 444 (27.0%) met ISGLS criteria for PHLF. Of the three definitions, the ISGLS criteria best predicted 90-day mortality (AUC = 0.72; sensitivity 69.4%). Patients with ISGLS grades B&C were at increased odds of CCI > 40 (grade B OR 4.0; 95% CI: 2.2-7.2; grade C OR 137.0; 95% CI: 59.2-317.4). Patients with ISGLS grade C were at increased odds of 90-day mortality (OR 113.6; 95% CI: 55.6-232.1). Grade A was not associated with CCI> 40 or 90-day mortality. CONCLUSIONS: In this diverse international cohort of major hepatectomies, ISGLS grade A was not associated with 90-day mortality or high CCI, calling into question the current classification of patients in this group as having clinically significant PHLF.

Virtual Interviews: Assessing How Expectations Meet Reality.

OBJECTIVE: This study aimed to determine the post-matriculation perceptions of interns and faculty who participated in the 2020-2021 virtual interview process and how their expectations of the program and the applicants, respectively, aligned with reality. DESIGN, SETTING, AND PARTICIPANTS: Published surveys on virtual interviewing were reviewed and modified to design two surveys, for interns and for faculty who interviewed. Interns and faculty members from the Departments of Surgery and Medicine at one institution who participated in the 2020-2021 virtual interview process completed the surveys four to six months after the start of the academic year. Following survey completion, surgical interns from the same application cycle participated in one in-person focus group nine months after the start of the academic year to clarify points raised in the surveys. RESULTS: Forty-six interns and faculty members responded to the survey (subgroup response rates ranging from 13-30%) and ten interns participated in the focus group (participation rate 100%). Most faculty and intern participants found that expectations formed during virtual interviews were accurate. However, our respondents noted limitations to virtual interviews that reduced their usefulness, including challenges with unnatural social interactions, understanding city fit, and getting a sense of resident and program culture. Participants provided possible solutions to address these challenges. CONCLUSIONS: Overall, this mixed-methods study at a single institution found that perceptions from virtual interviews were generally accurate but with some limitations. We describe several opportunities to improve the virtual interview process and optimize the application experience.

Mutant KRAS as a prognostic biomarker after hepatectomy for rectal cancer metastases: Does the primary disease site matter?

BACKGROUND: The prognostic implication of mutant KRAS (mKRAS) among patients with primary disease in the rectum remains unknown. METHODS: From 2000 to 2018, patients undergoing hepatectomy for colorectal liver metastases at 10 collaborating international institutions with documented KRAS status were surveyed. RESULTS: A total of 834 (65.8%) patients with primary colon cancer and 434 (34.2%) patients with primary rectal cancer were included. In patients with primary colon cancer, mKRAS served as a reliable prognostic biomarker of poor overall survival (OS) (hazard ratio [HR]: 1.58, 95% CI 1.28-1.95) in the multivariable analysis. Although a trend towards significance was noted, mKRAS was not found to be an independent predictor of OS in patients with primary rectal tumors (HR 1.34, 95% CI 0.98-1.80). For colon cancer, the specific codon impacted in mKRAS appears to reflect underlying disease biology and oncologic outcomes, with codon 13 being associated with particularly poor OS in patients with left-sided tumors (codon 12, HR 1.56, 95% CI 1.22-1.99; codon 13, HR 2.10 95% CI 1.43-3.08;). Stratifying the rectal patient population by codon mutation did not confer prognostic significance following hepatectomy. CONCLUSIONS: While the left-sided colonic disease is frequently grouped with rectal disease, our analysis suggests that there exist fundamental biologic differences that drive disparate outcomes. Although there was a trend toward significance of KRAS mutations for patients with primary rectal cancers, it failed to achieve statistical significance.

Performance of two prognostic scores that incorporate genetic information to predict long-term outcomes following resection of colorectal cancer liver metastases: An external validation of the MD Anderson and JHH-MSK scores.

INTRODUCTION: Two novel clinical risk scores (CRS) that incorporate KRAS mutation status were developed: modified CRS (mCRS) and GAME score. However, they have not been tested in large national and international cohorts. The aim of this study was to validate the prognostic discrimination utility and determine the clinical usefulness of the two novel CRS. METHODS: Patients undergoing hepatectomy for CRLM (2000-2018) in 10 centers were included. The discriminatory abilities of mCRS, GAME, and Fong CRS were evaluated using Harrell's C-index and Akaike's Information Criterion. RESULTS: In the entire cohort, the C-index of the GAME score (0.61) was significantly higher than those of Fong score (0.57) and mCRS (0.54), while the C-Index of mCRS was significantly lower than that of Fong score. When we compared the models in the various geographical regions, the C-index of GAME score was significantly higher than that of mCRS in North America, Europe, and South America. The AIC of Fong score, mCRS, and GAME score were 14 405, 14 447, and 14 319, respectively. CONCLUSION: In conclusion, using the largest and most heterogenous population of CRLM patients with known KRAS status, this independent, external validation demonstrated that the GAME score outperforms both the traditional Fong score and mCRS.

The optimal cut-off values for tumor size, number of lesions, and CEA levels in patients with surgically treated colorectal cancer liver metastases: An international, multi-institutional study.

BACKGROUND AND OBJECTIVES: Despite the long-standing consensus on the importance of tumor size, tumor number and carcinoembryonic antigen (CEA) levels as predictors of long-term outcomes among patients with colorectal liver metastases (CRLM), optimal prognostic cut-offs for these variables have not been established. METHODS: Patients who underwent curative-intent resection of CRLM and had available data on at least one of the three variables of interest above were selected from a multi-institutional dataset of patients with known KRAS mutational status. The resulting cohort was randomly split into training and testing datasets and recursive partitioning analysis was employed to determine optimal cut-offs. The concordance probability estimates (CPEs) for these optimal cut offs were calculated and compared to CPEs for the most widely used cut-offs in the surgical literature. RESULTS: A total of 1643 patients who met eligibility criteria were identified. Following recursive partitioning analysis in the training dataset, the following cut-offs were identified: 2.95 cm for tumor size, 1.5 for tumor number and 6.15 ng/ml for CEA levels. In the entire dataset, the calculated CPEs for the new tumor size (0.52), tumor number (0.56) and CEA (0.53) cut offs exceeded CPEs for other commonly employed cut-offs. CONCLUSION: The current study was able to identify optimal cut-offs for the three most commonly employed prognostic factors in CRLM. While the per variable gains in discriminatory power are modest, these novel cut-offs may help produce appreciable increases in prognostic performance when combined in the context of future risk scores.

The interplay of KRAS mutational status with tumor laterality in non-metastatic colorectal cancer: An international, multi-institutional study in patients with known KRAS, BRAF, and MSI status.

BACKGROUND: Although the prognostic relevance of KRAS status in metastatic colorectal cancer (CRC) depends on tumor laterality, this relationship is largely unknown in non-metastatic CRC. METHODS: Patients who underwent resection for non-metastatic CRC between 2000 and 2018 were identified from institutional databases at six academic tertiary centers in Europe and Japan. The prognostic relevance of KRAS status in patients with right-sided (RS), left-sided (LS), and rectal cancers was assessed. RESULTS: Of the 1093 eligible patients, 378 had right-sided tumors and 715 had left-sided tumors. Among patients with RS tumors, the 5-year overall (OS) and recurrence-free survival (RFS) for patients with KRASmut versus wild-type tumors was not shown to differ significantly (82.2% vs. 83.2% and 72.1% vs. 76.7%, respectively, all p > .05). Among those with LS tumors, KRAS mutation was associated with shorter 5-year OS and RFS on both the univariable (OS: 79.4% vs. 86.1%, p = .004; RFS: 68.8% vs. 77.3%, p = .005) and multivariable analysis (OS: HR: 1.52, p = .019; RFS: HR: 1.32, p = .05). CONCLUSIONS: KRAS mutation status was independently prognostic among patients with LS tumors, but this association failed to reach statistical significance in RS and rectal tumors. These findings confirm reports in metastatic CRC and underline the possible biologic importance of tumor location.

The Prognostic Impact of Primary Tumor Site Differs According to the KRAS Mutational Status: A Study By the International Genetic Consortium for Colorectal Liver Metastasis.

OBJECTIVE: To examine the prognostic impact of tumor laterality in colon cancer liver metastases (CLM) after stratifying by Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) mutational status. BACKGROUND: Although some studies have demonstrated that patients with CLM from a right sided (RS) primary cancer fare worse, others have found equivocal outcomes of patients with CLM with RS versus left-sided (LS) primary tumors. Importantly, recent evidence from unresectable metastatic CRC suggests that tumor laterality impacts prognosis only in those with wild-type tumors. METHODS: Patients with rectal or transverse colon tumors and those with unknown KRAS mutational status were excluded from analysis. The prognostic impact of RS versus LS primary CRC was determined after stratifying by KRAS mutational status. RESULTS: 277 patients had a RS (38.6%) and 441 (61.4%) had a LS tumor. Approximately one-third of tumors (28.1%) harbored KRAS mutations. In the entire cohort, RS was associated with worse 5-year overall survival (OS) compared with LS (39.4% vs 50.8%, P = 0.03) and remained significantly associated with worse OS in the multivariable analysis (hazard ratio 1.45, P = 0.04). In wild-type patients, a worse 5-year OS associated with a RS tumor was evident in univariable analysis (43.7% vs 55.5%, P = 0.02) and persisted in multivariable analysis (hazard ratio 1.49, P = 0.01). In contrast, among patients with KRAS mutated tumors, tumor laterality had no impact on 5-year OS, even in the univariable analysis (32.8% vs 34.0%, P = 0.38). CONCLUSIONS: This study demonstrated, for the first time, that the prognostic impact of primary tumor side differs according to KRAS mutational status. RS tumors were associated with worse survival only in patients with wild-type tumors.