Predicting Severe Complications from Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy: A Data-Driven, Machine Learning Approach to Augment Clinical Judgment.

BACKGROUND: CRS-HIPEC provides oncologic benefit in well-selected patients with peritoneal carcinomatosis; however, it is a morbid procedure. Decision tools for preoperative patient selection are limited. We developed a risk score to predict severity of 90 day complications for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). PATIENTS AND METHODS: Adults who underwent CRS-HIPEC at the University of Pittsburgh Medical Center (March 2001-April 2020) were analyzed as part of this study. Primary endpoint was severe complications within 90 days following CRS-HIPEC, defined using Comprehensive Complication Index (CCI) scores as a dichotomous (determined using restricted cubic splines) and continuous variable. Data were divided into training and test sets. Several machine learning and traditional algorithms were considered. RESULTS: For the 1959 CRS-HIPEC procedures included, CCI ranged from 0 to 100 (median 32.0). Adjusted restricted cubic splines model defined severe complications as CCI > 61. A minimum of 20 variables achieved optimal performance of any of the models. Linear regression achieved the highest area under the receiving operator characteristic curve (AUC, 0.74) and outperformed the NSQIP Surgical Risk calculator (AUC 0.80 vs. 0.66). Factors most positively associated with severe complications included peritoneal carcinomatosis index score, symptomatic status, and undergoing pancreatectomy, while American Society of Anesthesiologists 2 class, appendiceal diagnosis, and preoperative albumin were most negatively associated with severe complications. CONCLUSIONS: This study refines our ability to predict severe complications within 90 days of discharge from a hospitalization in which CRS-HIPEC was performed. This advancement is timely and relevant given the growing interest in this procedure and may have implications for patient selection, patient and referring provider comfort, and survival.

Impact of Primary Tumor Location and Genomic Alterations on Survival Following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemoperfusion for Colorectal Peritoneal Metastases.

BACKGROUND: Colorectal cancer leads to peritoneal metastases (CRPM) in 10% of cases. Cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC) improves survival. Primary tumor location and abnormalities in RAS, BRAF, and mismatch repair/microsatellite stability (MMR/MSI) may affect post-CRS-HIPEC survival, but studies have not been consistent. We estimated the effects of primary tumor site and genomic alterations on post-CRS-HIPEC survival. METHODS: This retrospective cohort study included CRS-HIPEC cases for CRPM at a high-volume center from 2001 to 2020. Next-generation sequencing and microsatellite testing defined the RAS, BRAF, and MMR/MSI genotypes. Adjusted effects of tumor sidedness and genomics on survival were evaluated using a multivariable Cox proportional hazards model. We analyzed these variables' effects on progression-free survival and the effects of immune checkpoint-inhibitors. RESULTS: A total of 250 patients underwent CRS-HIPEC with testing for RAS, BRAF, and MMR/MSI; 50.8% of patients were RAS-mutated, 12.4% were BRAF-mutated, and 6.8% were deficient-MMR/MSI-high (dMMR/MSI-H). Genomic alterations predominated in right-sided cancers. After adjustment for comorbidities and oncological and perioperative variables, rectal origin [hazard ratio (HR) 1.9, p = 0.01], RAS mutation (HR 1.6, p = 0.01), and BRAF mutation (HR 1.7, p = 0.05) were associated with worse survival. RAS mutation was also associated with shorter progression-free survival (HR 1.6, p = 0.01 at 6 months post-operatively), and dMMR/MSI-H status was associated with superior survival (HR 0.3, p = 0.01 at 2 years). dMMR/MSI-H patients receiving immune checkpoint-inhibitors trended toward superior survival. CONCLUSIONS: Rectal origin, RAS mutations, and BRAF mutations are each associated with poorer survival after CRS-HIPEC for CRPM. Patients with CRPM and dMMR/MSI-H status have superior survival. Further research should evaluate benefits of immune checkpoint-inhibitors in this subgroup.

Appendectomy Is Oncologically Equivalent to Right Hemicolectomy for Well-Differentiated T1 Appendiceal Adenocarcinoma.

BACKGROUND: Right hemicolectomy is recommended for appendiceal adenocarcinoma but may not be needed for early stage disease. OBJECTIVE: This study aimed to determine whether appendectomy offers adequate oncologic outcomes for T1 appendiceal adenocarcinoma from a national cohort of patients. DESIGN: Patients with T1 appendiceal adenocarcinoma (mucinous and nonmucinous histology) treated with either a right hemicolectomy or appendectomy between 2004 and 2016 were retrieved. Multivariate Cox regression analysis was used to identify predictors of overall survival. SETTING: The study was conducted using a national cancer database. PATIENTS: A total of 320 patients (median age, 62 y; 47% women) were identified: 69 (22%) underwent an appendectomy and 251 (78%) underwent a right hemicolectomy. MAIN OUTCOME MEASURE: Overall survival was measured. RESULTS: Nonmucinous adenocarcinoma was identified in 194 (61%), whereas 126 (39%) had mucinous adenocarcinoma. Of the overall cohort, 43% had well-differentiated histology, 39% had moderately differentiated disease, and 4% had poorly differentiated tumors. The rate of lymph node metastasis was lower in well-differentiated tumors (3%) compared with moderately (10%) or poorly differentiated tumors (25%). On univariate survival analysis, right hemicolectomy was associated with improved 1-, 3-, and 5-year overall survival in patients with moderately/poorly differentiated disease ( p < 0.001) but not for well-differentiated disease ( p = 1.000). After adjustment, right hemicolectomy was associated with overall survival improvement for moderately/poorly differentiated T1 adenocarcinoma (HR = 0.26 [95% CI, 0.08-0.82]; p = 0.02) but not for well-differentiated disease. LIMITATIONS: This study was limited by its retrospective nature. CONCLUSIONS: The current analysis from the National Cancer Database demonstrates that appendectomy is associated with equivalent survival to right hemicolectomy for well-differentiated T1 adenocarcinoma, whereas for moderately and poorly differentiated disease, right hemicolectomy is oncologically superior to appendectomy. See Video Abstract at http://links.lww.com/DCR/B689 . LA APENDICECTOMA ES ONCOLGICAMENTE EQUIVALENTE A LA HEMICOLECTOMA DERECHA PARA EL ADENOCARCINOMA APENDICULAR T BIEN DIFERENCIADO: ANTECEDENTES:La hemicolectomía derecha se recomienda para el adenocarcinoma apendicular, pero puede no ser necesaria para la enfermedad en estadio temprano.OBJETIVO:Este estudio tuvo como objetivo determinar si la apendicectomía ofrece resultados oncológicos adecuados para el adenocarcinoma apendicular T1 de una cohorte nacional de pacientes.DISEÑO:Se recuperaron pacientes con adenocarcinoma apendicular T1 (histología mucinoso y no mucinoso) tratados con hemicolectomía derecha o apendicectomía entre 2004-2016. Se utilizó un análisis de regresión de Cox multivariante para identificar los predictores de la supervivencia global.ENTORNO CLÍNICO:Base de datos nacional sobre cáncer.PACIENTES:Se identificaron un total de 320 pacientes (mediana de edad 62 años, 47% mujeres): 69 (22%) se sometieron a una apendicectomía y 251 (78%) se sometieron a una hemicolectomía derecha.PRINCIPAL MEDIDA DE RESULTADO:Sobrevida global.RESULTADOS:Se identificó adenocarcinoma no mucinoso en 194 (61%) mientras que 126 (39%) tenían adenocarcinoma mucinoso. De la cohorte general, el 43% tenía una histología bien diferenciada, el 39% tenía una enfermedad moderadamente diferenciada y el 4% tenía tumores poco diferenciados. La tasa de metástasis en los ganglios linfáticos fue menor en los tumores bien diferenciados (3%) en comparación con los tumores moderadamente (10%) o pobremente diferenciados (25%). En el análisis de sobrevida univariante, la hemicolectomía derecha se asoció con una mejor sobrevida general a 1, 3, y 5 años en pacientes con enfermedad moderada / pobremente diferenciada ( p < 0,001) pero no para la enfermedad bien diferenciada ( p = 1,000). Después del ajuste, la hemicolectomía derecha se asoció con una mejora de la sobrevida general para el adenocarcinoma T1 moderadamente / poco diferenciado (HR = 0,26, IC del 95%: 0,08-0,82, p = 0,02) pero no para la enfermedad bien diferenciada.LIMITACIONES:Este estudio estuvo limitado por su naturaleza retrospectiva.CONCLUSIONES:El análisis actual de la base de datos nacional de cáncer demuestra que la apendicectomía se asocia con una sobrevida similar a la hemicolectomía derecha para el adenocarcinoma T1 bien diferenciado, mientras que para la enfermedad moderada y pobremente diferenciada, la hemicolectomía derecha es oncológicamente superior a la apendicectomía. Consulte Video Resumen en http://links.lww.com/DCR/B689 . (Traducción-Dr. Yazmin Berrones-Medina ).

CD8 + T-cell Density Is an Independent Predictor of Survival and Response to Adjuvant Chemotherapy in Stage III Colon Cancer.

We assessed CD8 + T-cell density in 351 resected stage II to III colon cancers from 2011 to 2015 and correlated the findings with disease-free survival and survival effect of adjuvant chemotherapy. Most tumors (70%) had high/intermediate CD8 + T-cell density, and this was significantly associated with mismatch repair deficiency compared with tumors with low CD8 + T-cell density (28% vs. 13%, P =0.003). Fewer tumors with high/intermediate CD8 + T-cell density had adverse histologic features compared with tumors with low CD8 + T-cell density including high tumor budding (16% vs. 27%) and venous (22% vs. 35%), lymphatic (54% vs. 65%), and perineural (23% vs. 33%) invasion (all with P <0.05). In the stage III cohort, high/intermediate CD8 + T-cell density was an independent predictor of disease-free survival on multivariate analysis (hazard ratio: 0.39, 0.21 to 0.71 95% CI, P =0.002). For stage III patients with high/intermediate CD8 + T-cell density, adjuvant chemotherapy was significantly associated with improved disease-free survival (hazard ratio: 0.28, 0.11 to 0.74 95% CI, P =0.01) whereas stage III patients with low CD8 + T-cell density did not have improved survival with adjuvant chemotherapy. In conclusion, in stage III colon cancer, CD8 + T-cell density is an independent prognostic biomarker for disease-free survival and may help to identify patients who benefit from adjuvant chemotherapy.

DNA Mismatch Repair-deficient Rectal Cancer Is Frequently Associated With Lynch Syndrome and With Poor Response to Neoadjuvant Therapy.

We evaluated 368 consecutively resected rectal cancers with neoadjuvant therapy for DNA mismatch repair (MMR) protein status, tumor response to neoadjuvant therapy, histopathologic features, and patient survival. Nine (2.4%) rectal cancers were mismatch repair-deficient (MMRD): 8 (89%) Lynch syndrome-associated tumors and 1 (11%) sporadic MLH1-deficient tumor. Of the 9 MMRD rectal cancers, 89% (8/9) had a tumor regression score 3 (poor response) compared with 23% (81/359) of MMR proficient rectal cancers ( P <0.001). Patients with MMRD rectal cancer less often had downstaging after neoadjuvant therapy compared with patients with MMR proficient rectal cancer (11% vs. 57%, P =0.007). In the multivariable logistic regression analysis, MMRD in rectal cancer was associated with a 25.11-fold increased risk of poor response to neoadjuvant therapy (tumor regression score 3) (95% confidence interval [CI]: 3.08-44.63, P =0.003). In the multivariable Cox regression analysis, the only variables significantly associated with disease-free survival were pathologic stage III disease (hazard ratio [HR]=2.46, 95% CI: 1.54-3.93, P <0.001), College of American Pathologists (CAP) tumor regression score 2 to 3 (HR=3.44, 95% CI: 1.76-6.73, P <0.001), and positive margins (HR=2.86, 95% CI: 1.56-5.25, P =0.001). In conclusion, we demonstrated that MMRD in rectal cancer is an independent predictor of poor response to neoadjuvant therapy and infrequently results in pathologic downstaging following neoadjuvant therapy. We also confirmed that MMRD in rectal cancer is strongly associated with a diagnosis of Lynch syndrome. Our results suggest that MMR status may help to provide a more patient-centered approach when selecting neoadjuvant treatment regimens and may help predict tumor response to neoadjuvant therapy.

The Role of Adjuvant Chemotherapy Following Right Hemicolectomy for Non-metastatic Mucinous and Nonmucinous Appendiceal Adenocarcinoma.

BACKGROUND: Appendiceal adenocarcinoma (AA) represents a heterogenous group of neoplasms with distinct histologic features. The role and efficacy of adjuvant chemotherapy (AC) in non-metastatic disease remain controversial. The aim of this study was to ascertain the role of AC in non-metastatic AA in a national cohort of patients. METHODS: The National Cancer Database (NCDB) was queried to identify patients diagnosed with stage I-III mucinous and nonmucinous AA who underwent right hemicolectomy between 2006 and 2016. Kaplan-Meier and Cox regression analyses were used to evaluate the impact of AC on overall survival (OS) stratified by each pathologic stage. RESULTS: A total of 1433 mucinous and 1954 nonmucinous AA were identified; 578 (40%) and 722 (40%) received AC respectively. In both AC groups, there was a higher proportion of T4 disease, lymph node metastasis, pathologic stage III, and poorly/undifferentiated grade (all P<0.05). On unadjusted analysis, there was no significant association between AC and OS for stage I-III mucinous AA. For nonmucinous AA, AC significantly improved OS only for stage II and III disease. On adjusted analysis, AC was independently associated with an improved OS for stage III nonmucinous AA (HR: 0.61, 95%CI 0.45-0.84, P=0.002), while for mucinous AA, AC was associated with worse outcomes for stage I/II disease (HR: 1.4, 95%CI 1.02-1.91, P=0.038) and had no significant association with OS for stage III disease. CONCLUSION: This current analysis of a national cohort of patients suggests a beneficial role for AC in stage III nonmucinous AA and demonstrates no identifiable benefit for stage I-III mucinous AA.

Omission of Right Hemicolectomy May be Safe for Some Appendiceal Goblet Cell Adenocarcinomas: A Survival Analysis of the National Cancer Database.

BACKGROUND: Appendiceal goblet cell adenocarcinomas (GCC) are rare tumors with clinical behavior between classic carcinoids and adenocarcinomas. Current guidelines recommend right hemicolectomy for all GCCs. PATIENTS AND METHODS: The National Cancer Database was retrospectively queried for appendiceal GCCs undergoing appendectomy or right hemicolectomy between 2004 and 2016. Demographics, tumor characteristics, and post-operative outcomes were collected. The primary outcome was overall survival, which was examined by surgical type and tumor T stage. Multivariate logistic regression was utilized to identify predictors of survival. RESULTS: In total, 1083 GCCs were included, and 81.8% underwent right hemicolectomy. Mean age was 57 years, and 89% were White. Patients undergoing hemicolectomy had higher T-stage tumors (66.6%/14.4% T3/T4 vs. 55.8%/8.1%, p < 0.001). Lymph node positivity increased with T stage (1.1%, 2.1%, 9.9%, and 29.1% for T1-T4). GCCs undergoing colectomy were more frequently moderately or poorly differentiated (16.7%/9.0% vs. 12.2%/6.6%, p = 0.011). Appendectomy surgical margins were positive in 17.3% (3.4% hemicolectomy, p < 0.001). In T3/T4 tumors, a significant survival benefit at 5 years was observed in patients undergoing colectomy as compared with appendectomy (85.4% vs. 82.0%, p = 0.028). On multivariate analysis, lymph node positivity markedly decreased survival overall for the entire cohort (HR 7.58, p < 0.001) and for T3/T4 tumors (HR 7.63, p < 0.001). In patients with T3/T4 tumors, there was a trend towards improved survival with right hemicolectomy (HR 0.42, p = 0.068). CONCLUSION: Omitting right hemicolectomy can be considered for select T1/T2 appendiceal GCCs with negative appendectomy margins, given low rates of lymph node metastases and lack of survival benefit with right hemicolectomy.

Phase II Trial of Adjuvant Dendritic Cell Vaccine in Combination with Celecoxib, Interferon-α, and Rintatolimod in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Metastases.

BACKGROUND: Peritoneal metastases portend poor prognosis in the setting of standard chemotherapy. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) improves outcomes, but relapse is common. We report a phase II trial evaluating the safety and efficacy of adjuvant αDC1 vaccination with chemokine modulation (CKM) after CRS/HIPEC. METHODS: Patients undergoing CRS/HIPEC for appendiceal cancer, colorectal cancer, or peritoneal mesothelioma were enrolled. In addition to standard adjuvant chemotherapy, patients received intranodal and intradermal injections of autologous tumor-loaded αDC1 vaccine. After each vaccine booster, patients received CKM over 4 days, consisting of celecoxib, interferon (IFN)-α, and rintatolimod. RESULTS: Forty-six patients underwent CRS/HIPEC followed by αDC1 treatment, including 24 appendiceal primaries, 20 colorectal, and 2 mesotheliomas. DC maturation was successful, with 97% expressing HLA-DR and CD86. Tumor cell recovery from peritoneal tumors was challenging, resulting in only 17% of patients receiving the target dose of αDC1. The αDC1 and CKM regimen was well tolerated. CKM successfully modulated serum inflammatory cytokine and chemokine levels. Median progression-free survival (PFS) for appendiceal primaries was 50.4, 34.2, and 8.9 months for grade 1, 2, and 3 tumors, respectively, while median PFS for colorectal cancer was 20.5 and 8.9 months for moderately and poorly differentiated tumors, respectively. CONCLUSIONS: Adjuvant autologous tumor antigen-loaded αDC1 vaccine and CKM is well tolerated. The mucinous nature of peritoneal metastases limits the feasibility of obtaining adequate autologous tumor cells. The improvement in median PFS did not meet our predefined thresholds, leading us to conclude that αDC1 vaccination is not appropriate for patients undergoing CRS/HIPEC for peritoneal metastases.

The Role of Adjuvant Chemotherapy in Non-Metastatic Goblet Cell Carcinoid of the Appendix: An 11-Year Experience from the National Cancer Database.

BACKGROUND: Goblet cell carcinoids (GCC) are an aggressive, albeit rare, subtype of appendiceal tumors that exhibit distinct histologic features and lack clear treatment guidelines. We aimed to ascertain the impact of adjuvant chemotherapy (AC) for GCC in a national cohort of patients. METHODS: Patients who underwent a right hemicolectomy for stage I-III GCC of the appendix between 2006 and 2016 were selected from the National Cancer Database (NCDB). Stratification based on AC receipt was performed. Kaplan-Meier survival estimates and Cox proportional hazard regression were used to identify predictors of overall survival (OS). RESULTS: A total of 867 patients were identified, of whom 124 (14%) received AC. Patients in the AC group were significantly younger (54 vs. 57 years; p = 0.006) and were predominantly of male sex (60 vs. 48%; p = 0.012). On histopathology, patients in the AC group had a higher proportion of poorly/undifferentiated grade (27 vs. 5%; p < 0.001), T4 disease (35 vs. 11%; p < 0.001), and lymph node-positive disease (45 vs. 7%; p < 0.001) than patients who did not receive AC. After excluding patients diagnosed in 2016 due to a lack of follow-up data (n = 162), a survival advantage for the AC group was detected only after stratification for lymph node-positive disease (p = 0.007). On Cox proportional hazard regression, AC demonstrated an independent association with improved OS (hazard ratio 0.24, 95% confidence interval 0.084-0.683; p = 0.007). CONCLUSION: The current analysis from the NCDB supports the role of AC for GCC of the appendix, chiefly for patients with lymph node metastatic disease.

Improved chemosensitivity following mucolytic therapy in patient-derived models of mucinous appendix cancer.

Abundant intraperitoneal (IP) accumulation of extracellular mucus in patients with appendiceal mucinous carcinoma peritonei (MCP) causes compressive organ dysfunction and prevents delivery of chemotherapeutic drugs to cancer cells. We hypothesized that reducing extracellular mucus would decrease tumor-related symptoms and improve chemotherapeutic effect in patient-derived models of MCP. Mucolysis was achieved using a combination of bromelain (BRO) and N-acetylcysteine (NAC). Ex vivo experiments of mucolysis and chemotherapeutic drug delivery/effect were conducted with MCP and non-MCP tissue explants. In vivo experiments were performed in mouse and rat patient-derived xenograft (PDX) models of early and late (advanced) MCP. MCP tumor explants were less chemosensitive than non-MCP explants. Chronic IP administration of BRO + NAC in a mouse PDX model of early MCP and a rat PDX model of late (advanced) MCP converted solid mucinous tumors into mucinous ascites (mucolysis) that could be drained via a percutaneous catheter (rat model only), significantly reduced solid mucinous tumor growth and improved the efficacy of chemotherapeutic drugs. Combination of BRO + NAC efficiently lyses extracellular mucus in clinically relevant models of MCP. Conversion of solid mucinous tumors into mucinous ascites decreases tumor bulk and allows for minimally invasive drainage of liquified tumors. Lysis of extracellular mucus removes the protective mucinous coating surrounding cancer cells and improves chemotherapeutic drug delivery/efficacy in cancer cells. Our data provide a preclinical rationale for the clinical evaluation of BRO + NAC as a therapeutic strategy for MCP.

Synergistic apoptosis following endoplasmic reticulum stress aggravation in mucinous colon cancer.

BACKGROUND: Mucinous colon cancers (MCC) are characterized by abundant production of mucin 2 (MUC2) protein and are less sensitive to standard systemic chemotherapy. We postulated that severe/persistent endoplasmic reticulum stress (ERS) aggravation in MCC would overwhelm compensatory cytoprotective pathways and induce apoptosis. RESULTS: Basal levels of ERS markers were higher in MCC and dnTCF-LS174T cells than non-mucinous tumors and these levels were significantly increased by combinatorial treatment with ERS aggravators celecoxib + orlistat. Combination treatment inhibited cell viability and synergistically induced apoptosis. Treatment-induced cell death was ERS-dependent, apoptotic pathways were not activated following knockdown of ERS protein CHOP. Dual drug treatment significantly reduced mucinous tumor growth in vivo and induced ERS and apoptosis, consistent with in vitro experiments. CONCLUSIONS: Novel therapies are needed since MCC are more resistant to standard systemic chemotherapy. This study suggests ERS aggravation is a viable therapeutic strategy to reduce tumor growth in MCC.

Clinicopathological analysis of appendiceal goblet cell adenocarcinoma with peritoneal metastasis: World Health Organization grade predicts survival following cytoreductive surgery with intraperitoneal chemotherapy.

AIMS: Peritoneal spread is the most common route of metastasis in appendiceal goblet cell adenocarcinoma. The aim of this study was to assess the prognostic significance of the World Health Organization (WHO) 5th edition grading criteria in peritoneal metastases of goblet cell adenocarcinoma. METHODS AND RESULTS: We evaluated the clinicopathological features and survival of 63 patients with peritoneal metastasis of goblet cell adenocarcinoma who underwent cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC), stratified according to the WHO 5th edition and the Tang et al. grading schemes. The patients were also compared with 120 patients with peritoneal metastasis of appendiceal mucinous neoplasia. Most (73%) peritoneal metastases of goblet cell adenocarcinoma were WHO Grade 3 (G3), there being fewer cases of Grade 2 (G2) (16%) and Grade 1 (G1) (11%) disease. No significant differences in overall survival were observed between WHO G1 and G2 tumours or between the three Tang grades. In the multivariable model of survival, WHO G3 [hazard ratio (HR) 2.81, 95% confidence interval (CI) 1.02-7.70] and the presence of >50% extracellular mucin (HR 2.30, 95% CI 1.09-4.88) were associated with reduced overall survival for patients with goblet cell adenocarcinoma. As compared with patients with peritoneal metastasis of mucinous neoplasia, patients with goblet cell adenocarcinoma had significantly reduced survival (median overall survival of 37 months versus 102 months, P < 0.001), which was attributed to the reduced survival of patients with G1/G2 goblet cell adenocarcinoma as compared with patients with G1 mucinous neoplasia (median survival of 98 months versus 204 months, P < 0.001). CONCLUSIONS: Grade of peritoneal goblet cell adenocarcinoma determined according to the WHO 5th edition criteria is a clinically relevant measure that independently predicts survival in patients treated with CRS-HIPEC.

KRAS amplification in metastatic colon cancer is associated with a history of inflammatory bowel disease and may confer resistance to anti-EGFR therapy.

Mutations in RAS occur in 30-50% of metastatic colorectal carcinomas (mCRCs) and correlate with resistance to anti-EGFR therapy. Consequently, mCRC biomarker guidelines state RAS mutational testing should be performed when considering EGFR inhibitor treatment. However, a small subset of mCRCs are reported to harbor RAS amplification. In order to elucidate the clinicopathologic features and anti-EGFR treatment response associated with RAS amplification, we retrospectively reviewed a large cohort of mCRC patients that underwent targeted next-generation sequencing and copy number analysis for KRAS, NRAS, HRAS, BRAF, and PIK3CA. Molecular testing was performed on 1286 consecutive mCRC from 1271 patients as part of routine clinical care, and results were correlated with clinicopathologic findings, mismatch repair (MMR) status and follow-up. RAS amplification was detected in 22 (2%) mCRCs and included: KRAS, NRAS, and HRAS for 15, 5, and 2 cases, respectively (6-21 gene copies). Patients with a KRAS-amplified mCRC were more likely to report a history of inflammatory bowel disease (p < 0.001). In contrast, mutations in KRAS were associated with older patient age, right-sided colonic origin, low-grade differentiation, mucinous histology, and MMR proficiency (p ≤ 0.017). Four patients with a KRAS-amplified mCRC and no concomitant RAS/BRAF/PIK3CA mutations received EGFR inhibitor-based therapy, and none demonstrated a clinicoradiographic response. The therapeutic impact of RAS amplification was further evaluated using a separate, multi-institutional cohort of 23 patients. Eight of 23 patients with KRAS-amplified mCRC received anti-EGFR therapy and all 8 patients exhibited disease progression on treatment. Although the number of KRAS-amplified mCRCs is limited, our data suggest the clinicopathologic features associated with mCRC harboring a KRAS amplification are distinct from those associated with a KRAS mutation. However, both alterations seem to confer EGFR inhibitor resistance and, therefore, RAS testing to include copy number analyses may be of consideration in the treatment of mCRC.

Automated Quantitation of CD8-positive T Cells Predicts Prognosis in Colonic Adenocarcinoma With Mucinous, Signet Ring Cell, or Medullary Differentiation Independent of Mismatch Repair Protein Status.

Despite their association with DNA mismatch repair (MMR) protein deficiency, colonic adenocarcinomas with mucinous, signet ring cell, or medullary differentiation have not been associated with improved survival compared with conventional adenocarcinomas in most studies. Recent studies indicate that increased T-cell infiltration in the tumor microenvironment has a favorable prognostic effect in colonic adenocarcinoma. However, the prognostic effect of tumor-associated T cells has not been evaluated in histologic subtypes of colonic adenocarcinoma. We evaluated CD8-positive T-cell density in 259 patients with colonic adenocarcinoma, including 113 patients with tumors demonstrating mucinous, signet ring cell, or medullary differentiation, using a validated automated quantitative digital image analysis platform and correlated CD8-positive T-cell density with histopathologic variables, MMR status, molecular alterations, and survival. CD8-positive T-cell densities were significantly higher for MMR protein-deficient tumors (P<0.001), BRAF V600E mutant tumors (P=0.004), and tumors with medullary differentiation (P<0.001) but did not correlate with mucinous or signet ring cell histology (P>0.05 for both). In the multivariable model of factors predicting disease-free survival, increased CD8-positive T-cell density was associated with improved survival both in the entire cohort (hazard ratio=0.34, 95% confidence interval, 0.15-0.75, P=0.008) and in an analysis of patients with tumors with mucinous, signet ring cell, or medullary differentiation (hazard ratio=0.06, 95% confidence interval, 0.01-0.54, P=0.01). The prognostic effect of CD8-positive T-cell density was independent of tumor stage, MMR status, KRAS mutation, and BRAF mutation. Venous invasion was the only other variable independently associated with survival in both the entire cohort and in patients with tumors with mucinous, signet ring cell, or medullary differentiation. In summary, our results indicate that the prognostic value of MMR protein deficiency is most likely attributed to increased tumor-associated CD8-positive T cells and that automated quantitative CD8 T-cell analysis is a better biomarker of patient survival, particularly in patients with tumors demonstrating mucinous, signet ring cell, or medullary differentiation.

Rational application of targeted therapeutics in mucinous colon/appendix cancers with positive predictive factors.

Molecular-targeted therapies have demonstrated disappointing results against most advanced solid cancers. This may largey be attributed to irrational drug use against unselected cancers. We investigated the efficacy of dual MEK-PI3K drug therapy against KRAS mutated mucin 2 (MUC2)-secreting LS174T cells and patient-derived ex vivo and in vivo models of KRAS mutated mucinous colon/appendix cancers. These tumors demonstrate unique phenotypic and genotypic features that likely predict sensitivity to this targeted co-therapy. Co-treatment with MEK inhibitor (trametinib) and PI3K inhibitor (pictilisib)-induced synergistic cytotoxicity and intrinsic mitochondrial-mediated apoptosis in LS174T cells and tumor explants in vitro. Dual drug therapy also induced endoplasmic reticulum stress (ERS)-associated proteins (GRP78/BiP, ATF4, and CHOP). However, CHOP knock-down assays demonstrated that mitochondrial-mediated apoptosis in LS174T cells was not ERS-dependent. Dual drug therapy also significantly decreased MUC2 expression, MUC2 post-translational modification (palmitoylation) and secretion in LS174T cells, suggesting a simultaneous cytotoxic and mucin suppressive mechanism of action. We also demonstrated effective mucinous tumor growth suppression in ex vivo epithelial organoid (colonoid) cultures and in in vivo intraperitoneal patient-derived xenograft models derived from mucinous colon/appendix cancer. These promising preclinical data support a role for dual MEK-PI3K inhibitor therapy in mucinous colon/appendix cancers. We postulate that mucinous KRAS mutated cancers are especially vulnerable to this co-treatment based on their unique phenotypic and genotypic characteristics.

Surveillance of Low-Grade Appendiceal Mucinous Neoplasms With Peritoneal Metastases After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy: Are 5 Years Enough? A Multisite Experience.

BACKGROUND: Low-grade appendiceal mucinous neoplasms (LAMNs) are tumors that often present with widespread mucin in the peritoneal cavity (pseudomyxoma peritonei [PMP]). Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are effective treatment, but no published recommendations exist regarding surveillance. METHODS: Data from prospective databases of patients who underwent CRS-HIPEC from 2001 to 2017 at two high-volume institutions were retrospectively analyzed. Patients who underwent complete CRS-HIPEC for PMP secondary to LAMN were included in the analysis. Pathologic examination confirmed the diagnosis of LAMN. Cases of mucinous adenocarcinomas and neuroendocrine tumors (goblet cell carcinoids) were excluded. RESULTS: The study enrolled 156 patients. The median peritoneal cancer index (PCI) was 18 (interquartile range IQR1-3, 12-23), and 125 patients (80.1%) had a CC0 cytoreduction. According to American Joint Committee on Cancer (AJCC) grading, 152 patients (97.4%) presented with acellular mucin or G1 implants, 2 patients (1.3%) presented with G2 disease, and 2 patients (1.3%) presented with G3 disease. During the follow-up period (median, 45 months; IQR1-3 23-76 months), 23 patients (14.7%) experienced recurrence. All the recurrences were peritoneal and occurred within 5 years. The 1-, 3-, and 5-year disease-free survival (DFS) rates were respectively 95.5%, 83.4%, and 78.3%. Univariate Cox regression analysis showed that higher PCI scores (p < 0.001), a CC1 cytoreduction (p = 0.005), and higher preoperative levels of carcinoembryonic antigen (CEA) (p = 0.012) and CA-125 (p = 0.032) correlated with a shorter DFS. Only higher PCI scores independently predicted earlier recurrences (p < 0.001). CONCLUSION: Most patients had recurrence within 3 years after CRS-HIPEC, and none after 5 years. High PCI was the only independently significant variable. The study findings support intensive surveillance (every 3-6 months) with tumor markers and imaging methods during the first 3 years, and annual surveillance thereafter, with follow-up assessment after 5 years yielding limited benefit.