Causes of death in patients operated for colorectal cancer

BACKGROUND

Colorectal cancer remains the third leading cause of cancer-related mortality in the United States. This study evaluates the causes of death in patients operated on for colorectal cancer and their determinants.

METHODS

An Instructional Review Board-approved database containing patients who underwent surgical resection for colorectal cancer from 2004 to 2018 (last followed up in December 2020) in a tertiary care institution. Data on the underlying cause of death was extracted from the Registry of Vital Records and Statistics in Massachusetts.

RESULTS

A total of 576 deaths were recorded in the database, of which 290 (50.35%) patients died of colorectal cancer. Deaths from colorectal cancer gradually decreased over time, whereas deaths from other cancers increased, and deaths from cardiovascular diseases remained stable. Patients who died from colorectal cancer were younger, died earlier in the disease course, had fewer comorbidities, higher rates of stage IV disease, rectal cancer, neoadjuvant therapy, extramural vascular invasion, perineural invasion, R0 resection, and preserved mismatch repair protein status. On multivariate analysis, age (adjusted odds ratio for 10-year increase = 0.79, 95% confidence interval 0.65-0.95), American Society of Anesthesiologists score (adjusted odds ratio = 0.64, confidence interval 0.42-0.98), stage IV disease (adjusted odds ratio = 3.02, confidence interval 1.59-5.9), neoadjuvant therapy (adjusted odds ratio = 7.91, confidence interval 2.64-28.13), extramural vascular invasion (adjusted odds ratio = 2.3, confidence interval 1.36-3.91) & time from diagnosis to death (adjusted odds ratio = 0.76, confidence interval 0.68-0.83) predicted death due to colorectal cancer versus other causes, whereas tumor location, perineural invasion, R0 resection, and mismatch repair protein status did not.

CONCLUSION

There is a declining trend of deaths from colorectal cancer, presumably reflecting advances in colorectal cancer management strategies and better screening over time. However, younger patients disproportionately contribute to death due to colorectal cancer and need aggressive screening and management strategies.

Metformin Does not Affect Outcomes in Patients With Locally Advanced Rectal Cancer Treated With Neoadjuvant Therapy and Resection

INTRODUCTION

There is emerging evidence that metformin may have a protective effect in patients with cancer. However, its current evidence in locally advanced rectal cancer (LARC) is inconclusive. We aim to assess the effect of metformin on long-term outcomes in patients with LARC who received neoadjuvant therapy and surgical resection.

METHODS

A retrospective review of 324 patients with nonmetastatic LARC who received neoadjuvant therapy and major surgical resection from 2004 to 2018. There were 27 patients who received metformin before surgery and 297 patients who did not receive metformin.

RESULTS

Metformin users were associated with a significantly higher age, BMI, ASA score, and 30-day readmissions (P < .05). There was no difference in overall survival (OS, P = .18) or disease-free survival (DFS, P = .33) between the two groups. On Cox regression, metformin intake did not predict OS (HR 0.85, 95% CI 0.4-1.77) when controlled for age (HR 1.04, 1.02-1.06), sex (HR 1.13, 0.69-1.85), BMI (HR 0.97, 0.92-1.02), ASA score (HR: 1.7, 1.06-2.73), TNT (HR 0.31, 0.1-0.92), pathological Stage III disease (HR 2.55, 1.51-4.32), extramural vascular invasion (EMVI) (HR 3.06, 1.7-5.5), and adjuvant therapy (HR 0.1, 0.04-0.27 for <25 months OS and HR 0.3, 0.15-0.59 for ≥25 months). Disease-free survival showed a similar trend with no significant effect of metformin (HR 0.77, 0.39-1.52) when controlled for age, sex, BMI, ASA, TNT, Stage III disease, EMVI, and adjuvant therapy.

CONCLUSION

Metformin does not affect long-term survival in LARC treated with neoadjuvant therapy followed by surgical resection. Studies with larger sample sizes are needed to validate the findings further.

Incidence of Secondary Cancers After Neoadjuvant Therapy for Locally Advanced Rectal Cancer

INTRODUCTION

Whether neoadjuvant chemoradiation for locally advanced rectal cancer (LARC) induces secondary cancers is controversial. This retrospective cohort study describes the incidence of secondary cancers in LARC patients.

METHODS

We compared 364 LARC patients who received conventional (50.4 Gy) or short course neoadjuvant radiation (25 Gy x 5 fractions) followed by resection to 142 patients with surgically resected rectal cancer who did not receive radiation at a single institution from 2004 to 2018. Secondary cancer was defined as any nonmetastatic noncolorectal malignancy diagnosed via biopsy or definitive imaging criteria at least 6 mo after completion of neoadjuvant therapy or after resection in the comparison group.

RESULTS

Among the neoadjuvant radiation group (364 patients, 40% female, age 61 ± 13 y), 32 patients developed 34 (9.3%) secondary cancers. Three cases involved a pelvic organ. Among the comparison group (142 patients, 39% female, age 64 ± 15 y), 15 patients (10.6%) developed a secondary cancer. Five cases involved pelvic organs. Secondary cancer incidence did not differ between groups. Latency period to secondary cancer diagnosis was 6.7 ± 4.3 y. Patients who received radiation underwent longer median follow-up (6.8 versus 4.5 y, P < 0.01) and were significantly less likely to develop a pelvic organ cancer (odds ratio 0.18; 95% confidence interval, 0.04-0.83; P = 0.02). No genetic mutations or cancer syndromes were identified among patients with secondary cancers.

CONCLUSIONS

Neoadjuvant chemoradiation is not associated with increased secondary cancer risk in LARC patients and may have a local protective effect on pelvic organs, especially prostate. Ongoing follow-up is critical to continue risk assessment.

Trends and Determinants of Location of Death Due to Colorectal Cancer in the United States : A Nationwide Study

BACKGROUND

Colorectal cancer (CRC) is the second leading cause of cancer-related mortality in the United States (US); however, there are limited data on location of death in patients who die from CRC. We examined the trends in location of death and determinants in patients dying from CRC in the US.

METHODS

We utilized the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database to extract nationwide data on underlying cause of death as CRC. A multinomial logistic regression was performed to assess associations between clinico-sociodemographic characteristics and location of death.

RESULTS

There were 850,750 deaths due to CRC from 2003 to 2019. There was a gradual decrease in deaths in hospital, nursing home, or outpatient facility/emergency department over time and an increase in deaths at home and in hospice. Relative to White decedents, Black, Asian, and American Indian/Alaska Native decedents were less likely to die at home and in hospice compared with hospitals. Individuals with lower educational status also had a lower risk of dying at home or in hospice compared with in hospitals.

CONCLUSIONS

The gradual shift in location of death of patients who die of CRC from institutionalized settings to home and hospice is a promising trend and reflects the prioritization of patient goals for end-of-life care by healthcare providers. However, there are existing sociodemographic disparities in access to deaths at home and in hospice, which emphasizes the need for policy interventions to reduce health inequity in end-of-life care for CRC.

Patient Factors Affecting Inpatient Mortality Following Colorectal Cancer Resection

BACKGROUND

Our objective is to identify factors for inpatient death in patients undergoing resection for colorectal cancer (CRC).

STUDY DESIGN

Unmatched 1:3 case-control study of surgically resected CRC at a tertiary care institution between 2004 and 2018. Variables for multivariate analysis were selected using tetrachoric correlation followed by a least absolute shrinkage and selection operator (LASSO) penalized regression model.

RESULTS

A total of 140 patients were included (N = 35 patients who died inpatient, N = 105 patients who did not die). Patients who died were older, had higher Charlson Comorbidity Index (CCI), higher rates of preoperative anemia, hypoalbuminemia, emergency surgeries, blood transfusion, postoperative vasopressor requirement, anastomotic leak, and postoperative ICU admission than patients who underwent surgical resection without inpatient mortality. Anemia (aOR = 8.62, 1.44-91.58), emergency admission (aOR = 5.71, 1.46-24.36), and ICU admission (aOR 45.51, 8.31-448.4) significantly predicted inpatient mortality when controlled for CCI and hypoalbuminemia.

CONCLUSIONS

Surprisingly, it appears that pre-existing anemia and perioperative factors are more important in predicting inpatient mortality of patients undergoing CRC surgery than baseline comorbidity or nutritional status.

Association of age with outcomes in locally advanced rectal cancer treated with neoadjuvant therapy followed by surgery

INTRODUCTION

We aimed to assess the association of age with outcomes in patients with Locally Advanced Rectal Cancer (LARC) who received neoadjuvant therapy followed by major surgery.

METHODS

Retrospective review of 328 patients with LARC, N = 99 < 70 years (younger) versus N = 229 ≥ 70 years (elderly) from 2004 to 2018.

RESULTS

Elderly patients had a higher American Society of Anesthesiologists (ASA) score, Charlson Comorbidity Index (CCI), length of stay and 30-day readmissions (p < 0.05). They also had worse overall survival (OS) & disease-free survival (DFS) (p < 0.001), but similar disease-specific survival (DSS) compared to younger group. Age was not associated with hazard of death (HR 1.01, 0.98-1.03). Rather, CCI (HR 1.29, 1.01-1.5), extramural vascular invasion (HR 4.98, 2.84-8.74), and adjuvant therapy (0.37, 0.21-0.64) were significantly associated with the hazard of death; when controlled for stage, tumor distance from anal verge, and neoadjuvant completion.

CONCLUSION

Comorbidities and lower rates of adjuvant therapy, and not chronologic age, are associated with poor OS of elderly patients with LARC treated with neoadjuvant therapy and major surgery.

Impact of Bundled Payment Care Improvement Initiative on Health Care Expenditure in Major Bowel Procedures

BACKGROUND

The Bundled Payments for Care Improvement initiative links payments for Medicare beneficiaries during an episode of care (90 days from index surgery).

OBJECTIVE

This study aimed to determine whether major bowel participating Bundled Payments for Care Improvement organizations experience greater cost savings for colectomy while maintaining satisfactory quality outcomes compared to nonparticipating organizations.

DESIGN

This is an Analysis of all Bundled Payments for Care Improvement participating hospitals for major bowel procedures (major bowel group) and propensity score-matched against Bundled Payments for Care Improvement organizations that do not include major bowel procedures (nonmajor bowel group) and those that do not participate in any Bundled Payments for Care Improvement program (non-Bundled Payments for Care Improvement group).

SETTING

Programs accepting Medicare and Medicaid in the United States.

PATIENTS

Patients included were major bowel cases in the Medicare Standard Analytic file within Medicare Severity Diagnosis-Related Groups 329-331 at participating facilities between January 1, 2011, and June 30, 2016.

MAIN OUTCOME MEASURES

Main outcome measures included average total care expenditure and quality of care (length of stay, morbidity, and mortality) from 3 days preoperatively to 90 days postoperatively.

RESULTS

We abstracted 7609 major bowel episodes from 23 major bowel group facilities, 21,872 episodes from nonmajor bowel-matched hospitals, and 19,383 episodes from non-Bundled Payments for Care Improvement-matched hospitals. From the baseline (January 2011 to June 2012) to final period (July 2015 to June 2016), we noted a $2955 average reduction in care expenditures. The largest decrease in average total episode expenditure occurred within the major bowel group (14% reduction) compared to the other groups (6% reduction for nonmajor bowel and 5% reduction for non-Bundled Payments for Care Improvement). Utilizing a generalized estimating equation to adjust for patient demographics, comorbidities, and hospital characteristics, the average total episode expenditure for the major bowel group decreased by $4885 (95% CI $4838-$4932; p < 0.001) compared to $2050 (95% CI $2038-$2061) for the non-Bundled Payments for Care Improvement group. All groups had similar reductions in length of stay, 30-day and 90-day complication rates, and readmission rates.

LIMITATIONS

Analyses were limited by the retrospective nature of the study.

CONCLUSIONS

Bundled Payments for Care Improvement participation for major bowel procedures resulted in a greater decrease in average total cost per episode of care than in nonparticipating hospitals without compromise in quality of care. See Video Abstract at http://links.lww.com/DCR/B837.IMPACTO DE LA INICIATIVA BUNDLED PAYMENT AGRUPADOS PARA LA MEJORA DE LA ATENCIÓN DEL GASTO SANITARIO EN LOS PROCEDIMIENTOS INTESTINALES MAYORESANTECEDENTES:La iniciativa de Bundled Payment para la mejora de la atención vincula los pagos para los beneficiarios de Medicare durante un episodio de atención (90 días desde la cirugía índice).OBJETIVO:Determinar si las principales organizaciones de Bundled Payment para el mejoramiento de la atención relacionados a los procedimientos intestinales experimentan mayores ahorros en los costos para una colectomía manteniendo resultados satisfactorios de calidad en comparación con las organizaciones no participantes.DISEÑO:Análisis de todos los hospitales participantes del programa Bundled Payment para la mejora de la atención para procedimientos intestinales mayores (grupo que incluyen procedimientos intestinales mayores) y puntaje de propensión comparado con las organizaciones que no incluyen dichos procedimientos (grupo que no incluye procedimientos intestinales mayores) y aquellos que no participan en ningún programa de Bundled Payment para la mejora de la atención (grupo no BPCI).MARCO:Programas que aceptan Medicare y Medicaid en los Estados Unidos.PACIENTES:Casos intestinales mayores en el archivo analítico estándar de Medicare dentro de los grupos relacionados con el diagnóstico 329-331 en los centros participantes entre el 1/1/2011-30/6/2016.PRINCIPALES MEDIDAS DE RESULTADO:Gasto total promedio y calidad de la atención (duración de la estadía, morbilidad, mortalidad) desde los 3 días preoperatorio hasta los 90 días postoperatorio.RESULTADOS:Hemos extraído 7609 episodios intestinales mayores de 23 instalaciones del grupo que incluyen procedimientos intestinales mayores, 21.872 episodios de hospitales del grupo que no incluyen procedimientos intestinales mayores y 19.383 episodios de hospitales del grupo no BPCI. Desde la línea de base (1/2011 - 6/2012) hasta el período final (7/2015 - 6/2016), notamos una reducción promedio de $2955 en los gastos de atención. La mayor disminución en el gasto promedio total por episodios ocurrió dentro del grupo que incluyen intestinales mayores (14% de reducción) en comparación con los otros grupos (6% de reducción para el grupo que no incluyen procedimientos intestinales mayores, 5% de reducción para el no BPCI). Utilizando una ecuación de estimación generalizada para ajustar los datos demográficos del paciente, las comorbilidades y las características del hospital, el gasto total promedio por episodio para el grupo que incluyen procedimientos intestinales mayores disminuyó en $ 4885 (IC del 95%: $4838-4932; p <0,001) en comparación con $2050 (IC del 95%: $2038-2061) para el grupo que no pertenece al programa BPCI. Todos los grupos tuvieron reducciones similares en la duración de la estancia, tasas de complicaciones de 30/90 días y de readmisión.LIMITACIONES:Análisis limitados por la naturaleza retrospectiva del estudio.CONCLUSIONES:La participación de Bundled Payment para la mejora de la atención en aquellos procedimientos intestinales mayores resultó en una disminución mayor en el costo total promedio por episodio de atención que en los hospitales no participantes, sin comprometer la calidad de la atención. Consulte Video Resumen en http://links.lww.com/DCR/B837. (Traducción-Dr Osvaldo Gauto).

Anastomotic Troubleshooting

Anastomotic leak remains a critical and feared complication in colorectal surgery. The development of a leak can be catastrophic for a patient, resulting in overall increased morbidity and mortality. To help mitigate this risk, there are several ways to assess and potentially validate the integrity of a new anastomosis to give the patient the best chance of avoiding this postoperative complication. A majority of anastomoses will appear intact with no obvious sign of anastomotic dehiscence on gross examination. However, each anastomosis should be interrogated before the conclusion of an operation. The most common method to assess for an anastomotic leak is the air leak test (ALT). The ALT is a safe intraoperative method utilized to test the integrity of left-sided colon and rectal anastomoses and most importantly allows the ability to repair a failed test before concluding the operation. Additional troubleshooting is sometimes needed due to technical difficulties with the circular stapler. Problems, such as incomplete doughnuts and stapler misfiring, do occur and each surgeon should be prepared to address them.

Diverticular Disease Epidemiology: Rising Rates of Diverticular Disease Mortality Across Developing Nations

BACKGROUND

The incidence of diverticular disease is growing in the Western world. However, the global burden of disease is unknown in the developing world.

OBJECTIVE

This study aimed to determine the global burden of diverticular disease as measured by disease-specific mortality while identifying indicators of rising disease rates.

DESIGN

We undertook an ecological analysis based on data from the World Health Organization Mortality Database. Then, we analyzed global age-adjusted mortality rates from diverticular disease and compared them to national rates of overweight adults, health expenditures, and dietary composition.

SETTINGS

National vital statistics data were collected.

PATIENTS

Diverticular disease deaths from January 1, 1994 through December 31, 2016 were evaluated.

MAIN OUTCOME MEASURES

The primary outcome measured was the national age-adjusted mortality rate.

RESULTS

The average age-adjusted mortality rate for diverticular disease was 0.51 ± 0.31/100,000 with a range of 0.11 to 1.75/100,000. During the study period, we noted that 57% of nations had increasing diverticular disease mortality rates, whereas only 7% had decreasing rates. More developed nations (40%) than developing nations (24%) were categorized as having high diverticular disease mortality burden over the time period of the study, and developed nations had higher percentages of overweight adults (58.9 ± 3.1%) than developing nations (50.6 ± 6.7%; p < 0.0001). However, developing nations revealed more rapid increases in diverticular disease mortality (0.027 ± 0.024/100,000 per year) than developed nations (0.005 ± 0.025/100,000 per year; p = 0.001), as well as faster expanding proportions of overweight adults (0.76 ± 0.12% per year) than in already developed nations (0.53 ± 0.10% per year; p<0.0001).

LIMITATIONS

Ecological studies cannot define cause and effect.

CONCLUSIONS

There is considerable variability in diverticular disease mortality across the globe. Developing nations were characterized by rapid increases in diverticular disease mortality and expanding percentages of overweight adults. Public health interventions in developing nations are needed to alter mortality rates from diverticular disease. See Video Abstract at http://links.lww.com/DCR/B397. EPIDEMIOLOGÍA DE LA ENFERMEDAD DIVERTICULAR: TASAS CRECIENTES DE MORTALIDAD POR ENFERMEDAD DIVERTICULAR EN LOS PAÍSES EN DESARROLLO: La incidencia de la enfermedad diverticular está creciendo en el mundo occidental. Sin embargo, la carga mundial de la enfermedad es desconocida en el mundo en desarrollo.Determinar la carga global de la enfermedad diverticular medida por la mortalidad específica de la enfermedad mientras se identifican los indicadores de aumento de las tasas de enfermedad.Realizamos un análisis ecológico basado en datos de la Base de datos de mortalidad de la Organización Mundial de la Salud. Luego, analizamos las tasas globales de mortalidad ajustadas por edad por enfermedad diverticular y las comparamos con las tasas nacionales de adultos con sobrepeso, gastos de salud y composición dietética.Datos nacionales de estadísticas vitales.Muertes por enfermedades diverticulares desde el 1 de enero de 1994 hasta el 31 de diciembre de 2016.Tasa nacional de mortalidad ajustada por edad.La tasa promedio de mortalidad ajustada por edad para la enfermedad diverticular fue de 0,51 ± 0,31 / 100,000 con un rango de 0,11 a 1,75 / 100,000. Durante el período de estudio, notamos que el 57% de las naciones tenían tasas crecientes de mortalidad por enfermedades diverticulares, mientras que solo el 7% tenían tasas decrecientes. Las naciones más desarrolladas (40%) que las naciones en desarrollo (24%) se clasificaron como que tienen una alta carga de mortalidad por enfermedad diverticular durante el período de tiempo del estudio, y las naciones desarrolladas tuvieron porcentajes más altos de adultos con sobrepeso (58.9 ± 3.1%) que las naciones en desarrollo (50,6 ± 6,7%) (p <0,0001). Sin embargo, las naciones en desarrollo revelaron aumentos más rápidos en la mortalidad por enfermedades diverticulares (0.027 ± 0.024 / 100,000 por año) que las naciones desarrolladas (0.005 ± 0.025 / 100,000 por año) (p = 0.001), así como proporciones de adultos con sobrepeso en expansión más rápida (0.76 ± 0.12% por año) que en las naciones ya desarrolladas (0.53 ± 0.10% por año) (p <0.0001).Los estudios ecológicos no pueden definir causa y efecto.Existe una considerable variabilidad en la mortalidad por enfermedad diverticular en todo el mundo. Los países en desarrollo se caracterizaron por un rápido aumento en la mortalidad por enfermedades diverticulares y porcentajes crecientes de adultos con sobrepeso. Se necesitan intervenciones de salud pública en los países en desarrollo para alterar las tasas de mortalidad por enfermedad diverticular. Consulte Video Resumen en http://links.lww.com/DCR/B397.

Octogenarians present with a less aggressive phenotype of colon adenocarcinoma

BACKGROUND

Octogenarians constitute a growing percentage of patients diagnosed with colon malignancies. This study aims to determine if the clinical and pathologic presentation of octogenarians with colon cancer differs from that of patients diagnosed at a younger age.

METHODS

Data were collected retrospectively for all patients diagnosed with colon cancer who underwent resection at a single institution between January 1, 2004 and December 31, 2017; patients with rectal cancer were excluded. Patients were categorized by age at diagnosis: either 50 to 79 years of age or ≥80 years of age; those <50 years of age were excluded because of the greater risk of a hereditary etiology. The primary outcome was the correlation between patient age and pathologic features of the tumor, including tumor size, lymph node metastases, perineural invasion, and extramural venous invasion.

RESULTS

Of 1,301 patients, 329 (25%) were ≥80. Female patients predominated the octogenarian cohort (61% vs 39%; P < .001). Octogenarians presented with larger tumors when compared to patients age 50 to 79 (5.2 cm vs 4.5 cm; P < .001). More patients ≥80 had tumors which were >8 cm (17.3% vs 8.9%; P < .001). Tumors in younger patients were more often detected on screening colonoscopy (23.1% vs 7.3%; P < .001). Regardless of tumor size, octogenarians were less likely to have positive lymph nodes than younger patients (P = .02). In addition, octogenarians were less likely to exhibit extramural venous invasion compared to younger patients across all tumor sizes (P < .001). Younger patients had greater median overall survival (6.4 years vs 4.4 years; P < .001), yet 3-year disease-free survival was comparable between age groups (P = .12).

CONCLUSION

Octogenarians with colon cancer present with larger tumors but appear to have less aggressive disease, as reflected in a lower pathologic stage, less extramural venous invasion, and less lymph node metastases, than younger patients with similar size tumors. Three-year disease-free survival is comparable between octogenarians and patients aged 50 to 79.

Proving the Effectiveness of the Fundamentals of Robotic Surgery (FRS) Skills Curriculum: A Single-blinded, Multispecialty, Multi-institutional Randomized Control Trial

OBJECTIVE

To demonstrate the noninferiority of the fundamentals of robotic surgery (FRS) skills curriculum over current training paradigms and identify an ideal training platform.

SUMMARY BACKGROUND DATA

There is currently no validated, uniformly accepted curriculum for training in robotic surgery skills.

METHODS

Single-blinded parallel-group randomized trial at 12 international American College of Surgeons (ACS) Accredited Education Institutes (AEI). Thirty-three robotic surgery experts and 123 inexperienced surgical trainees were enrolled between April 2015 and November 2016. Benchmarks (proficiency levels) on the 7 FRS Dome tasks were established based on expert performance. Participants were then randomly assigned to 4 training groups: Dome (n = 29), dV-Trainer (n = 30), and DVSS (n = 32) that trained to benchmarks and control (n = 32) that trained using locally available robotic skills curricula. The primary outcome was participant performance after training based on task errors and duration on 5 basic robotic tasks (knot tying, continuous suturing, cutting, dissection, and vessel coagulation) using an avian tissue model (transfer-test). Secondary outcomes included cognitive test scores, GEARS ratings, and robot familiarity checklist scores.

RESULTS

All groups demonstrated significant performance improvement after skills training (P < 0.01). Participating residents and fellows performed tasks faster (DOME and DVSS groups) and with fewer errors than controls (DOME group; P < 0.01). Inter-rater reliability was high for the checklist scores (0.82-0.97) but moderate for GEARS ratings (0.40-0.67).

CONCLUSIONS

We provide evidence of effectiveness for the FRS curriculum by demonstrating better performance of those trained following FRS compared with controls on a transfer test. We therefore argue for its implementation across training programs before surgeons apply these skills clinically.

Association of Time Between Radiation and Salvage APR and Margin Status in Patients With Anal Cancer Treated With Concurrent Chemoradiation

There is a controversy regarding the optimal time to assess anal squamous cell carcinoma (SCC) response to chemoradiation and when salvage abdominoperineal resection (APR) should be offered. A retrospective cohort study was performed on patients with stage I-III anal SCC treated with chemoradiation in the National Cancer Database (2004-2015). The time between radiation and APR was recorded. Logistic regression and Cox proportional hazard analysis were used to determine predictors of resection margin status and overall survival. The cohort included 23 050 patients, of whom 545 (2.4%) underwent salvage APR. The median (IQR) time between radiation and resection was 3.8 (2.4-5.5) months. The rate of positive margins was 19.0%. Positive margins were more common in male, non-white patients with larger tumors, pathologic upstaging of T stage, and ≥3 months between chemoradiation and resection (all P < .05). Observing for ≥3 months between chemoradiation and APR remained associated with positive margins, even after adjusting for pretreatment tumor size (odds ratio = 2.56, 95% CI 1.46-4.47). Our data, based on the largest published cohort of anal SCC patients treated with chemoradiation and subsequent APR, suggest that patients at high risk of local treatment failure, particularly non-white men with large tumors, may benefit from early interim restaging and earlier consideration of salvage surgery.

Refusal of surgery for colon cancer: Sociodemographic disparities and survival implications among US patients with resectable disease

BACKGROUND

We aimed to identify factors associated with refusal of surgery among patients with colon cancer.

METHODS

This 2004-2016 NCDB retrospective study identified AJCC stage I-III colon cancer patients who were recommended surgery. Multivariable logistic regression defined adjusted odds ratios of refusing treatment, with sociodemographic and clinical covariates. Treatment propensity-adjusted Cox proportional hazard ratios defined differential survival stratified by clinical stage, controlling for potential confounders.

RESULTS

Of 170,594 patients recommended surgery, 1116 refused. Increased rates of surgery refusal were associated with older age, African American race, CDCC>3, and female sex. Decreased rates of surgery refusal were associated with higher income and private insurance. Stratifying by stage, refusal rates among African Americans remained disparately high. Refusal of surgery was associated with worse overall survival.

CONCLUSIONS

Disparate rates of refusal of surgery for resectable colon cancer by race and other sociodemographic factors highlight potential treatment adherence reinforcement beneficiaries, necessitating further study of shared decision-making.

Superior pathologic and clinical outcomes after minimally invasive rectal cancer resection, compared to open resection

BACKGROUND

While the ACOSOG and ALaCaRT trials found that laparoscopic resections for rectal cancer failed to demonstrate non-inferiority of pathologic outcomes when compared with open resections, the COLOR II and COREAN studies demonstrated non-inferiority of clinical outcomes, leading to uncertainty regarding the value of minimally invasive (MIS) techniques in rectal cancer surgery. We analyzed differences in pathologic and clinical outcomes between open versus MIS resections for rectal cancer.

METHODS

We identified patients who underwent resection for stage II or III rectal adenocarcinoma from the National Cancer Database (2010-2015). Surgical approach was categorized as open or MIS (laparoscopic or robotic). Logistic regression and Cox proportional hazard analysis were used to assess differences in outcomes and survival. Analysis was performed in an intention-to-treat fashion.

RESULTS

A total of 31,190 patients who underwent rectal adenocarcinoma resection were identified, of whom 52.8% underwent open resection and 47.2% underwent MIS resection (31.0% laparoscopic, 16.2% robotic). After adjustment for patient, tumor, and institutional characteristics, MIS approaches were associated with significantly decreased risk of positive circumferential resection margins (OR 0.82, 95% CI 0.72-0.94), increased likelihood of harvesting ≥ 12 lymph nodes (OR 1.12, 95% CI 1.04-1.21), shorter length of stay (OR 0.57, 95% CI 0.53-0.62), and improved overall survival (HR 0.90, 95% CI 0.83-0.98).

CONCLUSIONS

MIS approaches to rectal cancer resection were associated with improved pathologic and clinical outcomes when compared to the open approach. In this nationwide, facility-based sample of cancer cases in the United States, our data suggest superiority of MIS techniques for rectal cancer treatment.

What is the Long-Term Follow-Up of Nonoperatively Treated Patients with Appendicitis?

In this study, we determine outcomes after nonoperative treatment of appendicitis. First, we abstracted data for patients discharged with a diagnosis of appendicitis from a tertiary care facility from August 1, 2007, through June 30, 2017. For patients treated nonoperatively, we collected additional medical treatment for appendicitis, future surgical treatment, and date of last follow-up. In our study, we identified 487 patients treated for appendicitis. From this group, 66 patients were successfully treated nonoperatively. Eight patients (12%) had an interval appendectomy at a mean follow-up time of two months. Of the 58 remaining patients, 20 (34%) did not have any further appendicitis-related issues over a mean follow-up period of 25 months. A total of 38 (66%) had recurring or additional concerns requiring further treatment or emergent surgery within a mean time of four months. A large proportion, 76 per cent (n = 29), required unscheduled or emergent appendectomy. There were more patients diagnosed with an abscess (55%) in the group that had further appendicitis issues. In conclusion, nonoperative treatment of appendicitis is associated with significant likelihood of future appendicitis-related treatment or emergency surgery (66%). In addition, patients diagnosed with an abscess are at particularly high risk of future appendicitis-related issues.

What Is the Long-Term Follow-Up of Nonoperatively Treated Patients with Appendicitis?

In this study, we determine outcomes after nonoperative treatment of appendicitis. First, we abstracted data for patients discharged with a diagnosis of appendicitis from a tertiary care facility from August 1, 2007, through June 30, 2017. For patients treated nonoperatively, we collected additional medical treatment for appendicitis, future surgical treatment, and date of last follow-up. In our study, we identified 487 patients treated for appendicitis. From this group, 66 patients were successfully treated nonoperatively. Eight patients (12%) had an interval appendectomy at a mean follow-up time of two months. Of the 58 remaining patients, 20 (34%) did not have any further appendicitis-related issues over a mean follow-up period of 25 months. A total of 38 (66%) had recurring or additional concerns requiring further treatment or emergent surgery within a mean time of four months. A large proportion, 76 per cent (n = 29), required unscheduled or emergent appendectomy. There were more patients diagnosed with an abscess (55%) in the group that had further appendicitis issues. In conclusion, nonoperative treatment of appendicitis is associated with significant likelihood of future appendicitis-related treatment or emergency surgery (66%). In addition, patients diagnosed with an abscess are at particularly high risk of future appendicitis-related issues.

Is Diversion with Ileostomy Non-inferior to Hartmann Resection for Left-sided Colorectal Anastomotic Leak?

BACKGROUND

Treatment of left-sided colorectal anastomotic leaks often requires fecal stream diversion for prevention of further septic complications. To manage anastomotic leak, it is unclear if diverting ileostomy provides similar outcomes to Hartmann resection with colostomy.

METHODS

We identified all patients who developed anastomotic leak following left-sided colorectal resections from 1/2012 through 12/2014 using the American College of Surgeons National Surgical Quality Improvement Program. Then, we examined the risk of mortality and abdominal reoperation in patients treated with diverting ileostomy as compared to Hartmann resection.

RESULTS

There were 1745 patients who experienced an anastomotic leak in a cohort of 63,748 patients (3.7%). Two hundred thirty-five patients had a reoperation for anastomotic leak involving the formation of a diverting ileostomy (n = 77) or Hartmann resection (n = 158). There was no difference in mortality or abdominal reoperation in patients treated with diverting ileostomy (3.9, 7.8%) versus Hartmann resection (3.8, 6.3%) (p = 0.8).

CONCLUSION

There was no difference in the outcomes of mortality or need for second abdominal reoperation in patients treated with diverting ileostomy as compared to Hartmann resection for left-sided colorectal anastomotic leak. Thus, select patients with left-sided colorectal anastomotic leaks may be safely managed with diverting ileostomy.

What is the optimal management of an intra-operative air leak in a colorectal anastomosis?

AIM

An airtight anastomosis on intra-operative leak testing has been previously demonstrated to be associated with a lower risk of clinically significant postoperative anastomotic leak following left-sided colorectal anastomosis. However, to date, there is no consistently agreed upon method for management of an intra-operative anastomotic leak. Therefore, we powered a noninferiority study to determine whether suture repair alone was an appropriate strategy for the management of an intra-operative air leak.

METHOD

This is a retrospective cohort analysis of prospectively collected data from a tertiary care referral centre. We included all consecutive patients with left-sided colorectal or ileorectal anastomoses and evidence of air leak during intra-operative leak testing. Patients were excluded if proximal diversion was planned preoperatively, a pre-existing proximal diversion was present at the time of surgery or an anastomosis was ultimately unable to be completed. The primary outcome measure was clinically significant anastomotic leak, as defined by the Surgical Infection Study Group at 30 days.

RESULTS

From a sample of 2360 patients, 119 had an intra-operative air leak during leak testing. Sixty-eight patients underwent suture repair alone and 51 underwent proximal diversion or anastomotic reconstruction. The clinically significant leak rate was 9% (6/68; 95% CI: 2-15%) in the suture repair alone arm and 0% (0/51) in the diversion or reconstruction arm.

CONCLUSION

Suture repair alone does not meet the criteria for noninferiority for the management of intra-operative air leak during left-sided colorectal anastomosis. Further repair of intra-operative air leak by suture repair alone should be reconsidered given these findings.

Should We Use the Model for End-Stage Liver Disease (MELD) to Predict Mortality After Colorectal Surgery?

We sought to determine the accuracy of the Model for End-Stage Liver Disease and the Mayo Clinic Postoperative Mortality Risk in Patients with Cirrhosis Calculator in patients with ascites who underwent colorectal surgery. The National Surgical Quality Improvement Program database was queried for patients with ascites who underwent a major colorectal operation. Predicted 90-day mortality rate based on the Model for End-Stage Liver Disease and 30-day mortality based on the Mayo Clinic Postoperative Mortality Risk in Patients with Cirrhosis Calculator were compared with observed 30-day mortality. The cohort contained 3137 patients with ascites who underwent a colorectal operation. The Model for End-Stage Liver Disease predicted that 252 (8 %) of patients with ascites undergoing colorectal operations would die within 90 days postoperatively, yet we observed 821 deaths (26 % mortality) within 30 days after surgery (p < 0.001). The Mayo Clinic Postoperative Mortality Risk in Patients with Cirrhosis Calculator predicted that 491 (16.6 % mortality) of patients with ascites undergoing colorectal operations would die within 30 days postoperatively, yet we observed 707 (23.9 % mortality) at 30 days (p < 0.01). We concluded that the current risk prediction models significantly under predict mortality in patients with ascites who underwent colorectal surgery.

Do Appendicitis and Diverticulitis Share a Common Pathological Link?

OBJECTIVE

The aim of this study was to determine whether there is an association between appendicitis and diverticulitis.

DESIGN

This study is a retrospective cohort analysis.

SETTING

This study was conducted in a subspecialty practice at a tertiary care facility.

PATIENTS

We examined the rate of appendectomy among 4 cohorts of patients: 1) patients with incidentally identified diverticulosis on screening colonoscopy, 2) inpatients with medically treated diverticulitis, 3) patients who underwent left-sided colectomy for diverticulitis, and 4) patients who underwent colectomy for left-sided colorectal cancer.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

The primary outcome measured was the appendectomy rate.

RESULTS

We studied a total of 928 patients in this study. There were no differences in the patient characteristics of smoking status, nonsteroidal use, or history of irritable bowel syndrome across the 4 study groups. Patients with surgically treated diverticulitis had significantly more episodes of diverticulitis (2.8 ± 1.9) than the medically treated group (1.4 ± 0.8) (p < 0.0001). The rate of appendectomy was 8.2% for the diverticulosis control group, 13.5% in the cancer group, 23.5% in the medically treated diverticulitis group, and 24.5% in the surgically treated diverticulitis group (p < 0.0001). After adjusting for demographics and other clinical risk factors, patients with diverticulitis had 2.8 times higher odds of previous appendectomy (p < 0.001) than the control groups.

LIMITATIONS

The retrospective study design is associated with selection, documentation, and recall bias.

CONCLUSIONS

Our data reveal significantly higher appendectomy rates in patients with a diagnosis of diverticulitis, medically or surgically managed, in comparison with patients with incidentally identified diverticulosis. Therefore, we propose that appendicitis and diverticulitis share similar risk factors and potentially a common pathological link.

What Factors Predict Hospital Readmission after Colorectal Surgery?

Readmissions pose a significant hardship for patients and constitute a major quality and financial concern for hospitals. We sought to define risk factors associated with hospital readmission after colorectal surgery at a tertiary care hospital. We evaluated readmission among all patients who underwent a colorectal surgical procedure between July 16, 2007 and June 30, 2011. In a cohort of 4879 operative encounters, 492 (10%) were readmitted to the hospital within 30 days of discharge. Procedures with highest readmissions included stoma creation (22%), ileoanal pouch surgery (22%), and total proctocolectomy (30%). In multivariate analysis, the following variables were associated with risk of readmission: postoperative complication, use of anxiolytics, high comorbidity score, patient setting, alcohol use, and stoma creation. Surgeon of record was not associated with readmission. In conclusion, several patient, procedural, and postoperative factors were associated with an increased risk of readmission. Considerably high rates of readmission were noted after stoma creation, ileoanal pouch procedures, and proctocolectomy. Surgeon of record was not associated with risk of read-mission, indicating little value to this metric as a physician-specific indicator of quality.

What Factors Predict Hospital Readmission after Colorectal Surgery?

Readmissions pose a significant hardship for patients and constitute a major quality and financial concern for hospitals. We sought to define risk factors associated with hospital readmission after colorectal surgery at a tertiary care hospital. We evaluated readmission among all patients who underwent a colorectal surgical procedure between July 16, 2007 and June 30, 2011. In a cohort of 4879 operative encounters, 492 (10%) were readmitted to the hospital within 30 days of discharge. Procedures with highest readmissions included stoma creation (22%), ileoanal pouch surgery (22%), and total proctocolectomy (30%). In multivariate analysis, the following variables were associated with risk of readmission: postoperative complication, use of anxiolytics, high comorbidity score, patient setting, alcohol use, and stoma creation. Surgeon of record was not associated with readmission. In conclusion, several patient, procedural, and postoperative factors were associated with an increased risk of readmission. Considerably high rates of readmission were noted after stoma creation, ileoanal pouch procedures, and proctocolectomy. Surgeon of record was not associated with risk of readmission, indicating little value to this metric as a physician-specific indicator of quality.

What are the results of colonic volvulus surgery?

BACKGROUND

Operative results of volvulus are largely unknown because of infrequent diagnosis.

OBJECTIVE

We examined the results of operative intervention for colonic volvulus.

DESIGN

We merged trackable data from the California Inpatient Database with Supplemental Files for Revisit Analyses between January 1, 2005, and December 31, 2007.

SETTINGS

Trackable data from California discharge records.

PATIENTS

We identified all of the patients with colonic volvulus who underwent 1 of 4 surgical procedures, including manipulation/fixation of the colon, right colectomy, left colectomy, or total colectomy.

MAIN OUTCOME MEASURES

During the 36-month study period, we identified recurrence risk, recurrence requiring reoperation, time to reoperation, stoma formation, disposition on discharge, and in-hospital mortality. Fisher exact, χ(2), and ANOVA tests were used when appropriate.

RESULTS

We identified 2141 patients with colonic volvulus who were undergoing intraoperative manipulation/fixation of the colon (n = 209 (12%)), right (n = 728 (41%)), left (n = 781 (44%)), or total colectomy (n = 56 (3%)). Patients treated with intraoperative manipulation/fixation were younger, more likely to be women, and more likely to have private insurance. Patients who underwent total colectomy had the highest risk of mortality (21%), highest risk of stoma creation (64%), and longest length of stay (18 days); were more likely to be readmitted (9%); and were the most likely to be discharged to a skilled nursing facility (48%). Patients treated with intraoperative manipulation/fixation had the lowest mortality, risk of stoma formation, length of stay, and likelihood of discharge to skilled nursing facility but the highest risk of subsequent procedures for volvulus (26%) over a follow-up ranging from 0 to 687 days.

LIMITATIONS

This study was limited by retrospective study design, heterogeneous patient factors, and inability to identify the time of last follow-up.

CONCLUSIONS

The majority of patients with volvulus underwent a resectional procedure. A subset without resection had favorable initial outcomes but remained at high risk for subsequent procedures. There may be a potential role for evaluating intraoperative manipulation/fixation in a small subset of patients with colonic volvulus.

All things not being equal: readmission associated with procedure type

BACKGROUND

There is an accelerated effort to reduce hospital readmissions despite minimal data detailing risk factors associated with this outcome.

MATERIALS AND METHODS

We analyzed National Surgical Quality Improvement Project data from January 1, 2011-December 31, 2011, evaluating all patients undergoing one of 34 targeted operative procedures across all surgical specialties. Multivariate regression models of risk for readmission were developed including targeted procedure codes, demographic variables, preoperative variables, intraoperative variables, and postoperative adverse events. Our main outcome measure was hospital readmission.

RESULTS

A total of 217, 389 patients met study inclusion criteria. Minimal associations existed between patient factors and risk of readmission. Adverse events including unplanned operating room return (odds ratio [OR] 8.5; confidence interval [CI] 8.0-9.0), pulmonary embolism (OR 8.2; CI 7.1-9.6), deep incisional infection (OR 7.5; CI 6.7-8.5), and organ space infection (OR 5.8; CI 5.3-6.3) were associated with increased risk of readmission. Our data suggest the type of procedure performed is significantly associated with risk of readmission. Furthermore, multivariate analysis revealed procedures, involving the pancreas, rectum, bladder, and lower extremity vascular bypass, were associated with the highest risk of readmission.

CONCLUSIONS

Postoperative complications demonstrated stronger association with readmission than patient factors. Focused analysis of higher risk procedures may provide insight into strategies for risk reduction.

What is the effect of stoma construction on surgical site infection after colorectal surgery?

INTRODUCTION

The aim of our study was to evaluate the effect of stoma creation on deep and superficial surgical site infections after an index colorectal surgical procedure.

METHODS

We designed a retrospective cohort study from the National Surgical Quality Improvement Program. We evaluated all patients who underwent colorectal surgery procedures from January 2005 to December 2009 with or without creation of a stoma and sought to identify the effect of stoma creation on deep and superficial surgical site infections.

RESULTS

A total of 79,775 patients underwent colorectal procedures (laparoscopic 30.7%, open 69.3%), while 8,113 patients developed a surgical site infection (10.2%). The univariate analysis revealed that surgical site infections were much more common in patients with a stoma compared to those with no stoma (11.8% vs. 9.5%, p < 0.0001). On multivariate analysis, stoma construction during the index colorectal procedure (OR 1.3, CI 1.2 to 1.4), ASA class ≥2, smoking, and abnormal body mass index were associated with surgical site infection.

CONCLUSIONS

The construction of a stoma with colorectal procedures is associated with a higher risk of surgical site infection. Although the stoma effect on surgical site infection is attenuated with laparoscopic techniques, the association remained statistically significant.

The impact of pregnancy on surgical Crohn disease: an analysis of the Nationwide Inpatient Sample

BACKGROUND

The impact of pregnancy on the course of Crohn disease is largely unknown. Retrospective surveys have suggested a variable effect, but there are limited population-based clinical data. We hypothesized pregnant women with Crohn disease will have similar rates of surgical disease as a nonpregnant Crohn disease cohort.

MATERIAL AND METHODS

International Classification of Diseases, Ninth Revision, Clinical Modification codes were used to identify female Crohn patients from all patients admitted using the Nationwide Inpatient Sample (1998-2009). Women were stratified as either pregnant or nonpregnant. We defined Crohn-related surgical disease as peritonitis, gastrointestinal hemorrhage, intra-abdominal abscess, toxic colitis, anorectal suppuration, intestinal-intestinal fistulas, intestinal-genitourinary fistulas, obstruction and/or stricture, or perforation (excluding appendicitis).

RESULTS

Of the 92,335 women admitted with a primary Crohn-related diagnosis, 265 (0.3%) were pregnant. Pregnant patients were younger (29 versus 44 y; P<0.001) and had lower rates of tobacco use (6% versus 13%; P<0.001). Pregnant women with Crohn disease had higher rates of intestinal-genitourinary fistulas (23.4% versus 3.0%; P<0.001), anorectal suppuration (21.1% versus 4.1%; P<0.001), and overall surgical disease (59.6% versus 39.2%; P<0.001). On multivariate logistic regression analysis controlling for malnutrition, smoking, age, and prednisone use, pregnancy was independently associated with higher rates of anorectal suppuration (odds ratio [OR], 5.2; 95% confidence interval [CI], 3.8-7.0; P<0.001), intestinal-genitourinary fistulas (OR, 10.4; 95% CI, 7.8-13.8; P<0.001), and overall surgical disease (OR, 2.9; 95% CI, 2.3-3.7; P<0.001).

CONCLUSIONS

Pregnancy in women with Crohn disease is a significant risk factor for Crohn-related surgical disease, in particular, anorectal suppuration and intestinal-genitourinary fistulas.

Considerations and complications in patients undergoing ileal pouch anal anastomosis

Total proctocolectomy with ileal pouch anal anastomosis (IPAA) preserves fecal continence as an alternative to permanent end ileostomy in select patients with ulcerative colitis and familial adenomatous polyposis. The procedure is technically demanding, and surgical complications may arise. This article outlines both the early and late complications that can occur after IPAA, as well as the workup and management of these potentially morbid conditions.

MET expression and amplification in patients with localized gastric cancer

BACKGROUND

MET, the receptor for hepatocyte growth factor, has been proposed as a therapeutic target in gastric cancer. This study assessed the incidence of MET expression and gene amplification in tumors of Western patients with gastric cancer.

METHODS

Tumor specimens from patients enrolled on a preoperative chemotherapy study (NCI 5700) were examined for the presence of MET gene amplification by FISH, MET mRNA expression by quantitative PCR, MET overexpression by immunohistochemistry (IHC), and for evidence of MET pathway activation by phospho-MET (p-MET) IHC.

RESULTS

Although high levels of MET protein and mRNA were commonly encountered (in 63% and 50% of resected tumor specimens, respectively), none of these tumors had MET gene amplification by FISH, and only 6.6% had evidence of MET tyrosine kinase activity by p-MET IHC.

CONCLUSIONS

In this cohort of patients with localized gastric cancer, the presence of high MET protein and RNA expression does not correlate with MET gene amplification or pathway activation, as evidenced by the absence of amplification by FISH and negative p-MET IHC analysis.

IMPACT

This article shows a lack of MET amplification and pathway activation in a cohort of 38 patients with localized gastric cancer, suggesting that MET-driven gastric cancers are relatively rare in Western patients.

Ultimate fate of the leaking intestinal anastomosis: does leak mean permanent stoma?

BACKGROUND

The ultimate fate of the leaking intestinal anastomosis is unknown. We sought to analyze long-term outcomes of anastomotic leak with an emphasis on identifying the likelihood of re-establishing intestinal continuity and the potential for releak with corrective surgery.

METHODS

All consecutive subjects treated for clinical anastomotic leak from January 2001 through December 2007 were retrospectively reviewed. Patients were stratified by management of leak: (1) drainage alone, (2) proximal loop diversion, (3) repair/revision without diversion, (4) end stoma, or (5) tube enterostomy. We then determined management of anastomotic leak, mortality, corrective procedures, releak, and re-establishment of intestinal continuity.

RESULTS

In a database of 2,627 intestinal procedures, 79 patients had 88 anastomotic leaks with a final overall mortality of 10.1%. The aggregate rate of re-establishment of intestinal continuity was lowest for the patients treated by end stoma (44.4%) as compared to other initial management options (p < 0.01). Of the patients who survived their initial anastomotic leak, 20.5% had another leak (releak).

CONCLUSIONS

Patients who underwent resection of the leaking anastomosis and end stoma or proximal loop diversion have a high rate of long-term fecal diversion. The proportion of patients who experience an anastomotic releak is substantial following further corrective surgery to re-establish intestinal continuity.

L576P KIT mutation in anal melanomas correlates with KIT protein expression and is sensitive to specific kinase inhibition

Activating mutations in either BRAF or NRAS are seen in a significant number of malignant melanomas, but their incidence appears to be dependent to ultraviolet light exposure. Thus, BRAF mutations have the highest incidence in non-chronic sun damaged (CSD), and are uncommon in acral, mucosal and CSD melanomas. More recently, activating KIT mutations have been described in rare cases of metastatic melanoma, without further reference to their clinical phenotypes. This finding is intriguing since KIT expression is downregulated in most melanomas progressing to more aggressive lesions. In this study, we investigated a group of anal melanomas for the presence of BRAF, NRAS, KIT and PDGFRA mutations. A heterozygous KIT exon 11 L576P substitution was identified in 3 of 20 cases tested. The 3 KIT mutation-carrying tumors were strongly immunopositive for KIT protein. No KIT mutations were identified in tumors with less than 4+ KIT immunostaining. NRAS mutation was identified in one tumor. No BRAF or PDGFRA mutations were identified in either KIT positive or negative anal melanomas. In vitro drug testing of stable transformant Ba/F3 KIT(L576P) mutant cells showed sensitivity for dasatinib (previously known as BMS-354825), a dual SRC/ABL kinase inhibitor, and imatinib. However, compared to an imatinib-sensitive KIT mutant, dasatinib was potent at lower doses than imatinib in the KIT(L576P) mutant. These results suggest that a subset of anal melanomas show activating KIT mutations, which are susceptible for therapy with specific kinase inhibitors.

Novel xenograft model expressing human hepatocyte growth factor shows ligand-dependent growth of c-Met-expressing tumors

c-Met, a receptor tyrosine kinase responsible for cellular migration, invasion, and proliferation, is overexpressed in human cancers. Although ligand-independent c-Met activation has been described, the majority of tumors are ligand dependent and rely on binding of hepatocyte growth factor (HGF) for receptor activation. Both receptor and ligand are attractive therapeutic targets; however, preclinical models are limited because murine HGF does not activate human c-Met. The goal of this study was to develop a xenograft model in which human HGF (hHGF) is produced in a controllable fashion in the mouse. Severe combined immunodeficient mice were treated with adenovirus encoding the hHGF transgene (Ad-hHGF) via tail vein injection, and transgene expression was determined by the presence of hHGF mRNA in mouse tissue and hHGF in serum. Ad-hHGF administration to severe combined immunodeficient mice resulted in hHGF production that was (a) dependent on quantity of virus delivered; (b) biologically active, resulting in liver hypertrophy; and (c) sustainable over 40 days. In this model, the ligand-dependent human tumor cell line SW1417 showed enhanced tumor growth, whereas the ligand-independent cell lines SW480 and GTL-16 showed no augmented tumor growth. This novel xenograft model is ideal for investigating c-Met/HGF-dependent human tumor progression and for evaluating c-Met targeted therapy.

Molecular co-expression of the c-Met oncogene and hepatocyte growth factor in primary colon cancer predicts tumor stage and clinical outcome

INTRODUCTION/HYPOTHESIS

Over-expression of the c-Met receptor tyrosine kinase has been described in a variety of cancers and implicated in tumor progression. Unlike some solid tumors, current evidence indicates that c-Met activation in colon cancer is unrelated to gene mutation, is ligand dependent, and occurs via a paracrine fashion. We hypothesize that over-expression of the c-Met receptor and its ligand, hepatocyte growth factor (HGF) in the tumor microenvironment is associated with tumor progression and metastases.

METHODS

Primary tumor c-Met and HGF mRNA expression was analyzed in 60 colon adenocarcinomas. Receptor and ligand expression was analyzed for correlation and association with clinicopathologic features and outcome.

RESULTS

Compared to adjacent normal mucosa, 69% and 48% of tumors showed a greater than 2- and greater than 10-fold elevation in c-Met mRNA, respectively. Elevated HGF mRNA was noted in 47% of tumors with 19% having a greater than 10-fold increase. Tumor c-Met expression was correlated with HGF expression, and a cohort of 33 patients could be defined with both low c-Met and HGF expression. Compared with the 27 tumors with either high c-Met or HGF, the cohort with low c-Met and HGF expression had fewer nodal and distant metastases as well as improved overall survival (HR=2.3, p<0.05).

CONCLUSION

Evaluation of the c-Met receptor in context of ligand, HGF, allows identification of a metastatic phenotype that correlates with advanced stage and poor survival. c-Met and HGF co-expression in the tumor microenvironment could be useful in the molecular staging of colon cancer and viable therapeutic targets.

Direct Electrochemical Investigations of 17-Electron Complexes of CpM(CO)(3)(*) (M = Mo, W, and Cr)

Photolysis of complexes of the type M(2)(CO)(6)(RC(5)H(4))(2) (where M = W, Mo, Cr and R = H (Cp) or CH(3) (Cp')) leads to the production of short lived 17-electron radicals. Direct electrochemical characterization of these intermediates has been achieved using a technique known as photomodulated voltammetry (PMV). The results from PMV analysis are in excellent agreement with literature estimates for CpMo(CO)(3)(*) and CpCr(CO)(3)(*). However, CpW(CO)(3)(*) is found to be shifted oxidatively 115 mV relative to previous literature estimates. The change in the value for the tungsten complex changes previous estimates to the bond dissociation energy for tungsten metal hydrides by 3.0 +/- 0.9 kcal/mol. Lifetime information on the radicals is also reported based on the phase shift of the electrochemical signal observed by PMV under limiting current conditions.