RESUMEN
BACKGROUND: Anal adenocarcinoma (AA) represents 5% to 10% of anal cancer. Little is known about its natural history and prognosis. Using population-based data, we defined the outcomes of AA relative to other anorectal malignancies. PATIENTS AND METHODS: We analyzed the Surveillance, Epidemiology, and End Results 18 database to identify patients ≥ 18 years old with AA, squamous cell carcinoma of the anus (SCCA), and rectal adenocarcinoma (RA) diagnosed between 1990 and 2011. Median overall survival (OS), 1-year, 3-year, 5-year, and 10-year OS were computed using actuarial methods. The log rank test was used to estimate the difference between Kaplan-Meier survival curves. A Cox proportional hazard regression model was used to adjust the effects of other covariates on survival, including age, year diagnosed, sex, stage, surgery, and radiation. RESULTS: Of 57,369 cases, 0.8% (n = 462) were patients with AA, 87.8% (n = 50,382) were patients with RA, and 11.4% (n = 6525) were patients with SCCA. The median age for AA was 69 years (range, 20-96 years), 66 years (range, 18-103 years) for RA, and 66 years (range, 14-104 years) for SCCA. The median OS was significantly lower for AA (33 months), compared with SCCA (118 months) and RA (68 months) (P < .01). In multivariate analysis, AA had a worse prognosis compared with SCCA (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.59-0.75; P < .01) and RA (HR, 0.68; 95% CI, 0.61-0.77; P < .01), after adjusting for age, sex, race, stage, grade, radiation, and surgery. There was a strong trend for improved survival among patients who received radical surgery (HR, 0.71; 95% CI, 0.51-1.00; P = .05). CONCLUSION: AA confers a significantly worse prognosis than SCCA and RA.
Asunto(s)
Adenocarcinoma/mortalidad , Neoplasias del Ano/mortalidad , Carcinoma de Células Escamosas/mortalidad , Neoplasias del Recto/mortalidad , Adenocarcinoma/patología , Adenocarcinoma/terapia , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Antineoplásicos , Neoplasias del Ano/patología , Neoplasias del Ano/terapia , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/terapia , Quimioradioterapia , Terapia Combinada , Procedimientos Quirúrgicos del Sistema Digestivo , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estadificación de Neoplasias , Pronóstico , Modelos de Riesgos Proporcionales , Radioterapia , Neoplasias del Recto/patología , Neoplasias del Recto/terapia , Programa de VERF , Factores Sexuales , Tasa de Supervivencia , Adulto JovenRESUMEN
P2Y(12) receptor antagonism inhibits platelet aggregation by preventing adenosine diphosphate (ADP)-mediated amplification of activation pathways downstream of primary agonists, such as thrombin and collagen. However, the role of ADP signaling in maintaining aggregate stability and the effects of P2Y(12) antagonists on preestablished aggregates in vitro and arterial thrombus in vivo are not well understood. This study evaluated the impact of P2Y(12) signaling on platelet aggregate stability and early thrombotic occlusion using a reversible P2Y(12) antagonist, ticagrelor. There were 2 study objectives: (1) to determine if there was a time-dependent factor on the capacity of a P2Y(12) antagonist to affect human platelet aggregate stability in vitro using light transmission aggregometry and (2) to evaluate the extent of arterial thrombus reversal in a preclinical model upon administration of ticagrelor in vivo. Platelet aggregates were exposed to ticagrelor after ADP or collagen activation, monitored for stability by aggregometry, and visualized by microscopy. Freshly formed ADP- and collagen-induced platelet aggregates were more rapidly dispersed by a P2Y(12) antagonist than drug carrier control at clinically relevant concentrations (P < 0.05). However, stable aggregates were not noticeably affected. A murine arterial thrombosis model was used to evaluate thrombus stability in an in vivo mouse model. Thrombotic occlusion was induced by FeCl(3), followed by a bolus intravenous administration of ticagrelor or vehicle control. Doppler blood flow was monitored before injury and 30 minutes after bolus administration. Arteries were retrieved for inspection for residual thrombus. Early arterial thrombotic occlusion in vivo was partially reversed by ticagrelor administration. Blood flow through the injured artery increased, and thrombus size within the artery decreased (P < 0.05, n = 3). In conclusion, P2Y(12) antagonism disrupts the stability of newly formed platelet aggregates, promoting disaggregation, and reverses thrombotic vascular occlusion. Thus, in addition to activating platelets, signaling via P2Y(12) seems to be required for stabilizing platelet thrombi.
Asunto(s)
Agregación Plaquetaria/fisiología , Antagonistas del Receptor Purinérgico P2Y/farmacología , Receptores Purinérgicos P2Y12/metabolismo , Transducción de Señal/fisiología , Adenosina/análogos & derivados , Adenosina/farmacología , Adenosina/uso terapéutico , Animales , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Agregación Plaquetaria/efectos de los fármacos , Antagonistas del Receptor Purinérgico P2Y/uso terapéutico , Transducción de Señal/efectos de los fármacos , Trombosis/tratamiento farmacológico , Trombosis/metabolismo , Ticagrelor , Factores de TiempoRESUMEN
Glycoprotein IIb-IIIa (GPIIb-IIIa) antagonists have the capacity to destabilize coronary thrombi and restore vessel patency. Antagonist concentration and residence time, which can be increased by local intracoronary (LIC) administration, and thrombus age may be key factors that influence thrombus stability. Light transmission aggregometry was used to examine the effects of exposing human platelet aggregates to extremely high local levels of GPIIb-IIIa antagonists versus conventional therapeutic levels in vitro. Freshly-formed or aged platelet aggregates were subjected to GPIIb-IIIa antagonists (abciximab, eptifibatide) or direct thrombin inhibitor bivalirudin at concentrations simulating either conventional intravenous (IV) or LIC administration. The degree of antagonist-induced disaggregation was significantly higher using elevated (LIC) doses versus conventional (IV) doses (60.1 % vs. 7.4 % for abciximab, 41.6 % or 45.3 % vs. 17.6 % for eptifibatide, p < 0.01). Bivalirudin did not promote disaggregation. Microscopy confirmed noticeably smaller, more dispersed aggregates for antagonist LIC treatments. Dosing at LIC levels also induced more disaggregation than IV levels when aggregates were aged for 30 min prior to exposure. An in vitro perfusion model was used to simulate the fluid dynamics of IV or LIC administration of abciximab using a microporous local drug delivery balloon catheter such as the Atrium ClearWay™ RX. The perfusion model resulted in more rapid thrombus clearance with LIC dosing levels compared to IV. In summary, boosting the concentration of GPIIb-IIIa antagonists enhances dispersal of human platelet aggregates in vitro. These data provide a foundation for investigating increased local concentrations of GPIIb-IIIa antagonists in patients, as with LIC administration.