Salud Pública de México (Oct 2005)
Factores de riesgo de cáncer cervicouterino invasor en mujeres mexicanas Risk factors in invasive cervical cancer among Mexican women
Abstract
OBJETIVOS: Evaluar la asociación entre cáncer cervicouterino (CaCu) invasor y el virus del papiloma humano de alto riesgo (VPH-AR) (carga viral/tipo 16), así como con factores ginecológicos y socioeconómicos. MATERIAL Y MÉTODOS: Estudio de casos y controles pareado individualmente (215 casos con CaCu invasor y 420 controles). La población de estudio se reclutó entre los años 2000 y 2001. Se evaluaron variables tradicionalmente asociadas con CaCu (ginecológicas y socioeconómicas) y dos variables asociadas con la presencia de VPH (carga viral y el tipo 16). La presencia de VPH-AR se determinó mediante Captura de Híbridos II. La carga viral se midió a través de unidades relativas de luz y picogramos por ml (1 RLU=1 pg/ml), divididas en cuatro categorías: negativa (499 pg/ml). El análisis estimó razones de momios (RM) ajustadas a través de modelos de regresión logística condicionada. RESULTADOS: La presencia de VPH-AR incrementa en 78 veces la probabilidad de presentar CaCu invasor; cuando el VPH es tipo 16, el incremento es mayor (RM= 429.7) comparado con otros tipos (RM=64.1). Se observó una tendencia importante en la RM al elevarse la carga viral (RM=46.6 carga baja; RM=250.7 intermedia y RM=612.9 alta). Finalmente, los factores demográficos y obstétricos conocidos, incrementaron la probabilidad de CaCu invasor. No se observó asociación entre CaCu invasor y tabaquismo en la población de estudio. CONCLUSIONES: Este estudio contribuye a la identificación de las mujeres con alto riesgo de desarrollar CaCu invasor, entre las pacientes infectadas con VPH-AR. Por otra parte, confirma la importancia de la infección de VPH-AR y refleja la carga viral del VPH-AR como cofactor y posible promotor en el desarrollo de la enfermedad. Por último, este biomarcador puede contribuir a mejorar la prevención y la detección temprana de esta enfermedad.OBJECTIVE: To evaluate the association between invasive Cervical Cancer (CC) and high risk Human Papilloma Virus (HR-HPV) (viral load and type 16), along with other gynecological and socioeconomic factors. MATERIAL AND METHODS: Individually matched case-control study (215 women with invasive CC and 420 controls). The study population was recruited between 2000 and 2001. A set of variables traditionally linked with CC (gynecological and socioeconomic factors) and two variables related to HPV infection (viral load and type 16) were assessed. Hybrid Capture II was used to detect HR-HPV DNA. Viral load was measured by light measurements expressed as relative light units (RLU) and they were categorized for analysis into four groups: negative (499 RLU). The analysis included univariate, bivariate and multivariate techniques being the final step the estimation of Odds Ratios (OR) by means of conditional logistic regression models. RESULTS: The probability of having invasive CC was 78 times higher in patients with infection of HR-HPV. Risk increases with HPV type 16 (OR=429.7) as compared with other types of HR-HPV (OR=64.1). An important trend was observed with the increase of the viral load (from 46.6 with low viral load; to 250.7 with intermediate and 612.9 with high load). The findings also indicate significant diferences in the viral load between cases and controls according to age groups and HR-HPV types (16 versus others high risk types). Finally, the partner-demographic and obstetrical variables related to the disease increased the risk of invasive CC. No association between CC and smoking was observed in this population. CONCLUSIONS: This study helps in identifying women at higher risk of developing invasive CC as a subset of those patients infected with HR-HPV. The findings point strongly to the importance of the viral load in HR-HPV as a co-factor in the development of this disease. This biomarker contributes to improving the prevention and early detection of this disease and also to identify women at higher risk who carry a high viral load of HR-HPV.
