Abstract: Objective: Describe the prevalence of breast cancer (BC)-associated germline pathogenic variants (PVs) among Mexican patients with triple-negative BC (TNBC). Materials and methods: The spectrum of PVs identified among patients with TNBC who were enrolled in a prospective registry and underwent genetic testing was analyzed. Results: Of 387 patients with invasive TNBC and a median age at diagnosis of 39 years (range 21-72), 113 (29%) were carriers of PVs in BC-susceptibility genes: BRCA1 (79%), BRCA2 (15%), and other (6%: ATM, BRIP1, PALB2, PTEN, RAD51C, and TP53). PV carriers were younger at BC diagnosis (37 vs. 40 years, p=0.004) than non-carriers. Conclusion: A large proportion of TNBC in Mexican patients is associated with germline PVs, the vast majority in BRCA. The incremental yield of PVs in other BC-susceptibility genes was modest, and a stepwise approach starting with BRCA testing may be justified if it is more cost-effective than multigene panel testing.

Resumen: Objetivo: Describir la prevalencia de variantes patógenas (VPs) germinales en genes asociados con cáncer de mama (CM) en pacientes mexicanos con CM triple negativo (CMTN). Material y métodos: Se analizó el espectro de VPs identificadas en pacientes con CMTN que fueron incluidos prospectivamente en un registro y se realizó un estudio genético. Resultados: Se analizó un total de 387 pacientes con una mediana de edad al diagnóstico de 39 años; 113 (29%) eran portadores de VPs en genes de susceptibilidad a CM: BRCA1 (79%), BRCA2(15%), y otros (6%: ATM, BRIP1, PALB2, PTEN, RAD51C y TP53). Los portadores de VPs eran más jóvenes al diagnóstico de CM (37 vs. 40 años, p=0.004). Conclusiones: Existe una alta prevalencia de VPs en pacientes mexicanos con CMTN y la mayoría se encuentra en genes BRCA. La realización de pruebas genéticas se puede optimizar mediante la adopción de un proceso escalonado para la detección de VPs.

Abstract: In 2014, a partnership was established between the University of California and Mexico, which subsequently catalyzed formation of collaborations between cancer researchers at University of California, San Francisco and in Mexico. Over the past two decades cancer burden has dramatically increased in Mexicans on both sides of the California - Mexico border. Together, we face a growing burden of cancer in the context of globalized economies, diverse migration patterns, and dynamic immigration policies. Our partnership aims to: 1) understand the life course impact of cancer risk factors and interactions with changing environments; 2) address cancer disparities within Mexico, in Mexican migrants to the United States, and in naturalized Mexican-Americans; and 3) identify effective cancer screening strategies and cancer control policies that are tailored to existing healthcare systems and social and cultural factors. Herein, we describe the principles of partnership and early successes and challenges of this collaboration.

Resumen: En 2014, se estableció un convenio de colaboración colaboración entre la Universidad de California y México, que posteriormente catalizó colaboraciones específicas entre investigadores en cáncer en la Universidad de California, San Francisco y en México. En las últimas dos décadas, la carga del cáncer ha aumentado drásticamente en mexicanos de ambos lados de la frontera entre California y México. Juntos, enfrentamos una carga creciente de cáncer en un contexto de economías globalizadas y diversos patrones y políticas de migración dinámicas. Nuestra colaboración tiene como objetivo: 1) entender el impacto a lo largo de la vida de factores de riesgo de cáncer y sus interacciones en un entorno cambiante; 2) abordar disparidades del cáncer dentro de México, en os migrantes mexicanos a los Estados Unidos y en los mexicoamericanos naturalizados; y 3) identificar estrategias efectivas de detección del cáncer y políticas de control del cáncer que se adapten a sistemas de salud existentes y a factores sociales y culturales. Aquí describimos los principios de esta colaboración y los primeros éxitos y retos de la misma.

Abstract: Objective: To determine the exposure to aflatoxin B1 (AFB1) in southern Mexico and the presence of the aflatoxin signature mutation in hepatocellular carcinoma (HCC) tissue from patients from a cancer referral center. Materials and methods: We estimated the prevalence and distribution of AFB1 in a representative sample of 100 women and men from Chiapas using the National Health and Nutrition Survey 2018-19. We also examined the presence of the aflatoxin signature mutation in codon 249 (R249S), and other relevant mutations of the TP53 gene in HCC tissue blocks from 24 women and 26 men treated in a national cancer referral center. Results: The prevalence of AFB1 in serum samples was 85.5% (95%CI 72.1-93.1) and the median AFB1 was 0.117 pg/µL (IQR, 0.050-0.350). We detected TP53 R249S in three of the 50 HCCs (6.0%) and observed four other G>T transversions potentially induced by AFB1. Conclusion: Our analysis provides evidence that AFB1 may have a relevant role on HCC etiology in Mexico.

Resumen: Objetivo: Determinar la exposición a aflatoxina_B1 (AFB1) en el sur de México y la presencia de la mutación característica de AFB1 en tejido de carcinoma hepatocelular (CHC) de pacientes de un centro oncológico. Material y métodos: Se estimó la prevalencia y distribución de AFB1 en una muestra representativa de 100 mujeres y hombres de Chiapas a partir de la Encuesta Nacional de Salud y Nutrición 2018-19. También se observó la presencia de la mutación característica de AFB1 en el codón 249 (R249S), y otras mutaciones relevantes del gen TP53 en bloques de tejido de CHC de 24 mujeres y 26 hombres estudiados en un centro de referencia nacional de oncología. Resultados: La prevalencia de AFB1 en las muestras de suero fue de 85.5% (IC95% 72.1-93.1) y la mediana de la concentración 0.117 pg/µL (IQR, 0.050-0.350). Se detectó TP53 R249S en tres de 50 casos de CHC (6.0%) y se observaron cuatro transversiones G>T potencialmente inducidas por AFB1. Conclusión: El presente análisis proporciona evidencia de que la AFB1 puede tener un papel relevante en la etiología del CHC en México.

RESUMO: Objetivos: Descrever tendências na mortalidade por câncer de pulmão e no uso do tabaco. Métodos: Realizamos um estudo ecológico de séries temporais para determinar a tendência de mortalidade por câncer de pulmão de acordo com o consumo de tabaco, com base em fontes secundárias de acesso aberto, como as Pesquisas Nacionais. Prevalência de tabagismo, tendências de uso de tabaco, porcentagem e taxas de mortalidade foram determinadas pelo câncer de pulmão. A tendência de mortalidade por câncer de pulmão foi calculada e uma análise de regressão linear foi realizada para avaliar o impacto da lei geral para o controle do tabagismo. Resultados: A prevalência do uso de tabaco diminuiu continuamente entre 1988 e 2015, principalmente em homens. As taxas e percentuais de mortalidade diminuíram entre 1998 e 2018. Durante esse período, a taxa de mortalidade diminuiu de 6,3 para 5,4 por 100 mil habitantes (-0,032 por 100 mil a cada ano, p<0,001), com redução líquida de 0,9 por 100 mil. Observamos aumentos na mortalidade de mulheres nas regiões Centro e Sudeste. Dos 32 estados, 18 apresentaram tendência à perda (p<0,005). A taxa de mudança para os homens foi de -0,24, com redução total de 2,17 antes da introdução das leis e -0,32 após a sua introdução — redução total de 3,24 (p<0,005). As mulheres não apresentaram redução. Conclusões: As taxas de mortalidade mostraram redução limitada. Estratégias precisam ser fortalecidas, principalmente nas regiões Centro e Sudeste, e deve-se enfocar o controle do uso do tabaco pelas mulheres.

ABSTRACT: Objective: The aim of this study was to describe trends in lung cancer (LC) mortality and trends in tobacco use. Methods: This is an ecological time-series study to determine mortality trends due to lung cancer resulting from tobacco consumption, based on secondary open-access sources, such as the National Surveys. Smoking prevalence, tobacco use trends, mortality rates, and percentage were determined by LC. The mortality trend from LC was calculated, and a linear regression analysis was performed to evaluate the impact of the General Law for Tobacco Control. Results: The prevalence of tobacco use decreased steadily between 1988 and 2015, particularly in men. Mortality rates and percentage decreased between 1998 and 2018. During this period, the mortality rate decreased from 6.3 to 5.4 per 100,000 population (−0.032/100,000 each year, p<0.001), with a net decrease of 0.9 per 100,000. We observe increases in mortality in women in the central and southeastern regions. Of 32 states, 18 showed a tendency to loss (p<0.005). The rate of change for men was −0.24, with a total reduction of 2.17 before the introduction of the laws and −0.32 after their introduction, a total reduction of 3.24 (p<0.005). Women showed no reduction. Conclusions: Mortality rates showed a limited decrease. Strategies need to be strengthened, mainly in the central and southeastern regions, and to focus on the control of tobacco use by women.

RESUMO: Objetivos: Descrever tendências na mortalidade por câncer de pulmão e no uso do tabaco. Métodos: Realizamos um estudo ecológico de séries temporais para determinar a tendência de mortalidade por câncer de pulmão de acordo com o consumo de tabaco, com base em fontes secundárias de acesso aberto, como as Pesquisas Nacionais. Prevalência de tabagismo, tendências de uso de tabaco, porcentagem e taxas de mortalidade foram determinadas pelo câncer de pulmão. A tendência de mortalidade por câncer de pulmão foi calculada e uma análise de regressão linear foi realizada para avaliar o impacto da lei geral para o controle do tabagismo. Resultados: A prevalência do uso de tabaco diminuiu continuamente entre 1988 e 2015, principalmente em homens. As taxas e percentuais de mortalidade diminuíram entre 1998 e 2018. Durante esse período, a taxa de mortalidade diminuiu de 6,3 para 5,4 por 100 mil habitantes (-0,032 por 100 mil a cada ano, p<0,001), com redução líquida de 0,9 por 100 mil. Observamos aumentos na mortalidade de mulheres nas regiões Centro e Sudeste. Dos 32 estados, 18 apresentaram tendência à perda (p<0,005). A taxa de mudança para os homens foi de -0,24, com redução total de 2,17 antes da introdução das leis e -0,32 após a sua introdução — redução total de 3,24 (p<0,005). As mulheres não apresentaram redução. Conclusões: As taxas de mortalidade mostraram redução limitada. Estratégias precisam ser fortalecidas, principalmente nas regiões Centro e Sudeste, e deve-se enfocar o controle do uso do tabaco pelas mulheres.

ABSTRACT: Objective: The aim of this study was to describe trends in lung cancer (LC) mortality and trends in tobacco use. Methods: This is an ecological time-series study to determine mortality trends due to lung cancer resulting from tobacco consumption, based on secondary open-access sources, such as the National Surveys. Smoking prevalence, tobacco use trends, mortality rates, and percentage were determined by LC. The mortality trend from LC was calculated, and a linear regression analysis was performed to evaluate the impact of the General Law for Tobacco Control. Results: The prevalence of tobacco use decreased steadily between 1988 and 2015, particularly in men. Mortality rates and percentage decreased between 1998 and 2018. During this period, the mortality rate decreased from 6.3 to 5.4 per 100,000 population (−0.032/100,000 each year, p<0.001), with a net decrease of 0.9 per 100,000. We observe increases in mortality in women in the central and southeastern regions. Of 32 states, 18 showed a tendency to loss (p<0.005). The rate of change for men was −0.24, with a total reduction of 2.17 before the introduction of the laws and −0.32 after their introduction, a total reduction of 3.24 (p<0.005). Women showed no reduction. Conclusions: Mortality rates showed a limited decrease. Strategies need to be strengthened, mainly in the central and southeastern regions, and to focus on the control of tobacco use by women.

ABSTRACT Background: In Mexico, up to 15% of breast cancer (BC) patients are 40 years or younger. Therefore, fertility preservation and pregnancy after cancer treatment are major concerns in this population. However, no data are available regarding Mexican physicians' knowledge and attitudes toward these issues. Objective: The objective of the study was to describe physicians' attitudes, knowledge, and perceived barriers toward fertility preservation among young women with BC (YWBC) in a developing country. Methods: A cross-sectional study was conducted among physicians attending the 2016 Mexican Society of Oncology (SMeO) Annual Meeting or affiliated to SMeO. Chi-squared tests were used to assess factors associated with a higher likelihood of disclosing infertility risks, discussing fertility preservation methods, referring to specialists, and effective counseling. Results: Of the 314 participants, 83% reported a high sense of responsibility about informing treatment-related infertility risks, 58% always informed patients about those risks, 38% always discussed fertility preservation procedures, 52% always referred interested patients to fertility specialists, and 24% wrongly considered pregnancy and GnRH analogs detrimental in YWBC. Barriers for discussing fertility preservation were costs, lack of specialists, and prognosis. Conclusions: It is crucial to promote physicians' knowledge and to endorse policies to overcome barriers obstructing universal access to fertility preservation for YWBC in Mexico.

Background: Identifying and addressing breast cancer (BC) patients' unmet needs (UN) are crucial due to their possible contribution to higher levels of morbidity, particularly in vulnerable underserved populations, such as Latinas with BC. Objective: This study aimed to (1) identify and describe the most frequently reported items of moderate-high UN among Mexican women with BC covered by public healthcare insurance; (2) analyze the differences in UN domains according to participants' sociodemographic and clinical characteristics; and (3) validate the Supportive Care Needs Survey-Short Form-34 (SCNS-SF34). Methods: A cross-sectional study was conducted with 396 consecutive BC patients. A linguistically translated and culturally adapted version of the SCNS-SF34 for Mexican women with BC was completed by the participants. Results: The validation yielded a 32-item version of the SCNS with adequate psychometric properties. The Health System and Providers Information was the highest UN domain, followed by the psychological domain. "Fears about cancer spreading" (37.4%) and "Concerns about the worries of those close to you" (37.3%) were the most prevalent moderate-high UN. Sexuality was the only domain associated with clinical and sociodemographic characteristics. Conclusion: By defining the most urgent needs of this group of patients, our results will enable the development of targeted support services and patient-centered care.

Abstract Cancer represents a national and global public health problem. In Mexico, the real incidence and prevalence of the disease is unknown, and its mortality is partially acknowledged. In this context, population-based cancer registrieswere established in ten localities (including 12.15% of the Mexican population) and organized by a general coordination, the National Cancer Registry Network (NCRN). Data were collected and obtained by using a registration card including 29 standardized and structured variables, according to international guidelines. The NCRN aligned with the quality indicators proposed by the International Agency of Research in Cancer, for comparability, validity, timeliness and completeness. A NCRN has been already established in Mexico, which is considered an epidemiological surveillance system with active and continuous validity. Currently, there are 18,000 cases registered from public and private data sources. The NCRN will determine the incidence and survival rates of cancer among the Mexican population, in order to implement public policy actions for cancer control.

Resumen El cáncer representa un problema nacional y mundial de salud pública. En México, se desconoce la incidencia y la prevalencia real de la enfermedad, y solo se conoce parcialmente su mortalidad. Ante esta necesidad, se implementaron registros de cáncer de base poblacional en diez localidades (cubriendo el 12.15% de la población mexicana), organizados por una coordinación general, denominada Red Nacional de Registros de Cáncer (RNRC). La recolección de la información se lleva a cabo por medio de la cumplimentación de una cédula de registro con 29 variables estandarizadas y estructuradas según lineamientos internacionales. La RNRC se alinea a los indicadores de calidad propuestos por la International Agency of Research on Cancer de comparabilidad, validez, oportunidad y exhaustividad. En México ya se encuentra establecida una RNRC, la cual se considera un sistema de vigilancia epidemiológica con validez activa y continua. Actualmente se tienen registrados 18,000 casos obtenidos de fuentes de información públicas y privadas. La RNRC permitirá determinar la incidencia de cáncer y las tasas de supervivencia en la población mexicana, para implementar acciones de política pública para control del cáncer.

Abstract: Objective: To compare cancer mortality rates in Mexico from two national death registries that independently code and attribute cause of death. Materials and methods: We compared 5-year age-standardized total cancer and site-specific cancer mortality rates (2010-2014) from Mexico’s official death registry with a death registry from a disease surveillance system. We obtained age-adjusted mortality rates and 95% confidence intervals using the direct method and World Population Prospects 2010 as a standard. Results: Cancer mortality estimates for Mexico were minimally affected by the use of two distinct death certificate-coding procedures. Cancer mortality was 73.3 forInstituto Nacional de Estadística y Geografíaand 72.7 for System for Epidemiolo gic Death Statistics per 100 000 women. The corresponding estimates for men were 68.3 and 67.8. Conclusion: Mexico’s low cancer mortality is unlikely to be explained by death certificate processing. Further investigations into the process of death certification and cancer registration should be conducted in Mexico.

Resumen: Objetivo: Comparar la mortalidad por cáncer en México a partir de dos registros de mortalidad nacionales. Material y métodos: Se comparó la tasa de mortalidad estandarizada por edad para cáncer total y por sitio específico (2010-2014) utilizando dos fuentes con diferentes métodos de procesamiento de información. Se obtuvieron tasas estandarizadas e intervalos de confianza al 95% utilizando el método directo y como población estándar el World Population Prospects 2010. Resultados: Las tasas de mortalidad no se vieron afectadas por métodos distintos para procesar información. La mortalidad por cáncer en mujeres fue de 73.3 por cada 100 000 en el Instituto Nacional de Estadística y Geografía y 72.7 en el Subsistema Epidemiológico y Estadístico de Defunciones. Las estimaciones para hombres fueron 68.3 and 67.8, respectivamente. Conclusión: Es poco probable que la baja mortalidad por cáncer en México se explique por el procesamiento de la información. Es necesario realizar estudios enfocados en el proceso de certificación y registro de muerte por cáncer.

Abstract: Objective: To compare cancer mortality rates in Mexico from two national death registries that independently code and attribute cause of death. Materials and methods: We compared 5-year age-standardized total cancer and site-specific cancer mortality rates (2010-2014) from Mexico’s official death registry with a death registry from a disease surveillance system. We obtained age-adjusted mortality rates and 95% confidence intervals using the direct method and World Population Prospects 2010 as a standard. Results: Cancer mortality estimates for Mexico were minimally affected by the use of two distinct death certificate-coding procedures. Cancer mortality was 73.3 forInstituto Nacional de Estadística y Geografíaand 72.7 for System for Epidemiolo gic Death Statistics per 100 000 women. The corresponding estimates for men were 68.3 and 67.8. Conclusion: Mexico’s low cancer mortality is unlikely to be explained by death certificate processing. Further investigations into the process of death certification and cancer registration should be conducted in Mexico.

Resumen: Objetivo: Comparar la mortalidad por cáncer en México a partir de dos registros de mortalidad nacionales. Material y métodos: Se comparó la tasa de mortalidad estandarizada por edad para cáncer total y por sitio específico (2010-2014) utilizando dos fuentes con diferentes métodos de procesamiento de información. Se obtuvieron tasas estandarizadas e intervalos de confianza al 95% utilizando el método directo y como población estándar el World Population Prospects 2010. Resultados: Las tasas de mortalidad no se vieron afectadas por métodos distintos para procesar información. La mortalidad por cáncer en mujeres fue de 73.3 por cada 100 000 en el Instituto Nacional de Estadística y Geografía y 72.7 en el Subsistema Epidemiológico y Estadístico de Defunciones. Las estimaciones para hombres fueron 68.3 and 67.8, respectivamente. Conclusión: Es poco probable que la baja mortalidad por cáncer en México se explique por el procesamiento de la información. Es necesario realizar estudios enfocados en el proceso de certificación y registro de muerte por cáncer.

Abstract: Objective: To briefly describe the process of establishment and preliminary results of the Mérida Population-based Cancer Registry (Mérida-PBCR) Materials and methods: Mérida-PBCR started in 2016 as a research project in the IMSS, with a gradual increase in its information sources. It covers a population of 908 536 inhabitants. Data collection is active and passive, international standards are used; CanReg5 software enables data entry, storage and analysis. Results: Current data include 71.5% of sources. For the period 2015-2016, a total of 2 623 new cancer cases were registered, the majority of these (60.1%) among females. 81.5% of the cases had morphological verification. Prostate (17.4%), colorectal (8.5%) and stomach (8.1%) cancers were the most common among males, and breast (31.6%), cervix (12%) and corpus uteri (7.6%) cancers, the most common among females. Age-adjusted cancer incidence rates (per 100 000) for all sites combined were 114.9 among males and 145.1 among females. Conclusion: The implementation of the Mérida-PBCR has followed particular parameters, with important efforts to include new information sources. Although the data are still preliminary and must be interpreted with great caution, the main cancers follow a similar pattern to that of the national and regional estimates.

Resumen: Objetivo: Describir brevemente el proceso de implementación y resultados preliminares del Registro de Cáncer de Base Poblacional (RCBP) de Mérida. Material y métodos: RCBP-Mérida inició en 2016 como un proyecto de investigación del IMSS, con cobertura poblacional de 908 536 habitantes. El número de fuentes de información ha incrementado gradualmente. Se realizó colección de datos de forma pasiva y activa en software CanReg5 utilizando estándares internacionales. Resultados: Se han incluido al RCBP-Mérida 71.5% de las fuentes de información. Durante 2015-2016 se registraron 2 623 casos nuevos, la mayoría (60.1%) mujeres. El 81.5% de los casos tuvo verificación morfológica. En hombres, el cáncer de próstata (17.4%), colorrectal (8.5%) y estómago (8.1%) son los más comunes; en mujeres, mama (31.6%), cérvix (12.0%) y cuerpo-uterino (7.6%). Las tasas de incidencia ajustadas por edad (100 000 habitantes) para todos los sitios combinados son 114.9 hombres y 145.1 mujeres. Conclusión: La implementación del RCBP-Mérida ha seguido parámetros particulares, con importante esfuerzo para incluir fuentes de información. Aunque los datos son preliminares y se deben interpretar con precaución; los principales tipos de cáncer siguen un patrón similar a las estimaciones nacionales y regionales

Abstract: Objective: To briefly describe the process of establishment and preliminary results of the Mérida Population-based Cancer Registry (Mérida-PBCR) Materials and methods: Mérida-PBCR started in 2016 as a research project in the IMSS, with a gradual increase in its information sources. It covers a population of 908 536 inhabitants. Data collection is active and passive, international standards are used; CanReg5 software enables data entry, storage and analysis. Results: Current data include 71.5% of sources. For the period 2015-2016, a total of 2 623 new cancer cases were registered, the majority of these (60.1%) among females. 81.5% of the cases had morphological verification. Prostate (17.4%), colorectal (8.5%) and stomach (8.1%) cancers were the most common among males, and breast (31.6%), cervix (12%) and corpus uteri (7.6%) cancers, the most common among females. Age-adjusted cancer incidence rates (per 100 000) for all sites combined were 114.9 among males and 145.1 among females. Conclusion: The implementation of the Mérida-PBCR has followed particular parameters, with important efforts to include new information sources. Although the data are still preliminary and must be interpreted with great caution, the main cancers follow a similar pattern to that of the national and regional estimates.

Resumen: Objetivo: Describir brevemente el proceso de implementación y resultados preliminares del Registro de Cáncer de Base Poblacional (RCBP) de Mérida. Material y métodos: RCBP-Mérida inició en 2016 como un proyecto de investigación del IMSS, con cobertura poblacional de 908 536 habitantes. El número de fuentes de información ha incrementado gradualmente. Se realizó colección de datos de forma pasiva y activa en software CanReg5 utilizando estándares internacionales. Resultados: Se han incluido al RCBP-Mérida 71.5% de las fuentes de información. Durante 2015-2016 se registraron 2 623 casos nuevos, la mayoría (60.1%) mujeres. El 81.5% de los casos tuvo verificación morfológica. En hombres, el cáncer de próstata (17.4%), colorrectal (8.5%) y estómago (8.1%) son los más comunes; en mujeres, mama (31.6%), cérvix (12.0%) y cuerpo-uterino (7.6%). Las tasas de incidencia ajustadas por edad (100 000 habitantes) para todos los sitios combinados son 114.9 hombres y 145.1 mujeres. Conclusión: La implementación del RCBP-Mérida ha seguido parámetros particulares, con importante esfuerzo para incluir fuentes de información. Aunque los datos son preliminares y se deben interpretar con precaución; los principales tipos de cáncer siguen un patrón similar a las estimaciones nacionales y regionales

Abstract Background: Social Support (SS) has been an important variable to consider in the psychosocial understanding of patients with cancer. Objective: To test the 3-factor model for the Medical Outcomes Study Social Support Survey (MOS SSS) and estimate its internal consistency reliability in Mexican women with Breast Cancer (BC). Method: 300 women diagnosed with BC were enrolled in a convenience sampling. Participants were asked to complete the Spanish version of the MOS SSS (Argentina). After the approval of the Ethics and Research Review Board of Instituto Nacional de Cancerología, the Mexican adaptation was created through three phases: 1) linguistically adaptation; 2) presentation of the corrected and integrated version to another expert, and 3) pilot study. Results: The MOS SSS obtained a factorial structure with 13 items distributed among three factors. A high internal consistency (Alpha=0.912) and an acceptable explained-variance value (67%) were obtained; finally, the confirmatory analysis determined a proper adjustment with that structure. Conclusions: This instrument has adequate psychometric properties and is useful for evaluation and culturally appropriate to the clinical management of SS.

Resumen Antecedentes: el apoyo social (AS) ha sido una variable importante a considerar en la comprensión psicosocial de los pacientes con cáncer. Objetivo: evaluar el modelo de 3 factores de la escala de apoyo social MOS (Medical Outcomes Study Social Support Survey, MOS SSS) en mujeres mexicanas con cáncer de mama (CaMa). Método: 300 pacientes con diagnóstico de cáncer de mama aceptaron participar en el estudio a través de un muestreo por conveniencia, en el que se les pidió que contestaran la versión de la escala de AS MOS en español (Argentina). Después de la aprobación de los comités de ética e investigación del Instituto Nacional de Cancerología, la adaptación mexicana se realizó por fases: 1) adaptación lingüística, presentación de la versión integrada y corregida a expertos y estudio piloto. Resultados: la versión de MOS en español de México obtuvo una estructura factorial con 13 ítems distribuidos entre los tres factores. La consistencia interna (Alpha=0.912) y la varianza explicada fueron aceptables (67%). Finalmente, el análisis confirmatorio determinó una estructura con un ajuste apropiado. Conclusiones: El instrumento obtenido mostró propiedades psicométricas adecuadas y útiles para la evaluación y el manejo clínico culturalmente apropiado del AS.