[en] The osteonecrosis of the jaws is a serious adverse effect associated with bisphosphonate therapy (BFs), especially in patients with tumor pathology, gaining importance by the high morbidity associated with this type of injury. With the main objective of estimating its incidence in cancer patients and secondarily to identify the risk factors influencing its development, an observational historical cohort study was initiated. The study included a total of 206 patients who began or were in treatment with BFs between 1 January 2010 and 31 December 2014. The cohort studied, presented a distribution by gender of 158 women and 48 men, with an average age of 61 years. 63.1% of them were diagnosed with breast cancer, 21.5% Multiple Myeloma (MM), 7.8% of prostate cancer, lung 1.5%, and the percentage remaining, of other tumors. Of the 206 patients included, 17 (8.3%) developed a total of 21 bisphosphonate-related osteonecrosis of the jaw (BRONJ) lesions, during the study period. The cumulative incidence estimation in the presence of competing risks, found that the risk of developing BRONJ after one year of treatment was 0.48%, increasing to 2.54% at two years and 10% at five years. The incidence rates for the reference population were of 0.68 per 100,000 people per year. The only variables that showed a statistically significant association with the development of BRONJ were the periods of treatment with concomitant chemotherapy and the periods of treatment with antiangiogenic drugs and exclusively the latter when considering competing risk of death. Due to the frequency of occurrence of BRONJ found in this study, it objectively finds that it is not a rarity and in fact constitutes a serious complication associated to treatment with BFs with a negative impact on the quality of life and survival of cancer patients, therefore being necessary preventive interventions that minimize its occurrence.

[gl] A osteonecrose dos maxilares é un serio efecto adverso asociado á terapia con bifosfonatos (BFs), especialmente en pacientes con patoloxía tumoral de base, gañando importancia pola alta morbilidad asociada a este tipo de lesións. Co obxectivo principal de estimar a súa incidencia en pacientes oncolóxicos e secundariamente identificar os factores de risco que inflúen no seu desenvolvemento, realizouse un estudio observacional de cohorte histórica. Neste estudo foron incluidos un total de 206 pacientes que iniciaron ou se atopaban en tratamento con BFs entre o 1 de xaneiro de 2010 y el 31 de decembro de 2014. A cohorte estudada, presentou unha distribución por sexo de 158 mulleres y 48 homes, cunha media de idade en torno a los 61 anos. Deles, o 63,1% tiñan como diagnóstico cancro de mama, 21,5% mieloma múltiple (MM), cancro de próstata 7,8%, pulmón 1,5 %, e a porcentaxe restante outro tipo de tumores. Dos 206 pacientes incluidos, 17 (8,3%) desenvolveron un total de 21 lesións de osteonecrosis de los maxilares por bifosfonatos (OMB), durante o período de estudo. Na estimación da incidencia mediante a metodoloxía de riscos competitivos, atopouse que o risco de desenvolver OMB ó ano de tratamento foi do 0,48% aumentando a 2,54 % aos dous años e o 10 % aos cinco años. A tasa de incidencia para a poboación de referencia foi de 0,68 por cada 100.000 personas/año. As únicas variables que mostraron asociación estadísticamente significativa co desenvolvemento de OMB foron o tempo de tratamento con quimioterapia concomitante e o tempo de tratamento con fármacos antiangiogénicos, e exclusivamente este último cando se considera o risco competitivo de morte. Debido á frecuencia de aparición da OMB comprobada neste estudo, que obxectiva que non se trata dunha rareza e a que constitue unha seria complicación asociada ó tratamento con BFs con repercusions negativas sobre a calidade de vida e supervivencia dos pacientes oncolóxicos, son desexables intervencións preventivas que eviten a súa aparición.