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The individualized prediction of breast cancer survival (IPBS) model was recently developed. Although the model showed acceptable performance during derivation, its external performance remained unknown. This study aimed to validate the IPBS model using the data of breast cancer patients in Northern Thailand. An external validation study was conducted based on female patients with breast cancer who underwent surgery at Maharaj Nakorn Chiang Mai hospital from 2005 to 2015. Data on IPBS predictors were collected. The endpoints were 5-year overall survival (OS) and disease-free survival (DFS). The model performance was evaluated in terms of discrimination and calibration. Missing data were handled with multiple imputation. Of all 3581 eligible patients, 1868 were included. The 5-year OS and DFS were 85.2% and 81.9%. The IPBS model showed acceptable discrimination: C-statistics 0.706 to 0.728 for OS and 0.675 to 0.689 for DFS at 5 years. However, the IPBS model minimally overestimated both OS and DFS predictions. These overestimations were corrected after model recalibration. In this external validation study, the IPBS model exhibited good discriminative ability. Although it may provide minimal overestimation, recalibrating the model to the local context is a practical solution to improve the model calibration.
RESUMO
SUMMARY: The dorsalis pedis artery (DPA) is a vital artery that supplies the foot and ankle area which is clinically important for palpating when taking the pulse. This research was performed on fresh cadaveric dissection of 40 legs by injecting paint into popliteal artery for tracking the dorsalis pedis artery and its branches. The present research revealed that the Thai population has an anatomical variation and different location of the DPA and exact location of DPA for estimating the location of the DPA and may have clinical implications. The statistically descriptive analysis elucidated the distances of the DPA to the lateral malleolus and medial malleolus which were 51.48 ± 7.27 mm and 42.62 ± 11.40 mm, respectively. The distance of the extensor hallucis longus (EHL) to the DPA was 14.29 ± 4.11 mm. The length of the dorsalis pedis artery which measured from artery on intermalleolar line to its dipping in 1st intermetatarsal space to be 122.03 ± 21.07 mm. The arcuate loop which is anastomosis U-loop of lateral tarsal arteries of the DPA was found 55 % in Thais population. There were no statistically significant differences of all parameters between the side and sex in DPA consideration. An understanding of the variations of the anatomical vasculature of DPA is essential for precise clinical assessment because exact anatomical knowledge and location can contribute to the pulse taking and be applied in surgical procedure.
RESUMEN: La arteria dorsal del pie (ADP) es una arteria vital que irriga eldorso del pie y el tobillo, y es clínicamente importante para la toma del pulso. Esta investigación se realizó en disección cadavérica de 40 piernas inyectando látex coloreado en la arteria poplítea para rastrear la ADP y sus ramas. La presente investigación reveló que en la población tailandesa la ADP tiene una variación anatómica y una ubicación diferente. Por tanto, determinar la ubicación exacta del ADP será útil para las implicaciones clínicas. El análisis estadísticamente descriptivo determinó que las distancias del ADP al maléolo lateral y al maléolo medial eran 51,48 ± 7,27 mm y 42,62 ± 11,40 mm, respectivamente. La distancia del tendón del músculo extensor largo del halux (ELH) al ADP era de 14,29 ± 4,11 mm. La longitud de la ADP, desde la línea intermaleolar hasta su entrada al primer espacio intermetatarsiano, era de 122,03 ± 21,07 mm. El asa arqueada, que es una anastomosis U-loop de las arterias tarsales laterales de la ADP, se encontró en un 55 % de la población tailandesa. No hubo diferencias estadísticamente significativas en todos los parámetros de la ADP entre el lado y el sexo. La comprensión de las variaciones de la variaciones anatómicas de la ADP es esencial para una evaluación clínica precisa. El conocimiento anatómico exacto y la ubicación pueden contribuir a la toma del pulso y ser útil en el procedimiento quirúrgico.