LAUSR

To the Editor, We have read with interest the article published by Yasukawa et al. At present, many studies have focused on the preoperative C‐reactive protein to albumin ratio (CAR) because it is closely related to the prognosis after surgery. Although we believe it is a very interesting topic, we would like to offer the following points for your consideration. The comparison in Table 1 (relationship between proactive CAR and clinicopathological status) is too simple. To better exclude the influence of related factors on the results of this study, we should compare the clinical fracture scale (CFS) and the skeletal muscle index (SMI) in the two groups(CAR ≥ 0.031 and CAR < 0.031) because these factors are closely related to the prognosis of tumor patients. In recent years, more and more studies focus on sarcopenia and frailty and show that they will directly affect the survival rate of patients with cancer. At present, the diagnosis of sarcopenia is mainly based on the lumbar SMI, and its value range is SMI < 52.4 cm/m for men and SMI < 38.5 cm/m for women. Sierzega et al reported that sarcopenia can increase the postoperative morbidity and complications of patients with cancer, and prolong the postoperative hospital stay. At the same time, their research also shows that sarcopenia is an independent prognostic factor affecting the long‐term survival of patients with cancer. A study by Bingmer et al found that sarcopenia is associated with worse overall survival and progression‐free survival in patients with anal squamous cell cancer. The study of Levolger et al showed that the postoperative complications and mortality of sarcopenia patients were increased, and it was also related to the survival rate of patients with liver cancer. Joglekar et al reported that sarcopenia can predict the postoperative complications of pancreatic cancer, which is conducive to preoperative evaluation and can also make patients fully understand their own condition, reduce unnecessary anxiety, and accelerate postoperative recovery. The CFS is a frailty scale based on clinical evaluation in the domains of mobility, energy, physical activity, and function. Yamada et al found that frailty group had higher postoperative complications, longer postoperative hospital stay, and worse disease‐free survival rate than nonfrailty group. Their study also showed that frailty was detected as an independent predictive factor on multivariate analysis of cancer‐specific survival. Rosiello et al showed that in patients with radical nephrectomy, frailty patients had higher postoperative complications, mortality, total hospitalization costs, and longer hospital stay. Vermillion et al found that frailty was associated with the incidence of positive complications and mortality in elder surgical patients with gastrointestinal cancer. In the current study, the multivariate analysis showed that a high CAR was an independent predictive factor for both overall survival (OS) and disease‐free survival (DFS). However, many studies have shown that frailty and sarcopenia combined are also independent prognostic factors for OS and DFS in patients with cancer. If there are more sarcopenia and frailty patients in the high CAR group, then these factors will affect OS and DFS, resulting in false‐positive results. To reduce unnecessary false‐positive results, the combination of frailty and sarcopenia should be included and compared in this study. Only in this way can we better use the preoperative C‐reactive protein to albumin ratio predictor long‐term outcomes in patients with extrahepatic cholangiocarcinoma.