To the Editor:
We read the article “Volatile versus Total Intravenous Anesthesia for Cancer Prognosis in Patients Having Digestive Cancer Surgery” by Makito et al.1 with great interest. This study is a large clinical retrospective study of more than 190,000 surgical patients with cancer. For further statistical analysis, the authors did a score-matching analysis to compensate for the huge difference in the number of patients who received volatile or intravenous anesthesia. They concluded that there were no significant differences between anesthetic choices on cancer recurrence/survival after surgery. However, we found several limitations in this study which may distort the data analysis. First, various cancer types and surgeries were included in the same analysis; however, it is well known that cancer aggressiveness and malignancy largely differ between cancer types and their origins.2 Second, the subgroup analysis for each type of surgery (presented in table 2 of Makito et al.) did not specify open surgery or laparoscopic surgery. Previous studies have demonstrated in preclinical and clinical settings that surgical trauma/stress and associated systemic inflammation, which often occurs in major open surgeries, promoted cancer progression and malignancy, leading to worse outcomes.3,4 Lastly, there were no data about perioperative steroid and/or nonsteroidal anti-inflammatory drug use; those medications, which are often used during the perioperative period, have been found to improve the clinical outcome in several types of cancers.5 The crosslink between the inflammation and cancer progression after surgery would affect cancer surgical outcomes. It would be great if the authors could elaborate on our concerns for future refined studies wherever possible.
The authors declare no competing interests.