The short-term results of this study showed no notable association between frailty and postoperative complications. However, several studies on sarcopenia and frailty that did not include social and psychological factors have shown a significant association with postoperative complications. (9) (10) (11) (12) We also previously reported that, in gastric cancer patients, a low preoperative muscle mass increases the risk of postoperative complications, especially infectious complications. (13) Lutz et al. showed that, as skeletal muscle mass decreases and adipose tissue mass increases, the production of anti-inflammatory cytokines and adiponectin decreases, and levels of inflammatory molecules, such as leptin, chemelin, resistin, TNF-α, IL-1, and IL-6, increase. (20) These mechanisms suggest that sarcopenia patients are in a pro-inflammatory state, leading to decreased immunity and reduced postoperative wound healing, which may affect the risk of postoperative complications. (14)
A comprehensive index of frailty that includes psychological and social aspects is the clinical frailty scale (CFS), a simple 9-point global scale. (15) Tanaka et al. reported that preoperative frailty in gastric cancer assessed using the CFS was an independent prognostic factor but not an independent risk factor for postoperative complications, and there are few reports of frailty assessed using indices that include psychological and social aspects as risk factors for postoperative complications. (16) This suggests that a decrease in physical reserve, including sarcopenia, is particularly likely to influence postoperative complications.
While the present study did not find a significant association between frailty and complication rates, many frail patients cannot be discharged home and must be transferred to other hospitals. This suggests that not only physical factors but also psychological and social factors, such as the patient's home environment, may have a significant impact on being discharged home.
Regarding the prognosis, there was no clear difference in the prognosis between the frail and non-frail groups for gastric cancer of p Stage I, but the frail group had a worse prognosis than the non-frail group for gastric cancer of p Stage II/III. Furthermore, frailty was an independent prognostic factor for the OS in p Stage II/III gastric cancer. Tanaka et al. reported that, in frailty assessed by the CFS in patients over 80 years old who underwent laparoscopic gastrectomy, similar to our results, there was no marked difference in the OS in p Stage I, but for p Stage II/III, the OS was significantly worse in frail patients than in non-frail patients. (16) The main reason for this result may be that many patients in the frail group could not be discharged home after surgery and had to be transferred to other hospitals for rehabilitation and recuperation, and as shown in Fig. 2(A), few patients were able to receive chemotherapy even if they were eligible for postoperative adjuvant chemotherapy. In addition, as shown in Fig. 2(B), the fact that frail patients in p Stage III did not receive double postoperative adjuvant chemotherapy may have been influenced by a comprehensive assessment of frailty that included not only physiological reserve but also psychological and social background. However, the lack of a marked difference in the prognosis for gastric cancer of p Stage I may have been attenuated by that comprehensive assessment.
Various indices have been reported for the assessment of frailty; Fried et al. defined patients who had three or more of the five items of Shrinking, Weakness, Exhaustion, Slowness, and Low activity as being frail, and those who corresponded to one or two items had pre-frailty. (17) Kristine et al. showed an association with frailty as assessed by the Study of Osteoporotic Fractures (SOF) index, which consists of three simple items: weight loss, inability to rise from a chair, and loss of energy. (18) (19) However, all of these studies assessed frailty based on physical factors alone.
In gastric cancer, preoperative sarcopenia, malnutrition, and frailty assessed by the SOF index have been reported to adversely affect long-term prognosis, but all of them assessed frailty based on physical factors and nutritional status. (20) (21) (22) Reports on frailty in gastric cancer patients assessed by a comprehensive index and treatment outcome are rare, except for a study using the CFS by Tanaka et al. (16) In the present study, we used a questionnaire consisting of 5 categories and 50 items, as shown in Tables 1 and 2, which we believe can more accurately assess frailty than other indicators of frailty. The frail group had significantly higher frail scores in all five categories than the non-frail group, confirming that the questionnaire used in this study is an accurate indicator of frailty.
There are few reports of improved long-term outcomes with nutrition and rehabilitation interventions for frail patients, but there have been reports of decreased complications and a shortened hospital stay after surgery. (23) However, these interventions will never improve postoperative outcomes for all frail patients. Therefore, it is important for patients assessed as being frail to be offered preoperative nutrition and rehabilitation interventions as well as preoperative home care coordination and application for long-term-care services to support their discharge home. This will help maintain these patients’ QOL, which in turn will increase the proportion of patients receiving adjuvant chemotherapy and improve the prognosis.
Several limitations associated with the present study warrant mention. First, this study was conducted at a single institution, and the number of patients evaluated was small. A larger multicenter study is needed to validate the results of this study. Second, these results are based on a questionnaire that was created by making original modifications to an existing questionnaire. Its validity as a questionnaire to assess frailty is thus debatable and needs to be validated against Fried's criteria and other measures of frailty. Third, since frailty is a concept originally intended for the elderly, it should also be considered for elderly patients. Fourth, the cut-off values for the FI used in this study were calculated from an ROC analysis, and further validation studies with larger sample sizes should be conducted to determine more qualified cut-off values. In addition, prospective studies should be conducted to analyze the impact of interventions, such as early home care application, nutrition, and rehabilitation.