As the population worldwide steadily ages, the incidence of renal disease and the number of patients receiving HD are increasing (9). The mean age of the entire dialysis patient population is 66.6 years (10). Studies have reported that patients with chronic kidney disease have a higher incidence of malignancy than other individuals (9); as the number of elderly patients receiving HD increases, the number of HD patients requiring major surgery will also increase. Perioperative management of HD patients is critical for good surgical outcomes because of the high prevalence of comorbidities in this population, such as diabetes, peripheral atherosclerosis, anemia, hepatitis, and cachexia (3). However, even with careful perioperative care, patients undergoing HD are at a greater risk than other patients of having poor surgical outcomes and postoperative complications, such as a tendency to bleed, delayed wound healing, infection, electrolyte imbalances, hemodynamic instability, and anastomotic leakage following gastrointestinal surgery (5) (9) (10). Once a complication occurs, HD patients are less likely to survive than non-dialysis patients. Pneumonia, stroke/cerebrovascular accident, myocardial infarction, and unplanned intubation appear to be the most lethal complications in HD patients (5). Although the incidence of gastric cancer is decreasing slightly, gastric cancer remains the second most common cause of cancer-related death in Japan. However, there is no consensus on the extent of gastrectomy and lymph node dissection in HD patients because there are not enough data on postoperative outcomes after gastrectomy and risk factors in HD patients with gastric cancer.
In this study, the immune/inflammation index was poor in the HD group; however, there was no correlation between HD and postoperative complications. Importantly, there was no significant difference in DFS between the HD and control groups after gastric resection. Although this study only included eight dialysis patients, there were no postoperative complications and no significant difference was observed, compared with the control group. However, HD patients had a significantly higher prevalence of comorbidities, such as diabetes and cardiopulmonary disease, which may be associated with lower OS. Three of the HD patients died from causes other than gastric cancer after gastrectomy; two of these died within 3 years of surgery.
We found that HD, stage, and mGPS were independent prognostic factors of OS among all patients; stage and frailty were extracted as prognostic factors for OS among HD patients. Frailty was found in three of eight patients in the HD group, and frail HD patients had a significantly poorer OS rate than non-frail HD patients. HD is associated with immune system abnormalities and immunodeficiencies related to systemic inflammation (11). Other studies have found a correlation between mortality and nutritional parameters in patients on long-term dialysis. Malnutrition is common among patients with HD and has a complex pathogenesis (7); malnutrition in HD patients correlates with systemic inflammation and impacts prognosis (8). The Glasgow prognosis score, which is based on serum C-reactive protein (CRP) and albumin levels, was recently developed to assist in assessing cancer prognosis. An elevated score is associated with poor prognosis for many tumor types (1). However, hypoalbuminemia without elevated CRP is rare, and the mGPS reflects the observation that hypoalbuminemia alone is not associated with survival among cancer patients (12). Serum CRP and albumin levels are also important parameters for predicting mortality, even among HD patients (13); our results indicate that mGPS is an important prognostic factor for HD patients with gastric cancer.
In recent years, frailty has received research attention because of the increasing size of the elderly population. Frailty is defined as a condition of exacerbation resulting from age-related decline or increased vulnerability to stressful situations and is characterized by diminished biological reserve capacity (14). Frailty portends increased vulnerability to adverse outcomes after stressful medical or surgical conditions and has been considered very important in predicting surgical outcomes in older patients. Loss of energy reserves, physical fitness, and cognition in frail patients leads to vulnerability. Therefore, the postoperative outcomes of patients with gastric cancer may be affected by frailty. Among the currently available frailty measurements, the Clinical Frailty Scale is a simple semi-quantitative tool that provides an assessment of clinically relevant frailty (15) (16). Studies have estimated that 21% to 73% of HD patients have frailty (14). In the present study, many of the HD patients underwent reduction surgery, especially those with frailty. Limited lymph node dissection is often performed in elderly patients with gastric cancer, and limited lymph node dissection did not appear to affect the DFS rate among the HD patients in this study. These findings suggest that R0 resection with at least limited lymph node dissection should be considered, especially for frail HD patients.