Relationship between surgical procedures and preoperative clinicopathological factors

Of the 120 eligible participants, 57 were excluded because they had not undergone postoperative CT examinations at our institution. Consequently, 63 patients (36 male, 27 female) were included. The preoperative clinicopathological characteristics of the 63 patients, categorized into the LLR and LDG groups, are summarized in Table 1. The median age in the LLR and LDG groups was 68 and 67.5 years, respectively (P = 0.84). No significant differences were observed in median body weight or body mass index (BMI) between the two groups (P = 0.47 and P = 0.79, respectively). Regarding tumor location, tumors in the upper stomach were significantly more frequent in the LLR group, while those in the lower stomach were significantly more frequent in the LDG group (P < 0.01). The distribution of normal, osteopenia, sarcopenia, and osteosarcopenia showed no significant differences between the two groups (P = 0.50). Additionally, no significant differences were noted in the median preoperative values of NLR, PNI, CAR, or albumin between the two groups (P = 0.27, P = 0.30, P = 0.88, P = 0.28, P = 0.31, and P = 0.14, respectively).

Table 1 Relationship between surgical procedures and preoperative clinicopathological characteristics (N = 63)Relationship between surgical procedures and postoperative clinicopathological factors

The postoperative clinicopathological characteristics of the LLR and LDG groups are presented in Table 2. In the LLR group, all patients underwent sentinel lymphatic basin dissection, while in the LDG group, 1, 37, and 4 patients underwent D1, D1+, and D2 lymphadenectomy, respectively (P < 0.01). The sentinel lymphatic basins were classified into the following five regions: the left gastric artery basin (l-GA), right gastric artery basin, left gastroepiploic artery basin, right gastroepiploic artery basin, and posterior gastric artery basin [16]. Dissection of the l-GA was performed in 10 patients in the LLR group, whereas all patients in the LDG group underwent dissection in this region (P < 0.01). Both the resected specimen and pathological tumor sizes were significantly larger in the LDG group (P < 0.01). Postoperative complications of Clavien–Dindo grade ≥ 2 were observed in 13 (21%) patients, with a significantly higher incidence in the LDG group (P = 0.04). The most common complications included delayed gastric emptying (four cases, 6%) and anastomotic stricture (three cases, 5%). In the LLR group, postoperative complications occurred in only two patients, with one patient in the l-GA dissection group and one in the non-l-GA dissection group, showing no significant difference (P = 0.94). At 5 years postsurgery, body weight and BMI were higher in the LLR group; however, the differences were not statistically significant (P = 0.06 and P = 0.09, respectively). The distribution of normal, osteopenia, sarcopenia, and osteosarcopenia showed no significant differences between the two groups (P = 0.25).

Table 2 Relationship between surgical procedures and postoperative clinicopathological characteristics (N = 63)Prognostic analysis determined by surgical procedures

The 5-year overall survival was 94.4% and 100% in the LLR and LDG groups, respectively. No significant difference in overall survival was observed between the LLR and LDG groups (Fig. 2).

Fig. 2

Kaplan–Meier curves for overall survival in patients who underwent laparoscopic local resection and laparoscopic distal gastrectomy

Relationship between surgical procedures and SMI change rate

When comparing the median change rates in the SMI at 1, 3, and 5 years between the LLR and LDG groups, the change rate from presurgery to 1-year postsurgery or from pre-surgery to 3 years postsurgery showed no significant difference in both groups. However, from presurgery to 5 years postsurgery, the LLR group showed a significant increase (Fig. 3).

Fig. 3

Comparison of the rate of change in the skeletal muscle index among groups who underwent laparoscopic local resection and laparoscopic distal gastrectomy. LDG laparoscopic distal gastrectomy, LLR laparoscopic local resection, SMI skeletal muscle index

Relationship between surgical procedures and BMD change rate

When comparing the median change rates in BMD at 1, 3, and 5 years between the LLR and LDG groups, no significant difference was found from presurgery to 1 year postsurgery or from presurgery to 3 years postsurgery in both groups. However, from presurgery to 5 years postsurgery, the LLR group showed a significant increase (Fig. 4).

Fig. 4

Comparison of the rate of change in bone mineral density among groups who underwent laparoscopic local resection and laparoscopic distal gastrectomy. BMD bone mineral density, LDG laparoscopic distal gastrectomy, LLR laparoscopic local resection

Relationship between surgical procedures and change rate of body weight and BMI

Similar to the BMD and SMI change rates, the change rate of body weight and BMI was calculated. The median change rate of body weight and BMI at 1, 3, and 5 years postoperatively was compared between the LLR and LDG groups. Both groups showed a decrease from preoperative levels to 1 year postoperatively. However, from 1 to 3 years and 3 to 5 years postoperatively, the LLR group showed a greater increase than the LDG group, although the differences were not statistically significant (P = 0.39 and P = 0.36, respectively) (Fig. 5a, b).

Fig. 5

Comparison of the rate of change in body weight and body mass index among groups who underwent laparoscopic local resection and laparoscopic distal gastrectomy. (a) body weight; (b) body mass index. BMI body mass index, LDG laparoscopic distal gastrectomy, LLR laparoscopic local resection

Relationship between l-GA dissection and the rate of change in SMI and BMD

In the LLR group, patients were categorized into the l-GA dissection and non-l-GA dissection groups, and the median rates of change in SMI and BMD were calculated and compared for each group. In SMI, no significant differences were observed in its change rate from preoperative to 1 year postoperatively (P = 0.69), 1–3 years postoperatively (P = 0.52), or 3–5 years postoperatively (P = 1.00) (Fig. 6a).

Fig. 6

Comparison of the rate of change in skeletal muscle index and bone mineral density among groups who underwent l-GA dissection and non-l-GA dissection. (a) skeletal muscle index; (b) bone mineral density. BMD bone mineral density, l-GA left gastric artery basin, SMI skeletal muscle index

In BMD, a significant difference was noted in its change rate from 1 to 3 years postoperatively (P = 0.04). However, no significant differences were observed in the change rate of BMD from preoperative to 1 year postoperatively or 3–5 years postoperatively (P = 0.49 and P = 0.12, respectively) (Fig. 6b).