Impact of Body Mass Index on Survival Depending on Sex in 14,688 Patients with Gastric Cancer in a Tertiary Hospital in South Korea

Abstract

Background/aims: The incidence and prognosis of gastric cancer (GC) shows sex difference. This study aimed to evaluate the effect of body mass index (BMI) on GC survival depending on sex.

Methods: The sex, age, location, histology, TNM stages, BMI, and survival were analyzed in GC patients from May 2003 to February 2020 at the Seoul National University Bundang Hospital.

Results: Among 14,688 patients, there were twice as many males (66.6%) as females (33.4%). However, under age 40 years, females (8.6%) were more prevalent than males (3.1%). Cardia GC in males showed a U-shaped distribution for underweight (9.6%), normal (6.4%), overweight (6.1%), obesity (5.6%), and severe obesity (9.3%) but not in females (p=0.003). Females showed decreased proportion of diffuse-type GC regarding BMI (underweight [59.9%], normal [56.8%], overweight [49.5%], obesity [44.8%], and severe obesity [41.7%]), but males did not (p<0.001). Both sexes had the worst prognosis in the underweight group (p<0.001), and the higher BMI, the better prognosis in males, but not females. Sex differences in prognosis according to BMI tended to be more prominent in males than in females in subgroup analysis of TNM stages I, II, and III and the operative treatment group.

Conclusions: GC-specific survival was affected by BMI in a sex-dependent manner. These differences may be related to genetic, and environmental, hormonal factors; body composition; and muscle mass (Trial registration number: NCT04973631).

Keywords: Aging; Body mass index; Sex; Stomach neoplasms; Survival.

Conflict of interest statement

CONFLICTS OF INTEREST

J.W.K. is an editorial board member of the journal but was not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflicts of interest relevant to this article were reported.

Figures

Fig. 1

Sex differences in the proportion of cardia, non-cardia, and Lauren classification of gastric cancer (GC) according to body mass index (BMI). (A) A higher proportion of cardia GC was found in underweight and severely obese patients, with a U-shaped distribution in males. (B) In females, only the underweight group had a higher proportion of cardia GC. (C) In males, the distribution showed an almost uniform plateau regardless of BMI. (D) In underweight females, the proportions of intestinal and diffuse-type were 36.7% and 59.9%, respectively. These proportions became inverted in severe obesity, at 56.4% and 41.7%, respectively. Predefined BMI categories according to Asia-Pacific World Health Organization criteria were used: underweight, BMI 2; normal, BMI 18.5 to 22.9 kg/m2; overweight, BMI 23.0 to 24.9 kg/m2; obesity, BMI 25.0 to 29.9 kg/m2; severe obesity, BMI ≥30.0 kg/m2.

Fig. 2

Gastric cancer-specific survival distributed by sex and body mass index (BMI). Both males and females showed the worst prognosis in the underweight group. (A) Among males, overweight, obese, and severely obese patients had a better prognosis than normal weight patients. (B) Among females, there was no difference of survival according to overweight and severe obesity compared to that for normal weight. That is, in males, the higher the BMI was, the better the prognosis, but not in females. Cumulative survival was calculated using Kaplan-Meier estimates; the p-values were calculated using the log-rank test. Predefined BMI categories according to Asia-Pacific World Health Organization criteria were used: underweight, BMI 2; normal, BMI 18.5 to 22.9 kg/m2; overweight, BMI 23.0 to 24.9 kg/m2; obesity, BMI 25.0 to 29.9 kg/m2; severe obesity, BMI ≥30.0 kg/m2.

Fig. 3

Gastric cancer-specific survival distributed by sex and body mass index (BMI) according to treatment modality. Endoscopic treatment in males (A) and in females (B). Operative treatment in males (C) and in females (D). Chemotherapy in males (E) and in females (F). Conservative treatment in males (G) and in females (H). Cumulative survival was calculated using Kaplan-Meier estimates; the p-values were calculated using the log-rank test. Predefined BMI categories according to Asia-Pacific World Health Organization criteria were used: underweight, BMI 2; normal, BMI 18.5 to 22.9 kg/m2; overweight, BMI 23.0 to 24.9 kg/m2; obesity, BMI 25.0 to 29.9 kg/m2; severe obesity, BMI ≥30.0 kg/m2.

Fig. 3

Gastric cancer-specific survival distributed by sex and body mass index (BMI) according to treatment modality. Endoscopic treatment in males (A) and in females (B). Operative treatment in males (C) and in females (D). Chemotherapy in males (E) and in females (F). Conservative treatment in males (G) and in females (H). Cumulative survival was calculated using Kaplan-Meier estimates; the p-values were calculated using the log-rank test. Predefined BMI categories according to Asia-Pacific World Health Organization criteria were used: underweight, BMI 2; normal, BMI 18.5 to 22.9 kg/m2; overweight, BMI 23.0 to 24.9 kg/m2; obesity, BMI 25.0 to 29.9 kg/m2; severe obesity, BMI ≥30.0 kg/m2.