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Background/Aims: Gastric cancers (GCs), particularly the Lauren intestinal type, show a male predominance. The aim of this study was to investigate the effects of reproductive factors on GCs in females, according to Lauren classification. Methods: Medical records of 1,849 males and 424 females who underwent radical gastrectomy or endoscopic resection for GCs between 2010 and 2018 were reviewed. The incidences of intestinal-type GCs were compared between males and groups of females stratified according to postmenopausal period. Associations between reproductive factors in females and intestinal type GCs were analyzed using multivariate models. Results: The proportions of intestinal-type GCs were significantly lower in premenopausal (19%), less than 10 years postmenopausal (30.4%), and 10 to 19 years postmenopausal females (44.1%) than in males (61.0%) (p<0.05 for all). Females ≥20 years post menopause had a proportion of intestinal-type GCs similar to that in males (60.6% vs 61.0%; p=0.948). Multivariate analysis revealed that age (odds ratio [OR], 1.075; 95% confidence interval [CI], 1.039 to 1.113; p<0.001) and parity ≥3 (OR, 1.775; 95% CI, 1.012 to 3.114; p=0.045) were positively associated with an increased risk of intestinal-type GCs in postmenopausal females, while long fertility duration (OR, 1.147; 95% CI, 1.043 to 1.261; p=0.005) was positively associated with an increased risk of intestinal-type GCs in premenopausal females. Conclusions: There were no significant differences in the proportions of intestinal-type GCs between males and females ≥20 years post menopause, suggesting that female reproductive factors play a role in the prevention of intestinal-type GC. [ABSTRACT FROM AUTHOR]

Background/Aims: Small rectal neuroendocrine tumors (NETs) are often managed with local resection (endoscopic or transanal excision) owing to their low risk of metastasis and recurrence. However, the clinical significance of lymphovascular invasion in resected specimens remains controversial. In this study, we aimed to analyze the frequency of and risk factors for lymph node metastasis proven by histopathologic examination after radical resection. Methods: We retrospectively reviewed the records of 750 patients diagnosed with a rectal NET at four academic medical centers in South Korea between 2001 and 2019. The frequency of histopathologically proven lymph node metastasis and the associated risk factors were analyzed for small tumors (≤1.5 cm) with lymphovascular invasion. Results: Among 750 patients, 75 had a small tumor (≤1.5 cm) with lymphovascular invasion, of whom 31 patients underwent endoscopic resection only and 44 patients underwent additional radical surgery. Among the 41 patients who underwent surgery and had available data, the rate of regional lymph node metastasis was 48.8% (20/41). In multivariate analysis, the Ki-67 index (odds ratio, 6.279; 95% confidence interval, 1.212 to 32.528; p=0.029) was an independent risk factor for lymph node metastasis. During the mean follow-up period of 37.7 months, only one case of recurrence was detected in the surgery group. The overall survival was not significantly different between radical resection and local resection (p=0.332). Conclusions: Rectal NETs with lymphovascular invasion showed a significantly high rate of regional lymph node metastasis despite their small size (≤1.5 cm). [ABSTRACT FROM AUTHOR]

Background/Aims: This study examined the long-term outcomes of undifferentiated-type early gastric cancer (UD EGC) with positive horizontal margins (HMs) after endoscopic resection (ER) and compared them between additional surgery and nonsurgical management. Methods: From 2005 to 2015, a total of 1,124 patients with UD EGC underwent ER at 18 tertiary hospitals in Korea. Of them, 92 patients with positive HMs as the only noncurative factor (n=25) or with both positive HMs and tumor size >2 cm (n=67) were included. These patients underwent additional surgery (n=40), underwent additional endoscopic treatment (n=6), or were followed up without further treatment (n=46). Results: No lymph node (LN) metastasis was found in patients who underwent additional surgery. During a median follow-up of 57.7 months (interquartile range, 27.6 to 68.8 months), no LN or distant metastases or gastric cancer-related deaths occurred in the overall cohort. At baseline, the residual cancer rate was 57.8% (26/45) after additional surgery or ER. The 5-year local recurrence rate was 33.6% among patients who were followed up without additional treatment. The 5-year overall survival rates were 95.0% and 87.8% after additional surgery and nonsurgical management (endoscopic treatment or close follow-up), respectively (log-rank p=0.224). In the multivariate Cox regression analysis, nonsurgical management was not associated with an increased risk of mortality. Conclusions: UD EGC with positive HMs after ER may have favorable long-term outcomes and a very low risk of LN metastasis. Nonsurgical management may be suggested as an alternative, particularly for patients with old age or chronic illness. [ABSTRACT FROM AUTHOR]