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Determinant Factors on Differences in Survival for Gastric Cancer between the US and Japan Using Nationwide Databases: The Impact of Number of Lymph Nodes Examined

29 Pages Posted: 11 Dec 2018

See all articles by Yuri Ito

Yuri Ito

Osaka Medical College - Department of Medical Statistics

Isao Miyashiro

Osaka International Cancer Institute

Takashi Ishikawa

Niigata University

Kohei Akazawa

Niigata University

Keisuke Fukui

Osaka International Cancer Institute

Hitoshi Katai

National Cancer Center Hospital - Department of Gastric Surgery

Souya Nunobe

Cancer Institute Ariake Hospital

Ichiro Oda

National Cancer Center Hospital - Endoscopy Division

Yoh Isobe

National Tokyo Medical Center

Shunichi Tsujitani

Tottori University

Hiroyuki Ono

Shizuoka Cancer Centre

Satoshi Tanabe

Kitasato University - Research and Development Center for New Frontiers

Takeo Fukagawa

Teikyo University

Satoshi Suzuki

Kobe University

Yoshihiro Kakeji

Kobe University - Division of Gastrointestinal Surgery

Mitsuru Sasako

Hyogo College of Medicine

Anton Bilchik

The John Wayne Cancer Institute

Manabu Fujita

The John Wayne Cancer Institute

Registration Committee of the Japanese Gastric Cancer Association

Independent

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Abstract

Background: Although the incidence and mortality have decreased, gastric cancer (GC) is still a public health issue globally. An international collaborative study reported much higher survival in Korea and Japan than other countries, including the US. We examined the determinant factors of the high survival in Japan, compared with the US.  

Methods: We analysed data on 78,648 cases from the nationwide GC registration project, the Japanese Gastric Cancer Association (JGCA), from 2004-2007 and compared them with 16,722 GC cases from the Surveillance, Epidemiology, and End Results Program (SEER), a US population-based cancer registry data from 2004-2010. We estimated five-year relative survival and applied a multivariate excess hazard model to compare the two countries. We considered the effect of number of lymph nodes (LNs) examined on differences in survival.  

Findings: Five-year relative survival in Japan was 81.0%, compared with 45.0% in the US. After controlling for confounding factors, we still observed significantly higher survival in Japan. The effect of number of LNs examined showed different trends according to TNM-N categories. N0 and N1 patients showed much wider gaps between the two countries. Among N2 patients, a higher number of LNs examined showed better survival in both countries. Among N3 patients, the relationship between number of LNs examined and differences in survival between the two countries disappeared.  

Interpretation: The wide differences in gastric cancer survival between Japan and US can be largely explained by differences in the stage at diagnosis, which were related to early detection in Japan, mainly due to the screening system and greater awareness of gastric cancer. Stage migration, which is related to differences in the number of retrieved and examined LNs, also helps explain the wide gap in gastric cancer survival between the two countries.  

Funding Statement: Ministry of Health, Labour and Welfare, Japan  

Declaration of Interests: The authors have no conflict of interest.

Keywords: Gastric Cancer, Survival Analysis, Cancer Registries

Suggested Citation

Ito, Yuri and Miyashiro, Isao and Ishikawa, Takashi and Akazawa, Kohei and Fukui, Keisuke and Katai, Hitoshi and Nunobe, Souya and Oda, Ichiro and Isobe, Yoh and Tsujitani, Shunichi and Ono, Hiroyuki and Tanabe, Satoshi and Fukagawa, Takeo and Suzuki, Satoshi and Kakeji, Yoshihiro and Sasako, Mitsuru and Bilchik, Anton and Fujita, Manabu and Association, Registration Committee of the Japanese Gastric Cancer, Determinant Factors on Differences in Survival for Gastric Cancer between the US and Japan Using Nationwide Databases: The Impact of Number of Lymph Nodes Examined (January 12, 2018). Available at SSRN: https://ssrn.com/abstract=3296687 or http://dx.doi.org/10.2139/ssrn.3296687

Yuri Ito (Contact Author)

Osaka Medical College - Department of Medical Statistics ( email )

569-0801 Osaka Prefecture
Takatsuki
Japan

Isao Miyashiro

Osaka International Cancer Institute

Osaka
Japan

Takashi Ishikawa

Niigata University

8050 Ikarashi 2 Nocho Nishi Ward
Niigata Prefecture
Niigata, 950-218
Japan

Kohei Akazawa

Niigata University

8050 Ikarashi 2 Nocho Nishi Ward
Niigata Prefecture
Niigata, 950-218
Japan

Keisuke Fukui

Osaka International Cancer Institute

Osaka
Japan

Hitoshi Katai

National Cancer Center Hospital - Department of Gastric Surgery

Research Center for Cancer Prevention and Screenin
Tokyo
Japan

Souya Nunobe

Cancer Institute Ariake Hospital

3-8-31 Ariake, Koto-Ku
Tokyo, 135-8550
Japan

Ichiro Oda

National Cancer Center Hospital - Endoscopy Division ( email )

Japan

Yoh Isobe

National Tokyo Medical Center

2-5-1 Higashigaoka
Meguro-ku, Tokyo, 152-8902
Japan

Shunichi Tsujitani

Tottori University

Tottori, 680-8552
United States

Hiroyuki Ono

Shizuoka Cancer Centre

Shizuoka
Japan

Satoshi Tanabe

Kitasato University - Research and Development Center for New Frontiers ( email )

Sagamihara, 252-0374
Japan

Takeo Fukagawa

Teikyo University

Hachiojishi, Tokyo, 192-0395
United States

Satoshi Suzuki

Kobe University

2-1, Rokkodai-cho, Nada-ku
Kobe, 657-8501, 657-8501
Japan

Yoshihiro Kakeji

Kobe University - Division of Gastrointestinal Surgery

2-1, Rokkodai-cho, Nada-ku
Kobe, 657-8501, 657-8501
Japan

Mitsuru Sasako

Hyogo College of Medicine

Japan

Anton Bilchik

The John Wayne Cancer Institute

Santa Monica, CA
United States

Manabu Fujita

The John Wayne Cancer Institute

Santa Monica, CA
United States