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Incidence of cancer-associated thromboembolism in Japanese gastric and colorectal cancer patients receiving chemotherapy: a single-institutional retrospective cohort analysis (Sapporo CAT study)
  1. Ayane Oba Aonuma1,
  2. Michio Nakamura1,
  3. Kentaro Sakamaki2,
  4. Taichi Murai1,
  5. Chika Matsuda1,
  6. Kazufumi Itaya1,
  7. Takayuki Sone1,
  8. Masataka Yagisawa3,
  9. Yuta Koike1,
  10. Ayana Endo1,
  11. Yoko Tsukuda1,
  12. Yuji Ono1,
  13. Atsushi Nagasaka1,
  14. Shuji Nishikawa1,
  15. Takeharu Yamanaka4,
  16. Naoya Sakamoto5
  1. 1 Department of Gastroenterology, Sapporo City General Hospital, Sapporo, Japan
  2. 2 Department of Biostatistics and Bioinformatics, University of Tokyo, Tokyo, Japan
  3. 3 Department of Gastroenterology, National Cancer Center Hospital East, Kashiwa, Japan
  4. 4 Department of Biostatics, Yokohama City University, Yokohama, Japan
  5. 5 Department of Gastroenterology and Hepatology, Hokkaido University, Sapporo, Japan
  1. Correspondence to Dr Michio Nakamura; michio.nakamura{at}


Objective Few data regarding the incidence of cancer-associated thromboembolism (TE) are available for Asian populations. We investigated the incidence of TE (TEi) and its risk factors among gastric and colorectal cancer (GCC) patients received chemotherapy in a daily practice setting.

Design A retrospective cohort study.

Setting A single-institutional study that used data from Sapporo City General Hospital, Japan, on patients treated between January 2008 and May 2015.

Participants Five hundred Japanese GCC patients who started chemotherapy from January 2008 to May 2015.

Primary and secondary outcome measures TE was diagnosed by reviewing all the reports of contrast-enhanced CT performed during the follow-up period. All types of thrombosis detected by CT or additional imaging tests, such as venous TE, arterial TE and cerebral infarction, were defined as TE. Medical records of all identified patients were reviewed and potential risk factors for TE, including clinicopathological backgrounds, were collected. We defined the following patients as ‘active cancer’; patients with unresectable advanced GCC, cancer recurrence during or after completing adjuvant chemotherapy and/or presence of other malignant tumours.

Results Of the 500 patients, 70 patients (14.0%) developed TE during the follow-up period. TEi was 9.2% and 17.3% in GCC patients, 18.1% and 3.5% in active and non-active cancer patients, and 24.0% and 12.9% in multiple and single primary, respectively. Multivariate logistic regression analysis showed that colorectal cancer (CRC) (OR 2.371; 95% CI 1.328 to 4.233), active cancer (OR 7.593; 95% CI 2.950 to 19.543) and multiple primary (OR 2.527; 95% CI 1.189 to 5.370) were independently associated with TEi.

Conclusion TEi was 14.0% among Japanese GCC patients received chemotherapy, and was significantly higher among patients with CRC, active cancer and multiple primary than among those with gastric cancer, non-active cancer and single primary, respectively.

Trial registration number UMIN000018912.

  • thromboembolism
  • venous thromboembolism
  • pulmonary thromboembolism
  • gastric cancer
  • colorectal cancer
  • chemotherapy

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  • Contributors AOA and MN designed the study and wrote the initial draft of the manuscript. AOA, MN, KS and TY contributed to analysis and interpretation of data, and assisted in the preparation of the manuscript. TM, CM, KI, TS, MY, YK, AE, YT, YO, AN, SN and NS have contributed to data collection and interpretation, and critically reviewed the manuscript. All the authors approved the final version of the manuscript and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Ethics approval The institutional review board and the clinical research ethics review board of Sapporo City General Hospital approved the research protocol.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement No additional data are available.

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