Retrospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Oncol. Aug 10, 2016; 7(4): 324-330
Published online Aug 10, 2016. doi: 10.5306/wjco.v7.i4.324
Risk of second primary malignancies in a population-based study of adult patients with essential thrombocythemia
Rajesh Shrestha, Smith Giri, Ranjan Pathak, Vijaya Raj Bhatt
Rajesh Shrestha, Division of Hospital Medicine, Department of Medicine, Rhode Island Hospital, Brown University, Rhode Island, RI 02903, United States
Smith Giri, Department of Medicine, University at Tennessee, Tennessee, TN 38163, United States
Ranjan Pathak, Department of Medicine, Reading Health System, Reading, PA 19612, United States
Vijaya Raj Bhatt, Division of Hematology and Oncology, Department of Internal Medicine, University of Nebraska Medical Center, Nebraska, NE 68191, United States
Author contributions: Shrestha R and Giri S contributed equally to this manuscript; Giri S, Pathak R and Bhatt VR designed the study; Giri S conducted data analysis; Shrestha R, Giri S and Bhatt VR interpreted the data and wrote the manuscript; all authors contributed to the critical revision of the manuscript and approved the final version.
Supported by The University of Nebraska Medical Center, College of Medicine, Physician-Scientist Training Program Grant 2015-2016 (to Bhatt VR).
Institutional review board statement: Institutional review board waiver was obtained from the University of Nebraska Medical Center’s Institutional Review Board prior to conducting this study.
Informed consent statement: Patients were not required to give informed consent to the study because this database study utilized deidentified publicly available data.
Conflict-of-interest statement: None.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Vijaya Raj Bhatt, MD, Division of Hematology and Oncology, Department of Internal Medicine, University of Nebraska Medical Center, 42nd and Emile, Nebraska, NE 68191, United States. vijaya.bhatt@unmc.edu
Telephone: +1-402-5595166 Fax: +1-402-5596520
Received: February 2, 2016
Peer-review started: February 14, 2016
First decision: March 21, 2016
Revised: April 27, 2016
Accepted: May 17, 2016
Article in press: May 27, 2016
Published online: August 10, 2016
Abstract

AIM: To determine the risk of second primary malignancy (SPM) and survival of patients with essential thrombocythemia (ET).

METHODS: We identified all patients with ET diagnosed during 2001 to 2011 from the Surveillance, Epidemiology and End Results (SEER) 18 database. Actuarial and relative survival methods were used to calculate the survival statistics. We utilized the SEER 13 database to calculate SPM. We used multiple primary standardized incidence ratio (SIR) session of the SEER*Stat software (version 8.1.5) to calculate SIR and excess risk of SPM for ET patients.

RESULTS: Age standardized five-year cause-specific survival was greater for patients < 50 years vs those ≥ 50 years (99.4% vs 93.5%, P < 0.01). Five-year cause-specific survival was lower for men vs women (70.2% vs 79.7%). A total of 201 patients (2.46%) developed SPM at a median age of 75 years. SPMs occurred at an observed/expected (O/E) ratio of 1.26 (95%CI: 1.09-1.45, P = 0.002) with an absolute excess risk (AER) of 37.44 per 10000 population. A significantly higher risk was noted for leukemia (O/E 3.78; 95%CI: 2.20-6.05, P < 0.001; AER 11.28/10000).

CONCLUSION: ET patients have an excellent cause-specific five-year survival but are at an increased risk of SPM, particularly leukemia, which may contribute to excess deaths.

Keywords: Essential thrombocythemia, Second primary malignancy, Survival

Core tip: Second primary malignancy (SPM) contributes to worse survival in essential thrombocythemia (ET). We utilized the Surveillance, Epidemiology and End Results database to analyze the risk of SPM in ET patients diagnosed during 2001-2011. Two hundred and one patients (2.46%) developed SPM at a median age of 75 years. SPMs occurred at an observed/expected (O/E) ratio of 1.26 (95%CI: 1.09-1.45, P = 0.002) with an absolute excess risk of 37.44 per 10000 population. A significantly higher risk was noted for leukemia (O/E 3.78; 95%CI: 2.20-6.05, P < 0.001). An increased risk of SPM, particularly leukemia, may contribute to excess deaths in ET.