Secondary primary malignancy (SPM) in localized gastrointestinal (GI) cancer: A national database study.

Abstract

529 Background: With improvement in survival in patients with early GI cancers, there is a perceived increased risk of SPMs. Through our study, we seek to investigate the risk of SPM in localized GI cancer. Methods: The surveillance, epidemiology and end results (SEER) database was searched to obtain data on incidence of SPM in adult patients (age 20-99y) diagnosed with localized (Stage I-III) GI cancers such as colorectal (CRC), esophageal, gastric, hepatobiliary (HB) and pancreatic, from 2004-2022. Standardized incidence ratios (SIRs) with 95% confidence interval (CI) were calculated. SIR was defined as observed SPMs from each category of GI cancer divided by expected number of SPMs in the age –matched US population. A latency period of 60 months from the time of initial diagnosis was used to study SIR of true SPMs after completion of the acceptable surveillance period. Lastly, data was sub stratified by age (20-49 years and >=50 years), race (white, black, American Indian/Alaskan native (AI/AN), Asian/Pacific islander [A/PI]), ethnicity (Hispanic and non-Hispanic), chemotherapy, and radiation, to assess high risk subgroups. Results: About 146024 patients were included in this study. The overall risk of SPM in this cohort was SMR:1.06, 95%CI: 1.04-1.07. Young adults had higher risk of SPM as compared to older adults (SIR:1.49 vs 1.03). Blacks had a higher risk of development of SPM as compared to whites (1.18 vs 1.02). AI/AN had higher risk of SPM as compared to A/PI (1.73 vs 1.34). Non-Hispanics were observed to have a higher SPM risk as compared to Hispanics (1.07 vs 0.93). Patients treated with chemotherapy had a higher risk of SPM as compared to those who did not (1.15 vs 1.04). Patients who did not receive radiation therapy had a higher risk of SPM as compared to those who received radiation therapy (1.20 vs 1.04). Data summarizing the risk of developing non-GI sites SPM is attached in the table. Conclusions: Current guidelines recommend a surveillance period up to 5 years for localized GI cancers . This study sheds light on the risk of occurrence of SPMs in this post surveillance period. Appropriate screenings and symptom evaluation are needed, for timely diagnosis and management of SPMs. Site of SPM SIR (95%CI) Eye and Orbit - Non-Melanoma 2.53 [1.31-4.42] Hypopharynx 1.75 [1.16-2.53] Penis 1.67 [1.06-2.51] Soft Tissue including Heart 1.46 [1.21-1.75] Vulva 1.35 [1.01-1.78] Pharynx 1.34 [1.02-1.73] Endocrine System 1.27 [1.1-1.44]