Malignancies in Inflammatory Bowel Disease Patients - A Population-Based Study of the Last Two Decades

Introduction: Inflammatory Bowel Disease (IBD) is a chronic inflammatory disorder of the gut with prevalence estimated to be more than 3 million in the USA. Many studies suggest that IBD patients have an increased risk of developing intestinal and extraintestinal malignancies. It is suspected, IBD-related inflammation and carcinogenic properties of immunosuppressive drugs are main culprits of initiation and progression of tumor formation. This study aimed to analyze the nationwide prevalence of malignant neoplasms in IBD patients. Methods: NIS database was queried from January 2000 to December 2019 to retrieve records of patients admitted with a principal or secondary diagnosis of IBD. We compared the incidence of malignant neoplasms in IBD (cases) based on ICD codes to patients who did not have IBD (controls). Controls were 1:1 fixed ratio nearest neighbor (greedy) propensity score-matched using the patient’s age, sex, and race. We performed univariate logistic regression to calculate the odds ratio. Statistical analysis is performed in R (Studio 1.4). The p-values of < 0.01 were considered to be significant. Results: A total of 1,109,008 records were identified with IBD. IBD patients have increased risk of some cancers including small intestine (OR, 4.40; 99% CI, 3.69 – 5.25; p < 0.001), bile duct (OR, 3.97; 99% CI, 3.32 – 4.74; p < 0.001), myelodysplastic syndrome (OR, 1.66; 99% CI, 1.52 – 1.81; p < 0.001, anorectal (OR, 1.64; 99% CI, 1.55 – 1.73; p < 0.001), skin (OR, 1.62; 99% CI, 1.57 – 1.68; p < 0.001), colorectal (OR, 1.29; 99% CI, 1.25 – 1.33; p < 0.001), urinary (OR, 1.09; 99% CI, 1.05 – 1.13; p < 0.001),and prostate (OR, 1.13; 99% CI, 1.10 – 1.17; p < 0.001). IBD patients are at low risk of head and neck, esophagus, stomach, respiratory, bone, breast, nervous system, myeloma, ovary, testis, and pancreas (Table). Conclusion: IBD and malignancies have been discussed in the past. Despite these efforts, much remains unknown regarding the increased risk of cancers in IBD. Our results showed that IBD patients are at an increased risk of certain neoplasms, specifically small bowel, bile duct, and myelodysplastic syndrome. Although inflammatory injury and immunosuppression can play a role in carcinogenesis, we still know little about the risk factors contributing to neoplasms. Therefore, more studies are needed to determine the risk factor and mechanism for developing malignancies in IBD patients. It is essential to emphasize age-appropriate cancer screening in our IBD patients. Table 1. - Prevalence of malignant Neoplasms in IBD vs. age-, sex-, and race-matched non-IBD patients National Inpatient Sample 2000 - 2019 Variables IBD = No (n= 1,108,914) 50% IBD = Yes (n= 1,109,008) 50% OR (99%CI) P value Head and Neck 3413 (0.31%) 2186 (0.06%) 0.64 (0.60– 0.69) < .0001 Esophagus 1314 (0.12%) 714 (0.06%) 0.54 (0.48 – 0.59) < .0001 Stomach 1450 (0.13%) 1146 (0.10%) 0.79 (0.71– 0.87) < .0001 Small Intestine 264 (0.02%) 1161 (0.10%) 4.40 (3.69– 5.25) < .0001 Colorectal 11758 (1.06%) 15163 (1.37%) 1.29 (1.25– 1.33) < .0001 Liver 1379 (0.12%) 1472 (0.13%) NA 0.0818 Bile Duct 265 (0.02%) 1052 (0.09%) 3.97 (3.32 – 4.74) < .0001 Respiratory 15699 (1.42 %) 10791 (0.97 %) 0.68 (0.66– 0.71) < .0001 Bone 1666 (0.15%) 694 (0.06%) 0.41 (0.37 – 0.47) < .0001 Skin 8554 (0.77%) 13797 (1.24%) 1.62 (1.57 – 1.68) < .0001 Breast 21129 (1.91%) 17994 (1.62%) 0.85 (0.83– 0.87) < .0001 Urinary 9092 (0.82%) 9913 (0.89%) 1.09 (1.05 – 1.13) < .0001 Nervous System 2135 (0.19%) 1277 (0.12%) 0.60 (0.55 – 0.65) < .0001 Lymphoma 8311 (0.75%) 8110 (0.73%) NA 0.1141 Leukemia 6174 (0.56%) 6142 (0.55%) NA 0.7689 Myeloma 2314 (0.21%) 1890 (0.17%) 0.82 (0.75– 0.88) < .0001 Myelodysplastic Syndrome 1394 (0.13%) 2316 (0.21%) 1.66 (1.52– 1.81) < .0001 Anorectal 3716 (0.34%) 6074 (0.55%) 1.64 (1.55– 1.73) < .0001 Uterus 3433 (0.31%) 3236 (0.29%) NA 0.0155 Cervix 3849 (0.35%) 3818 (0.34%) NA 0.7201 Ovary 3276 (0.30%) 2577 (0.23%) 0.79 (0.74– 0.84) < .0001 Prostate 12489 (1.13 %) 14109 (1.27 %) 1.13 (1.10– 1.17) < .0001 Testis 1073 (0.10%) 787 (0.07%) 0.73 (0.65 – 0.83) < .0001 Thyroid 2472 (0.22%) 2650 (0.24%) NA 0.0129 Pancreas 2259 (0.20%) 1880 (0.17%) 0.83 (0.76– 0.90) < .0001 Neuroendocrine Tumors 536 (0.11%) 618 (0.06%) NA 0.0158