Familial adenomatous polyposis complicated with Crohn's disease

Hereditary Colorectal Cancer Syndromes and Inflammatory Bowel Diseases: an ECCO CONFER Multicentre Case Series

BACKGROUND

Hereditary colorectal cancer syndromes [HCCS] are rare polyposis or nonpolyposis syndromes with a higher risk of developing colorectal cancer [CRC]. Coexisting inflammatory bowel disease [IBD], including ulcerative colitis [UC] and Crohn's disease [CD], with HCCS is exceedingly rare and presumably increases the risk of early-onset CRC.

METHODS

This was a multicentre case series performed as a part of the European Crohn's and Colitis Organisation [ECCO] Collaborative Network of Exceptionally Rare case reports [CONFER] project.

RESULTS

This report includes 26 patients with IBD (10 UC, 15 CD, and one with IBD unclassified [IBD-U]) and concomitant HCCS. Among these 26 patients([median age 33 years, interquartile range [IQR] 20-44], 15 [57.7%] were males, 24 [92.3%] Caucasians, and two [7.7%] of Arab origin. HCCS was diagnosed before the IBD diagnosis in 11 patients [42.3%], after diagnosis of IBD in 11 patients [42.3%], and concurrently in four patients [15.4%]. Sixteen patients had Lynch syndrome, seven had familial adenomatous polyposis [FAP], two had MYH-associated polyposis [MAP], and one had attenuated FAP [AFAP]. The most frequent genetic mutations were those of APC [n = 7] and MLH1 [n = 7]. Overall, CRC developed in 38.5% of patients [n = 10]: in four patients [40%] after IBD diagnosis, in four [40%] patients before IBD diagnosis, and in two patients the two conditions were diagnosed simultaneously. Eighteen [69.2%] patients underwent colectomy or abdominal surgery: nine patients due to CRC diagnosis, five patients preventively due to the underlying HCCS, three due to the underlying HCCS and concomitant active IBD disease, and one patient because of active IBD disease. One patient died due to CRC.

CONCLUSIONS

To date, this is the largest case series of patients with IBD and HCCS. The most frequent diagnosis of HCCS associated with IBD was Lynch syndrome. These data demonstrate the high malignancy rate and surgical intervention rate in this IBD cohort, despite the endoscopic surveillance. The optimal medical approach still needs to be addressed.

Malignancy risk in individuals with familial adenomatous polyposis receiving biologics and immunomodulators

Clinicians may be hesitant to prescribe biologics or immunomodulators to individuals with familial adenomatous polyposis (FAP) and comorbid inflammatory disease (CID) because of increased cancer risk. Our aim was to compare the risk of malignancy in FAP individuals with inflammatory bowel (IBD) and/or rheumatic disease that received biologics/immunomodulators to those who did not. Individuals with FAP and CID were included in the study. We compared the incidence of cancer between individuals exposed to biologics/immunomodulators compared to unexposed from the date of diagnosis of comorbid disease till last follow up or death. Hazard ratio (HR) for cancer was computed using Cox regression model and compared by exposure status to biologic/immunomodulators. 25 individuals with FAP and a comorbid inflammatory disease were identified including 9 (36%) with IBD and 16 (64%) with rheumatic disease. 14 (56%) were exposed to a biologic and or immunomodulator. Median duration of biologic/immunomodulator exposure was 48 (2-180) months. 3 (21.4%) in the exposed group compared to 1 (9.1%) in the unexposed group developed cancer with a HR for exposure of 1.92 (CI 0.2-18.5, p = 0.57). Median duration of follow up after the diagnosis of inflammatory disease was 10 (5.5-17.0) years in the exposed and 6 (3.0-15.0) years in the unexposed group. In the exposed group, 1 patient developed gastric and 2 developed colon cancer. One unexposed patient developed medullary thyroid cancer. There is a possible trend of more cancers in the group that received biologics/immunomodulators-but given the small number of patients and p-value, there may be no difference at all. This preliminary finding warrants study in a larger cohort.

Familial adenomatous polyposis and Crohn's disease in one patient: dilemmas and concerns

Familial adenomatous polyposis (FAP) and Crohn's disease (CD) are two entities with no known etiologic or physiopathogenic relation. The rarity of the former makes the coincidence of both diagnoses in one patient very unlikely. Nevertheless, management in such cases can be puzzling as surgical options must be considered, and immunosuppression/immunomodulation is set in a territory of accelerated carcinogenesis. We report the case of a 29-year-old male with a diagnosis of FAP since adolescence, already submitted to prophylactic proctocolectomy, presenting with anemia and bloody diarrhea, revealing small bowel CD. This case allows for a rich discussion of the clinical dilemmas presenting when FAP and CD are diagnosed in the same patient and for a deep analysis of the concerns inherent to the available therapeutic options.

Using biological networks to search for interacting loci in genome-wide association studies

Genome-wide association studies have identified a large number of single-nucleotide polymorphisms (SNPs) that individually predispose to diseases. However, many genetic risk factors remain unaccounted for. Proteins coded by genes interact in the cell, and it is most likely that certain variants mainly affect the phenotype in combination with other variants, termed epistasis. An exhaustive search for epistatic effects is computationally demanding, as several billions of SNP pairs exist for typical genotyping chips. In this study, the experimental knowledge on biological networks is used to narrow the search for two-locus epistasis. We provide evidence that this approach is computationally feasible and statistically powerful. By applying this method to the Wellcome Trust Case-Control Consortium data sets, we report four significant cases of epistasis between unlinked loci, in susceptibility to Crohn's disease, bipolar disorder, hypertension and rheumatoid arthritis.