RESUMO
OBJECTIVES: As there are no US population-based studies examining Lynch syndrome (LS) screening frequency by microsatellite instability (MSI) and immunohistochemistry (IHC), we seek to quantitate statewide rates in patients aged ≤50 years using data from a Centers for Disease Control and Prevention-funded Comparative Effectiveness Research (CER) project and identify factors associated with testing. Screening rates in this young, high-risk population may provide a best-case scenario as older patients, potentially deemed lower risk, may undergo testing less frequently. We also seek to determine how frequently MSI/IHC results are available preoperatively, as this may assist with decisions regarding colonic resection extent. METHODS: Data from all Louisiana colorectal cancer (CRC) patients aged ≤50 years diagnosed in 2011 were obtained from the Louisiana Tumor Registry CER project. Registry researchers and physicians analyzed data, including pathology and MSI/IHC. RESULTS: Of the 2,427 statewide all-age CRC patients, there were 274 patients aged ≤50 years, representing health care at 61 distinct facilities. MSI and/or IHC were performed in 23.0% of patients. Testing-associated factors included CRC family history (P<0.0045), urban location (P<0.0370), and care at comprehensive cancer centers (P<0.0020) but not synchronous/metachronous CRC or MSI-like histology. Public hospital screening was disproportionately low (P<0.0217). Of those tested, MSI and/or IHC was abnormal in 21.7%. Of those with abnormal IHC, staining patterns were consistent with LS in 87.5%. MSI/IHC results were available preoperatively in 16.9% of cases. CONCLUSIONS: Despite frequently abnormal MSI/IHC results, LS screening in young, high-risk patients is low. Provider education and disparities in access to specialized services, particularly in underserved populations, are possible contributors. MSI/IHC results are infrequently available preoperatively.
Assuntos
Colectomia , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/genética , Detecção Precoce de Câncer , Testes Genéticos , Programas de Rastreamento , Instabilidade de Microssatélites , Adulto , Fatores Etários , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/prevenção & controle , Neoplasias Colorretais Hereditárias sem Polipose/cirurgia , Fatores de Confusão Epidemiológicos , Detecção Precoce de Câncer/métodos , Detecção Precoce de Câncer/normas , Detecção Precoce de Câncer/estatística & dados numéricos , Feminino , Humanos , Imuno-Histoquímica , Louisiana/epidemiologia , Masculino , Programas de Rastreamento/métodos , Programas de Rastreamento/normas , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Neoplasias Primárias Múltiplas/genética , Segunda Neoplasia Primária/genética , Período Pré-Operatório , Prevalência , População Rural/estatística & dados numéricos , Fatores de Tempo , Estados Unidos/epidemiologia , População Urbana/estatística & dados numéricosRESUMO
OBJECTIVES: Determine whether colorectal cancer (CRC) rates are disproportionately high in the French-Acadian region (population 1.2 million) of Louisiana, home of the Cajuns, a founder population. METHODS: 2005-2009 cancer incidence rates were stratified by age/race/gender in the 18 Acadian parish region and 9-parish subgroup with higher proportions of French speakers and compared with Louisiana and United States rates. Parishes were identified through language census data. A total of 3,288 CRC cases were identified in the Acadian region and 11,737 in Louisiana. RESULTS: CRC rates in whites and white males in the 18 parishes were statistically significantly higher than both Louisiana and US rates. In the 9 parishes, rates increased further; whites had an incidence of 56.1/100,000, 13% higher than Louisiana (P<0.0003) and 23% higher than US rates (P<0.0001). In white males, incidence was 72.6/100,000, 19% higher than Louisiana (P<0.0002) and 37% higher than US rates (P<0.0001). If the 9-parish regions were considered a "state," white males would have the highest CRC incidence in the United States by 11% (P<0.0175) compared with other white male populations. CONCLUSIONS: CRC rates are among the highest in the United States, increasing with the proportion of French speakers, a marker for the Cajun population. This appears to be the first study identifying a high rate of cancer in a large, regional, US founder population, raising the possibility of a genetic predisposition. Alternatively, an unidentified, robust environmental risk factor may be present. Future studies are needed to identify genetic and/or other risk factors in this population.