Endometrial Cancer Survival in Populations of African Descent

To examine whether the endometrial cancer (EC) survival disadvantage among Black populations is US-specific, a comparison between African descent populations from different countries with a high development index is warranted. We analyzed 28,213 EC cases from cancer registries in Florida (2005-2018) and Martinique (2005-2018)/Guadeloupe (2008-2018), French Caribbean islands. Kaplan-Meier and all-cause Cox proportional hazards models were used to compare survival. Models were stratified by EC histology type and the main predictor examined was race/ethnicity [non-Hispanic White (NHW) and Black (NHB) women in the US versus Black women residing in the Caribbean]. For endometrioid and non-endometrioid EC, after adjusting for age, histology, stage at diagnosis, receipt of surgery, period of diagnosis, and poverty level, US NHB women and Caribbean Blacks had a higher risk of death relative to US NHWs. There was no difference between US NHBs and Caribbean Blacks (HR 1.07, 95% CI: 0.88-1.30) with endometrioid EC. However, Caribbean Black women with non-endometrioid carcinomas had a 40% (HR 1.40, 95% CI: 1.13-1.74) higher risk of death than US NHBs. The low EC survival among US Black women extends to foreign populations of African descent. For the aggressive non-endometrioid ECs, survival in Caribbean Blacks outside of the US is considerably worse.

Mutation spectrum and risk of colorectal cancer in African American families with Lynch syndrome

BACKGROUND & AIMS

African Americans (AAs) have the highest incidence of and mortality resulting from colorectal cancer (CRC) in the United States. Few data are available on genetic and nongenetic risk factors for CRC among AAs. Little is known about cancer risks and mutations in mismatch repair (MMR) genes in AAs with the most common inherited CRC condition, Lynch syndrome. We aimed to characterize phenotype, mutation spectrum, and risk of CRC in AAs with Lynch syndrome.

METHODS

We performed a retrospective study of AAs with mutations in MMR genes (MLH1, MSH2, MSH6, and PMS2) using databases from 13 US referral centers. We analyzed data on personal and family histories of cancer. Modified segregation analysis conditioned on ascertainment criteria was used to estimate age- and sex-specific CRC cumulative risk, studying members of the mutation-carrying families.

RESULTS

We identified 51 AA families with deleterious mutations that disrupt function of the MMR gene product: 31 in MLH1 (61%), 11 in MSH2 (21%), 3 in MSH6 (6%), and 6 in PMS2 (12%); 8 mutations were detected in more than 1 individual, and 11 have not been previously reported. In the 920 members of the 51 families with deleterious mutations, the cumulative risks of CRC at 80 years of age were estimated to be 36.2% (95% confidence interval [CI], 10.5%-83.9%) for men and 29.7% (95% CI, 8.31%-76.1%) for women. CRC risk was significantly higher among individuals with mutations in MLH1 or MSH2 (hazard ratio, 13.9; 95% CI, 3.44-56.5).

CONCLUSIONS

We estimate the cumulative risk for CRC in AAs with MMR gene mutations to be similar to that of individuals of European descent with Lynch syndrome. Two-thirds of mutations were found in MLH1, some of which were found in multiple individuals and some that have not been previously reported. Differences in mutation spectrum are likely to reflect the genetic diversity of this population.