First-degree relatives play defining role in developing certain blood cancers

Washington: People who have a parent, sibling, or child with blood cancer have an increased likelihood of being diagnosed with the disease, suggests a study. According to the study published in the journal 'Blood' age of diagnosis, whether the relative is a parent, sibling, or child, and the number of affected first-degree relatives play a defining role in the relative risk of developing certain blood cancers.

"This information improves our understanding of the causes of - and potential inherited predisposition to - blood cancers and should inform the identification and characterisation of genetic risk factors for blood cancer, as well as how we best clinically manage patients and their relatives," said Amit Sud, the study's lead author.

Cases with a familial link represented 4.1 per cent of all blood cancer diagnoses. Highest relative risks were seen for certain Hodgkin lymphoma (HL) subtypes, lymphoplasmacytic lymphoma, and mantle cell lymphoma. Markedly elevated familial risks were also observed for polycythemia vera, myelodysplasia, and essential thrombocythemia.

While there are currently no definitive screening initiatives for blood cancers, a 2016 revision to the World Health Organisation classification of myeloid neoplasms and acute leukaemia recognised the familial disease as an essential component of diagnosing certain subsets of blood cancers and underscores the need to further examine and understand familial risk.

"We hope this robust data will be used to inform guidelines on genetic testing and screening. Certainly, there are a number of individuals, such as those with a relative diagnosed at a young age and or with more than one affected first-degree relatives, for whom counselling, genetic testing, and surveillance may be appropriate," Dr. Sud said.

The present analysis included 153,115 patients with confirmed blood cancer and 391,131 first-degree relatives, which allowed Dr. Sud and colleagues to fully characterize familial risk across all blood cancer types.

For specific blood cancers such as chronic lymphocytic leukaemia (CLL), the increase in risk is dependent on the age of the affected relative; whether it is a parent, sibling, or child; and the number of affected first-degree relatives. For example, for non-Hodgkin lymphoma, HL, and CLL, the risk was higher among those who had a sibling with the disease, whereas others blood cancers were more likely to occur if a parent had been diagnosed.

Generally, the familial risk was more pronounced when relatives were diagnosed at younger ages. Dr. Sud added that the analysis also has potential implications for the selection of related stem-cell donors used for the treatment of these malignancies.