In the largest and most comprehensive population-based evaluation to date, new data show that those who have a parent, sibling, or child with blood cancer are more likely to be diagnosed with the disease themselves.
 
The study, published in Blood, also showed that the age of diagnosis and the number of affected first-degree relatives are major factors that contribute to this risk.
 
Blood cancer cases with a familial link represent 4.1% of all blood cancer diagnoses, according to the authors. For the analysis, the authors analyzed data from 16 million individuals in the Swedish Family-Cancer Database, including 153,115 patients with a confirmed blood cancer and 391,131 first-degree relatives.
 
Overall, the highest relative risks were seen for certain Hodgkin lymphoma (HL) subtypes, lymphoplasmacytic lymphoma, and mantle cell lymphoma, according to the findings.
 
The analysis also showed factors associated with increased risk across the spectrum of blood cancer types. For example, in chronic lymphocytic leukemia (CLL), the increase in risk is dependent on the age of the affected relative and the number of first-degree relatives. In non-Hodgkin lymphoma, HL, and CLL, those who had a sibling with the disease were at higher risk. 
 
According to the findings, the familial risk was more pronounced when relatives were diagnosed at younger ages.
 
“We hope these robust data will be used to inform guidelines on genetic testing and screening,” lead author Amit Sud, MD, PhD, of The Institute of Cancer Research, said in a press release. “The results should also encourage conversations among families, clinicians, and patients about familial risk.”
 
Greater understanding about familial risks can help better inform screening practices based on evidence, according to the study. In addition, the authors suggest that the analysis may have potential implications for the selection of related stem-cell donors used for the treatment of these malignancies.
 
“Collectively these dates provide evidence for shared etiological factors for many hematological malignancies and provide information for identifying individuals at increased risk as well as informing future gene discovery initiatives,” the authors concluded in the study.
 
Reference
Sud A. Chattopadhyay S, Thomsen H, et al. Analysis of 153,115 patients with hematological malignancies refines the spectrum of familial risk. Blood. 2019. doi: https://doi.org/10.1182/blood.2019001362
 
Having a Parent, Sibling, or Child with Blood Cancer Increases One’s Own Risk [news release]. American Society of Hematology. https://www.hematology.org/Newsroom/Press-Releases/2019/9841.aspx. Accessed August 8, 2019.