Close relatives of patients with hematologic malignancies may be more likely to be diagnosed with these conditions as well, according to a recent long-term analysis of patient records published in Blood. This analysis of records spanned several decades and has enabled researchers to estimate levels of familial relative risk (FRR) associated with hematologic malignancies.
The researchers examined 153,115 records of hematologic malignancies from the Swedish Family-Cancer Database that were diagnosed between 1958 and 2015 in order to calculate FRR. FRRs were measured using standardized incident ratios (SIRs) of hematologic malignancies among the first-degree relatives of patients whose records were included in the analysis.
For hematologic malignancies, 4.1% of diagnoses were familial cases. This percentage is higher than those for cancers of the pancreas (3.0%), kidney (2.8%), or nervous system (1.8%), but it is lower than those for prostate (15.3%), colorectal (10.1%), and breast cancers (8.5%).
FRRs tended to be highest in association with specific tumor types. Mixed cellularity Hodgkin lymphoma (HL) showed the highest FRR (SIR, 16.7), followed by lymphoplasmacytic lymphoma (LPL; SIR, 15.8), and mantle cell lymphoma (SIR, 13.3). Chronic lymphocytic leukemia (CLL) was associated with enhanced FRRs for B-cell malignancies in general.
FRRs were highest for relatives of patients who had received diagnoses at younger ages for HL, CLL, and many of the myeloid malignancies.
For non-Hodgkin lymphoma, HL, CLL, and acute myeloid leukemia, FRRs were higher for siblings compared with parent-child relationships. However, for LPL and polycythemia vera, risks appeared stronger within parent-child relationships compared with siblings.
For many hematologic malignancies, there were increases in FRRs based on the number of affected first-degree relatives.
“Due to the large sample size and long follow-up time, we have been able not only to demonstrate significantly elevated relative risks in [first-degree relatives] for the same tumor type but also to detect associations between the different hematologic tumor types,” the researchers wrote.
The researchers noted that FRRs with hematologic malignancies are greater than with some cancer types, but overall the risk remains small.
- Sud A, Chattopadhyay S, Thomsen H, et al. Analysis of 153,115 patients with hematological malignancies refines the spectrum of familial risk [published online August 8, 2019]. Blood. doi:10.1182/blood.2019001362