Familial Malignant Hematological Disorders: A Systematic Assessment in 216 Consecutive Patients with Acute Leukaemia.

Purpose

Our objective was to describe the biological characteristics of acute leukemia (AL) patients with or without a familial form of malignant hematological disorders.

Population

The study population included all newly diagnosed cases of AL treated in the departments of hematology of Institut Paoli-Calmettes between January 2002 and December 2004. We identified 291 eligible patients, of which 216 (74.2%) provided consent to participate in the study and filled a short questionnaire collecting demographic, personal and familial medical data. A face to face interview was arranged for 185 patients (85.7%) and a pedigree compiled for each family and reviewed by 2 familial cancer consultants.

Results

Among the 185 patients with full data on personal and familial history of cancer, 34 (18.4%) had a strong familial history of cancer of which 16 (8.6%) presented a familial form of malignant hematological disorders (at least another case of hematological malignancy in the 1, 2 or 3 degree relatives). Seven families had at least 2 first degree family members with leukemia and 2 families had 5 relatives (1^st, 2^nd or 3^rd degree) diagnosed with leukaemia.

Most index cases were diagnosed with AML in both groups (88.1%). Among familial forms, 7 AML (50%) were classified as FAB M1 or M2. No M3, M6 or M7 were identified. White blood cell count was higher than 30 G/l in 37.5% of familial form as compared to 23.5% in sporadic cases (NS). The mean circulating blast percentage was higher in familial forms (66.6% (SD= 35.5)) than in sporadic cases (36.7% (SD=32.1)) (p=0.001). None of the familial forms were consecutive to pre-existing myelodysplasic or myeloproliferative syndrome. Among familial cases with AML, 43% had normal cytogenetics (vs 36% in sporadic cases); none had a complex karyotype; one presented with a t(3;15)(p26;q11) as a mosaic, a translocation not previously reported. Complete remission (CR) rates after 1^st induction and Overall Survival (OS) were similar in both groups (CR in both groups: 61.5% (n=112); OS: median: 16 months (95%CI = 10.2 – 21.8) in familial forms vs 23.9 months (18.8 – 28.9)).

Conclusion

According to our data, among the 15 900 new cases of AL diagnosed every year in the US, 1 370 may correspond to familial forms. This warrants awareness of clinicians who should systematically assess family cancer history. Familial AL tends to present as a proliferative form, with no prior hematologic malignancies and normal cytogenetics. This is consistent with pathogenesis pathways described in other familial cancer syndrome.