International Prognostic Scoring System-independent cytogenetic risk categorization in primary myelofibrosis

Among 200 patients with primary myelofibrosis, karyotype at diagnosis was abnormal in 83 (42%). To assess their individual prognostic impact, specific cytogenetic abnormalities with more than or equal to 5 informative cases were identified and the rest grouped separately as other abnormalities. Median survival in patients with sole + 9 (n = 6), sole 20q- (n = 21), sole 13q-(n = 8), normal karyotype (n = 117), other abnormalities (n = 28), complex karyotype (n = 13), and sole +8 (n = 7) were not reached, 112, 105, 80, 46, 34, and 28 months, respectively (P = .01). Accordingly, 4 cytogenetic risk groups were considered: (1) favorable (sole + 9, 20q-, or 13q-), (2) normal, (3) unfavorable (complex karyotype or sole +8), and (4) other abnormalities. Multivariable analysis confirmed the International Prognostic Scoring System (IPSS)-independent prognostic value of both 4-way and 2-way (ie, favorable/normal vs unfavorable/other abnormalities; IPSS-adjusted hazard ratio = 0.37; 95% confidence interval, 0.24-0.58) cytogenetic risk categorization (P<.01). The ability to prognostically dissect a specific IPSS category has major therapeutic implications. (Blood. 2010; 115: 496-499)