highly significantP < 0·001
The most recent efforts to improve the understanding of clinical prognostic factors in PTCL‐NOS were undertaken by the International Peripheral T cell Lymphoma Project (IPTCLP) on a sample of 340 cases diagnosed between 1990 and 2002: both the PIT and the IPI remained highly significant for both OS and progression‐free survival (PFS) ( P < 0·001) (Weisenburger et al , 2011 ).