TARC Is Useful as Additional Prognostic Factor for Hodgkin's Lymphoma Outcome.

The CC thymus and activation related chemokine TARC, a protein highly expressed by Reed-Sternberg cells and in the microenvironment of Hodgkin's lymphoma (HL) involved lymph nodes, as well as detectable in the serum of HL patients (pts), has been reported to have prognostic value in retrospective analysis. The aim of our study was to prospectively investigate the association among PET-2 results and TARC serum levels (T) in HL and the prognostic role of T in disease relapse or progression.

Between November 2006 and June 2009, T was measured by ELISA in 73 pts: 50 newly diagnosed untreated pts (Group U) and 23 pts relapsing or progressing after first line CT±RT (Group S). Group U pts received stage-directed therapy consisting in 4 ABVD cycles followed by IFRT for stage I-II A, and 6-8 ABVD cycles ± RT on bulky sites of disease for stage II B, III-IV. Group S pts received cytoreductive CT with Ifosfamide-containing regimens followed by HDBEAM+ASCT. T evaluation was repeated after each CT cycle, at the end of treatment and during follow-up.

Main pts characteristics were as follows: males/females: 32/41; age<45/≥45yrs: 59/16; Nodular Sclerosis (NS) histology/other: 54/73; stage I+II/III+IV: 46/27; B symptoms: 37; bulky disease: 35; nodal/extra±nodal involvement: 49/24; >3/≤3 involved sites: 34/39; IPS>2/≤2: 8/65. Basal T (T0) (median, IQ range) was significantly higher in Group U vs S (23540, 6528-50710 vs 1448, 735-8278; Mann-Whitney test P=0.002); T0 values >536 were observed in 43 (86%) Group U pts and 18 (78%) Group S pts (536 was the 95^th centile of T distribution in a group of 40 independent healthy subjects). Pts with NS, bulky disease and extranodal involvement had significantly higher T0 levels than their counterparts. After 2 CT cycles, T (T2) was significantly lower than T0 in Group U (Wilcoxon paired sample test P<0.001), but not in Group S pts (p=0.090); T2 values >536 were observed in 18 (36%) Group U pts and 14 (61%) Group S pts. PET-2 scan was positive in 20 pts (27%) (Group U: 18%, Group S: 48%); PET- 2 was positive in 19/61 pts (31%) with T0 >536 and in 1/12 pts (8%) with T0 ≤ 536; in 17/32 (53%) pts with T2 >536 and in 2/35 (6%) pts with T2 ≤ 536. The chance of having a positive PET-2 was similar in pts with T0 >536 and T2 ≤ 536 compared with pts with T0 ≤ 536 (OR: 1.1; 95% CI: 0.9-13.5), whereas it was 13-fold greater in pts with both T0 and T2 >536 (OR: 12.6; 95% CI 1.4-110). Median follow-up was 18 months (interquartile range: 13-25 months); 13 (18%) pts had relapse or progression (7 Group U, 6 Group S), 24-months progression-free survival (PFS) was 83.4% in Group U and 60.6% in Group S. PFS was 100% vs 78.6% vs 59.4% in pts with T0 ≤ 536, T0 >536 and T2 ≤ 563, and both T0 and T2 >536, respectively.

Our study confirms that HL pts have increased serum TARC values at baseline compared with healthy subjects; moreover T0 combined with values observed after 2 cycles of CT may have a role in predicting PET-2 results and disease outcome.

No relevant conflicts of interest to declare.