Predictive Value of Modeled AUCAFP-hCG , a Dynamic Kinetic Parameter Characterizing Serum Tumor Marker Decline in Patients With Nonseminomatous Germ Cell Tumor

• Published in: Urology (Ridgewood, N.J.) N.J.), 2010, Vol.76 (2), p.423-429.e2
• Main Authors: You, Benoit, Fronton, Ludivine, Boyle, Helen, Droz, Jean-Pierre, Girard, Pascal, Tranchand, Brigitte, Ribba, Benjamin, Tod, Michel, Chabaud, Sylvie, Coquelin, Henri, Fléchon, Aude
• Format: Article
• Language: English
• Subjects: Urology
• ISSN: 0090-4295
• DOI: 10.1016/j.urology.2010.02.049

Objective The early decline profile of alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) in patients with nonseminomatous germ cell tumors (NSGCT) treated with chemotherapy may be related to the risk of relapse. We assessed the predictive values of areas under the curve of hCG (AUChCG ) and AFP (AUCAFP ) of modeled concentration–time equations on progression-free survival (PFS). Methods Single-center retrospective analysis of hCG and AFP time-points from 65 patients with IGCCCG intermediate-poor risk NSGCT treated with 4 cycles of bleomycin-etoposide-cisplatin (BEP). To determine AUChCG and AUCAFP for D0-D42, AUCs for D0-D7 were calculated using the trapezoid rule and AUCs for D7-D42 were calculated using the mathematic integrals of equations modeled with NONMEM. Combining AUCAFP and AUChCG enabled us to define 2 predictive groups: namely, patients with favorable and unfavorable AUCAFP-hCG . Survival analyses and ROC curves assessed the predictive values of AUCAFP-hCG groups regarding progression-free survival (PFS) and compared them with those of half-life (HL) and time-to-normalization (TTN). Results Mono-exponential models best fit the patterns of marker decreases. Patients with a favorable AUCAFP-hCG had a significantly better PFS (100% vs 71.5%, P = .014). ROC curves confirmed the encouraging predictive accuracy of AUCAFP-hCG against HL or TTN regarding progression risk (ROC AUCs = 79.6 vs 71.9 and 70.2 respectively). Because of the large number of patients with missing data, multivariate analysis could not be performed. Conclusion AUCAFP-hCG is a dynamic parameter characterizing tumor marker decline in patients with NSGCT during BEP treatment. Its value as a promising predictive factor should be validated.