Quantification of Early, Intermediate and Late Volumetric and Metabolic Response during Fractionated Radiation Therapy for non-Hodgkin's Lymphoma

Abstract

paired signed rank test, p = 0.02, medians - 0.034 Gy -1 and - 0.017 Gy -1 ), and a trend for the volumes (p = 0.24, medians - 0.035 Gy -1 and- 0.019Gy -1 ).Theearlyandintermediatevolumeresponsesalsoshowedsomedegreeofnegativecorrelation(Spearman’s rho = - 0.33) whereas they did not for the SUV responses (rho = - 0.02). For late response assessment (F1m - F3m), all SD and PD patientsshowedincreasingSUVandvolumes,whereasfortheCRpatientsthesevalueswerecontinuingtodecrease.Thedifference between these two groups was significant (Wilcoxon rank sum test, p = 0.01 for SUV, p = 0.03 for volumes). Conclusions: These data in a small number of patients suggest that early and intermediate metabolic response during RT does not predict eventual local control, whereas a lack of a late metabolic and volumetric response between F1m and F3m, as well as large initial tumor bulk are associated with treatment failure.