Impact of FDG-PET/CT in Staging, Response Evaluation and Decision of Radiotherapy for Pediatric Hodgkin Lymphoma

PURPOSE: To review the role of FDG-PET/CT in staging, assessment of treatment response, and decision of radiotherapy among Pediatric Hodgkin Lymphoma patients.

MATERIALS & METHOD: 125 hodgkin lymphoma patients up to 18 years of age who were evaluated with FDG-PET/CT for staging workup, treatment response and planning for radiatherapy during 2010-2013 in Shaukat Khanum Memorial Cancer Hospital & Research Center, Lahore, Pakistan were retrospectively reviewed for this study. 104 out of 125 patients were evaluated in mid treatment with FDG-PET/CT by giving F18 FDG dose 0.21mg/Kg intravenously in resting condition followed by imaging over 25-30 min; contrast enhanced CT was required as a part of PET/CT protocol. Remaining 21 patients were evaluated for treatment response with isolated contrast enhanced CT due to non-availability of FDG-PET/CT.

RESULTS: Majority (82%) of the patients fall under the age group of 5 to 15 years. However, ratio of male patients was greater than female i.e. about 3:1. From Chi square analysis it is revealed that there is substantial association between staging with FDG-PET/CT and conventinal CT. From cross tabulation it is concluded that FDG-PET/CT downstaged one patient and up staged eight patients. On the bases of interim CT, radiotherapy was given to 7 patients of which 5 relapsed. Based on FDG-PET/CT 19 patients received radiotherapy, out of these 19 patients 10 relapsed.

The 48% of 21 patients evaluated by conventional CT relapsed and 15% of 104 patients evaluated by FDG-PET replaped.

CONCLUSION:Based on our data , initial staging FDG-PET/CT upstaged more patients than convential CT, while at mid-treatment response evaluation less patients received radiation in FDG-PET/CT group. Relapse rate was lower in FDG-PET/CT group.