BACKGROUND: To date, Hodgkin’s lymphoma (HL) patients
have achieved long-term survival of more than 80%. Unfortunately,
longer follow-up has shown serious adverse effects of
the treatments used. For this reason, therapeutic strategies are
becoming more tailored to the individual patient´s prognosis.
Pre-treatment risk factors for early-stage and advanced-stage
HL are well known indicators of prognosis. Recently, early interim
18F-FDG PET has been shown as a strong and independent
predictor of progression-free survival in HL. Our aim was
to assess response to therapy by repeating 18F-FDG-PET/CT
after four and six chemotherapy cycles.
MATERIAL AND METHODS: We evaluated 21 consecutive patients
affected by (HL) and presenting for assessment over
a period of three years. All patients underwent initial staging
with 18F-FDG-PET/CT along with standard staging procedures. We tailored an individual treatment plan dependent on pre-treatment
risk factors and initial 18F-FDG-PET/CT. With the aim of
the best definition of response to treatment, we repeated
18F-FDG-PET/CT after two (FDG-PET 2), four (FDG-PET 4) and
six (FDG-PET 6) chemotherapy cycles. Chemotherapy was typically
given for four cycles in early disease stages and was prolonged
to six to eight cycles in advanced disease stages, depending
on PET findings.
RESULTS: Our results showed a strong negative predictive value
in detecting responders in early stage HL and a positive
predictive value in advanced-stage patients. Clinical stage,
extra-nodal sites and the positivity of the 18F-FDG-PET/CT performed
during chemotherapy were also noted as strong determinants
of response to treatment. Moreover, in our series the
18F-FDG-PET/CT data obtained after only two chemotherapy
cycles (FDG-PET 2) were the same of those obtained after FDGPET
4 and FDG-PET 6 controls.
CONCLUSION: The preliminary data of the present study confirm
those of previous published studies about the negative predictive
value of 18F-FDG-PET/CT performed after four and six
chemotherapy cycles, which contributed to the decision to stop
treatment and to avoid radiotherapy in HL patients. Nonetheless,
our preliminary data seems to suggest that only the
18F-FDG-PET/CT performed after two cycles of chemotherapy
(FDG-PET 2) is able to provide the same prognostic information
of the FDG-PET 4 and FDG-PET 6 earlier
