PET/CT adapted therapy in Hodgkin disease: current state of the art and future directions.

Current therapy of Hodgkin disease (HD) is based on risk assessment, taking into consideration both staging and risk factors. Interim positron emission tomography/computerized tomography (PET/CT) has proven to distinguish between patients with advanced disease who have early response and good prognosis and those with interim positive response who have inferior progression free survival (PFS) with current therapy. Several issues need to be elucidated: (1) Which interim study should be defined as positive? (2) Should the same cutoff value be used for decision-making about escalation vs de-escalation of therapy? (3) Should it apply to different chemotherapy protocols? Currently, there are several ongoing studies where treatment is modified based on interim PET/CT. These studies may enable the medical community to establish whether bleomycin or radiation therapy could be omitted in early responders, whether chemotherapy could be shortened in these patients, and whether therapy escalation for patients with interim positive PET/CT could decrease disease progression rate.