PET scans in determining outcomes for patients with Hodgkin lymphoma treated with chemotherapy

This study aimed to investigate the role of positron emission tomography (PET; an imaging technique) in determining the outcomes for patients with Hodgkin lymphoma treated with chemotherapy.

This study concluded that negative-PET scans after chemotherapy predict good outcomes for these patients, regardless of stage at diagnosis. 

Ann Arbor staging is the staging system for Hodgkin lymphomas (HL). The stage depends on the location of the tumors and symptoms due to the lymphoma. 

A PET scan produces 3D, color images that show how the tissues inside the body work. PET scans can be used in cancer for diagnosis or to determine the stage. It can also show if cancer has spread, help decide the treatment and show if chemotherapy is working. A negative PET result indicates that the cancer has responded to treatment.  

The role of Ann Arbor staging in determining the treatment intensity after a negative PET scan is not known in classical Hodgkin lymphoma (cHL). 

This study involved 377 patients who had stage I – IV cHL. All patients received three cycles of treatment. This involved ABVD chemotherapy. This includes doxorubicin (adriamycin), bleomycin (Blenoxane), vinblastine (Velban) and dacarbazine (DTIC). After these 3 cycles, all patients had a PET scan (PET3).

PET3-negative patients received no further therapy. PET3-positive patients received three more cycles of ABVD. These patients also had radiation therapy only to the affected area of the body or salvage chemotherapy. They were then re-evaluated by PET scan (PET6). Salvage chemotherapy is given after the initial treatment fails. Patients were followed up for an average of 69 months. 

70% of patients were PET3-negative. The 3-year progression-free survival (PFS; patients alive without cancer worsening) rate was 90% for the PET3-negative patients compared to 65% for the PET3-positive patients. The 5-year PFS was 89% for PET3-negative patients compared to 60% in PET3-positive patients.

The 3-year overall survival (OS; the percentage of patients alive after 3 years) rate was 98% for the PET3-negative patients and 92% for the PET3-positive patients. All PET3-negative patients (regardless of disease stage) achieved good PFS and OS. 

This study concluded that patients with cHL who have a negative-PET3 after ABVD have a good outcome, regardless of stage at diagnosis.