Many early-stage patients with bulky classic Hodgkin lymphoma (cHL) can avoid radiotherapy treatment and still have excellent outcomes, according to a clinical study in which treatment was adapted to findings on PET imaging.

Bulky disease (characterised by large tumours typically in the centre of the chest) is associated with poorer outcomes in cHL and is traditionally treated with radiotherapy following chemotherapy.

However, radiation treatment to the chest can have long-term toxic effects including an increased risk of breast cancer and heart problems.

The results, presented by Ann LaCasce, MD, MMSc, of Dana-Farber, included 94 patients with stage IA-IIB cHL and disease bulk greater than 10 cm or .33 maximum intrathoracic diameter on chest X-ray.

Patients received two cycles of chemotherapy (ABVD) and then underwent PET imaging. Patients whose disease showed uptake less than liver on interim PET scan (PET2-) - 78% of the patients, received four additional cycles of chemotherapy, but no radiotherapy.

Patients classed as PET2+ received intensified chemotherapy with four cycles of escBEACOPP plus radiation therapy.

The estimated progression-free survival (PFS) was 93.1% in the PET2- patients and 89.7% in PET2+ patients.

With a median follow-up of 5.5 years, estimated 3-year overall survival was 98.6% in PET2- patients and 94.4% in PET2+ patients. (Overall survival was not a primary or secondary outcome of the study).

The investigators said the PET-adapted approach achieved excellent PFS outcomes "that allowed omission of radiotherapy in 78 percent of patients." The PET2+ patients who received BEACOPP and radiotherapy "did not have inferior outcomes."

Source: Dana-Farber Cancer Institute