Volumetric assessment of mediastinal lymphoma masses in Hodgkin lymphoma

The large mediastinal mass (LMM) at initial staging represents a risk factor in Hodgkin lymphoma (HL) and is measured by X-ray. Depending on location of the LMM, different results can occur regardless of the initial lymphoma volume. To assess this risk factor more accurately, we evaluated the method of volumetry in 77 patients of HD13/14 study of the German Hodgkin Study Group. Furthermore, volume calculations based on three or only one diameter, were performed to simplify volume assessment. Inter-rater reliability was good for all methods. The 3-diameter measurement produced larger volumes than volumetric assessment with an intraclass correlation coefficient (ICC) of 0.93, which could be improved to 0.95 by multiplying volumes with a correction factor of 0.86. The 1-dimensional measurement strongly overestimated the volume with an ICC of 0.7. In conclusion, the simplified volume estimation based on 3 largest diameters provides a reliable concept for the staging of HL patients.

Concordance in the interpretation of PET after chemotherapy in advanced stage Hodgkin lymphoma

The aim was to analyze the degree of agreement between the central review panel and the local PET interpretation within the HD15 trial and its impact on subsequent treatment and progression free survival.

PATIENTS, METHODS

The analysis set consisted of 739 patients with residues ≥ 2.5 cm after 6 or 8 cycles of BEACOPPesc from the HD15 trial performed by the German Hodgkin Study Group. The recommendation for or against further radiotherapy was based on the central [(18)F]FDG-PET interpretation. Central PET interpretation was compared to the local PET interpretation and concordance was measured using Cohen's Kappa coefficient. Prognostic impact of the analysis of concordance between local and central PET interpretations was evaluated using progression free survival (PFS); groups were compared with the log rank test.

RESULTS

The central panel rated 548 of 739 patients (74%) as PET negative. Of these, 513 were also rated as PET negative in the local PET interpretation. PET positivity was seen by central reviewers in the remaining 191 patients (26%), in concordance with local reviewers in 155 cases. Even though substantial agreement was found (Cohen's Kappa 0.81), the interpretation of the central PET review panel led to a different therapeutic recommendation in 71/739 (10%) patients. PFS was equally high in groups in which the therapeutic regime had been changed on the basis of the central panel decision.

CONCLUSION

High concordance is found between local and central reviewers with regard to PET interpretation in residual tissue after intense chemotherapy. The existence of the central PET review panel allows the identification of additional patients as PET negative so that radiotherapy can be safely omitted (35 of 548 patients = 4.7%).