Tumor burden in Hodgkin's lymphoma can be reliably estimated from a few staging parameters

Total tumor burden in lymphoma - an evolving strong prognostic parameter

Total metabolic tumor volume (TMTV), a new parameter extracted from baseline FDG-PET/CT, has been recently proposed by several groups as a prognosticator in lymphomas before first-line treatment. TMTV, the sum of the metabolic volume of each lesion, is an index of the metabolically most active part of the tumor and highly correlates with the total tumor burden. TMTV measurement is obtained from PET images processed with different software and techniques, many being now freely available. In the various lymphoma subtypes where it has been measured, such as diffuse large B-cell lymphoma, Hodgkin lymphoma, Follicular Lymphoma, and Peripheral T-cell lymphoma, TMTV has been reported as a strong predictor of outcome (progression-free survival and overall survival) often outperforming the clinical scores, molecular predictors, and results of interim PET. Combined with these scores, TMTV improves the stratification of the populations into risk groups with different outcomes. TMTV cut-off separating the high-risk from the low-risk population impacts the outcome whatever the technique used for its measurement and an international harmonization is ongoing. TMTV is a unique and easy tool that could replace the surrogate of tumor burden included in the prognostic indexes used in lymphoma and help tailor therapy. Other parameters extracted from the baseline PET may give an information on the dissemination of this total tumor volume such as the maximum distance between the lesions. Trials based on TMTV would probably demonstrate its predictive value.

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.

Prognostic factors in hodgkin lymphoma

Hodgkin lymphoma (HL) is among the neoplastic diseases that has the best long-term outcome after cytotoxic treatment. Cure rates approach 80–90%; however, 15–20% of patients will be resistant to therapy (primary refractory) or relapse after treatment. Prognostic factors should help to stratify treatment according to the risk profile and identify patients at risk for failure. Significance of prognostic factors partly depends on the efficacy of the treatments administered, since new effective therapies can variably counterbalance the adverse effects of some unfavorable clinical determinants. As a consequence, some prognostic factors thought to be important in the past may become meaningless when modern successful therapies are used. Therefore, the value of prognostic factors has to be updated periodically, and then adapted to new emerging biomarkers. Besides the prognostic role of PET imaging, tissue and circulating biomarkers, as the number of tumor-infiltrating macrophages, cytokine and chemokine levels and profiling of circulating nucleic acids (DNA and microRNAs) have shown promise.