Chemoresistance as a function of the pretherapy tumor burden and the chemotherapy regimen administered: differences observed with 2 current chemotherapy regimens for advanced Hodgkin lymphoma

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.

Metabolic Tumour Volume for Response Prediction in Advanced-Stage Hodgkin Lymphoma

Rationale: (18F)fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) for staging Hodgkin lymphoma may allow for accurate and reliable assessment of the metabolic tumour volume (MTV) as baseline risk factor. Our aim was to analyse the prognostic impact of MTV measurements, obtained by different means in advanced-stage Hodgkin lymphoma patients treated within the German Hodgkin Study Group HD18 trial. Methods: Within the German Hodgkin Study Group trial HD18, 310 patients underwent 18F-FDG PET/CT scanning for staging which was available to the central review panel for quantitative analysis. We calculated the MTV by four different thresholding methods and performed receiver operating characteristic (ROC) analysis to evaluate the potential for prediction of early response determined by PET after two cycles (PET-2) dose-escalated bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (eBEACOPP). Logistic regression was used to evaluate its prognostic value concerning progression-free survival (PFS) and overall survival (OS). Results: All different MTV calculations used predicted PET-2 response to a moderate and comparable degree (area under the curve = 0.62-0.63, P = 0.01-0.06). With none of the measuring methods did the ROC curves point to any unique cut-off values, but indicated a wide range of possible cut-offs. However, none of the MTV measurements was prognostic for PFS (Hazard ratio 1.2-1.5, P = 0.15-0.52) or OS (Hazard ratio 1.0-1.5, P = 0.95 - 0.27). Conclusion: Baseline MTV as determined by different means, is a predictive factor for early response to eBEACOPP after two cycles. However, value as a prognostic factor after highly effective PET-2 adapted treatment strategy could not be observed.

Baseline metabolic tumour volume is an independent prognostic factor in Hodgkin lymphoma

PURPOSE

The presence of a bulky tumour at staging in Hodgkin lymphoma (HL) is a predictor of a poor outcome. The total metabolic tumour volume at baseline (TMTV0) computed on PET may improve the evaluation of tumour burden. To explore the clinical usefulness of TMTV0, we compared the prognostic value of TMTV0, tumour bulk and interim PET response in a retrospective single-centre study.

METHODS

From 2007 to 2010, 59 consecutive patients with a first diagnosis of HL were treated in our institution. PET was done at baseline (PET0) and after two cycles of chemotherapy (PET2), and treatment was not modified according to the PET2 result. TMTV0 was measured with a semiautomatic method using a 41 % SUVmax threshold. SUVmax reduction between PET0 and PET2 (ΔSUVmaxPET0-2) was also computed. Based on ROC analysis, patients with a ΔSUVmaxPET0-2 >71 % were considered good responders and a TMTV0 >225 ml was considered to represent hypermetabolic bulky disease.

RESULTS

Median TMTV0 was 117 ml and 17 patients (29 %) had a TMTV0 >225 ml. TMTV0 (>225 ml vs. ≤225 ml) and tumour bulk (<10 cm vs. ≥10 cm) were predictive of 4-year PFS: 42 % vs. 85 % (p = 0.001) and 44 % vs. 79 % (p < 0.03), respectively. In multivariate analysis, using ΔSUVmaxPET0-2, TMTV0 and bulky tumour as covariates, only ΔSUVmaxPET0-2 (p = 0.0005, RR 6.3) and TMTV0 (p < 0.006, RR 4.4) remained independent predictors of PFS. Three prognosis groups were thus identified: ΔSUVmaxPET0-2 >71 % and TMTV0 ≤225 ml (n = 37, 63 %), ΔSUVmaxPET0-2 = <71 % or TMTV0 >225 ml (n = 17, 29 %), and ΔSUVmaxPET0-2 = <71 % and TMTV0 >225 ml (n = 5, 8 %). In these three groups the 4-year PFS rates were 92 %, 49 %, and 20 % (p < 0.0001), respectively.

CONCLUSION

TMTV0 is more relevant than tumour bulk for predicting the outcome in patients with HL, and adds a significant prognostic insight to interim PET response assessment. The combination of TMTV0 and ΔSUVmaxPET0-2 made it possible to identify three subsets of HL patients with different outcomes. This may guide clinicians in their choice of therapeutic strategy.

Tumour burden is an independent prognostic factor in metastatic renal cell carcinoma

Study Type--Prognosis (cohort series) Level of Evidence 2b. What's known on the subject? and What does the study add? In the literature, few studies have evaluated the role of tumour burden (TB) in metastatic real cell carcinoma (mRCC), even though it has been considered as important in localized tumours. In metastatic patients the role of TB is uncertain because it was analyzed in chemotherapy treated patients or using a partial evaluation of TB. This study, first reports the independent prognostic and predictive role of TB in mRCC patients treated with targeted agents in prospective clinical trials. TB is able to predict prognosis independently to localization of metastases and prognostic class defined by MSKCC criteria, moreover it is strictly related to patient's performance status.

OBJECTIVE

• To investigate the possible prognostic role of baseline tumour burden (TB) in terms of progression-free survival (PFS) and overall survival (OS), in patients with metastatic renal cell carcinoma (mRCC).

PATIENTS AND METHODS

• A homogenous group of patients with mRCC enrolled in second-line trials post-cytokine treatment were selected for the present analysis. • The Response Evaluation Criteria in Solid Tumors (the sum of the longest unidimensional diameter of each target lesion) were used to assess TB. • The PFS and OS rates were estimated using the Kaplan-Meier method and compared across the groups using the log-rank test. • The association between TB and PFS or OS was evaluated using a Cox proportional hazards model. Multivariable analyses were adjusted for other prognostic variables: the Memorial Sloan Kettering Cancer Centre (MSKCC) risk class and treatment.

RESULTS

• A total of 124 patients were included in the final analysis. Of these, 66% received sorafenib or sunitinib and 34% received placebo. The median follow-up was 80.1 month. • TB was directly related to PFS and OS and these associations remained significant after adjusting for modified MSKCC risk class and treatment,. • Each 1-cm increase in TB increased the risk of progression by 4.5% (hazard ratio [HR]: 1.05; 95% confidence interval [CI] 1.02-1.07; P < 0.001) and the risk of death by 5% (HR: 1.05; 95% CI 1.03-1.08; P < 0.001).

CONCLUSIONS

• TB is easy to calculate from standard computed tomography and significantly relates to OS in patients with mRCC. • We report for the first time the independent prognostic role of baseline TB in multivariate analysis. •  We believe that this information could be translated into clinical practice.

Tumour burden predicts treatment resistance in patients with early unfavourable or advanced stage Hodgkin lymphoma treated with ABVD and radiotherapy

The purpose of the work was to investigate the factors predicting early resistance to treatment in Hodgkin lymphoma. Many staging parameters, including relative tumour burden (rTB), were analysed in 246 patients with Hodgkin lymphoma in relation to early failure, that is, less than complete remission (i.e. partial response, null response or progression) or occurrence of early relapse, as clinical expressions of resistance to treatment. Patients with early unfavourable disease were 129 and were treated with four to six cycles of ABVD + involved field radiotherapy; 117 patients with advanced stage disease received six cycles of ABVD + optional irradiation to no more than two sites. The rTB was volumetrically measured through the evaluation of staging computed tomography for all the lesions except bone marrow involvement, which was quantified by calculation. The relationship with early resistance was analysed with logistic regressions. The rTB demonstrated to be the best predictor of early failure in both patient subsets, being superior to the multiparameter International Prognostic Score. The rTB showed a significant exponential relationship with the relative risk of early failure, and with inclusion of the extranodal involvement into the model, a single equation became adequate to predict resistance in both early unfavourable and advanced stage patients. The conclusions are that the rTB is the best pretreatment factor related to the risk of resistance to combined ABVD + radiotherapy and that this relationship can be mathematically expressed in an easy way. A simplified assessment of rTB is highly desirable.