Improved prediction of chemoresistance in patients with diffuse large B-cell lymphoma through a new interim positron emission tomography-computed tomography evaluation model.

OBJECTIVES: The positron emission tomography (PET) could predict the prognosis of DLBCL patients, but the exact procedure on interim PET (iPET) to determine chemoresistant patients remains elusive. METHODS: We retrospectively analyzed 593 newly diagnosed DLBCL patients uniformly treated with R-CHOP regimen. Among them, 352 patients diagnosed from August 2010 to December 2016 were included in the test cohort and 241 patients diagnosed from January 2017 to December 2019 were included in the validation cohort. The iPET was evaluated with Deauville criteria and ΔSUVmax method. The reduction of maximal SUV between baseline and after 4 cycles of chemotherapy were defined as ΔSUVmax. The survival functions were depicted using the Kaplan-Meier method and compared with the log-rank test. RESULTS: Patients with iPET Deauville 4 had heterogeneous outcome and end of treatment complete response rates (eCRR). Combined Deauville with ΔSUVmax method, we proposed a modified-Deauville model: patients with Deauville 4 and ΔSUVmax > 70%, as well as those with Deauville 1-3, were reclassified into the modified-Deauville negative group, while patients with Deauville 4 and ΔSUVmax ≤ 70%, as well as those with Deauville 5, into the modified-Deauville positive group. In the test cohort, 3-year PFS, OS and eCRR of modified-Deauville negative group were 80.2%, 89.9% and 91.8%, significantly higher than those of positive group (12.5%, 27.3% and 29.2%, p ≤ .001). Similar results were found in the validation cohort, that 3-year PFS, OS and eCRR were 87.8%, 95.4%, 96.3% in modified-Deauville negative group, and 27.4%, 32.5%, 13.5% in positive group. Through modified-Deauville model, patients in iPET positive group had very low eCRR and were resistant to conventional chemotherapy. CONCLUSIONS: The modified-Deauville model could better distinguish DLBCL patients with poor response to chemotherapy. Accordingly, these patients could be recognized early and provided with alternative therapeutic agents, which might improve the clinical outcome of refractory DLBCL patients.

Interim PET-CT-guided therapy in elderly patients with Hodgkin lymphoma-a retrospective national multi-center study.

Hodgkin lymphoma (HL), a disease of mostly young patients, also peaks in the elderly. Despite the profound improvement in the outcome of young patients, in the elderly, 5-year progression-free survival (PFS) rates are under 70%. Interim PET-CT (iPET) is known to be highly predictive for PFS in young HL patients, but it has not been sufficiently validated in the elderly patient population. In this multi-center collaboration, all consecutive elderly patients (age ≥ 60) diagnosed with HL between 1998 and 2016 were retrospectively reviewed. Baseline characteristics, outcome measures, and iPET results, classified according to the Deauville score, were recorded and analyzed. We identified 78 elderly HL patients (median age 69) who underwent iPET. ABVD was the treatment regimen in 52 (67%) patients. Eighty-three percent of patients had iPET scores of 1-3 while 17% had scores of 4-5. Patients with iPET scores of 1-3 had 5-year PFS and OS rates of 72% and 82% compared with 25% and 45%, respectively, in patients with scores of 4-5 (p < 0.001). Our findings show that iPET is highly predictive of outcome in elderly HL patients and provide evidence that iPET-guided therapy in this patient population may be key to achieving superior treatment outcome.

Interim 18F-FGD PET/CT may not predict the outcome in primary central nervous system lymphoma patients treated with sequential treatment with methotrexate and cytarabine.

18F-fluoro-2-dexoy-D-glucose-positron emission tomography (PET)/computed tomography (CT) is a useful imaging technique for monitoring the treatment response in lymphoma cases. We investigated the value of interim brain PET/CT (I-PET/CT) for monitoring the response to intensive methotrexate-based chemotherapy in primary central nervous system lymphoma (PCNSL) patients with diffuse large B cell lymphoma (DLBCL). Of the 76 PCNSL patients treated with intensive methotrexate and cytarabine chemotherapy between September 2006 and December 2012, 66 patients with DLBCL were included in this study. The patient cohort of 66 individuals comprised 43 men and 23 women with a median age of 59 years (range, 17-75 years). During chemotherapy, 36 patients (54.5%) showed a negative metabolism on I-PET/CT, and 47 (71.2%) were negative on final (F) PET/CT. The baseline characteristics were similar between I-PET/CT-negative (n = 36) and I-PET/CT-positive patients (n = 30) except ECOG performance status. After a median follow-up of 27.5 months, there was no difference in the progression-free survival (PFS; P = 0.701) or overall survival (OS; P = 0.620) between the I-PET/CT-negative and I-PET/CT-positive groups. However, PFS in the F-PET/CT-negative group was significantly longer than that in the F-PET/CT-positive group (P < 0.001) without a significant difference in OS (P = 0.892). I-PET/CT may not predict the survival outcome of PCNSL patients with DLBCL treated with intensive methotrexate and cytarabine chemotherapy. Prospective trials are required to fully evaluate the role of I-PET/CT.

Phase II study of interim PET-CT-guided response-adapted therapy in advanced Hodgkin's lymphoma.

BACKGROUND: Combination chemotherapy ABVD (doxorubicin, bleomycin, vinblastine and dacarabazine) cures ∼70% of patients with advanced Hodgkin's lymphoma (aHL, stages IIB, III and IV) while more toxic escalated BEACOPP (EB, combination of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisolone) increases cure rates to 85%. Patients with a positive interim positron emission tomography-computerized tomography (PET-CT) scan after two cycles (PET-2) of ABVD have very poor outcomes with continued ABVD. Intensifying therapy with EB in PET-2-positive patients ('response-adapted therapy') may improve cure rates, whereas the negative patients can continue ABVD alone. PATIENTS AND METHODS: Eligible patients with newly diagnosed aHL received two cycles of ABVD and underwent PET-2 (scored with semi-quantitative 5-point visual criteria, 'Deauville score'). PET-2-negative patients continued four additional cycles of ABVD, whereas PET-2-positive patients received four cycles of EB. A phase II sample size of 50 was estimated keeping the lower and higher proportion of rejection of the event-free survival (EFS) as 70% and 85%, respectively. RESULTS: Fifty patients [median age 28 (12-60) years; male : female: 39 : 11; stages: IIB-3 (6%), III-29 (58%) and IV-18 (36%); International Prognostic Score (IPS): 0-3: 34 (68%); 4-7: 16 (32%)] were enrolled; 49 underwent PET-2. Eight (16%) were PET-2-positive, whereas 41 (84%) were negative. Forty-seven were evaluable for EFS and all 50 for overall survival (OS). The 2-year EFS was 76% (95% CI: 68-83) and OS was 88% (95% CI: 82-94). PET-2 was strongly prognostic-2-year EFS, negative versus positive: 82% versus 50%; P = 0.013. CONCLUSION: PET-2 response-adapted strategy could not achieve EFS of 85% in aHL. However, escalated therapy improved outcomes in PET-2-positive patients compared with historical data. TRIAL REGISTRATION: CTRI/2012/06/002741 (http://www.ctri.nic.in) and NCT01304849 (http://www.clinicaltrials.gov).

Treatment Strategies in Advanced-Stage Hodgkin Lymphoma.

The last 3 decades have witnessed a major evolution in the treatment of advanced-stage Hodgkin lymphoma (HL). The most prominent of these developments include the introduction of the international prognostic scoring (IPS) system; therapeutic decision-making based on both IPS and interim PET/CT data; the finding that a negative interim PET/CT result could be safely used for treatment de-escalation; the introduction of intensive combination chemotherapy like escalated BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, oncovin (vincristine), procarbazine, and prednisone); and further modification of this protocol with the incorporation of a conjugated anti-CD30 antibody brentuximab vedotin (BV) into first-line regimens, like BV-AVD (BV+ adriamycin, vinblastine and dacarbazine) and BrECADD (brentuximab vedotin, etoposide, cyclophosphamide, doxorubicin, dacarbazine, and dexamethasone). The accruing data about the toxicity of the escalated BEACOPP protocol have led to decreasing the number of therapeutic cycles, substitution of toxic agents like procarbazine with dacarbazine (e.g., BEACOPDac), and reduction/omission of radiation therapy. Lately, a significant advancement has been made by the integration of checkpoint inhibitors in the first-line treatment, with preliminary results demonstrating the superiority of anti-PD1 combined with chemotherapy (nivolumab-AVD) compared to the BV-AVD regimen. This review aims to analyze recently published studies whose findings could change the treatment practice in advanced-stage HL.

Clinical Outcomes in Patients With DLBCL Treated With R-CHOP According to Radiotherapy and Interim PET Response.

Background/Aim: Interim positron emission tomography/computed tomography (PET/CT) scan is a valuable tool for assessing the early metabolic response to chemotherapy in diffuse large B-cell lymphoma (DLBCL). Although radiotherapy is an effective treatment for lymphoma, especially for local tumor control, the role of consolidative radiotherapy in diffuse large B-cell lymphoma (DLBCL) remains controversial. This study analyzed the clinical outcomes of patients with DLBCL treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), stratified by interim PET response and the administration of radiotherapy. Patients and Methods: We conducted a retrospective review of 107 patients with DLBCL treated with R-CHOP chemotherapy between January 2012 and December 2016. Overall survival (OS), recurrence-free survival (RFS), and freedom from disease progression (FFDP) were calculated using the Kaplan-Meier method and compared using the log-rank test. Results: Forty-six patients were included in this analysis, with a median follow-up time of 65.9 months (range=4.7-125.3 months). The metabolic CR (mCR) group exhibited superior OS, RFS, and FFDP compared with the metabolic PR (mPR) group (p=0.003, p=0.001, and p=0.008, respectively). The 1-, 2-, and 5-year FFDP were 92.97%, 89.3%, and 85.6%, respectively, in the mCR group and 78.6%, 61.9%, and 44.2%, respectively, in the mPR group. In subgroup analysis, the FFDP of the mPR group without radiotherapy was significantly lower than that of the other groups (mCR with/without radiotherapy and mPR with radiotherapy, p=0.001). Conclusion: Consolidative radiation therapy using interim PET can benefit patients who do not achieve mCR. Further well-controlled prospective randomized trials are required.

Prognosis and risk stratification of peripheral T-cell lymphomas.

Peripheral T-cell lymphomas represent a rare heterogeneous group of non-Hodgkin lymphomas with generally worse outcomes with standard chemotherapy compared to B-cell lymphomas. Clinical risk prediction tools at baseline have been shown to be prognostic but generally do not impact clinical decision making. However, improving understanding of the prognostic implications of histology and its molecular underpinnings as well as strategies surrounding the use of CD30 as a predictive biomarker for brentuximab vedotin have led to better understanding of how to risk stratify patients. Baseline, interim, and end of treatment PET/CT as evaluated by the Lugano criteria as well as by baseline metabolic tumor volume have also been shown to be prognostic. The role of minimal residual disease tools such as cell free DNA and T-cell gene receptor sequencing remain active areas of investigation in hopes to develop predictive biomarkers in these rare diseases. This review focuses on strategies used to prognosticate in more common forms of peripheral T-cell lymphoma as well as in extranodal NK/T-cell lymphoma.

Prognostic Role of Early Interim Fluorodeoxyglucose Positron Emission Tomography in Patients With Advanced Seminoma Undergoing Standard Treatment.

BACKGROUND: Patients with advanced seminoma have an exceedingly favorable prognosis. Studies aiming to reduce the total treatment burden and side effects in patients with well-defined disease and very good prognosis are warranted. PATIENTS AND METHODS: In a prospective observational study, patients with advanced stage seminoma were treated with bleomycin, etoposide, and cisplatin (BEP) or EP according to guidelines. Fluorodeoxyglucose with positron emission tomography and computed tomography (FDG-PET/CT) examinations were performed at baseline, after 2 cycles (PET/CT2) in all patients, and after chemotherapy at the physician's discretion. Disease response to treatment assessed by PET/CT was qualitatively evaluated by 2 independent nuclear medicine physicians. Contrast-enhanced CT scans were also performed according to guidelines (at baseline, after treatment, during follow-up). The study's primary endpoint was to evaluate the association between PET/CT2 findings and relapse-free survival. RESULTS: From January 2009 to January 2017, a total of 75 consecutive patients were enrolled, of whom 70 were included for analysis. The clinical disease stage was IIA-B and IIC-III in 40% and 60%, respectively. By local assessment, 46 PET/CT2 scans (65.7%) were reported as negative, and 46% of these patients had stage IIC-III disease. Five-year relapse-free survival of PET/CT2-positive patients was 75% (95% confidence interval, 60-95) compared to 97.8% (95% confidence interval, 93.7-100) of PET/CT2-negative patients (P = .002). In univariate analyses, PET/CT2 was significantly associated with relapse-free survival (P = .02). CONCLUSIONS: No residual FDG uptake after 2 cycles of conventional chemotherapy is prognostic in advanced seminoma, but it may be useful to optimize the standard prognostic risk groups and may be tested within larger prospective clinical trials of chemotherapy deescalation.

PROGNOSTIC VALUE OF POST-INDUCTION CHEMOTHERAPY VOLUMETRIC PET/CT PARAMETERS FOR STAGE IIIA/B NON-SMALL CELL LUNG CANCER PATIENTS RECEIVING DEFINITIVE CHEMORADIOTHERAPY.

Purpose/Objective(s): The aim of this follow-up analysis of the ESPATUE phase-3 trial was to explore the prognostic value of post-induction chemotherapy PET metrics in patients with stage III non-small cell lung cancer (NSCLC) who were assigned to receive definitive chemoradiotherapy. Materials/Methods: All eligible patients stage IIIA (cN2) and stage IIIB of the trial received induction chemotherapy consisting of 3 cycles of cisplatin/paclitaxel and chemoradiotherapy up to 45 Gy/1.5 Gy per fraction twice-a-day, followed by a radiation-boost with 2 Gy once per day with concurrent cisplatin/vinorelbine. The protocol definition prescribed a total dose of 65-71 Gy. 18F-FDG-PET/CT (PETpre) was performed at study entry and before concurrent chemoradiotherapy (interim-PET; PETpost). Interim PETpost metrics and known prognostic clinical parameters were correlated in uni- and multivariable survival analyses. Leave-one-out cross-validation was used to show internal validity. Results: Ninety-two patients who underwent 18F-FDG-PET/CT after induction chemotherapy were enrolled. Median MTVpost value was 5.9 ml. Altogether 85 patients completed the whole chemoradiation with the planned total dose of 60-71 Gy. In univariable proportional hazard analysis, each of the parameters MTVpost, SUVmax(post) and TLGmax(post) was associated with overall survival (P < 0.05). Multivariable survival analysis, including clinical and post-induction PET parameters, found TLGmax(post) (hazard ratio: 1.032 (95%-CI: 1.013-1.052) per 100 ml increase) and total radiation dose (hazard ratio: 0.930 (0.902-0.959) per Gray increase) significantly related with overall survival in the whole group of patients, and also in patients receiving a total dose ≥ 60 Gy. The best leave-one-out cross-validated 2 parameter classifier contained TLGmax(post) and total radiation dose. TLGmax(post) was associated with time to distant metastases (P = 0.0018), and SUVmax(post) with time to loco-regional relapse (P = 0.039) in multivariable analysis of patients receiving a total dose ≥ 60 Gy. Conclusion: Post-induction chemotherapy PET parameters demonstrated prognostic significance. Therefore, an interim 18F-FDG-PET/CT is a promising diagnostic modality for guiding individualized treatment intensification.

The presence of a bulky mediastinal mass of 7 cm or greater in diameter confers an adverse prognosis to patients with advanced Hodgkin lymphoma in case of negative interim PET/CT.

In the PET-adapted therapy era, a bulky mediastinal mass (BMM) is not considered a risk factor in patients with advanced-stage Hodgkin lymphoma (HL). The current retrospective study aimed to estimate the prognostic significance of BMM presence and size for disease-free survival (DFS) and determine the most accurate mass size cutoff (among 5 cm, 7 cm, 10 cm) to predict inferior DFS in such patients. The study included 196 advanced-HL patients treated at Rambam (n = 121) and Memorial Sloan Kettering Cancer Center (n = 75) between 2002 and 2016. At a median follow-up of 66.5 (1-222) months, 36 relapses occurred. In multivariate analysis, only the cutoff of 7 cm predicted inferior DFS and PFS (p < 0.007 and <0.038, respectively) in interim PET/CT (PET-2) negative (79%) patients. This study identifies the BMM size cutoff of 7 cm in any plane as most precise in predicting adverse prognosis in PET-2-negative patients with advanced-stage HL. More aggressive initial chemotherapy than ABVD improves such prognosis.

Assessment of the prognostic value of interim fluorodeoxyglucose positron emission tomography/computed tomography in nasal-type extranodal natural killer/T-cell lymphoma.

BACKGROUND: The prognostic value of interim positron emission tomography/computed tomography (PET/CT) for nasal-type extranodal natural killer/T-cell lymphoma (ENKTL) is controversial. We evaluated the prognostic value of interim PET/CT in ENKTL patients to facilitate risk stratification and guide clinical treatment. METHODS: Patients with ENKTL who received first-line chemotherapy based on L-asparaginase/pegaspargase with/without involved-field radiotherapy were recruited for this study. Pretreatment and interim PET/CT evaluations were performed. Interim PET/CT was evaluated via the maximum standardized uptake value (SUVmax) and the Deauville 5-point scale (DS); and the capacity to predict progression-free survival (PFS) and overall survival (OS) was evaluated. Receiver operating characteristic (ROC) curves were used to determine the optimal SUVmax cutoff. Fisher's exact test was used to analyze relationships between interim PET/CT results and clinical characteristics. Univariate and multivariate analyses were performed to examine the independent effects of interim PET/CT. The Cochran-Mantel-Haenszel test was used to assess the prognostic value of interim PET/CT at different timepoints. RESULTS: Overall, 129 ENKTL patients were enrolled. The optimal interim PET/CT SUVmax cut-off was 4.95. The median follow-up was 34 [2-90] months, in the low SUVmax group (≤4.95), the 2-year PFS and OS rates were 76.3% and 88.0%, respectively; in the high SUVmax group (>4.95), the PFS and OS rates were 15.6% and 44.5%, respectively. Likewise, for the DS 1-3 group, the PFS and OS rates were 78.9% and 91.2%, respectively; and in the DS 4 or 5 group, the rates of PFS and OS were 49.7% and 69.0%, respectively. In univariate analysis, interim PET/CT evaluation based on SUVmax and DS scores were both PFS and OS predictors. In multivariate analysis, SUVmax was independently significantly associated with PFS (P<0.001) and OS (P=0.002), and DS was independently significantly associated with PFS (P=0.004) but not OS (P=0.204). In the Cochran-Mantel-Haenszel testing, the SUVmax and DS were significantly associated with PFS and OS after adjustments for the interim PET/CT timing. CONCLUSIONS: Interim PET/CT was of prognostic value concerning ENKTL. The SUVmax is an independent prognostic indicator of PFS and OS, while the DS is an independent prognostic indicator of PFS but not OS. The SUVmax is of greater prognostic value than DS.

Prognostic value of interim 18F-FDG PET/CT in T-cell lymphomas.

18F-FDG PET/CT is recommended for staging and response assessment in FDG-avid lymphomas, such as HL and DLBCL. But evidence of PET/CT regarding T-cell lymphomas (TCLs) was limited. In this retrospective study, we conducted survival analysis using interim PET/CT in 51 TCLs patients. PET/CT were reported using the Deauville 5-point score (DS) and the ΔSUVmax. In univariate analysis, I-PET/CT had a significant prognostic value of survival outcomes based on DS (p < .001 for progression-free survival (PFS), p = .010 for overall survival (OS)) and ΔSUVmax (p < .001 for PFS, p = .023 for OS). In multivariate analysis, DS remained a statistically independent predictor of PFS (p < .001) and OS (p = .017). ΔSUVmax remained a statistically independent predictor of PFS (p = .008), but not of OS (p = 0.311). Therefore, DS on I-PET/CT had a remarkable value of predicting survival outcomes in TCLs.

Quantitative Assessment of Interim PET/CT Could Have More Prognostic Relevance than Visual Assessment for Predicting Clinical Outcome of Extranodal Diffuse Large B Cell Lymphoma.

BACKGROUND/AIM: The present study retrospectively investigated the predictive accuracy of interim positron emission tomography/computed tomography (iPET/CT) based on the Deauville 5-point scale (5-PS) and a quantitative SUV-based assessment in patients with extranodal (EN) diffuse large B cell lymphoma (DLBCL). PATIENTS AND METHODS: The Deauville 5-PS and the SUVmax reduction (ΔSUVmax) assessment for interpreting the response to iPET/CT were used. RESULTS: A total of 163 patients were enrolled in this study. With a median follow-up of 52.5 months, ΔSUVmax successfully predicted the survival outcomes of patients with one extranodal (EN) involvement in terms of overall survival (OS) (p=0.012) and progression-free survival (PFS) (p<0.001). Visual assessment using the Deauville 5-PS did not predict survival outcomes in patients with one or more EN involvements in terms of OS and PFS. CONCLUSION: The quantitative SUV-based assessment with iPET/CT was a significant prognosticator for long-term survival outcomes, especially in patients with one EN involvement.

Clinical and prognostic role of interim 18F-FDG PET/CT in elderly Hodgkin lymphoma: a dual-center experience.

Hodgkin lymphoma (HL) has a bimodal age distribution curve, with a second peak in people aged more than 60 years. Interim PET/CT (iPET/CT) is highly predictive for PFS and OS in young HL, but it has not been sufficiently studied in the elderly. In this retrospective dual-center study, 82 patients with HL and aged 65 or more who performed iPET/CT were included. At iPET/CT, 60 patients had a complete metabolic response, 18 partial responses, and 4 progressions of disease. Baseline PET/CT metabolic features were not significantly correlated with the metabolic response at interim. In patients with interim complete metabolic response, PFS and OS were significantly longer than in patients without complete response(p < 0.001 and p = 0.004). Patients with negative iPET had 2-year PFS and OS rates of 57 and 88% compared with 24 and 58% in patients with positive iPET (p < 0.001). iPET/CT results demonstrated to be independent prognostic factors for PFS and OS.

Interim PET/CT in diffuse large B-cell lymphoma may facilitate identification of good-prognosis patients among IPI-stratified patients.

Treating patients with DLBCL remains a challenge, as the response to first-line immunochemotherapy is somewhat unpredictable. The International Prognostic Index (IPI) is one of the most widely used methods for assessing prognosis. Interim PET/CT (iPET/CT) can play an important role in the early identification of 'non-responder' patients before the end of treatment examination. In this study, we retrospectively analyzed 104 newly diagnosed DLBCL patients treated with R-CHOP-like regimens who underwent iPET/CT imaging during therapy. There was a significant difference in 2-year OS between patients with negative iPET/CT and those with positive iPET/CT. Patients who had positive iPET/CT showed inferior 2-year PFS compared to those with negative iPET/CT. According to IPI, there was a statistically significant difference in 2-year OS and PFS between patients in the lower and higher risk groups. However, these patients can be further subdivided according to iPET/CT. The iPET/CT results in the present study clearly separate good- and poor-prognosis patients according to differences in 2-year OS, both in the lower and higher IPI risk groups. These results are in agreement with those of previous studies that demonstrated that iPET/CT has high negative predictive value, clearly identifying good-prognosis patients even within the poor-prognosis IPI group.

Interim PET/CT based on visual and semiquantitative analysis predicts survival in patients with diffuse large B-cell lymphoma.

PURPOSE: The role of interim 18 F-FDG PET/CT (iPET/CT) in diffuse large B-cell lymphoma (DLBCL) remains controversial. The purpose of this study was to assess the prognostic value of iPET/CT in patients with newly diagnosed DLBCL according to visual and semiquantitative interpretation methods. METHODS: A total of 129 newly diagnosed DLBCL patients with baseline PET/CT data were retrospectively screened. The iPET/CT findings were evaluated by the Deauville 5-point scale (DS) and ΔSUVmax. Furthermore, the reduction in SUVmax incorporated with tumor size (ΔSUVmax*ΔSLD) was calculated. The optimal cutoff values of ΔSUVmax and ΔSUVmax*ΔSLD were determined by receiver operating characteristic (ROC) analysis. Kaplan-Meier analysis was applied to test for the influence of prognostic values. Univariate and multivariate analyses were conducted to examine the potential independent impacts of iPET/CT. RESULTS: Seventy-seven patients with PET/CT images acquired both at baseline and after four cycles of chemotherapy were finally enrolled. The optimal cutoff values for ΔSUVmax and ΔSUVmax*ΔSLD were 74% and 30%, respectively. After a median follow-up of 23 months, iPET/CT findings were significant predictors of PFS and OS whenever iPET/CT was interpreted by DS, ΔSUVmax, or ΔSUVmax*ΔSLD methods. ΔSUVmax-based methods were more accurate than those based on DS. The IPI, DS, ΔSUVmax, and ΔSUVmax*ΔSLD were predictive in univariate analyses. However, in the multivariate analysis, only IPI and ΔSUVmax remained independent predictors of PFS and OS. CONCLUSIONS: Interim PET/CT may help to identify DLBCL patients with different prognoses. ΔSUVmax analysis shows the best accuracy and the strongest predictive value among these three methods. ΔSUVmax*ΔSLD may be a promising parameter to interpret iPET/CT images, reflecting both the changes in tumor size and metabolic activity.

(18)F-fluorodeoxyglucose-positron emission tomography/computed tomography after one cycle of chemotherapy in patients with diffuse large B-cell lymphoma: results of a Nordic/US intergroup study.

We evaluated the predictive value of interim positon emission tomography (I-PET) after one course of chemoimmunotherapy in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL). One hundred and twelve patients with DLBCL were enrolled. All patients had PET/computed tomography (CT) scans performed after one course of chemotherapy (PET-1). I-PET scans were categorized according to International Harmonization Project criteria (IHP), Deauville 5-point scale (D 5PS) with scores 1-3 considered negative (D 5PS > 3) and D 5PS with scores 1-4 considered negative (D 5PS = 5). Ratios of tumor maximum standardized uptake value (SUVmax) to liver SUVmax were also analyzed. We found no difference in progression-free survival (PFS) between PET-negative and PET-positive patients according to IHP and D 5PS > 3. The 2-year PFS using D 5PS = 5 was 50.9% in the PET-positive group and 84.8% in the PET-negative group (p = 0.002). A tumor/liver SUVmax cut-off of 3.1 to distinguish D 5PS scores of 4 and 5 provided the best prognostic value. PET after one course of chemotherapy was not able to safely discriminate PET-positive and PET-negative patients in different prognostic groups.

Role of 2-Deoxy-2-[18F]-fluoro-d-glucose-PET/Computed Tomography in Lymphoma.

The role of PET and PET/computed tomography (CT) has evolved significantly in the last few decades. 2-Deoxy-2-[18F]-fluoro-d-glucose (FDG)-PET/CT is now an integral part of the management of patients with lymphoma. FDG-PET/CT at the time of initial staging can help in appropriate staging of the patients. Both interim and end-of-therapy PETs have significant prognostic value in patients with Hodgkin lymphoma and aggressive non-Hodgkin lymphoma and more accurately assess for the presence of residual malignancy than anatomic imaging. The impact of interim FDG-PET/CT on risk-adapted strategies is an area of active investigation and the results of ongoing clinical trials will be informative.

The utility and limitations of (18)F-fluorodeoxyglucose positron emission tomography with computed tomography in patients with primary mediastinal B-cell lymphoma: single institution experience and literature review.

There are limited data regarding the role of (18)F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET-CT) scanning in primary mediastinal B-cell lymphoma (PMBL). We analyzed 28 patients with PMBL treated with chemotherapy, of whom 25 (89%) also received rituximab and 17 (61%) radiotherapy. PET-CT scans were interpreted using visual analysis and a 5-point scale. After a median follow-up of 2.6 years, four patients relapsed and two died. The 2-year progression-free survival and overall survival were 86% and 94%. PET-CT has excellent negative predictive value (interim, 86-87%; end of treatment, 95%) but limited positive predictive value due to the high frequency of positive scans. Several patients with persistent metabolically active masses underwent biopsies, which showed necrosis but no lymphoma. Thus a negative PET-CT is an excellent predictor of subsequent outcome. However, residual metabolically active masses after treatment should be biopsied to confirm viable lymphoma prior to salvage therapy.