Use of subsequent PET/CT in diffuse large B-cell lymphoma patients in complete remission following primary therapy

Interim 18F-fluorodeoxyglucose(FDG) positron emission tomography/computed tomography(I-PET/CT) is a powerful tool for monitoring the response to therapy in diffuse large B-cell lymphoma(DLBCL). This retrospective study aimed to determine when and how to use I-PET/CT in DLBCL. A total of 197 patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone(R-CHOP) were enrolled between October 2005 and July 2011; PET/CT was performed at the time of diagnosis(PET/CT0), after 2 and 4 cycles of chemotherapy(PET/CT2 and PET/CT4, respectively), and at the end of treatment(F-PET/CT). According to the International Harmonization Project for Response Criteria in Lymphoma, 110 patients had negative PET/CT2 scans, and 87 had positive PET/CT2 scans. The PET/CT2-negative patients had significantly higher 3-year progression-free survival rate(75.8% vs. 38.2%) and 3-year overall survival rate(93.5% vs. 55.6%) than PET/CT2-positive patients. All PET/CT2-negative patients remained negative at PET/CT4, but 3 were positive at F-PET/CT. Among the 87 PET/CT2-positive patients, 57 remained positive at F-PET/CT, and 32 progressed during chemotherapy(15 at PET/CT4 and 17 at F-PET/CT). Comparing PET/CT4 with PET/CT0, 7 patients exhibited progression, and 8 achieved partial remission. Comparing F-PET/CT with PET/CT0, 10 patients exhibited progression, and 7 achieved partial remission. In conclusion, our results indicate that I-PET/CT should be performed after 2 rather than 4 cycles of immunochemotherapy in DLBCL patients. There is a limited role for subsequent PET/CT in the detection of relapse in PET/CT2-negative patients, but repeat PET/CT is required if the PET/CT2 findings are positive.

Maximum standardized uptake value on PET/CT in preoperative assessment of lymph node metastasis from thoracic esophageal squamous cell carcinoma

The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer.Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate treatment and forecasting disease progression.Positron emission tomography combined with computed tomography(PET/CT)is becoming an important tool in the workup of esophageal carcinoma.Here,we evaluated the effectiveness of the maximum standardized uptake value(SUVmax)in assessing lymph node metastasis in esophageal squamous cell carcinoma(ESCC)prior to surgery.Fifty-nine surgical patients with pathologically confirmed thoracic ESCC were retrospectively studied.These patients underwent radical esophagectomy with pathologic evaluation of lymph nodes.They all had18F-FDG PET/CT scans in their preoperative staging procedures.None had a prior history of cancer.The pathologic status and PET/CT SUVmax of lymph nodes were collected to calculate the receiver operating characteristic(ROC)curve and to determine the best cutoff value of the PET/CT SUVmax to distinguish benign from malignant lymph nodes.Lymph node data from 27 others were used for the validation.A total of 323 lymph nodes including 39 metastatic lymph nodes were evaluated in the training cohort,and 117lymph nodes including 32 metastatic lymph nodes were evaluated in the validation cohort.The cutoff point of the SUVmax for lymph nodes was 4.1,as calculated by ROC curve(sensitivity,80%;specificity,92%;accuracy,90%).When this cutoff value was applied to the validation cohort,a sensitivity,a specificity,and an accuracy of 81%,88%,and 86%,respectively,were obtained.These results suggest that the SUVmax of lymph nodes predicts malignancy.Indeed,when an SUVmax of 4.1 was used instead of 2.5,FDG-PET/CT was more accurate in assessing nodal metastasis.

Qualitative visual trichotomous assessment improves the value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in predicting the prognosis of diffuse large B-cell lymphoma

Introduction:Fluorine-18 fluorodeoxyglucose(18F-FDG)positron emission tomography/computed tomography(PET/CT)is a powerful tool for monitoring the response of diffuse large B-cell lymphoma(DLBCL)to therapy,but the criteria to interpret PET/CT results remain under debate.We investigated the value of post-treatment PET/CT in predicting the prognosis of DLBCL patients when interpreted according to qualitative visual trichotomous assessment(QVTA)criteria compared with the Deauvil e criteria.Methods:In this retrospective study,final PET/CT scans of DLBCL patients treated with rituximab-based regimens between October 2005 and November 2010 were interpreted using the Deauvil e and QVTA criteria.Survival curves were estimated using Kaplan-Meier analysis and compared using the log-rank test.Results:A total of 253 patients were enrol ed.The interpretation according to the Deauvil e criteria revealed that 181patients had negative PET/CT scan results and 72 had positive results.The 3 year overal survival(OS)rate was significantly higher in patients with negative scan results than in those with positive results(91.6%vs.57.5%,P<0.001).The72 patients with positive scan results according to the Deauville criteria were divided into two groups by the interpretation according to the QVTA criteria:29 had indeterminate results,and 43 had positive results.The 3 year OS rate was significantly higher in patients with indeterminate scan results than in those with positive results(91.2%vs.33.5%,P<0.001)but was similar between patients with negative and indeterminate scan results(91.6%vs.91.2%,P=0.921).Conclusions:Compared with the Deauvil e criteria,using the QVTA criteria for interpreting post-treatment PET/CT scans of DLBCL patients is likely to reduce the number of false positive results.The QVTA criteria are feasible for therapeutic outcome evaluation and can be used to guide risk-adapted therapy.