No abstract

Purpose Interim positron emission tomography (PET) using the tracer, [F]fluorodeoxyglucose, may predict outcomes in patients with aggressive non-Hodgkin lymphomas. We assessed whether PET can guide therapy in patients who are treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). Patients and Methods Newly diagnosed patients received two cycles of CHOP-plus rituximab (R-CHOP) in CD20-positive lymphomas-followed by a PET scan that was evaluated using the ΔSUV method. PET-positive patients were randomly assigned to receive six additional cycles of R-CHOP or six blocks of an intensive Burkitt's lymphoma protocol. PET-negative patients with CD20-positive lymphomas were randomly assigned or allocated to receive four additional cycles of R-CHOP or the same treatment with two additional doses rituximab. The primary end point was event-free survival time as assessed by log-rank test. Results Interim PET was positive in 108 (12.5%) and negative in 754 (87.5%) of 862 patients treated, with statistically significant differences in event-free survival and overall survival. Among PET-positive patients, 52 were randomly assigned to R-CHOP and 56 to the Burkitt protocol, with 2-year event-free survival rates of 42.0% (95% CI, 28.2% to 55.2%) and 31.6% (95% CI, 19.3% to 44.6%), respectively (hazard ratio, 1.501 [95% CI, 0.896 to 2.514]; P = .1229). The Burkitt protocol produced significantly more toxicity. Of 754 PET-negative patients, 255 underwent random assignment (129 to R-CHOP and 126 to R-CHOP with additional rituximab). Event-free survival rates were 76.4% (95% CI, 68.0% to 82.8%) and 73.5% (95% CI, 64.8% to 80.4%), respectively (hazard ratio, 1.048 [95% CI, 0.684 to 1.606]; P = .8305). Outcome prediction by PET was independent of the International Prognostic Index. Results in diffuse large B-cell lymphoma were similar to those in the total group. Conclusion Interim PET predicted survival in patients with aggressive lymphomas treated with R-CHOP. PET-based treatment intensification did not improve outcome.

These initial results indicate that FET PET is a useful method to identify malignant brain lesions. It appears that high- and low-grade brain tumours exhibit a different uptake kinetics of FET. A kinetic analysis of FET PET may provide additional information in the differentiation of suspected brain lesions.

We evaluated the diagnostic value and accuracy of prostatespecific membrane antigen (PSMA) PET for the intraprostatic delineation of prostate cancer before prostatectomy. Methods: We identified 6 patients with biopsy-proven high-risk prostate cancer who were referred for 68 Ga-PSMA PET/CT before radical prostatectomy to rule out metastasis. After prostatectomy, a histologic map of the prostate was reconstructed. The histologic extent and Gleason score of each segment of the prostate were compared with 68 Ga-PSMA PET images resliced to the histologic axis. Sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratios were calculated. The SUV of each segment was measured, and median values were compared. Results: Of the 132 segments, 112 were eligible for analysis. The correlation of histologic results with 68 Ga-PSMA PET images showed a specificity and sensitivity of 92%. The positive and negative likelihood ratio and the positive and negative predictive value for detection of prostate cancer on 68 Ga-PSMA PET were 11.5, 0.09, 96%, and 85%, respectively. The median SUV max of true-positive prostate segments was significantly higher than that of true-negative segments (11.0 ± 7.8 vs. 2.7 ± 0.9, P , 0.001), and a cutoff of 4 revealed a sensitivity and specificity of 86.5% and an accuracy of 87.5%. Conclusion: These preliminary results show that the intraprostatic localization and extent of prostate cancer may be estimated by 68 Ga-PSMA PET. This imaging method may be helpful for identifying target lesions before prostate biopsy and may support decision making before focal or radical therapy.

Results from 50 therapies show that radioligand therapy with Lu-PSMA-617 is effective and well tolerated and seems to increase overall survival. A future randomized controlled prospective study will be necessary to confirm these results.