Prognostic significance of delayed complete metabolic response on PET/CT after primary chemoradiation treatment of cervical cancer.

OBJECTIVE: To investigate the prognostic significance of near-complete metabolic response on initial follow-up PET/CT after primary chemoradiation treatment of cervical cancer. METHODS: Survival data were retrospectively compared between patients who had complete metabolic response on first follow-up PET/CT, 3 months after chemoradiation (group 1) with those who had near-complete metabolic response on first PET/CT and later showed complete metabolic response at subsequent PET/CT, 6 months or more after treatment (group 2). RESULTS: Of the 108 patients included in the final analysis, 74 (68.5%) showed complete metabolic response on initial PET/CT, 3 months after treatment, and 34 patients (31.5%) showed complete metabolic response on subsequent PET/CT, 6 months after treatment. Tumor characteristics were comparable between groups. Group 1 had higher percent of stage 1 (12% vs 0%) and lower percent of stage 4 disease (3% vs 14%) than those of group 2. Group 2 patients had significantly fewer cases of recurrences and deaths than group 1 patients (6% vs 26%, p=0.018; 0% vs 20%, p=0.003, respectively), with comparable 3-year survival rates (group 1, 90% vs group 2, 100%, p=0.31). Twelve patients had progressive disease on first follow-up PET/CT; these patients had significantly worse overall survival compared with all other patients (log-rank test, p<0.001). Younger age and delayed complete metabolic response were associated with lower chance of recurrence and death on univariate analysis. On multivariate analysis, delayed complete metabolic response remained significantly associated with no recurrence HR=0.14 (95% CI 0.25 to 0.84), p=0.031. CONCLUSIONS: Survival outcome of patients with cervical cancer who show residual 18F-fluorodeoxyglucose uptake on initial PET/CT after treatment, but reach complete metabolic response on follow-up PET/CT, is not inferior compared with survival of patients who show complete metabolic response on initial PET/CT 3 months after treatment. Watchful waiting with follow-up PET/CT seems a safe option for these patients.

Staging 68 Ga-PSMA PET/CT in 963 consecutive patients with newly diagnosed prostate cancer: incidence and characterization of skeletal involvement.

PURPOSE: The aim of the study was to elaborate the incidence and type of skeletal involvement in a large cohort of patients with newly diagnosed prostate cancer (PCa) referred for Ga-68 PSMA-11 PET/CT staging in a single center. METHODS: Study cohort included 963 consecutive patients with newly diagnosed PCa referred for Ga-68 PSMA-11 PET/CT study for staging. The incidence of bone involvement, type of bone metastases, and extent of disease were determined and correlated with the ISUP Grade Group (GG) criteria and PSA levels. RESULTS: Bone metastases were found in 188 (19.5%) of 963 patients. Bone metastases were found in 10.7% of patients with PSA < 10 ng/dL and in 27.4% of patients with PSA > 10 ng/dL and in 6.1% of patients with GG ≤ 2/3 and in 8.9% of patients with GG 4/5. In 7.6% of the patients, skeletal involvement was extensive, while 11.9% of patients had oligometastatic disease. Osteoblastic type metastases were the most common type of bone metastases presented in 133 of the patients with malignant bone involvement (70.7%). More than half of them had only osteoblastic lesions (72 patients (38.3%)), while the other (61 patients (32.5%)) had also intramedullary and/or osteolytic type lesions. Intramedullary metastases were found in 97 patients (51.6%), while 41 (21.8%) of them were only intramedullary lesions. Osteolytic metastases were detected in 36 patients (19.2%), of which 8 were only osteolytic lesions. CONCLUSION: Although traditionally bone metastases of PCa are considered osteoblastic, osteolytic and intramedullary metastases are common, as identified on PET with labeled PSMA. Skeletal spread may be present also in patients with GG ≤ 2/3 and PSA < 10 ng/dL.