Chiara Fuccio

Influence of Trigger PSA and PSA Kinetics on 11C-Choline PET/CT Detection Rate in Patients with Biochemical Relapse After Radical Prostatectomy

The purpose of this study was to investigate the effect of total prostate-specific antigen (PSA) at the time of 11C-choline PET/CT (trigger PSA), PSA velocity (PSAvel), and PSA doubling time (PSAdt) on 11C-choline PET/CT detection rate in patients treated with radical prostatectomy for prostate cancer, who showed biochemical failure during follow-up. Methods: A total of 190 patients treated with radical prostatectomy for prostate cancer who showed an increase in PSA (mean, 4.2; median, 2.1; range, 0.2–25.4 ng/mL) were retrospectively enrolled. All patients were studied with 11C-choline PET/CT. Patients were grouped according to trigger PSA (PSA ≤ 1 ng/mL, 1 < PSA ≤ 2 ng/mL, 2 < PSA ≤ 5 ng/mL, and PSA > 5 ng/mL). In 106 patients, data were available for calculation of PSAvel and PSAdt. Logistic regression analysis was used to determine whether there was a relationship between PSA levels and PSA kinetics and the rate of detection of relapse using PET. Results: 11C-choline PET/CT detected disease relapse in 74 of 190 patients (38.9%). The detection rate of 11C-choline PET/CT was 19%, 25%, 41%, and 67% in the 4 subgroups—PSA ≤ 1 ng/mL (51 patients), 1 < PSA ≤ 2 ng/mL (39 patients), 2 < PSA ≤ 5 ng/mL (51 patients), and PSA > 5 ng/mL (49 patients)—respectively. Trigger PSA values were statistically different between PET-positive patients (median PSA, 4.0 ng/mL) and PET-negative patients (median PSA, 1.4 ng/mL) (P = 0.0001). Receiver-operating-characteristic analysis showed an optimal cutoff point for trigger PSA of 2.43 ng/mL (area under the curve, 0.76). In 106 patients, PSAdt and PSAvel values were statistically different between patients with PET-positive and -negative scan findings (P = 0.04 and P = 0.03). The 11C-choline PET/CT detection rate was 12%, 34%, 42%, and 70%, respectively, in patients with PSAvel < 1 ng/mL/y (33 patients), 1 < PSAvel ≤ 2 ng/mL/y (26 patients), 2 < PSAvel ≤ 5 ng/mL/y (19 patients), and PSAvel > 5 ng/mL/y (28 patients). The 11C-choline PET/CT detection rate was 20%, 40%, 48%, and 60%, respectively, in patients with PSAdt > 6 mo (45 patients), 4 < PSAdt ≤ 6 mo (20 patients), 2 < PSAdt ≤ 4 mo (31 patients), and PSAdt ≤ 2 mo (10 patients). There was no statistical difference between PET-positive and -negative scan detection rates according to the Gleason score, pT and N status, patient age, or duration between surgery and biochemical relapse. Trigger PSA and PSAvel were found to be independent predictive factors for a PET-positive result (P = 0.002; P = 0.04) and PSAdt was found to be an independent factor only in patients with trigger PSA less than 2 ng/mL (P = 0.05) using multivariate analysis. Conclusion: The 11C-choline PET/CT detection rate is influenced by trigger PSA, PSAdt, and PSAvel. This finding could be used to improve the selection of patients for scanning by reducing the number of false-negative scans and increasing the detection rate of disease in patients with early relapse and potentially curative disease.

Role of 11C-choline PET/CT in the re-staging of prostate cancer patients with biochemical relapse and negative results at bone scintigraphy

AIM to evaluate the utility of (11)C-choline PET/CT in prostate cancer (PC) patients who have demonstrated a biochemical recurrence and a negative bone scintigraphy (BS). MATERIALS AND METHODS 123 consecutive PC patients (mean age 67.6 years; range 54-83) with a biochemical relapse (mean PSA value 3.3ng/mL; range 0.2-25.5) after radical prostatectomy (RP) were included in our retrospective study. Patients underwent a BS that resulted negative and a (11)C-choline PET/CT within 4 months from BS (range: 1 day to 4 months; mean: 2.5 months). Validation of results was established by: (1) a positive biopsy, (2) a positive subsequent BS, CT or MR and (3) a normalization of (11)C-choline uptake after systemic therapy or a progression of the disease. RESULTS (11)C-choline PET/CT was positive in 42/123 patients (34.1%). (11)C-choline PET/CT detected lesions in: bone (10 patients), lymph-nodes (20 patients), bone and lymph nodes (7 patients), bone and lung (1 patient), lymph-nodes and lung (1 patient), local relapse (3 patients). Overall, (11)C-choline PET/CT showed a total of 30 unknown bone lesions in 18/123 (14.6%) patients. CONCLUSION (11)C-choline PET/CT showed a better sensitivity than BS in patients with biochemical relapse after RP: (11)C-choline PET/CT detected unknown bone lesions in 18/123 (14.6%) patients.

COMBINED 18F-FDG-PET/CT IMAGING IN RADIOTHERAPY TARGET DELINEATION FOR HEAD-AND-NECK CANCER

PURPOSE To evaluate the effect of the use of (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in radiotherapy target delineation for head-and-neck cancer compared with CT alone. METHODS AND MATERIALS A total of 38 consecutive patients with head-and-neck cancer were included in this study. The primary tumor sites were as follow: 20 oropharyngeal tumors, 4 laryngeal tumors, 2 hypopharyngeal tumors, 2 paranasal sinuses tumors, 9 nasopharyngeal tumors, and 1 parotid gland tumor. The FDG-PET and CT scans were performed with a dedicated PET/CT scanner in one session and then fused. Subsequently, patients underwent treatment planning CT with intravenous contrast enhancement. The radiation oncologist defined all gross tumor volumes (GTVs) using both the PET/CT and CT scans. RESULTS In 35 (92%) of 38 cases, the CT-based GTVs were larger than the PET/CT-based GTVs. The average total GTV from the CT and PET/CT scans was 34.54 cm(3) (range, 3.56-109) and 29.38 cm(3) (range, 2.87-95.02), respectively (p < 0.05). Separate analyses of the difference between the CT- and PET/CT-based GTVs of the primary tumor compared with the GTVs of nodal disease were not statistically significant. The comparison between the PET/CT-based and CT-based boost planning target volumes did not show a statistically significant difference. All patients were alive at the end of the follow-up period (range, 3-38 months). CONCLUSION GTVs, but not planning target volumes, were significantly changed by the implementation of combined PET/CT. Large multicenter studies are needed to ascertain whether combined PET/CT in target delineation can influence the main clinical outcomes.

Choline PET/CT for prostate cancer: Main clinical applications

Several studies investigated the potential roles of imaging modalities in prostate cancer patients for the evaluation of intra-prostatic disease, stage and restage. However no precise guidelines exist about the use of imaging modalities, in particular about the role of PET/CT hybrid imaging. Considering the results of the literature and our experience, we tried to summarize the main applications of choline positron emission tomography (PET) in prostate cancer patients. The use of choline PET/CT for initial diagnosis and staging is not recommended as a first-line method. Instead the main and important application of choline PET/CT is represented by the restaging of the disease in case of biochemical relapse for the detection of lymph node and distant recurrence. In particular choline PET/CT could play a crucial role as first diagnostic procedure in prostate cancer patients who show a fast growing Prostate Specific Antigen (PSA) kinetics.

The role of 11C-choline PET imaging in the early detection of recurrence in surgically treated prostate cancer patients with very low PSA level <0.5 ng/mL.

Purpose This study aims to evaluate the role of 11C-choline PET/CT in patients with biochemical relapse after radical prostatectomy (RP) showing prostate-specific antigen (PSA) values lower than 0.5 ng/mL. Methods We performed 11C-choline PET/CT in 71 consecutive patients previously treated with RP showing PSA values lower than 0.5 ng/mL. 11C-Choline PET/CT was performed following standard procedure. 11C-Choline PET/CT–positive findings were validated by transrectal ultrasonography + biopsy, repeated 11C-choline PET/CT, other conventional imaging modality, and histology. Results 11C-Choline PET/CT was true positive in 15/71 (21.1%). 11C-Choline uptake was observed in pelvic lymph nodes (7/71; 9.9%), in the prostatic bed (7/71; 9.9%), and in bone (1/71; 1.4%). Mean PSA, PSA doubling time (PSAdt), and PSA velocity (PSAvel) values ± SD in 11C-choline PET/CT–positive patients was 0.37 ± 0.1 ng/mL, 3.4 ± 2.1 months, and 0.05 ± 0.1 ng/mL/yr, respectively. 11C-Choline PET/CT was false negative in 2 patients and false positive in 1 patient. Among all variables, only PSAdt and the ongoing hormonal treatment were statistically significant in the prediction of a positive 11C-choline PET/CT at multivariate analysis. Conclusions 11C-Choline PET/CT could be used early after biochemical failure even if PSA values are very low, preferentially in hormonal resistant patients showing fast PSA kinetics. An early detection of the site of relapse could lead to a personalized and tailored treatment.

Incidence of Increased 68Ga-DOTANOC Uptake in the Pancreatic Head in a Large Series of Extrapancreatic NET Patients Studied with Sequential PET/CT

The aim of our retrospective study was to assess the incidence of increased uptake of 68Ga-DOTANOC in the head of the pancreas among a large population of patients with extrapancreatic neuroendocrine tumors studied with serial 68Ga-DOTANOC PET/CT. Methods: Patients who had undergone at least two 68Ga-DOTANOC PET/CT studies over time were included. Uptake in the head of the pancreas was measured and compared with uptake in normal liver parenchyma (target-to-liver ratio). Patients were followed up for 6–24 mo. Results: We reviewed 245 studies performed on 100 patients and classified the pancreatic uptake as either diffuse or focal. Twenty-three patients (66 scans) showed diffuse uptake; 8 patients (16 scans) showed focal uptake. None of these 31 patients had negative findings on their subsequent scans, and vice versa. During follow-up, localization of neuroendocrine tumors in the pancreas was not suspected in any patient. Conclusion: Focal and diffuse uptake of 68Ga-DOTANOC in the head of the pancreas occurred, respectively, in 23% and 8% of the patients. The main finding of our study was that increased pancreatic uptake was stable over time.

Restaging clear cell renal carcinoma with 18F-FDG PET/CT.

Aim The aim of our retrospective study was to assess the usefulness of 18F-FDG PET/CT in the restaging of clear cell renal cell carcinoma (RCC) patients. Patients and Methods Sixty-nine patients (median age = 62 years; range = 36–86 years) affected by clear cell RCC (TNM at staging: T1, 42 patients; T2, 13 patients; T3, 11 patients; T4, 3 patients; Fuhrman grade: G2, 47 patients; G3, 20 patients; G4, 2 patients) underwent whole-body 18F-FDG PET/CT to restage the disease after nephrectomy for clinical or radiological suspicion of metastases. Areas of abnormal uptake at PET/CT were classified, taking the liver uptake as reference, as follows: 1 = faint uptake, lower than liver; 2 = moderate uptake, equal to liver; and 3 = high uptake, higher than liver. Validation of 18F-FDG PET/CT results was established by (1) biopsy (23 patients) and (2) other imaging modalities (addressed BS; c.e.CT; MRI; 18F-fluoride PET/CT; subsequent 18F-FDG PET/CT), and/or clinical and radiological follow-up of 12 months (46 patients). Results 18F-FDG PET/CT was positive in 42 patients and negative in 27 patients. Sixteen patients presented single lesions and 26 patients presented multiple localizations of the disease. On a patient basis, 40 patients resulted true positive, 2 patient false positive, 23 patients true negative, and 4 patients false negative. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 90%, 92%, 91%, 95%, and 85%, respectively. On a lesion basis, PET/CT detected 114 areas of abnormal uptake in 42 positive patients of which 112 resulted to be true positive. FDG uptake of the true positive lesions resulted to be high in 83 cases, moderate in 17 lesions, and finally faint in 12 lesions. Conclusions 18F-FDG PET/CT demonstrated a good sensitivity in the restaging of clear cell RCC. Most of the lesions showed intense activity. According to our results, it seems that the use of 18F-FDG PET/CT in the restaging of RCC is feasible because the number of false-negative cases is limited.

11C-choline PET/CT scan in patients with prostate cancer treated with intermittent ADT: a sequential PET/CT study.

Aim The purpose of this preliminary study was to evaluate the usefulness of 11C-choline PET/CT in patients with recurrent prostate cancer and hormone-sensitive disease treated with intermittent antiandrogen therapy scheme. Patients and Methods We retrospectively evaluated 10 patients after radical prostatectomy (n = 8) or external beam radiotherapy (n = 2) as primary therapy, studied with sequential 11C-choline PET/CT. The first PET/CT (PET1) was performed during antiandrogen therapy (ADT) and the second PET/CT (PET2) was performed after therapy interruption. Only patients with negative results at PET1 were included in the study. At the time of PET1, all patients were under ADT from at least 6 months (mean PSA 0.54 ng/mL). At the time of PET2, all patients had completed ADT for a mean period of 7 months. 11C-Choline PET/CT findings were validated by a follow-up of at least 12 months or histological confirmation in case of local relapse. Results PET2 has been able to detect the site of recurrences in all cases. At the time of PET2, mean PSA was 3.88 ng/mL; mean PSAdt was 2.46 months; and mean PSAvel was 6.94 ng/mL/year. Four out of 10 patients showed a single lesion, 5 out of 10 patients showed 2 lesions and 1 patient showed multiple lymph-node lesions. Conclusion When performed during ADT interruption, 11C-choline PET/CT has been able to detect the site of recurrence in patients with increasing PSA values. In this context, 11C-choline PET/CT may help to assess the burden of disease or to change the therapeutic approach using more aggressive and addressed therapies like guided RT or salvage lymph-node dissection.

Noninvasive and invasive staging of ovarian cancer: review of the literature.

The use of F-18 FDG PET/CT in the characterization of doubtful adnexal findings and in the staging of ovarian cancer is being extensively evaluated. The purpose of our article is to review the literature and to add our experience to the published works. We concluded that F-18 FDG PET/CT could represent an important method in addition to other imaging modalities (transvaginal ultrasound-, and contrast-enhanced computed tomography) in the characterization of adnexal masses and in the staging of ovarian cancer patients, particularly in assessing the presence of extra-abdominal metastatic spread.

Prostate-specific antigen kinetics and choline PET/CT in patients with biochemical relapse after primary treatment for prostate cancer.

Over the past few years, several studies have proved the potential role of diagnostic procedures in patients with treated prostate cancer who develop biochemical relapse. Notably, no precise indications exist regarding the use of emerging modalities such as positron emission tomography/computerized tomography (PET/CT) scanning with radiolabeled choline. However, the literature suggests that the main and most important application of choline PET/CT at present is in disease restaging in cases of biochemical relapse for the detection of local, lymph node-related or distant recurrence. In this setting, it is well known that prostate-specific antigen (PSA) values play a significant role in the follow-up of these patients. This short review aims at summarizing the results of the most relevant published studies with particular interest directed towards a better understanding of the relationship between PSA kinetics and choline PET/CT detection rate and the potential use of PSA kinetics for an optimal selection of patients who may benefit most from this diagnostic procedure particularly at an early stage of biochemical recurrence.