Marko Seppänen

A prospective diagnostic accuracy study of 18F-fluorodeoxyglucose positron emission tomography/computed tomography, multidetector row computed tomography, and magnetic resonance imaging in primary diagnosis and staging of pancreatic cancer.

Objective:To prospectively compare the accuracy of combined positron emission tomography/computed tomography using 18F-fluorodeoxyglucose (FDG-PET/CT), multidetector row computed tomography (MDCT), and magnetic resonance imaging (MRI) in the evaluation of patients with suspected pancreatic malignancy. Summary Background Data:FDG-PET/CT imaging is increasingly used for staging of pancreatic cancer. Preliminary data suggest a significant influence of FDG-PET/CT on treatment planning, although its role is still evolving. Methods:Thirty-eight consecutive patients with suspicion of pancreatic malignancy were enrolled. Patients underwent a protocol including FDG-PET/CT, MDCT, and MRI combined with magnetic resonance cholangiopancreatography, all of which were blindly evaluated. The findings were confirmed macroscopically at operation and/or by histopathologic analysis (n = 29) or follow-up (n = 9). Results of TNM classification of different imaging methods were compared with clinical TNM classification. Results:Pancreatic adenocarcinoma was diagnosed in 17 patients, neuroendocrine tumor in 3, mass-forming pancreatitis in 4, cystic lesion in 6, and fibrosis in 2. Six patients had a finding of a normal pancreas. The diagnostic accuracy of FDG-PET/CT for pancreatic malignancy was 89%, compared with 76% and 79% for MDCT and MRI, respectively. In the differential diagnosis of suspected malignant biliary stricture at endoscopic retrograde cholangiopancreaticography (n = 21), FDG-PET/CT had a positive predictive value of 92%. In 17 patients with advanced pancreatic adenocarcinoma, FDG-PET/CT had a sensitivity of 30% for N- and 88% for M-staging. Both MDCT and MRI had sensitivities of 30% for N- and 38% for M-staging. Furthermore, the clinical management of 10 patients (26%) was altered after FDG-PET/CT. Conclusion:FDG-PET/CT was more sensitive than conventional imaging in the diagnosis of both primary pancreatic adenocarcinoma and associated distant metastases. In contrast, the sensitivity of FDG-PET/CT was poor in detecting local lymph node metastasis, which would have been important for an assessment of resectability. We recommend the use of FDG-PET/CT in the evaluation of diagnostically challenging cases, especially in patients with biliary strictures without evidence of malignancy in conventional imaging.

18F-EF5: A New PET Tracer for Imaging Hypoxia in Head and Neck Cancer

The aim of this study was to evaluate 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide (EF5) labeled with 18F-fluorine to image hypoxia in patients with squamous cell carcinoma of the head and neck (HNSCC). Methods: Fifteen patients with HNSCC were studied. Measurement of tumor blood flow was followed by an 18F-EF5 PET/CT scan. On a separate day, 18F-FDG PET/CT was performed to determine the metabolically active tumor volume. In 6 patients, dynamic 18F-EF5 images of the head and neck area were acquired, followed by static images acquired at 1, 2, and 3 h after injection. In the remaining 9 patients, only static images were obtained. 18F-EF5 uptake in tumors was compared with that in neck muscle, and the 18F-EF5 findings were correlated with the 18F-FDG PET/CT studies. Results: A total of 13 primary tumors and 5 lymph node metastases were evaluated for their uptake of 18F-EF5. The median tumor-to-muscle 18F-EF5 uptake ratio (T/M) increased over time and was 1.38 (range, 1.1–3.2) 3 h after tracer injection. The median blood flow in tumors was 36.7 mL/100 g/min (range, 23.3–78.6 mL/100 g/min). Voxel-by-voxel analysis of coregistered blood flow and 18F-EF5 images revealed a distinct pattern, resulting in a T/M of 1.5 at 3 h to be chosen as a cutoff for clinically significant hypoxia. Fourteen of 18 tumors (78%) had subvolumes within the metabolically active tumor volumes with T/M greater than or equal to 1.5. Conclusion: On the basis of these data, the potential of 18F-EF5 to detect hypoxia in HNSCC is encouraging. Further development of 18F-EF5 for eventual targeting of antihypoxia therapies is warranted.

Decreased Blood Flow with Increased Metabolic Activity: A Novel Sign of Pancreatic Tumor Aggressiveness

Purpose: To study blood flow (BF) and metabolism in normal pancreas and in different pancreatic lesions. We then determined the effect of these biomarkers on outcome in patients with pancreatic cancer. Experimental Design: Oxygen-15–labeled water and fluorodeoxyglucose positron emission tomography/computed tomography scans were used in 26 patients with a suspicion of pancreatic cancer to measure pancreatic BF and metabolism. In addition, the ratio of standardized uptake value to BF (SUV/BF) was calculated. Patients were divided into three groups: patients with a finding of normal pancreas (n = 7), benign lesions (n = 8), and malignant tumors (n = 11). Results: Patients with benign and malignant pancreatic tumors had decreased BF of the lesion by 48% and 60%, respectively, compared with patients with normal pancreatic tissue. SUVmax was 3-fold higher in malignant tumors compared with both benign lesions and normal pancreas (P < 0.05). In contrast, the SUVmax of patients with benign lesions and normal pancreas did not differ. The SUV/BF ratio was significantly higher in malignant lesions than in benign lesions or in patients with normal pancreas (P < 0.05). In patients with cancer, high SUV/BF ratio was a stronger predictor of poor survival compared with high metabolism or lower-than-normal pancreatic BF. Conclusions: BF in pancreatic cancer is significantly reduced compared with the normal pancreas, which may in part explain the poor success of both radiotherapy and chemotherapy. We suggest that the composite measurement of BF and metabolism in pancreatic cancer could serve as a novel tool in the planning of treatments targeting vasculature. (Clin Cancer Res 2009;15(17):5511–7)

Boron Neutron Capture Therapy in the Treatment of Locally Recurred Head-and-Neck Cancer: Final Analysis of a Phase I/II Trial

PURPOSE To investigate the efficacy and safety of boron neutron capture therapy (BNCT) in the treatment of inoperable head-and-neck cancers that recur locally after conventional photon radiation therapy. METHODS AND MATERIALS In this prospective, single-center Phase I/II study, 30 patients with inoperable, locally recurred head-and-neck cancer (29 carcinomas and 1 sarcoma) were treated with BNCT. Prior treatments consisted of surgery and conventionally fractionated photon irradiation to a cumulative dose of 50 to 98 Gy administered with or without concomitant chemotherapy. Tumor responses were assessed by use of the RECIST (Response Evaluation Criteria in Solid Tumors) and adverse effects by use of the National Cancer Institute common terminology criteria version 3.0. Intravenously administered L-boronophenylalanine-fructose (400 mg/kg) was administered as the boron carrier. Each patient was scheduled to be treated twice with BNCT. RESULTS Twenty-six patients received BNCT twice; four were treated once. Of the 29 evaluable patients, 22 (76%) responded to BNCT, 6 (21%) had tumor growth stabilization for 5.1 and 20.3 months, and 1 (3%) progressed. The median progression-free survival time was 7.5 months (95% confidence interval, 5.4-9.6 months). Two-year progression-free survival and overall survival were 20% and 30%, respectively, and 27% of the patients survived for 2 years without locoregional recurrence. The most common acute Grade 3 adverse effects were mucositis (54% of patients), oral pain (54%), and fatigue (32%). Three patients were diagnosed with osteoradionecrosis (each Grade 3) and one patient with soft-tissue necrosis (Grade 4). Late Grade 3 xerostomia was present in 3 of the 15 evaluable patients (20%). CONCLUSIONS Most patients who have inoperable, locally advanced head-and-neck carcinoma that has recurred at a previously irradiated site respond to boronophenylalanine-mediated BNCT, but cancer recurrence after BNCT remains frequent. Toxicity was acceptable. Further research on novel modifications of the method is warranted.

Pulmonary hemodynamics after synthetic surfactant replacement in neonatal respiratory distress syndrome

To evaluate the acute effects of surfactant replacement therapy on pulmonary circulation in neonatal respiratory distress syndrome, we studied 25 infants before and for 1 hour after either synthetic surfactant administration (n = 15) or endotracheal suctioning (n = 10). The noninvasive Doppler method was used to estimate systolic pulmonary artery pressure from tricuspid regurgitant flow velocity and to measure blood flow velocity of the left-to-right shunt through the ductus arteriosus. Pulmonary artery pressure decreased significantly within 15 minutes after surfactant administration and remained low throughout the study period, whereas suctioning did not change pulmonary artery pressure levels. No changes in systemic pressure were found in either group. Velocity of the ductal left-to-right shunting increased and remained elevated for 1 hour only in surfactant-treated infants. In addition, right-to-left ductal shunting disappeared in four infants after surfactant administration. Our data thus indicate that administration of synthetic surfactant to infants with respiratory distress syndrome reduces pulmonary vascular resistance, resulting in a decrease in pulmonary artery pressure and an increase in ductal flow velocity.

The clinical value of [18F]-fluoro-dihydroxyphenylalanine positron emission tomography in primary diagnosis, staging and restaging of neuroendocrine tumors

The study was set up to determine the clinical value of dihydroxyphenylalanine positron emission tomography-computed tomography ([(18)F]DOPA PET-CT) in patients with neuroendocrine tumors (NETs). Eighty-two patients with suspected/known NET were imaged with PET(-CT) using [(18)F]DOPA. Patients were divided into two groups: primary diagnosis/staging and restaging of disease. All patients without previous diagnosis of NET had biochemical proof of disease. The diagnostic accuracy of PET was assessed by comparing the histopathology and clinical follow-up. The overall accuracy of [(18)F]DOPA PET was 90%. In patients having PET for primary diagnosis/staging (n=32), the accuracy of PET was 88%, and for restaging 92% (n=61). The mean s.d. sizes of primary and metastatic lesions detected by PET were 26+/-11 and 16+/-9 mm respectively. In organ-region-specific analysis, the sensitivity and specificity were 100% in the primary diagnosis of pheochromocytoma (n=16) and metastases were found in all cases with recurrent disease (n=5). The accuracy for NET of gastrointestinal tract was 92% in restaging (n=24). For the NETs located in the head-neck-thoracic region (n=19), the overall accuracy of PET was 89% including 12 cases of recurrent medullary thyroid cancer with a sensitivity of 90%. In analysis of patients with biochemical proof of disease combined with negative conventional imaging methods, PET had positive and negative predictive value of 92% and 95% respectively. [(18)F]DOPA PET-CT provided important additional information in the diagnosis of pheochromocytoma and restaging of known NET. Both in primary diagnosis and in patients with formerly known NET and increasing tumor markers, [(18)F]DOPA PET-CT is a sensitive first-line imaging method.

Carbon-11 acetate PET/CT based dose escalated IMRT in prostate cancer

PURPOSE To demonstrate the theoretical feasibility of [(11)C]acetate PET/CT in delineating the malignant intraprostatic lesions (IPLs) in prostate cancer and to use the data in external beam radiotherapy to boost the biologically defined target volume (BTV). METHODS AND MATERIALS Twelve men with intracapsular prostate carcinoma were imaged with [(11)C]acetate PET/CT and the data were used to delineate the BTV. Six dynamic IMRT plans were generated to each patient: a standard IMRT (sIMRT) plan with a 77.9 Gy dose to PTV (prostate gland with a 6-mm margin) and a simultaneous integrated boost IMRT (SIB(IMRT)) plan to deliver 77.9 Gy, 81 Gy, 84 Gy, 87 Gy and 90 Gy to the BTV and 72 Gy to the rest of PTV. To study the theoretical dose escalation based on the delineation of BTV, tumor control probabilities (TCPs) and normal tissue complication probabilities (NTCPs) of bladder and rectum were calculated and compared between the treatment plans. RESULTS [(11)C]Acetate was used to delineate the IPLs of all 12 patients. With every patient the TCP was increased with SIB(IMRT) without increasing the NTCP of the bladder or rectum. The probability of uncomplicated control (PUC) was increased on average by 28% with the SIB(IMRT) treatment plans. The highest PUC was achieved with an average dose of 82.1 Gy to the BTV. CONCLUSIONS Our study indicates that [(11)C]acetate can be used to define the IPLs and in combination with SIB(IMRT) the defined areas can theoretically be treated to ultra high doses without increasing the treatment toxicity. These results motivate the formal validation of [(11)C]acetate PET for biological dose planning in prostate cancer.

Prospective evaluation of planar bone scintigraphy, SPECT, SPECT/CT, 18F-NaF PET/CT and whole body 1.5T MRI, including DWI, for the detection of bone metastases in high risk breast and prostate cancer patients: SKELETA clinical trial

Purpose. Detection of bone metastases in breast and prostate cancer patients remains a major clinical challenge. The aim of the current trial was to compare the diagnostic accuracy of 99mTc-hydroxymethane diphosphonate (99mTc-HDP) planar bone scintigraphy (BS), 99mTc-HDP SPECT, 99mTc-HDP SPECT/CT, 18F-NaF PET/CT and whole body 1.5 Tesla magnetic resonance imaging (MRI), including diffusion weighted imaging, (wbMRI+DWI) for the detection of bone metastases in high risk breast and prostate cancer patients. Material and methods. Twenty-six breast and 27 prostate cancer patients at high risk of bone metastases underwent 99mTc-HDP BS, 99mTc-HDP SPECT, 99mTc-HDP SPECT/CT, 18F-NaF PET/CT and wbMRI+DWI. Five independent reviewers interpreted each individual modality without the knowledge of other imaging findings. The final metastatic status was based on the consensus reading, clinical and imaging follow-up (minimal and maximal follow-up time was 6, and 32 months, respectively). The bone findings were compared on patient-, region-, and lesion-level. Results. 99mTc-HDP BS was false negative in four patients. In the region-based analysis, sensitivity values for 99mTc-HDP BS, 99mTc-HDP SPECT, 99mTc-HDP SPECT/CT, 18F-NaF PET/CT, and wbMRI+DWI were 62%, 74%, 85%, 93%, and 91%, respectively. The number of equivocal findings for 99mTc-HDP BS, 99mTc-HDP SPECT, 99mTc-HDP SPECT/CT, 18F-NaF PET/CT and wbMRI+DWI was 50, 44, 5, 6, and 4, respectively. Conclusion. wbMRI+DWI showed similar diagnostic accuracy to 18F-NaF PET/CT and outperformed 99mTc-HDP SPECT/CT, and 99mTc-HDP BS.

FDG PET/CT in staging of advanced epithelial ovarian cancer: Frequency of supradiaphragmatic lymph node metastasis challenges the traditional pattern of disease spread

OBJECTIVE Epithelial ovarian cancer (EOC) spreads intra-abdominally and to the retroperitoneal lymph nodes. A greater number of distant metastases are revealed by (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) compared to conventional imaging methods. We aimed to investigate the presence and anatomic distribution of supradiaphragmatic lymph node metastasis (LNM) detected with pretreatment FDG PET/CT. METHODS Thirty women with advanced stage (IIC-IV) EOC were scanned with whole body contrast-enhanced FDG PET/CT prior to surgery/neoadjuvant chemotherapy. We performed PET/CT analysis qualitatively and quantitatively. Additionally, contrast-enhanced CT was analyzed blinded to PET/CT scan. Intra-abdominal dissemination was verified by surgery and histopathology. Metabolically active lymph nodes were biopsied when possible. The clinical characteristics of patients with and without supradiaphragmatic LNM were compared. RESULTS In 20/30 patients (67%) FDG PET/CT detected supradiaphragmatic LNM in one or more locations, whereas conventional CT found LNM in 10 patients (33%). Fourteen patients had parasternal, 14 cardiophrenic, 8 other mediastinal, 6 axillar, and 1 subclavian LNM. Microscopy of all four biopsied lymph nodes (three axillar and one subclavian) confirmed metastatic dissemination. The patients with supradiaphragmatic LNM had significantly more ascites (p<0.01), higher CA 125 levels, and more frequent subdiaphragmal carcinomatosis (p<0.03) compared to patients without supradiaphragmatic LNM in preoperative FDG PET/CT. CONCLUSIONS A significant number of patients with advanced EOC showed supradiaphragmatic LNM in pre-treatment PET/CT. Our findings suggest that the route of EOC cells from the peritoneal cavity to the lymphatic system permeates the diaphragm mainly to the cardiophrenic and continues to parasternal lymph nodes.

A prospective comparison of integrated FDG-PET/contrast-enhanced CT and contrast-enhanced CT for pretreatment imaging of advanced epithelial ovarian cancer.

OBJECTIVE The use of tumor debulking surgery in the management of epithelial ovarian cancer (EOC), which is often disseminated in the peritoneal cavity at the time of diagnosis, has a significant impact on prognosis. We compared (18)F-fluorodeoxyglucose (FDG) positron emission tomography/contrast-enhanced computed tomography (PET/CT) to contrast-enhanced CT for the detection of dissemination into the abdominal cavity preventing successful primary debulking surgery. METHODS Forty-one women with EOC underwent preoperative whole-body low-dose FDG-PET/CT followed by diagnostic high dose contrast-enhanced CT scan, and the results were compared with systematically recorded surgical findings as a reference standard. Both site-based and patient-based analyses were conducted. RESULTS FDG-PET/CT was superior to conventional CT for the detection of carcinomatosis in subdiaphragmatic peritoneal surfaces (p=0.020) and in the bowel mesentery (p=0.001). Patient-based analysis of upper abdominal areas requiring extensive surgical procedures showed no significant differences between the two imaging methods. The sensitivity of PET/CT and CT was poor in certain areas of the peritoneal cavity (64% vs. 27% in the small bowel mesentery and 65% vs. 55% in the right upper abdomen). Extra-abdominal disease spread was detected by PET/CT in 32 patients and by CT in 25 patients. CONCLUSIONS PET/CT was not superior to CT for the detection of intra-abdominal disease spread. Patients with suspected EOC should be referred for upfront radical surgery regardless of the results of preoperative imaging studies. PET/CT is more effective for the detection of extra-abdominal disease than CT, but the clinical significance of this finding is unclear.