Role Of Positron Emission Tomography Imaging Research Articles

Abstract PO2-07-07: The role of PET imaging with [18F]16α-fluoro-17β-fluoroestradiol in predicting response to endocrine therapies in patients with breast cancer

Abstract Background Fluoroestradiol F18 is a radioactive diagnostic agent (18F-FES) used with positron emission tomography (PET) imaging to detect estrogen-receptor (ER)-positive lesions in patients with breast cancer. Convened by the Society of Nuclear Medicine and Molecular Imaging (SNMMI), an expert working group published appropriate use criteria (AUC) for 18F-FES PET including, but not limited to, use of 18F-FES for selection of endocrine therapies. Quantitative determination of ER status, and thus treatment response, has the potential to prevent ineffective courses of endocrine therapies and associated therapeutic/financial burden. This meta-analysis reviewed the AUC-cited studies to assess the utility of 18F-FES in predicting treatment response to endocrine therapies. Methods Eight studies cited in the AUC were selected based on having comparable 18F-FES PET standardized uptake values (SUV) and progression-free survival (PFS) measures, and one additional study was included upon further systematic search of the same selected parameters defined in the AUC. With the nine studies (n = 327), we conducted three investigations to explore the association between: (1) the patient baseline 18F-FES PET SUVmean, across all lesions or across up to seven of the most intense lesions, and patient response to endocrine therapy (response/no response); (2) in the same population as investigation 1, the change (%) in 18F-FES PET SUV from baseline to at 7 to 10 days post-treatment; (3) the 18F-FES interlesional heterogeneity and PFS (months). Interlesional heterogeneity was qualitatively defined as patients displaying both 18F-FES positive and negative lesions versus those with all FES-positive lesions. Results A fixed effects model was used to analyze three studies (n = 102). Findings reveal that patients who responded to endocrine therapy had a significantly higher baseline SUVmean versus non-responders (mean difference 0.91; CI 95% 0.49 to 1.34; P < 0.001); a sensitivity analysis was conducted via random effects modelling and revealed similar results (mean difference 0.92; CI 95% 0.48 to 1.36; P < 0.001). This was consistent with findings from an additional analysis performed on two papers (n = 62), whereby odds ratio estimates indicated that a response to therapy is 89% less likely to occur when baseline 18F-FES SUVmax is < 1.5 (OR 0.11; CI 95% 0.02 to 0.72 P = 0.02). Findings from the analysis of mean percentage change in 18F-FES SUV from baseline to 7-10 days post-treatment initiation showed no significant difference in the percentage change of SUV observed between responders and non-responders (mean difference -0.22; 95% CI -0.69 to 0.26; P = 0.37). The final heterogeneity analysis revealed higher median PFS in all FES-positive cohort, suggesting that this group may respond better to endocrine therapy (Table 1). Conclusion The AUC states that the presence of ER by immunohistochemistry may not be the optimal predictive biomarker for the success of endocrine therapies. Our findings support this statement, as a significantly higher baseline SUVmean of 18F-FES may serve as a predictive biomarker for endocrine therapy response. Patients with a 18F-FES lesion SUVmax < 1.5 are 89% less likely to respond to endocrine therapies; patients demonstrating heterogeneity (FES+/FES- lesions) have a lower median PFS, reinforcing the predictive value of 18F-FES. Table 1. Median PFS scores from FES heterogeneity analysis *Patients with all FES positive lesions were categorised by the median ratio of FES/FDG SUVmax into low FES/FDG ( <0.96), and high FES/FDG (>0.96); only patients with FES/FDG of >0.96 were included in the positive lesions arm. Citation Format: Nicholas DiGregorio, Christine Brand, Dustin Dunham, Eleanor McManus. The role of PET imaging with [18F]16α-fluoro-17β-fluoroestradiol in predicting response to endocrine therapies in patients with breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-07-07.

The Role of PET Imaging in Patients with Prion Disease: A Literature Review.

Prion diseases are rare, rapidly progressive, and fatal incurable degenerative brain disorders caused by the misfolding of a normal protein called PrPC into an abnormal protein called PrPSc. Their highly variable clinical presentation mimics various degenerative and non-degenerative brain disorders, making diagnosis a significant challenge for neurologists. Currently, definitive diagnosis relies on post-mortem examination of nervous tissue to detect the pathogenic prion protein. The current diagnostic criteria are limited. While structural magnetic resonance imaging (MRI) remains the gold standard imaging modality for Creutzfeldt-Jakob disease (CJD) diagnosis, positron emission tomography (PET) using 18fluorine-fluorodeoxyglucose (18F-FDG) and other radiotracers have demonstrated promising potential in the diagnostic assessment of prion disease. In this context, a comprehensive and updated review exclusively focused on PET imaging in prion diseases is still lacking. We review the current value of PET imaging with 18F-FDG and non-FDG tracers in the diagnostic management of prion diseases. From the collected data, 18F-FDG PET mainly reveals cortical and subcortical hypometabolic areas in prion disease, although fails to identify typical pattern or laterality abnormalities to differentiate between genetic and sporadic prion diseases. Although the rarity of prion diseases limits the establishment of a definitive hypometabolism pattern, this review reveals some more prevalent 18F-FDG patterns associated with each disease subtype. Interestingly, in both sporadic and genetic prion diseases, the hippocampus does not show significant glucose metabolism alterations, appearing as a useful sign in the differential diagnosis with other neurodegenerative disease. In genetic prion disease forms, PET abnormality precedes clinical manifestation. Discordant diagnostic value for amyloid tracers among different prion disease subtypes was observed, needing further investigation. PET has emerged as a potential valuable tool in the diagnostic armamentarium for CJD. Its ability to visualize functional and metabolic brain changes provides complementary information to structural MRI, aiding in the early detection and confirmation of CJD.

PET imaging in adaptive radiotherapy of gastrointestinal tumors.

Radiotherapy is a cornerstone in the multimodality treatment of several gastrointestinal (GI) tumors. Positron-emission tomography (PET) has an established role in the diagnosis, response assessment and (re-)staging of these tumors. Nevertheless, the value of PET in adaptive radiotherapy remains unclear. This review focuses on the role of PET in adaptive radiotherapy, i.e. during the treatment course and in the delineation process. The MEDLINE database was searched for the terms ("Radiotherapy"[Mesh] AND "Positron-Emission Tomography"[Mesh] AND one of the site-specific keywords, yielding a total of 1710 articles. After abstract selection, 27 papers were identified for esophageal neoplasms, 1 for gastric neoplasms, 9 for pancreatic neoplasms, 6 for liver neoplasms, 1 for biliary tract neoplasms, none for colonic neoplasms, 15 for rectal neoplasms and 12 for anus neoplasms. The use of PET for truly adaptive radiotherapy during treatment for GI tumors has barely been investigated, in contrast to the potential of the PET-defined metabolic tumor volume for optimization of the target volume. The optimized target definition seems useful for treatment individualization such as focal boosting strategies in esophageal, pancreatic and anorectal cancer. Nevertheless, for all GI tumors, further investigation is needed. In general, too little data are available to conclude on the role of PET imaging during radiotherapy for ART strategies in GI cancer. On the other hand, based on the available evidence, the use of biological imaging for target volume adaptation seems promising and could pave the road towards individualized treatment strategies.

Role of PET imaging for biochemical recurrence following primary treatment for prostate cancer

Prostate cancer is one of the most common cancers in men worldwide, and primary prostate cancer is typically treated with surgery, radiation, androgen deprivation, or a combination of these therapeutic modalities. Despite technical advances, approximately 30% of men will experience biochemical recurrent within 10 years of definitive treatment. Upon detection of a rise in serum prostate specific antigen (PSA), there is great need to accurately stage these patients to help guide further therapy. As a result, there are considerable efforts underway to establish the role of positron emission tomography (PET) in the diagnostic algorithm of biochemically recurrent prostate cancer. This manuscript provides an overview of PET tracers used for the detection and localization of prostate cancer in the setting of biochemical recurrence with a focus on PET tracers that are currently being used in clinical practice in the United States.

Invited Commentary

The treatment and survival of patients with early-stage lung cancer has remained relatively unchanged for the past 20 years. Despite attempts to improve survival rates in this population, few studies have shown any survival advantage for adjuvant chemotherapy in these patients. The studies that have shown a benefit have shown only modest results [1Strauss G, Herndon II J, Maddaus M, et al. Adjuvant paclitaxel plus carboplatin compared with observation in stage IB non-small-cell lung cancer: CALGB9633 with the Cancer and Leukemia Group B, Radiation Therapy Oncology Group, and North Central Cancer Treatment Group Study Groups. J Clin Oncol 26:5043–51.Google Scholar]. Okada and colleagues’ study attempts to use maximum standardized uptake values (SUVmax) on positron emission tomography (PET) scans to differentiate patients with stage I lung cancer who will benefit from adjuvant chemotherapy from those who will not [2Sasada S. Miyata Y. Tsubokawa N. Mimae T. Yoshiya T. Okada M. Role of positron emission tomography/computed tomography findings for adjuvant chemotherapy indications in stage T1b-2aN0M0 Lung Adenocarcinoma.Ann Thorac Surg. 2014; 98: 417-423Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar]. The study’s limitations are pointed out by the authors and include a nonrandomized study design, small sample size, and subjective use of adjuvant chemotherapy based on surgeon discretion. Nevertheless, the study shows an impressive survival advantage for patients with T1a tumors (> 2 cm) and those with T1b tumors who received adjuvant chemotherapy. When the groups were evaluated further, the survival advantage seemed to be limited to patients with a SUVmax greater than 2.6. Other studies have suggested that PET imaging may have prognostic value in patients with early-stage lung cancer. Shiono and colleagues [3Shiono S. Abiko M. Sato T. Positron emission tomography/computed tomography and lymphovascular invasion predict local recurrence in stage i lung cancer.J Thorac Oncol. 2011; 6: 43-47Crossref PubMed Scopus (61) Google Scholar] showed that patients with SUVmax greater than 4.7 and lymphovascular invasion had greater recurrence rates and worse disease-free survival. Likewise, Uehara and colleagues [4Uehara H. Tsutani Y. Okumura S. et al.Prognostic role of positron emission tomography and high-resolution computed tomography in clinical stage IA lung adenocarcinoma.Ann Thorac Surg. 2013; 96: 1958-1965Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar] found that SUVmax was able to predict nodal metastases, early recurrence, and survival in patients with stage I lung cancer. The role of PET imaging and adjuvant chemotherapy for stage I lung cancer remains unclear. Studies like the one by Okada and colleagues suggest that this technology could potentially be used to direct additional therapy for patients with completely resected early-stage lung cancer and improve survival. The current studies in the literature are all limited by small sample size, nonrandomized study design, and modest survival improvements; however, the data are intriguing enough to warrant a prospective trial to better evaluate the true benefit of this therapeutic approach. Role of Positron Emission Tomography/Computed Tomography Findings for Adjuvant Chemotherapy Indications in Stage T1b-2aN0M0 Lung AdenocarcinomaThe Annals of Thoracic SurgeryVol. 98Issue 2PreviewThis study aimed to determine the significance of the maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) images on postoperative adjuvant chemotherapy for lung adenocarcinoma. Full-Text PDF

The Role of PET Imaging Before, During, and After Percutaneous Hepatic and Pulmonary Tumor Ablation.

The combination of anatomic and metabolic information provided by positron emission tomography (PET)/computed tomography makes it an important imaging modality to be obtained in conjunction with percutaneous ablation of primary and secondary malignancies of the lungs and liver. Advantages include more accurate preprocedural staging to determine appropriate treatment options, intraprocedural guidance to target difficult-to-see lesions, and postprocedural detection of residual or recurrent disease. Future applications of PET include strategies for intraprocedural guidance with real-time determination of incompletely ablated tumor, and combined PET/magnetic resonance imaging before, during, and after ablation for greater sensitivity to detect disease.

Positive Positron Emission Tomography (PET) Scan in Non-Hodgkin Lymphoma Pre-Transplant Had No Impact On Relapse and Survival After Allogenenic Transplantation

AbstractAbstract 1999Allogeneic donor hematopoetic stem cell transplantation (HCT) is increasingly used for patients with non-Hodgkin lymphoma (NHL). Positron emission tomography (PET) has become a standard for lymphoma evaluation and a valuable prognostic tool to risk-stratify treatment and time of the autologous HCT. Role of PET imaging in allogeneic HCT setting is controversial.We sought to investigate the value of PET status pre-transplantation and at day 100 post donor HCT as an indicator predictive of relapse and survival post allograft.Seventy-three patients (median age 50 years [range 2–69 years]) with NHL received allogeneic HCT at University of Minnesota from 2004–2010 and had PET imaging within 4 weeks pre-transplant. All PET and CT images were reviewed centrally by nuclear medicine radiologist. Follicular lymphoma (n=26) was more common than large cell, mantle cell lymphoma and others. PET scan pre-transplant was positive in 44 patients (PET+ group 57% vs PET- group 43%). Two thirds of PET+ group were in partial remission (PR), 7% CR and 16% were chemo-refractory prior to transplant compared to 25% in PR, 68% in CR and 7% refractory in PET+ cohort (p<0.01). Forty percent had PET-avid extra-nodal involvement. In both PET positive and negative groups the two thirds received reduced intensity conditioning and related donor (52% and 51%) or umbilical cord blood grafts (55% and 41%, respectively).5-years disease-free survival (DFS) and overall survival (OS) of the cohort was 51% (95%CI 35– 64%) and 60% (95%CI 44–73%). DFS and OS of PET+ group was similar to PET- group (DFS: 50% vs 52%, p=0.31; OS: 63% vs 56%, p=0.63). In univariate analysis, the lymphoma subtype, disease status at transplant, extranodal disease, elevated LDH, high B2 macroglobulin or marrow involvement at the time of transplant had no impact on survival or relapse rate.At median follow-up of 3.33 years (range 1.00–6.74) the cumulative 2 year relapse rate was 17%; similar in PET+ and PET- groups (19% [95% CI 7– 31%] vs 15% [95% CI 1– 28%]; p=0.48). Transplant mortality at 1-year was low for entire cohort (11% [95% CI 3–18%]) and particularly low in follicular lymphoma (4% [95%CI 0–10%]) compared to DL/MCL (10% [95%CI 0–21%]) and other NHL (25% [95%CI 4–46%]; p=0.51). PET status (pos vs neg) had no impact on grade III-IV acute GVHD and chronic GVHD.Fifty-four patients with available surveillance PET evaluation at day 100 post-transplant. The 1-year relapse rate and 5 yr DFS was significantly improved for those patient who were PET-negative (day 100 PET- vs PET+ group: relapse 9% vs 42%; p<0.01; DFS 57% vs 25%, p<0.01 and OS 68% vs 59%, p=0.63).In conclusion, pre-allo HCT PET scan for NHL does not predict transplant outcomes, however negative PET scan 100 days post-allo SCT is a valuable tool predictive of superior transplant DFS. Future studies evaluating role of PET in patients with specific lymphoma subsets and development of novel peri-transplant or post-transplant interventions for patients at high relapse risk are warranted. Disclosures:Off Label Use: decitabine for relapsed ALL vorinostat for relapsed ALL.

Whither the PET Scan? The Role of PET Imaging in the Staging and Treatment of Breast Cancer

Metabolic imaging may contribute to a better knowledge of the biology of breast cancer and to new drugs development. Positron emission tomography (PET) with the radiolabeled glucose analogue 2- [18F]-fluorodeoxyglucose (18F-FDG) allows quantitative assessment of glucose utilization in tumor tissue. This technique utilizes a class of radioisotopes that decay by emitting a positron. The positron travels a short distance (1 mm) before interacting with an electron in what is called an annihilation reaction. This results in the creation of two high-energy photons that are emitted in opposite directions. The PET scanner detects such annihilation radiations and produces a three-dimensional picture of the distribution of the radiolabeled tracer. 18F-FDG PET has currently a limited role in breast cancer, due to its low sensitivity that makes it not recommended in most of the cases, especially in early disease. Potentially, the most useful application of PET/CT is monitoring the changes in 18F-FDG uptake during chemotherapy in order to detect an early response to treatment. In fact, while morphological changes due to effective chemotherapy are not detectable until late in the course of treatment, metabolic changes generally occur earlier. In this paper, we summarize the current and future applications of PET in the management of breast cancer.

The role of positron emission tomography in the evaluation of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease that affects the gastrointestinal tract. Information obtained from a clinical history, physical exam, laboratory testing, imaging studies, and endoscopic evaluations must be combined to accurately diagnose IBD. Further testing often becomes necessary to evaluate symptom relapse in patients with an established IBD diagnosis. Endoscopy, while effective in assessing mucosal disease, is invasive and associated with inherent risks. Positron emission tomography (PET) is an effective, noninvasive tool for the evaluation of active inflammation. This review will focus on the role of PET imaging in the evaluation and management of IBD.

Is there a role for positron emission tomography imaging in the early evaluation of prostate cancer relapse?

The patient population with a rising prostate specific antigen (PSA) post-therapy with no evidence of disease on standard imaging studies currently represents the second largest group of prostate cancer patients. Little information is still available regarding the specificity and sensitivity of positron emission tomography (PET) tracers in the assessment of early biochemical recurrence. Ideally, PET imaging would allow one to accurately discriminate between local vs nodal vs distant relapse, thus enabling appropriate selection of patients for salvage local therapy. The vast majority of studies show a relatively poor yield of positive scans with PSA values < 4 ng ml(-1). So far, no tracer has been shown to be able to detect local recurrence within the clinically useful 1 ng ml(-1) PSA threshold, clearly limiting the use of PET imaging in the post-surgical setting. Preliminary evidence, however, suggests that 11C-choline PET may be useful in selecting out patients with early biochemical relapse (PSA < 2 ng ml(-1)) who have pelvic nodal oligometastasis potentially amenable to local treatment. The role of PET imaging in prostate cancer is gradually evolving but still remains within the experimental realm. Well-conducted studies comparing the merits of different tracers are needed.

Blood Flow Imaging of the Brain: 50 Years Experience

Blood Flow Imaging of the Brain: 50 Years Experience