Personalised PET imaging in oncology: an umbrella review of meta-analyses to guide the appropriate radiopharmaceutical choice and indication

PURPOSE

For several years, oncological positron emission tomography (PET) has developed beyond 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG). This umbrella review of meta-analyses aims to provide up-to-date, comprehensive, high-level evidence to support appropriate referral for a specific radiopharmaceutical PET/computed tomography (CT) or PET/magnetic resonance (MR) in the diagnosis and staging of solid cancers other than brain malignancies.

METHODS

We performed a systematic literature search on the PubMed/MEDLINE and EMBASE databases for meta-analyses assessing the accuracy of PET/CT and/or PET/MRI with [18F]FDG, somatostatin- receptor-targeting 68Ga-DOTA-peptides, 18F-labelled dihydroxyphenylalanine ([18F]DOPA), prostate-specific membrane antigen (PSMA)-targeted radioligands, and fibroblast activation protein inhibitors (FAPI) in the diagnosis/disease characterisation and staging of solid cancers other than brain tumours.

RESULTS

The literature search yielded 449 scientific articles. After screening titles and abstracts and applying inclusion and exclusion criteria, we selected 173 meta-analyses to assess the strength of evidence. One article was selected from references. Sixty-four meta-analyses were finally considered. The current evidence corroborates the role of [18F]FDG as the main player in molecular imaging; PSMA tracers are useful in staging and re-staging prostate cancer; somatostatin-targeting peptides (e.g. [68Ga]Ga- DOTA-TOC and -TATE) or [18F]DOPA are valuable in neuroendocrine tumours (NETs). FAPI has emerged in gastric cancer assessment. According to search and selection criteria, no satisfactory meta-analysis was selected for the diagnosis/detection of oesophageal cancer, the diagnosis/detection and N staging of small cell lung cancer and hepatic cell carcinoma, the diagnosis/detection and M staging of melanoma and Merkel cell carcinoma, cervical, vulvar and penis cancers, the N and M staging of lung and gastroenteropancreatic NET, testicular cancer, and chondrosarcoma, and the M staging of differentiated thyroid, bladder and anal cancers.

CONCLUSION

The comprehensive high-level evidence synthesised in the present umbrella review serves as a guiding compass for clinicians and imagers, aiding them in navigating the increasingly intricate seascape of PET examinations.

Role of 18F-Fluorodeoxyglucose Positron Emission Tomography in Children With Germ Cell Tumor After Chemotherapy

BACKGROUND/AIM

18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a diagnostic tool widely used in adult oncology and some pediatric oncological settings. There are no established recommendations for the use of this imaging modality in pediatric malignant germ cell tumors (mGCT), however. Our aim is to evaluate the role of 18F-FDG PET/CT in the restaging of mGCT after chemotherapy in children and adolescents.

METHODS

We retrospectively reviewed patients with mGCT treated in Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) centers who underwent 18F-FDG PET/CT between 2011 and 2021.

RESULTS

Seventeen patients (median age 13 y) were included in the study. In 14 patients, 18F-FDG PET/CT was performed at diagnosis; 12 showed pathologic uptake. The 2 18F-FDG PET/CT negative cases were histologically defined as yolk sac tumor (YST) and mixed (chorioncarcinoma, YST). Nine of the 12 patients who had pathologic 18F-FDG PET/CT at diagnosis repeated the examination after neoadjuvant chemotherapy, before, second look surgery. In 5 cases, no pathologic uptake was evident. Histology showed necrosis alone in 4 cases and necrosis and mature teratoma in 1. In 3 of the 6 cases with pathologic uptake (2 of 6 patients did not perform the examination at diagnosis), histology showed persistence of malignant component, whereas in the remaining 3 cases, necrosis and mature teratoma were present.

CONCLUSION

In our review of a series of children with mGCT, 18F-FDG PET/CT after neoadjuvant chemotherapy showed 1 of 5 false negatives and was unable to discriminate between residual malignant component and mature teratoma.

Peripubertal Presentation of Metastatic Testicular Mixed, Nonseminomatous Germ Cell Tumor

Testicular tumors are relatively rare in children and those in prepubertal children tend to present with different histological types and behaviors than their postpubertal counterparts. The majority of these pre- and peripubertal testicular tumors tend to be benign and those that are malignant, tend to present at low stages, not generally requiring systemic treatment. Here we present a rare case of a peri-pubertal, mixed nonseminomatous germ cell tumor of the testes which was found to be widely metastatic at presentation, classifying as poor risk disease.

The evolution of PET imaging in renal, bladder, upper urinary tract urothelial, testicular and penile carcinoma - Today's impact, tomorrow's potential

INTRODUCTION

The advancement of hybrid PET/CT or PET/MRI imaging for non-prostate genitourinary cancers has not experienced the rapid progress of prostate cancer. Nevertheless, these neoplasms are aggressive and reliable imaging plays a pivotal role in enhancing patients' quality of life and prognosis.

AREAS COVERED

the main evidence regarding [18F]FDG and non-[18F]FDG PET/CT or PET/MRI in non-prostate uro-oncological malignancies are summarized and discussed. Moreover, potential future directions concerning PET imaging in these neoplasms are debated, with the aim to stimulate future research projects covering these fields.

EXPERT OPINION

In Renal Cell Carcinoma (RCC), [18F]FDG PET/CT demonstrates varying efficacy in staging, restaging, and prognostic stratification, but PSMA PET/CT is emerging as a potential game-changer, particularly in advanced, high-grade aggressive clear cell RCC. [18F]FDG PET/CT may see an increased use in N and M-staging of bladder cancer, as well as for detecting recurrence and response to neoadjuvant chemotherapy. Preliminary data regarding [68Ga]-FAPI also looks promising in this context. [18F]FDG PET/MRI could be useful for the T-staging of bladder cancer, while upper tract urothelial carcinoma still lacks of molecular imaging literature reports. In testicular and penile cancer [18F]FDG PET/CT has demonstrated its usefulness in several clinical settings, although experiences with non-[18F]FDG radiotracers are lacking.

[Testicular and penile cancer-survival and quality of life : New guideline and network for second opinions]

Testicular cancer occupies a special position in several respects. Although it belongs to the group of rare tumors, which is why extensive experience in treating this tumor can not be guaranteed, interdisciplinary experts collaboration and the consequent implementation of clinical studies have resulted in standardized treatment recommendations. Because testicular cancer is one of the most curable cancers, long-term toxicity and treatment sequelae are of special importance. In the early stages, toxicity could be reduced by minimizing therapy to the extent possible, but without decreasing treatment success. Nevertheless, treatment is still controversially discussed, especially concerning treatment of stage I disease. Finally particular focus should be paid to non-germinal tumors which are even more rare, but partly also more dangerous. Therefore known facts should be made available for the broad medical community. In penile cancer, which is also a very rare tumor entity, organ-sparing surgery and consequent invasive lymph node staging are mandatory.

PET/CT limitations and pitfalls in urogenital cancers

Hybrid FDG PET/CT plays a vital role in oncologic imaging and has been widely adopted for the staging and restaging of a variety of malignancies. Its diagnostic value in urogenital malignancies is less well-known, not at least because of the variable FDG avidity of these tumor entities, the sites of these tumors, and technical challenges associated with sequential imaging of CT and PET. PET/CT interpretation thus can be especially challenging and is associated with many pitfalls, which can lead to both false-positive and false-negative diagnoses as well as incorrect assessment of metabolic change following therapy. Currently, FDG PET/CT is not the standard of care for the initial diagnosis or staging of early-stage or low-risk urogenital cancers; however, it can help evaluate distant metastatic disease, response to therapy, and disease recurrence in high-risk patients. Knowledge of imaging features of tumor metabolic avidity and pitfalls is essential for accurate interpretation.

Multimodality Radiological Pictorial Review of Testicular Carcinoma: From Initial Staging to Restaging

With an overall 5-year survival rate >95%, patients with testicular cancer have a great prognosis. Although initial diagnosis is based on clinical examination, imaging does play a significant role in the diagnosis and prognosis of testicular cancer, which are dependent on tumor burden and staging. Successful treatment requires appropriate disease assessment throughout a patient’s treatment: evaluating treatment response, restaging, and monitoring for disease recurrence after treatment completion. Ultrasound is usually the initial screening modality for painless testicular masses, and computedtomography (CT) the most commonly used for staging and restaging. However, with regard to seminomas, positron-emission tomography (PET) combined with CT is slowly taking priority. With regard to nonseminomatous germ-cell tumors, PET-CT has not proven to be completely effective, due to a high number of false-negative results. The purpose of this paper is to provide radiologists with a pictorial review of testicular carcinoma from initial staging through posttreatment follow-up.

Significance of 18F-FDG PET/CT in Characterization of Equivocal Lesions in High-Risk Testicular Carcinoma in Restaging Setting

OBJECTIVES

The present study aims to evaluate the role of Positron emission tomography (PET) -computed tomography (CT) with 18F-fluorodeoxyglucose (18F-FDG) in the restaging of high-risk testicular cancer.

METHODS

Forty-five patients (mean age of 38.1±11.3 years and range 23-81 years) with testicular carcinoma, underwent 18F-FDG PET-CT during their clinical course were prospectively selected. PET positivity was defined as a site of abnormal 18F-FDG uptake in tissue histologically proven or clinically or radiographically suspected to represent tissue involvement. The sites of disease were characterized as either nodal or extranodal. All patients were followed-up for at least 12 months with a diagnostic and/or functional imaging modality.

RESULTS

Of the 45 patients 38 (84%) patient presented with seminoma and 7 (16%) were Non-seminomatous germ cell tumors. Analysis of secondary disease spectrum showed nodal involvement in 65%, osseous involvement in 23% and mixed visceral/soft tissue lesions in 12% of patients. Nineteen (42%) were negative for any metastatic disease. All negative patients remain disease free in the follow-up of one year. Out of the positive 26/45 patients, PET-CT showed progressive disease in 3/26, stable disease 1/26 and partial response in 2/26 and complete metabolic resolution in 20/26 patients. 18F-FDG PET-CT was able to characterize all patients leading to significant change of primary decision of wait and watch to go for treatment and vice versa.

CONCLUSION

18F-FDG PET-CT scan is potentially an excellent tool for characterization of equivocal lesions on CT scan in the restaging settings and follow up of high-risk testicular cancer patients.

Diagnostic accuracy of DWI in patients with ovarian cancer: A meta-analysis

BACKGROUND

Diffusion weighted imaging (DWI) is recently developed for identifying different malignant tumors. In this article the diagnostic accuracy of DWI for ovarian cancer was evaluated by synthesis of published data.

METHODS

A comprehensive literature search was conducted in PubMed/MEDLINE and Embase databases on the diagnostic performance of DWI for ovarian cancer published in English. Methodological quality was evaluated following Quality Assessment for Studies of Diagnostic Accuracy 2 (QUADAS 2) tool. We adopted the summary receiver operating characteristic (SROC) curve to assess the DWI accuracy.

RESULTS

Twelve studies including 1142 lesions were analyzed in this meta-analysis to estimate the pooled Sen (sensitivity), Spe (specificity), PLR (positive likelihood ratio), NLR (negative likelihood ratio), and construct SROC (summary receiver operating characteristics) curve. The pooled Sen and Spe were 0.86 (95% confidence interval [CI], 0.83-0.89) and 0.81 (95%CI, 0.77-0.84), respectively. The pooled PLR and pooled NLR were 5.07 (95%CI, 3.15-8.16) and 0.17 (95%CI, 0.10-0.30), respectively. The pooled diagnostic odds ratio (DOR) was 35.23 (95%CI, 17.21-72.14). The area under the curve (AUC) was 0.9160.

CONCLUSION

DWI had moderately excellent diagnostic ability for ovarian cancer and promised to be a helpful diagnostic tool for patients of ovarian cancer.

Incidental abnormal FDG uptake in the prostate on 18-fluoro-2-deoxyglucose positron emission tomography-computed tomography scans

18-fluoro-2-deoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) scans are commonly used for the staging and restaging of various malignancies, such as head and neck, breast, colorectal and gynecological cancers. However, the value of FDG PET/CT for detecting prostate cancer is unknown. The aim of this study was to evaluate the clinical value of incidental prostate 18F-FDG uptake on PET/CT scans. We reviewed 18F-FDG PET/CT scan reports from September 2009 to September 2013, and selected cases that reported focal/diffuse FDG uptake in the prostate. We analyzed the correlation between 18F-FDG PET/CT scan findings and data collected during evaluations such as serum prostate-specific antigen (PSA) levels, digital rectal examination (DRE), transrectal ultrasound (TRUS), and/or biopsy to confirm prostate cancer. Of a total of 18,393 cases, 106 (0.6%) exhibited abnormal hypermetabolism in the prostate. Additional evaluations were performed in 66 patients. Serum PSA levels were not significantly correlated with maximum standardized uptake values (SUVmax) in all patients (rho 0.483, p=0.132). Prostate biopsies were performed in 15 patients, and prostate cancer was confirmed in 11. The median serum PSA level was 4.8 (0.55-7.06) ng/mL and 127.4 (1.06-495) ng/mL in the benign and prostate cancer groups, respectively. The median SUVmax was higher in the prostate cancer group (mean 10.1, range 3.8-24.5) than in the benign group (mean 4.3, range 3.1-8.8), but the difference was not statistically significant (p=0.078). There was no significant correlation between SUVmax and serum PSA, prostatic volume, or Gleason score. 18F-FDG PET/CT scans did not reliably differentiate malignant or benign from abnormal uptake lesions in the prostate, and routine prostate biopsy was not usually recommended in patients with abnormal FDG uptake. Nevertheless, patients with incidental prostate uptake on 18F-FDG PET/ CT scans should not be ignored and should be undergo further clinical evaluations, such as PSA and DRE.

Appropriateness criteria of FDG PET/CT in oncology

(18)Fluorine-2-fluoro-2-Deoxy-d-glucose ((18)F-FDG) positron emission tomography/computerized tomography (PET/CT) is a well-established functional imaging method widely used in oncology. In this article, we have incorporated the various indications for (18)FDG PET/CT in oncology based on available evidence and current guidelines. Growing body of evidence for use of (18)FDG PET/CT in select tumors is also discussed. This article attempts to give the reader an overview of the appropriateness of using (18)F-FDG PET/CT in various malignancies.

Knowledge, attitude and practices of technicians working at hospitals towards testicular cancer and self-examination of testicles in Turkey

BACKGROUND

The present study was conducted to determine knowledge level of technicians working in hospitals about testicular cancer (TC) and self-examination of testicles (TSE) and to determine levels of consciousness and implementation status about TSE.

MATERIALS AND METHODS

This cross-sectional study was conducted with technicians working in hospitals (n=243) between 2nd January-31st May 2012 at private and governmental hospitals in urban Kayseri. Healthy control subjects (n=235) who were similar to technicians in terms of age, education level and income status were also included to the study. Chi-square test was used in comparison of categorical variables.

RESULTS

Technicians were significantly more aware of TC than controls, but the latter were found to have significantly more information about TSE. There was no significant difference between the two groups in terms of knowing how to do TSE and 80% of both groups were unaware this exam. Of technicians, 19.8% and of controls, 25.5% did TSE, the difference being statistically insignificant. First reason for not doing TSE was "not-knowing" among technicians (48.1%) while it was "ignorance" among controls (66.8%). Of technicians doing TSE, 37.5% did as it came to their mind while 51.7% of controls performed TSE several times in the previous year. Technicians were significantly more afraid of getting TC than controls (p=0.037).

CONCLUSIONS

It was determined in the present study that rates of TSE were similar between technicians and controls. However compliance with the recommended frequency and right method was low. Consequently, public health educationshould be planned and applied in order to increase the knowledge of TC and TSE.

Review of the Literature: Organ of Giraldes Epididymal Appendage Presenting as a Painless Scrotal Mass in a 19-Year-Old Male—A Rare Urologic Entity

An incidental finding of a testicular mass in young male population is always a case of great concern for the patient and controversy for the physician. Differential diagnosis ranges from acute scrotum (notably testicular torsion), to acute inflammation and infection, all the way to testicular tumors. We present a case of an incidental finding of a painless testicular solid mass in a 19-year-old male patient, with an end pathological result of paradidymis (organ of Giraldes) following orchiectomy. To the best of our knowledge, this is the first case of its kind to be reported in the literature.