PET Imaging for Prostate Cancer

Targeted Molecular Imaging as a Biomarker in Urologic Oncology

Urologic malignancies constitute a large portion of annually diagnosed cancers. Timely diagnosis, accurate staging, and assessment of tumor heterogeneity are essential to devising the best treatment strategy for individual patients. The high sensitivity of molecular imaging allows for early and sensitive detection of lesions that were not readily detectable using conventional imaging techniques. Moreover, molecular imaging enables the interrogation of molecular processes used in targeted cancer therapies and predicts cancer response to treatment. Here we review the current advancements in molecular imaging of urologic cancers, including prostatic, vesical, renal testicular, and ureteral cancers.

How can we best manage biochemical failure after radical prostatectomy?

Biochemical recurrence (BCR) is common after radical prostatectomy, but effective treatment options for men with BCR after curative treatment remain controversial. Although prostate-specific antigen is widely used as a surrogate marker for prostate cancer survival, it cannot fully differentiate between prostate-cancer-specific survival and overall survival. Thus, it is challenging for physicians to determine the timing of treatment to halt or slow the clinical progression of disease in patients with BCR while avoiding overtreatment for patients whose disease may not progress beyond BCR. Adjuvant therapy for radical prostatectomy or radiotherapy in intermediate- or high-risk localized prostate cancer has a benefit in terms of disease progression and survival but is not recommended in low-risk prostate cancer because of the significant adverse effects related to radiotherapy and androgen-deprivation therapy (ADT). Salvage radiotherapy (SRT) is also recommended for patients with BCR after radical prostatectomy. Several options for management of BCR after radical prostatectomy include SRT to the prostatic bed and/or pelvis, continuous or intermittent ADT, or observation. Patients' comorbidity, preferences, and cancer-related factors must be considered when deciding the best management strategy. Modern imaging technology such as positron emission tomography imaging of prostate-specific membrane antigen-positive regions enables earlier detection of disease progression, thus enhancing decision making for future disease management.

18F-Fluciclovine PET/CT: A Potential Imaging Biomarker for the Evaluation of Multiple Myeloma

ABSTRACT

Incidental concomitant second primary malignancy may be detected on PET/CT imaging. We present an 18F-fluciclovine PET/CT of a patient undergoing evaluation of biochemically recurrent prostate cancer with incidental radiotracer uptake within lytic osseous lesions confirmed to be multiple myeloma. We present the 18F-fluciclovine PET/CT images of an 83-year-old man with prostate cancer treated in 2005 who presented with back pain and a CT scan revealing multiple lytic osseous lesions concerning for metastases versus a plasma cell neoplasm. Prostate-specific antigen at the time of evaluation was 0.1 ng/mL.

Developments in proton MR spectroscopic imaging of prostate cancer

In this paper, we review the developments of 1H-MR spectroscopic imaging (MRSI) methods designed to investigate prostate cancer, covering key aspects such as specific hardware, dedicated pulse sequences for data acquisition and data processing and quantification techniques. Emphasis is given to recent advancements in MRSI methodologies, as well as future developments, which can lead to overcome difficulties associated with commonly employed MRSI approaches applied in clinical routine. This includes the replacement of standard PRESS sequences for volume selection, which we identified as inadequate for clinical applications, by sLASER sequences and implementation of 1H MRSI without water signal suppression. These may enable a new evaluation of the complementary role and significance of MRSI in prostate cancer management.

Radiomics and artificial intelligence in prostate cancer: new tools for molecular hybrid imaging and theragnostics

In prostate cancer (PCa), the use of new radiopharmaceuticals has improved the accuracy of diagnosis and staging, refined surveillance strategies, and introduced specific and personalized radioreceptor therapies. Nuclear medicine, therefore, holds great promise for improving the quality of life of PCa patients, through managing and processing a vast amount of molecular imaging data and beyond, using a multi-omics approach and improving patients’ risk-stratification for tailored medicine. Artificial intelligence (AI) and radiomics may allow clinicians to improve the overall efficiency and accuracy of using these “big data” in both the diagnostic and theragnostic field: from technical aspects (such as semi-automatization of tumor segmentation, image reconstruction, and interpretation) to clinical outcomes, improving a deeper understanding of the molecular environment of PCa, refining personalized treatment strategies, and increasing the ability to predict the outcome. This systematic review aims to describe the current literature on AI and radiomics applied to molecular imaging of prostate cancer.

[18F]DCFPyL PET/CT for Imaging of Prostate Cancer

Prostate-specific membrane antigen (PSMA)-directed positron emission tomography (PET) has gained increasing interest for imaging of men affected by prostate cancer (PC). In recent years, ⁶⁸Ga-labeled PSMA compounds have been widely utilized, although there is a trend towards increased utilization of ¹⁸F-labeled agents. Among others, [¹⁸F]DCFPyL (piflufolastat F 18, PYLARIFY) has been tested in multiple major trials, such as OSPREY and CONDOR, which provided robust evidence on the clinical utility of this compound for staging, restaging, and change in management. Recent explorative prospective trials have also utilized [¹⁸F]DCFPyL PET/CT for response assessment, e.g., in patients under abiraterone or enzalutamide, rendering this ¹⁸F-labeled PSMA radiotracer as an attractive biomarker for image-guided strategies in men with PC. After recent approval by the U.S. Food and Drug Administration, one may expect more widespread use, not only in the U.S., but also in Europe in the long term. In the present review, we will provide an overview of the current clinical utility of [¹⁸F]DCFPyL in various clinical settings for men with PC.