[11C]Choline PET/CT in therapy response assessment of a neoadjuvant therapy in locally advanced and high risk prostate cancer before radical prostatectomy

Nuclear medicine imaging for bone metastases assessment: what else besides bone scintigraphy in the era of personalized medicine?

Accurate detection and reliable assessment of therapeutic responses in bone metastases are imperative for guiding treatment decisions, preserving quality of life, and ultimately enhancing overall survival. Nuclear imaging has historically played a pivotal role in this realm, offering a diverse range of radiotracers and imaging modalities. While the conventional bone scan using 99mTc marked bisphosphonates has remained widely utilized, its diagnostic performance is hindered by certain limitations. Positron emission tomography, particularly when coupled with computed tomography, provides improved spatial resolution and diagnostic performance with various pathology-specific radiotracers. This review aims to evaluate the performance of different nuclear imaging modalities in clinical practice for detecting and monitoring the therapeutic responses in bone metastases of diverse origins, addressing their limitations and implications for image interpretation.

18F-Choline PET/CT or PET/MR and the evaluation of response to systemic therapy in prostate cancer: are we ready?

Purpose

During the last decade, [18F]F-choline positron emission tomography (PET) had a rising role in prostate cancer (PCa) imaging. However, despite auspicious premises, [18F]F-choline PET is not currently recommended for the evaluation of response to therapy assessment in PCa, mainly due to the lack of large-scale prospective trials.

Methods

We report the cases of seven patients affected by PCa, in which [18F]F-choline PET (either with computed tomography—CT or magnetic resonance imaging—MR) contributed significantly in the systemic therapy response evaluation.

Results and conclusion

[18F]F-choline PET/CT or PET/MR demonstrated to be a useful imaging modality in the assessment of response to systemic therapy in metastatic PCa patients, irrespective of the stage of disease (either in hormone sensitive and in castrate resistant condition) and the kind of systemic treatment. In most cases, PSA serum values and [18F]F-choline PET showed a synchronous disease evolution after systemic therapy. ADT can alter [18F]F-choline uptake, therefore the time of scan should be correctly planned. Finally, PET/CT with [18F]F-choline is a useful tool for reinforcing the identification of metastatic disease in case of a switch from metastatic castration sensitive to castration resistant PCa.

PSMA and Choline PET for the Assessment of Response to Therapy and Survival Outcomes in Prostate Cancer Patients: A Systematic Review from the Literature

Simple Summary

Radiolabeled choline and PSMA PET have been largely tested in the initial staging of prostate cancer and for biochemical recurrence. Moreover, diverse data are now available about their role in the evaluation of response to local and systematic therapies, and their predictive impact on the prognosis, before and after therapy. Therefore, in the present systematic review, we aimed to describe the available data, to summarize the current evidence in these settings of disease.

Abstract

The aims of this systematic review were to (1) assess the utility of PSMA-PET and choline-PET in the assessment of response to systemic and local therapy, and to (2) determine the value of both tracers for the prediction of response to therapy and survival outcomes in prostate cancer. We performed a systematic literature search in PubMed/Scopus/Google Scholar/Cochrane/EMBASE databases (between January 2010 and October 2021) accordingly. The quality of the included studies was evaluated following the “Quality Assessment of Prognostic Accuracy Studies” tool (QUAPAS-2). We selected 40 articles: 23 articles discussed the use of PET imaging with [⁶⁸Ga]PSMA-11 (16 articles/1123 patients) or [¹¹C]/[¹⁸F]Choline (7 articles/356 patients) for the prediction of response to radiotherapy (RT) and survival outcomes. Seven articles (three with [⁶⁸Ga]PSMA-11, three with [¹¹C]Choline, one with [¹⁸F]Choline) assessed the role of PET imaging in the evaluation of response to docetaxel (as neoadjuvant therapy in one study, as first-line therapy in five studies, and as a palliative regimen in one study). Seven papers with radiolabeled [¹⁸F]Choline PET/CT (n = 121 patients) and three with [⁶⁸Ga]PSMA-11 PET (n = 87 patients) were selected before and after enzalutamide/abiraterone acetate. Finally, [¹⁸F]Choline and [⁶⁸Ga]PSMA-11 PET/CT as gatekeepers for the treatment of metastatic prostate cancer with Radium-223 were assessed in three papers. In conclusion, in patients undergoing RT, radiolabeled choline and [⁶⁸Ga]PSMA-11 have an important prognostic role. In the case of systemic therapies, the role of such new-generation imaging techniques is still controversial without sufficient data, thus requiring additional in this scenario.

Prognostic Value of 18F-Fluorocholine PET Parameters in Metastatic Castrate-Resistant Prostate Cancer Patients Treated with Docetaxel

Background and Aim

The availability of new treatments for metastatic castrate-resistant prostate cancer (mCRPC) patients increases the need for reliable biomarkers to help clinicians to choose the better sequence strategy. The aim of the present retrospective and observational work is to investigate the prognostic value of ¹⁸F-fluorocholine (¹⁸F-FCH) positron emission tomography (PET) parameters in mCRPC.

Materials and Methods

Between March 2013 and August 2016, 29 patients with mCRPC were included. They all received three-weekly docetaxel after androgen deprivation therapy, and they underwent ¹⁸F-FCH PET/computed tomography (CT) before and after the therapy. Semi-quantitative indices such as maximum standardized uptake value (SUV_max), mean standardized uptake value (SUV_mean) with partial volume effect (PVC-SUV) correction, metabolically active tumour volume (MATV), and total lesion activity (TLA) with partial volume effect (PVC-TLA) correction were measured both in pre-treatment and post-treatment ¹⁸F-FCH PET/CT scans for each lesion. Whole-body indices were calculated as sum of values measured for each lesion (SSUV_max, SPVC-SUV, SMATV, and STLA). Progression-free survival (PFS) and overall survival (OS) were considered as clinical endpoints. Univariate and multivariate hazard ratios for whole-body ¹⁸F-FCH PET indices were performed, and p < 0.05 was considered as significant.

Results

Cox regression analysis showed a statistically significant correlation between PFS, SMATV, and STLA. No correlations between OS and ¹⁸F-FCH PET parameters were defined probably due to the small sample size.

Conclusions

Semi-quantitative indices such as SMATV and STLA at baseline have a prognostic role in patients treated with docetaxel for mCRPC, suggesting a potential role of ¹⁸F-FCH PET/CT imaging in clinical decision-making.