Reporting PSMA PET with PROMISE
miTNM for the stage, an expression score for the target, a likelihood score for the doubt
A PSMA PET report has to tell the urologist where the disease is, the oncologist how much target there is, and everyone how sure you are. PROMISE answers the first two. PSMA-RADS and the E-PSMA 5-point scale answer the third.
Two systems, two jobs
- PROMISE (now version 2) is a whole-body staging language: molecular imaging TNM (miTNM) plus a PSMA expression score. It stages the patient.
- PSMA-RADS grades each lesion from 1 (definitely benign) to 5 (definitely cancer), with subcategories 1A, 1B and 3A–3D. Version 2.0 adds 5T for treated metastases and an overall score equal to the highest lesion score.
- E-PSMA (EANM) combines miTNM, the expression score and a simpler 5-point likelihood scale in one structured report.
miTNM in brief
| Category | Meaning |
|---|---|
| miT0 / miTr | No local tumour / local recurrence after prostatectomy |
| miT2u, miT2m | Organ-confined, unifocal or multifocal |
| miT3a, miT3b, miT4 | Extraprostatic extension; seminal vesicles; adjacent structures |
| miN1, miN2 | Pelvic nodes in one region, or in several (miN1a/miN1b in version 1) |
| miM1a | Extrapelvic nodes: name the region |
| miM1b | Bone: unifocal, oligometastatic (3 or fewer lesions), disseminated, or diffuse marrow involvement |
| miM1c | Organ metastases: name the organ |
The expression score
Grade uptake visually against reference organs: 0, below blood pool; 1, at or above blood pool but below liver; 2, at or above liver but below parotid; 3, at or above parotid. For ¹⁸F-PSMA-1007, which has high liver uptake, use spleen instead of liver. Version 2 modified the score slightly, so use the definitions in your template. Scores 2 and 3 are typical of prostate cancer and favour PSMA radioligand therapy.
If therapy is in view, also state uptake relative to liver (spleen for ¹⁸F-PSMA-1007) and the site and size of any PSMA-negative lesion.
What goes in the impression
- Normal or abnormal, and an answer to the referral question.
- Findings grouped by site: prostate or bed, pelvic nodes, extrapelvic nodes, bone, organs.
- The miTNM stage, with the number of lesions per region; E-PSMA allows “poly-metastatic” for a region with more than about five.
- A likelihood score for any lesion that changes management, and what would resolve an equivocal one, such as MRI or biopsy.
- Relevant context: androgen-deprivation therapy and its timing, since it can raise PSMA uptake.
miTNM says where, not how sure. If the M category rests on one equivocal lesion, say so: give its likelihood score and the test that would settle it.
- PROMISE stages the patient (miTNM plus expression score); PSMA-RADS and the E-PSMA scale grade confidence lesion by lesion.
- Expression score: blood pool, liver (spleen for ¹⁸F-PSMA-1007) and parotid set the thresholds for scores 1, 2 and 3.
- The impression should answer the question, give the miTNM stage, and flag equivocal lesions with a likelihood score and a next step.
- Seifert R, Emmett L, Rowe SP, et al. Second version of the Prostate Cancer Molecular Imaging Standardized Evaluation framework including response evaluation for clinical trials (PROMISE V2). Eur Urol. 2023;83(5):405-12.
- Eiber M, Herrmann K, Calais J, et al. Prostate Cancer Molecular Imaging Standardized Evaluation (PROMISE): proposed miTNM classification for the interpretation of PSMA-ligand PET/CT. J Nucl Med. 2018;59(3):469-78.
- Rowe SP, Pienta KJ, Pomper MG, Gorin MA. Proposal for a structured reporting system for prostate-specific membrane antigen-targeted PET imaging: PSMA-RADS version 1.0. J Nucl Med. 2018;59(3):479-85.
- Werner RA, Hartrampf PE, Fendler WP, et al. Prostate-specific membrane antigen reporting and data system version 2.0. Eur Urol. 2023;84(5):491-502.
- Ceci F, Oprea-Lager DE, Emmett L, et al. E-PSMA: the EANM standardized reporting guidelines v1.0 for PSMA-PET. Eur J Nucl Med Mol Imaging. 2021;48(5):1626-38.
- Fendler WP, Eiber M, Beheshti M, et al. PSMA PET/CT: joint EANM procedure guideline/SNMMI procedure standard for prostate cancer imaging 2.0. Eur J Nucl Med Mol Imaging. 2023;50(5):1466-86.