To evaluate the diagnostic accuracy of [68Ga]Ga-PSMA-11 PET/CT (PET-PSMA) in local and loco-regional nodal staging compared with histopathological results in intermediate- and high-risk prostate cancer patients treated with radical prostatectomy (RP) and pelvic lymph node dissection (PLND).
Materials y methodsA total of 122 intermediate- and high-risk prostate cancer (PCa) patients staged with PET-PSMA and treated with RP (36/122) and RP plus PLND (86/122) from December 2018 to December 2023 were included. Visual and semiquantitative analysis findings using the SUVmax of the molecular imaging were correlated with histopathological results.
ResultsThe primary tumor was visible by PET-PSMA in 96.7% of the patients. A positive correlation was found between PSA levels and SUVmax (Spearman’s r: 0.303, p < 0.001). PET-PSMA detected nodal involvement in 25/89 patients (28.08%). The sensitivity, specificity, and diagnostic accuracy of PET-PSMA for detecting nodal involvement were 75%, 82.2%, and 80.9%, respectively. Patients with PSA levels >20 ng/mL, Gleason score ≥7b, ISUP grade >2, and extracapsular extension showed significantly higher SUVmax values. No differences were observed in SUVmax between risk groups or in other histopathological variables.
ConclusionsPET-PSMA is an effective tool for the initial staging of intermediate- and high-risk PCa. SUVmax values were significantly higher in patients with unfavorable clinical features.
Evaluar la precisión diagnóstica de la PET/TC con [68Ga]Ga-PSMA-11 (PET-PSMA) en la estadificación local y ganglionar loco-regional en comparación con los resultados anatomopatológicos en pacientes con cáncer de próstata (cPr) de riesgo intermedio y alto tratados con prostatectomía radical (PR) y linfadenectomía pélvica (LDNP).
Material y métodosSe incluyeron 122 pacientes con cPr de riesgo intermedio y alto estadificados mediante PET-PSMA y tratados mediante PR (36/122) y PR más LDNP (86/122) desde diciembre de 2018 hasta diciembre de 2023. Los hallazgos del análisis visual y semicuantitativo mediante el SUVmax de la imagen molecular se correlacionaron con los resultados anatomopatológicos.
ResultadosEl tumor primario fue visible mediante PET-PSMA en el 96,7% de los pacientes. Se encontró una correlación positiva entre los valores de PSA y SUVmax (r de Spearman: 0,303, p < 0,001). La PET-PSMA detectó infiltración ganglionar en 25/89 pacientes (28,08%). La sensibilidad, especificidad y precisión diagnóstica de la PET-PSMA para detectar infiltración ganglionar fue de 75%, 82,2% y 80,9% respectivamente. Los pacientes con valores de PSA > 20 ng/mL, grado de Gleason ≥7b, grado de la ISUP > 2 y extensión extracapsular mostraron valores de SUVmax significativamente mayores. No se observaron diferencias en el SUVmax por grupos de riesgo ni en el resto de variables anatomopatológicas.
ConclusionesLa PET-PSMA es una herramienta eficaz para la estadificación inicial del cPr de riesgo intermedio y alto. Los valores de SUVmax fueron significativamente mayores en pacientes con características clínicas desfavorables.
Prostate cancer (PCa) is the most frequent tumor in males throughout the world and the second cause of mortality, being only surpassed by lung cancer.1
In recent years, prostate-specific membrane antigen positron emission tomography (PSMA-PET) has become the reference imaging technique for the detection of PCa recurrence and for initial staging, due to it greater sensitivity (S), specificity (Sp) and fewer erroneous results compared with conventional imaging techniques, such as computerized tomography (CT) and bone scintigraphy.2–5
In lymph node staging, a recent meta-analysis reported a S of 77% and a Sp of 97% in the analysis of patients following radical prostatectomy (RP) and pelvic lymph node dissection (PLND).6
The aim of this study was to analyze the diagnostic value of PSMA-PET in the presurgical staging of patients with intermediate- and high-risk PCa, comparing the molecular imaging findings of the primary tumor and locoregional lymph node involvement with the anatomy pathology results to understand its utility and limitations.
Material and methodsPatient selectionWe included patients with a histological diagnosis of intermediate- or high-risk PCa according to the classification of the European Association of Urology (EAU),7 who were consecutively studied with [68Ga]Ga-PSMA-11 PET/CT (PSMA-PET) between December 2018 and December 2023 to determine disease extension prior to RP ± PLND in our institution. All the patients who received hormonal treatment prior to PSMA-PET and patients with metastatic disease at onset were excluded. Locoregional lymph node disease was considered as involvement of the internal iliac, external iliac, obturator and presacral lymph node chains, while metastatic disease was defined as distant lymph node involvement including the common iliac, retroperitoneal, inguinal and supradiaphragmatic (M1a) chains, the presence of bone metastasis (M1b) and visceral disease (M1c). PLND was performed in patients with a greater probability of lymph node involvement according to the different predictive nomograms and PSMA-PET findings.8,9 PLND included the lymph nodes of the obturator and external iliac chains (standard PLND) and the internal and presacral iliac chains (extended PLND).
We collected demographic data, the prostate-specific antigen (PSA) value at diagnosis, the clinical tumoral stage (cT) and the Gleason score and the International Society of Urological Pathology (ISUP) grade from the clinical histories.
The protocol was approved by the Ethical Committee of our institution (Reference: 2021.201) and the study was carried out according to the ethical norms established by the 1964 Declaration of Helsinki and all the posterior revisions. Informed consent was obtained from all the patients.
[68Ga]Ga-PSMA-11 PET/CT imagesThe patients received an intravenous injection of 151 ± 32 MBq of [68Ga]Ga-PSMA-11. PSMA-PET was performed according to the guidelines of the European Association of Nuclear Medicine (EANM) and the Society of Nuclear Medicine and Molecular Imaging.10 The PSMA-PET images were acquired in two tomographs (Siemens Biograph mCT 64 and Siemens Vision 600, Siemens, Knoxville, USA). A CT without low-dose contrast was performed (Care Dose 4D with a reference quality of 80 mAs at 120 kV) from the vertex to the proximal region of the thigh in craniocaudal direction at 69 ± 13 min post-injection. The PET data were reconstructed using an iterative algorithm with 3 iterations, 21 subset (OSEM 3.21) in a 200 × 200 matrix. For each acquisition, two different reconstructions were made: one of high quality, optimized for the detection of lesions (point spread function [PSF] + time of flight [TOF], Gaussian filter of 2 mm and another reconstruction was performed for quantification (TOF, Gaussian filter of 5 mm) for both tomographs following the guidelines of the EANM and its program of harmonization and accreditation called the European Association Research Ltd.11,12
Interpretation of the PET imagesThe PET images were reviewed by two medical specialists in Nuclear Medicine (JJR and MRF). Lesions were considered to be PSMA positive when showing PSMA expression greater than or equal to the vascular activity of the mediastinum (score ≥1) and a reader confidence score ≥3 for both pelvic lymph node disease (N1) and distant disease (M1a). Tumoral and lymph node staging were reported following the criteria of the standardized reporting guidelines for PSMA-PET (E-PSMA).13
The variables of the PSMA-PET imaging included: molecular tumor stage (miT), tumor laterality, molecular stage by imaging of the locoregional lymph nodes (miN), lymph node chain and laterality of the miN, laterality and infiltration of the seminal vesicles and the maximum standard uptake value (SUVmax) of the tumor of the most representative lesion. To calculate the SUVmax of the tumor, the automatic segmentation tool (isocontour of the volume of interest [VOI]) was used with a threshold at 40% using the processing software syngo.via (Siemens Healthineers, Knoxville, TN) (Fig. 1).
(A) Maximum intensity projection in a patient with high-risk prostate cancer, with primary lesion in the left prostatic lobe (red arrow) and locoregional lymph node involvement (yellow arrow), without distant metastasis. (B) Example of automatic segmentation for calculating the SUVmax in the prostatic tumor (red arrow). (C) Foci of pathological lymph node uptake in the right internal iliac region (yellow arrow, Score = 2; reader confidence = 5).
The initial diagnosis of PCa was obtained by anatomical pathology study of the sample obtained by prostatic biopsy. However, the correlation of the PSMA-PET imaging findings was performed by study of the resected RP surgical piece. The anatomical pathology categories of the tumor (pT) and the lymph node (pN) were classified according to the TNM of the 8th edition of the American Joint Committee on Cancer.14 Likewise, the Gleason score and the final ISUP grade, extracapsular extension, lymphovascular, perineural and seminal vesicle infiltration, including laterality and the stage of the surgical margins (R) were registered, in addition to the proportion of patients showing a change in the Gleason score and ISUP grade in the RP compared to the preoperative biopsy.
Correlation of the PSMA-PET findings with the anatomical pathology analysisFor the evaluation of the primary tumor, PSMA uptake in the prostate gland (unifocal or multifocal) and the laterality of the pathological uptake were considered. Uptake was considered pathological when showing activity clearly greater than the uptake of the healthy prostatic parenchyma. Foci visualized only in a single plane and those suggestive of urinary elimination, because of localization or by the CT image, were excluded.
The diagnostic performance of PSMA-PET was studied using the anatomical pathology results as the reference pattern and taking into account the lymph node chain affected and laterality in the case of lymph node disease as well as the laterality for the infiltration of the seminal vesicles. Lesions considered to be tumoral in both the anatomical pathological analysis and in the PSMA-PET were considered true positives, while lesions deemed to be non-tumoral by both techniques were considered true negatives. Lesions showing uptake in the PSMA-PET with no evidence of tumor were classified as false positives, and finally, lesions without pathological PSMA uptake, but with tumor in the biopsy were considered as false negatives. From these results, we calculated the S, Sp, positive predictive value (PPV), negative predictive value (NPV) and the diagnostic accuracy (DA) for both infiltration of the seminal vesicles and extracapsular extension and locoregional lymph node disease.
Statistical analysisThe clinical characteristics of the patients were described as frequency and percentage for categorical variables and by median and interquartile range (IQR) for continuous variables. Differences among the different groups were evaluated using the Mann-Whitney U test and the correlation of the SUVmax with the different clinical and pathological variables were evaluated with the Spearman correlation test. A p value < 0.05 was considered statistically significant.
All the statistical analyses were done using IBM SPSS Statistics for Windows, version 29 (IBM Corp., Armonk, N.Y., USA).
ResultsPatient characteristicsWe analyzed 122 consecutive patients who underwent a PSMA-PET study with staging prior to RP. In 89 patients (73%) a standard PLND (69 patients) or extended PLND (20 patients) was also performed due to the clinical characteristics of the patient, including all the patients with PSMA positive locoregional lymph nodes (miN+)
The median time between the biopsy and the PSMA-PET was 34 days (IQR: 22–61.50) and was 20 days (IQR: 6.35) between the PSMA-PET and the RP. PSA values were <10 ng/mL in 52 patients (42.6%), between 10 and 20 ng/mL in 47 patients (38.5%) and >20 ng/mL in 23 patients (18.9%).
Table 1 shows the frequencies of the groups of risk, Gleason score and ISUP grade as well as the remaining clinical variables.
Basal clinical-pathological characteristics of the patients prior to PSMA-PET.
| Characteristics | n (%) |
|---|---|
| EAU risk group | 122 |
| Intermediate | 59 (48.4) |
| High | 63 (51.5) |
| Age (years) | |
| Median (IQR) | 65 (60.75−70) |
| ISUP grade. Biopsy | |
| 1 | 26 (21.3) |
| 2 | 29 (23.8) |
| 3 | 21 (17.2) |
| 4 | 30 (24.6) |
| 5 | 16 (13.1) |
| Gleason score. Biopsy | |
| 6 | 26 (21.3) |
| 3 + 4 (7a) | 28 (23) |
| 4 + 7 (7b) | 21 (17.2) |
| 8 | 31 (25.4) |
| 9 | 14 (11.5) |
| 10 | 2 (1.6) |
| PSA at PET (ng/mL) | |
| Median (IQR) | 10.91 (7.08−16.93) |
EAU: European Association of Urology, ISUP: International Society of Urological Pathology, IQR: Interquartile range.
The anatomical pathology study of the surgical piece showed infiltration by PCa in both lobes in 100 patients (82%), exclusive involvement of the left prostatic lobe in 14 patients (11.5%) and of the right prostatic lobe in 8 patients (6.6%). In 70 patients (57.4%) differences were observed between the Gleason score and the preoperative biopsy and that of the surgical piece, showing a reduction in 39/70 (55.7%) and an increase in the remaining 31/70 (44.3%).
The most frequent tumoral stage was pT2, which was observed in 56.6% of the patients, followed by stage pT3a and pT3b in 31.1% and 16.4%, respectively. Lymphovascular infiltration was found in 7.4% of the patients; 65.6% had perineural infiltration and 42.6% of the patients had positive surgical margins after RP.
In the 89 patients undergoing PLND, a total of 1021 lymph nodes were resected, with a mean of 11.8 lymph nodes (±8). There was no tumoral infiltration (pN0) in 73 patients (82.02 %) and 16 patients (17.98 %) presented a total of 49 metastatic lymph nodes in the locoregional chains (pN1).
Table 2 shows the histopathological characteristics.
Findings of the characteristics of the primary tumor and the locoregional lymph nodes in both the anatomopathological study and in the PSMA-PET.
| Characteristics | PSMA-PET (n; %)* | AP (n; %) |
|---|---|---|
| Tumor stage | ||
| T2 | 72 (56.6) | 64 (52.5) |
| T3a | 15 (12.3) | 38 (31.1) |
| T3b | 31 (25.4) | 20 (16.4) |
| Lymph node stage | ||
| Nx | n.a | 33 (27.1) |
| N0 | 97 (79.5) | 73 (59.8) |
| N1 | 25 (20.5) | 16 (13.1) |
| Lymphovascular infiltration | ||
| Present | n.a | 9 (7.4) |
| Absent | 113 (92.6) | |
| Perineural infiltration | ||
| Present | n.a | 80 (65.6) |
| Absent | 42 (34.4) | |
| Surgical margins + | ||
| Present | n.a | 52 (42.6) |
| Absent | 70 (57.4) | |
n.a: not applicable; AP: anatomical pathology.
The S of the PSMA-PET for the localization of the primary tumor was 96.7 % (118/122) in the analysis by patients and 84.6 % when considering the lobe and the laterality of the prostatic tumoral infiltration. Four patients did not present PSMA uptake in the primary tumor (2 with a Gleason score of 6; 1 of 7a and 1 of 7b). Since all the patients were diagnosed with PCa, the Sp of the test could not be calculated.
The PSMA-PET detected extracapsular extension (Fig. 2A and B) in 15 patients, in whom 7 were true positives and 8 were false positives. Among the remaining 107 patients showing no extracapsular extension in the PSMA-PET, 76 were true negatives and 31 false negatives.
Example of extracapsular extension and invasion of the seminal vesicles in two patients with prostate cancer. Extracapsular extension is visible in the fusion PSMA-PET/CT images (A: yellow arrows) and in the magnetic resonance study (B, yellow arrows). (C) Axial images of fusion PSMA-PET/CT images in which a pathological deposit is identified in the right seminal vesicle with morphological correlation in the CT image (D, red arrows).
PSMA-PET showed infiltration of the seminal vesicles (Fig. 2D and 2C) in 26 patients (21.3 %), with 15 being true positives and 11 false positives. Of the 96 remaining patients (78.7 %) with no uptake observed by PSMA-PET in the seminal vesicles, 5 were false negatives and 91 were true negatives.
The S, Sp, PPV, NPV and DA of the PSMA-PET for extracapsular extension and infiltration of the seminal vesicles are shown in Table 3.
Diagnostic value of PSMA-PET in extracapsular extension and infiltration of the seminal vesicles.
| % (95% CI) | ||
|---|---|---|
| Extracapsular extension (T3a) | Seminal vesicle infiltration (T3b) | |
| Sensitivity | 18.4 (7.7−34.3) | 59.2 (38.8−77.6) |
| Specificity | 90.4 (82.1−95.8) | 93.1 (88.8−96.1) |
| PPV | 46.6 (25.4−69.1) | 51.6 (37.4−65.5) |
| NPV | 71 (67.5−74.3) | 94.8 (92.1−96.6) |
| Diagnostic accuracy | 68 (58.9−76.2) | 89.3 (84.7−92.9) |
PPV: positive predictive value, NPV: negative predictive value, CI confidence interval.
The pT was equal to the miT in 54.1% of the patients, higher in 23.8% and lower in 22.1 %. The S, Sp and DA of the PSMA-PET for the diagnosis of locally advanced disease (pT ≥3) were 61%, 77% and 70% (95% confidence interval [CI]: 61.5–78.4), respectively.
PSMA-PET detected a total of 73 positive lymph nodes in 25 of 89 patients (28.1%) who underwent PLND. In 12 patients, tumoral infiltration was confirmed in the anatomical pathology study, while 13 patients were false positives. Of the 64 patients with a negative PSMA-PET for tumoral lymph node infiltration, 60 were true negatives and 4 false negatives. The S, Sp, PPV, NPV and DA values of the PSMA-PET for the detection of lymph node infiltration were 75%, 82.2%, 48%, 93.7% and 80.9%, respectively (Table 4).
Concordance of the findings of tumoral lymph node infiltration by PSMA-PET and that observed in the anatomical pathology analysis after pelvic lymph node dissection (n = 89).
| PSMA-PET | AP | Indexes | |
|---|---|---|---|
| Positive, n (%) | Negative, n (%) | ||
| Positive, n (%) | 12 (13.6) | 13 (14.6) | PPV: 48 % |
| Negative, n (%) | 4 (4.5) | 60 (67.4) | NPV: 93.7 % |
| Indexes | S: 75 % | Sp: 82.2 % | DA: 80.9 % |
AP: Anatomical pathology, S: Sensitivity, Sp: Specificity PPV: positive predictive value, NPV: negative predictive value, and DA: diagnostic accuracy.
For the study of the relationship between the SUVmax and the different clinical and pathological variables, 4 patients not showing uptake of PSMA in the primary tumor were excluded, and thus, the remaining 118 patients were included.
According to the PSA value at diagnosis, patients with levels <20 ng/mL had a median SUVmax of 8.9 with respect to those with PSA values >20 ng/mL in whom the median SUVmax was significantly greater at 15.3. There was a positive, albeit weak, correlation between the PSA values and the SUVmax of the tumor (Spearman’s r = 0.303, p < 0.001) (Fig. 3).
Likewise, the SUVmax values were significantly higher in the patients with a Gleason score ≥7b and ISUP grade >2, with median values of 11.6 in comparison with the patients with a Gleason score ≤7a and ISUP grade ≤2 in whom the median was 8.8. Similarly, the patients with extracapsular extension in the anatomical pathology study of the surgical piece showed significantly greater SUVmax values than those with extracapsular infiltration.
In the patients with intermediate- and high-risk the medians of the SUVmax were 9.4 and10, respectively, although this difference did not achieve statistical significance. Neither were there differences in the SUVmax values and the tumoral stage, lymphovascular, perineural, seminal vesicle infiltration, surgical margins or lymph node status. Table 5 shows the SUVmax values in the prostatic tumor according to the different clinical and histopathological variables.
SUVmax in the prostatic tumor according to the clinical variables and the anatomical pathology study. ISUP: International Society of Urological Pathology, IQR (interquartile range).
| n | Median SUVmax (IQR) | p | ||
|---|---|---|---|---|
| PSA (ng/mL) | ≤20 | 95 | 8.9 (5.7−12.9) | 0.003* |
| >20 | 23 | 15.3 (9.2−23.5) | ||
| Risk group | Intermediate | 57 | 9.4 (5.8−12.8) | 0.195 |
| High | 61 | 10 (6.3−18) | ||
| Gleason score | <7b | 67 | 8.8 (5.8−17.4) | 0.034* |
| ≥7b | 51 | 11.6 (7−18.6) | ||
| ISUP grade | ≤2 | 67 | 8.8 (5.8−17.4) | 0.034* |
| >2 | 51 | 11.6 (7−18.6) | ||
| Tumoral stage (pT) | ≤pT2 | 61 | 9.4 (5.6−13.4) | 0.076 |
| >pT2 | 57 | 10.7 (7.1−16.9) | ||
| Lymphovascular infiltration | No | 109 | 9.9 (5.9−14.7) | 0.812 |
| Si | 9 | 10.7 (6.7−11.6) | ||
| Perineural infiltration | No | 41 | 11.6 (5.8−14.3) | 0.304 |
| Si | 77 | 9.4 (6−14.7) | ||
| Extracapsular extension | No | 81 | 9.4 (5.4−12.7) | 0.004* |
| Si | 37 | 12.1 (8.3−18.7) | ||
| Surgical margins | R0 | 68 | 10.6 (5.1−14.9) | 0.777 |
| R1 | 50 | 9.8 (7.1−14.6) | ||
| Seminal Vesícles | No | 98 | 9.9 (6.5−14.7) | 0.235 |
| Si | 20 | 9.2 (4.8−11.5) | ||
| (pN) | pN0-Nx | 102 | 9.6 (5.8−13.9) | 0.121 |
| pN1 | 16 | 11.1 (7.2−23-2) |
The aim of this study was to describe the experience of our center in the use of PSMA-PET in the initial staging of patients with intermediate- and high-risk PCa prior to surgical treatment and compare the findings of the molecular imaging with the anatomopathological characteristics of both the tumor and the lymph node involvement following RP and PLND.
The primary tumor was visible by PSMA-PET in most of the patients, with a detection rate of 96.7%, similar to that observed by Basha et al. in a study of 173 patients using [68Ga]Ga-PSMA-11.15 In contrast, the primary tumor was not visible in less than 4% of the sample, coinciding with previous studies reporting that up to 10 % of the patients with PCa are negative in the PSMA-PET and do not show PSMA expression using immunohistochemical techniques.5,16,17
Despite the variability in terms of S and Sp of the PSMA-PET described in the literature in regard to the detection of locally advanced disease, a recent study of a large number of patients (n = 579) and different PSMA-targeted radiopharmaceuticals, including 68[Ga]Ga-PSMA-11, demonstrated a S of 68%, a Sp of 61% and a DA of 64% for the detection of tumors pT ≥3, being results that are comparable to those obtained in our study.18
Several series have demonstrated significant differences in the SUVmax values among the risk groups of the EAU.19,20 However, despite the SUVmax values in our study being slightly higher in the patients with high- versus those with intermediate-risk, these differences did not achieve statistical significance. One of the possible causes could be the elevated percentage of discrepancies between the Gleason score of the biopsy and that of the surgical piece (57.7%), which represents incorrect classification of the group of risk prior to RP. Several series with an elevated number of patients have reported a coincidence between the Gleason score pre- and post-surgery in up to 43% of the patients, similar to our findings.21,22 This highlights the need for additional tools for better stratification of patients with PCa and the fact that the categorization of the risk group should not exclusively depend on the Gleason score of the biopsy, the PSA levels or the clinical tumoral stage by digital rectal examination.
Basal immunohistochemistry studies have reported greater PSMA expression in the RP piece in patients with higher PSA levels and a higher ISUP grade.23 Several studies have evaluated the relevance of the SUVmax as a marker of PSMA expression in the primary staging of PCa by directed PSMA radiopharmaceuticals, using both PET/CT and SPECT/CT, observing that patients with higher PSA levels or a higher ISUP grade present higher SUVmax values.24–27 In line with these studies, we found significantly higher SUVmax values in patients with a PSA level >20 ng/mL, a Gleason score ≥7b and an ISUP grade >2, thereby supporting the hypothesis of the relationship between the semiquantitative parameters of the PSMA-PET, PSA expression and tumoral grade. The use of other semiquantitative parameters in PSMA-PET, such as molecular tumoral volume of the ratios of tumor to healthy organs, could be of special interest in the initial evaluation of PCa and could have prognostic value for biochemical recurrence.
In the subgroup of patients with PLND, the S found in the analysis by patient was 75%. A recent systematic review reported a S greater than or equal to 50% in 15 out of 18 studies, with a weighted S of 59%. Nonetheless, the Sp and the PPV were notably lower in our study in comparison with the data described in the literature (Sp 93% and PPV ≥ 80%).28 This may be due, in part, to the high rate of false positives of the test, suggesting the need to apply stricter criteria or to establish more accurate cut-off points for defining when a lymph node should be considered positive. Sixteen percent of the patients showed lymph node involvement in the anatomical pathology study that was not detected in the PSMA-PET. Thus, in miN0 patients, the decision to perform PLND should not only be based on the PSMA-PET results, since metastatic lymph node disease may be present that is not visible due to different factors, including spatial resolution of the current PET/CT equipment.
The limitations of our study include its retrospective nature, the lack of comparison with other imaging methods, the exclusion of patients with metastatic disease and the evaluation of the findings based on patients and not individual lesions, using segmentation templates for both the detection of intraprostatic lesions and for lymph node involvement, similar to what has previously been studied by other groups.29,30
ConclusionsPSMA-PET is an effective tool for the initial staging of PCa in patients with intermediate and high risk. The SUVmax values were significantly greater in patients with criteria of high risk, including PSA levels >20 ng/mL, Gleason score ≥7b and an ISUP grade >2, thereby supporting the evidence that a higher tumoral grade is associated with greater PSMA expression. This suggests that semiquantitative parameters, such as SUVmax, could play an important role in the evaluation of tumor aggressiveness in a pre-surgical setting.
The S and Sp of PSMA-PET for the detection of locoregional lymph node disease were 75% and 82.2%, respectively.
