Potential Candidates for Focal Therapy in Prostate Cancer in the Era of Magnetic Resonance Imaging-targeted Biopsy: A Large Multicenter Cohort Study

Select black men are potential candidates for prostate hemi-ablation based on radical prostatectomy histopathology for intermediate-risk prostate cancer-a multicenter SEARCH cohort study

IMPORTANCE AND OBJECTIVE

Partial gland ablation (PGA) is increasingly popular as a treatment for men with intermediate-risk prostate cancer (IR-PCa) to preserve functional outcomes while controlling their cancer. We aimed to determine the impact of race and clinical characteristics on the risk of upstaging (≥pT2c) and having adverse pathological outcomes including seminal vesicle invasion (SVI), extra prostatic extension (EPE) and lymph node invasion (LNI) at radical prostatectomy (RP) among men with IR disease eligible for PGA with hemi-ablation (HA).

DESIGN

Retrospective analysis.

SETTING

Multicenter.

PARTICIPANTS AND MEASURES

We studied patients diagnosed with unilateral IR-PCa treated with RP between 1988 and 2020 at 9 different Veterans Affairs hospitals within the SEARCH cohort. We analyzed differences in clinicopathological characteristics and outcome variables (odds of ≥pT2c and SVI, EPE and LNI) by race using multivariable logistic regression after adjusting for covariates.

RESULTS

Among 3127 patients, 33% were African American (AA) men with unilateral IR-PCa undergoing RP. Compared to non-AA men, AA individuals were younger (61 vs. 65 years, p < 0.001), presented with a higher prostate specific antigen (PSA) category (≥10 ng/ml; 34 vs. 26%, p < 0.001), and had a lower clinical stage (p < 0.001). Among the 2,798 (89.5%) with ≥pT2c stage, AA men exhibited higher ≥ pT2c rates (93 vs. 89%, p < 0.001), primarily due to increased pT2c staging (64 vs. 57%), where upstaging beyond pT2 was lower than non-AA men (29 vs. 32%). On multivariable analysis, AA men were found to have higher odds of ≥pT2c (odds ratio [OR]: 1.39 CI, 1.02-1.88, p = 0.04), lower odds of EPE (OR: 0.73 CI, 0.58-0.91, p < 0.01) and no statistically significant associations with LNI (OR: 0.79 CI, 0.42-1.46, p = 0.45) and SVI (OR: 1 CI, 0.74-1.35, p = 0.99) compared to non-AA men. On multivariable analysis, clinical features associated with higher odds of ≥pT2c were pre-operative PSA ≥ 15 (OR = 2.07, P = 0.01) and higher number of positive cores (HPC) on biopsy (OR = 1.36, P < 0.001). Similarly, PSA ≥ 15, Gleason grade ≥3 and HPC on biopsy were associated with higher odds of SVI, EPE and LNI, respectively.

CONCLUSIONS

In men with IR-PCa undergoing RP, AA men demonstrated an overall higher likelihood of ≥pT2c with lower upstaging beyond pT2, lower likelihood of EPE and no significant difference in likelihood of SVI and LNI compared to non-AA men. These findings support select AA men to be potential candidates for PGA, such as HA. Clinical factors are predictive of higher pathological stage and adverse pathological outcomes at RP and could be considered when selecting candidates for PGA.

Follow-up of vascular-targeted photodynamic therapy in a real-world setting

PURPOSE

Vascular-targeted photodynamic therapy (VTP) is an approved treatment option for unilateral low-risk prostate cancer (PCa).

METHODS

Patients with unilateral low- or intermediate-risk PCa undergoing hemiablation by VTP were evaluated in a real-world setting. Oncological outcome after VTP was measured by MRI-based re-biopsy at 12 and 24 months. Functional outcome after 1 year was investigated by IIEF-5 and IPSS questionnaires. Progression was defined as the evidence3 of ISUP ≥ 2 PCa.

RESULTS

At any control biopsy (n = 46) after VTP, only 37% of patients showed no evidence of PCa. Recurrence-free survival was 20 months (95% CI 4.9-45.5) and progression-free survival was 38.5 months (95% CI 33.5-43.6 months). In-field and out-field recurrent PCa occurs in 37% (55% ISUP ≥ 2 PCa) and 35% (56% ISUP ≥ 2 PCa). Seventy-nine percent of patients preserved erectile function, respectively. Ten percent of patients presented long-term bladder outlet obstruction. None of the patients presented incontinence.

CONCLUSION

Due to the high-recurrence in- and out-field recurrence rate in a mainly low-risk prostate cancer cohort, VTP has to be regarded critically as a therapy option in these patients. Pre-interventional diagnostic evaluation is the main issue before focal therapy to reduce the risk of tumor recurrence and progression.

Follow-Up of Men Who Have Undergone Focal Therapy for Prostate Cancer with HIFU-A Real-World Experience

PURPOSE

To determine oncological and functional outcomes and side effects after focal therapy of prostate cancer (PCa) with high-intensity focused ultrasound (HIFU).

METHODS

This retrospective single-center study included 57 consecutive patients with localised PCa. Aged 18-80 with ≤2 suspicious lesions on mpMRI (PIRADS ≥ 3), PSA of ≤15 ng/mL, and an ISUP GG of ≤2. HIFU was performed between November 2014 and September 2018. All men had an MRI/US fusion-guided targeted biopsy (TB) combined with a TRUS-guided 10-core systematic biopsy (SB) prior to focal therapy. HIFU treatment was performed as focal, partial, or hemiablative, depending on the prior histopathology. Follow-up included Questionnaires (IIEF-5, ICIQ, and IPSS), prostate-specific antigen (PSA) measurement, follow-up mpMRI, and follow-up biopsies.

RESULTS

The median age of the cohort was 72 years (IQR 64-76), and the median PSA value before HIFU was 7.3 ng/mL (IQR 5.75-10.39 ng/mL). The median follow-up was 27.5 (IQR 23-41) months. At the time of the follow-up, the median PSA value was 2.5 ng/mL (IQR 0.94-4.96 ng/mL), which shows a significant decrease (p < 0.001). In 17 (29.8%) men, mpMRI revealed a suspicious lesion, and 19 (33.3%) men had a positive biopsy result. Only IIEF values significantly decreased from 16 (IQR 10.75-20.25) to 11.5 (IQR 4.5-17) (p < 0.001). The rate of post-HIFU complications was low, at 19.3% (11 patients). The limitation of this study is the lack of long-term follow-up.

CONCLUSIONS

HIFU as a therapy option for nonmetastatic, significant prostate cancer is effective in the short term for carefully selected patients and shows a low risk of adverse events and side effects.

Improving diagnostic efficacy of primary prostate cancer with combined 99mTc-PSMA SPECT/CT and multiparametric-MRI and quantitative parameters

Purpose

This prospective study aimed to evaluate the difference between 99mTc-PSMA single-photon emission computed tomography (SPECT)/CT and multiparametric magnetic resonance imaging (mpMRI) in the detection of primary prostate cancer (PCa).

Materials and methods

Fifty-six men with suspected PCa between October 2019 and November 2022 were prospectively enrolled in this study. The median age of the patients was 70 years (range, 29-87 years). Patients were divided into high-(Gleason score>7, n=31), medium- (Gleason score=7, n=6) and low-risk groups (Gleason score < 7, n=6). All patients underwent 99mTc-PSMA SPECT/CT and mpMRI at an average interval of 3 days (range, 1-7 days). The maximum standardized uptake value (SUVmax), the minimum apparent diffusion coefficient (ADCmin), and their ratio (SUVmax/ADCmin) were used as imaging parameters to distinguish benign from malignant prostatic lesions.

Results

Of the 56 patients, 12 were pathologically diagnosed with a benign disease, and 44 were diagnosed with PCa. 99mTc-PSMA SPECT/CT and mpMRI showed no significant difference in the detection of primary PCa (kappa =0.401, P=0.002), with sensitivities of 97.7% (43/44) and 90.9% (40/44), specificities of 75.0% (9/12) and 75.0% (9/12), and AUC of 97.4% and 95.1%, respectively. The AUC of SUVmax/ADCmin was better than those of SUVmax or ADCmin alone. When SUVmax/ADCmin in the prostatic lesion was >7.0×103, the lesion was more likely to be malignant. When SUVmax/ADCmin in the prostatic lesion is >27.0×103, the PCa patient may have lymph node and bone metastases. SUVmax was positively correlated with the Gleason score (r=0.61, P=0.008), whereas ADCmin was negatively correlated with the Gleason score (r=-0.35, P=0.023). SUVmax/ADCmin was positively correlated with the Gleason score (r=0.59, P=0.023). SUVmax/ADCmin was the main predictor of the high-risk group, with an optimal cut-off value of 15.0×103.

Conclusions

The combination of 99mTc-PSMA SPECT/CT and mpMRI can improve the diagnostic efficacy for PCa compared with either modality alone; SUVmax/ADCmin is a valuable differential diagnostic imaging parameter.

Medium-term Oncological Efficacy and Patient-reported Outcomes After Focal High-intensity Focused Ultrasound: The FOXPRO Trial

BACKGROUND

Multiparametric magnetic resonance imaging (mpMRI)/transrectal ultrasound (TRUS) fusion-guided high-intensity focused ultrasound (HIFU) is a focal treatment option for MRI-visible localized prostate cancer (PCa). High-quality evidence regarding the clinical efficacy remains limited.

OBJECTIVE

To assess medium-term oncological efficacy along with patient-reported outcome measures (PROMs).

DESIGN, SETTING, AND PARTICIPANTS

This prospective single-center cohort study was performed from 2014 to 2020. Patients with primary International Society of Urological Pathologists (ISUP) grade group (GG) ≤2 by combined MRI/TRUS fusion and systematic prostate biopsy and prostate-specific antigen (PSA) <10 ng/ml were included.

INTERVENTION

MRI/TRUS fusion-guided focal HIFU therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the cancer-free rate of the HIFU-treated lesion by biopsy after 1 yr. Secondary endpoints included salvage treatment-free survival (STFS), metastasis-free survival (MFS), overall survival (OS), and PROMs according to International Consortium for Health Outcomes Measurement recommendations.

RESULTS AND LIMITATIONS

Fifty patients were included (median [range] age 68 [48-80] yr; median PSA 6.5 [1.2-9.9] ng/ml; GG 1 54% [n = 27], and GG 2 46% [n = 23]). The median (range) PSA decrease from baseline to 12 mo was 51% (35.9-72.7%). In total, 37/50 patients (74%) underwent a 1-yr biopsy. PCa was detected in 23 patients (46%; GG 1 20% [n = 10]; GG >1 26% [n = 13]; infield 40% [n = 20]). At a median follow-up of 42 (13-73) mo, PCa was detected in 30 men (60%). Among all patients, 19 (38%) underwent salvage treatments (median [95% confidence interval] STFS 53 [44.3-61.7] mo). MFS and OS were 100% and 98%, respectively. The Expanded Prostate Cancer Index Composite-26 sexual domain decreased by 20.8 points (p = 0.372).

CONCLUSIONS

MRI/TRUS-guided focal HIFU therapy results in complete cancer ablation in only half of the treated patients after 1 yr, with further recurrences at medium-term follow-up. A decline of potency occurs in a subset of patients.

PATIENT SUMMARY

Focal image-guided high-intensity focused ultrasound therapy controls cancer in one of two patients. Its impact on urinary continence and erectile function is low.

A narrative review of MRI acquisition for MR-guided-radiotherapy in prostate cancer

Magnetic resonance guided radiotherapy (MRgRT), enabled by the clinical introduction of the integrated MRI and linear accelerator (MR-LINAC), is a novel technique for prostate cancer (PCa) treatment, promising to further improve clinical outcome and reduce toxicity. The role of prostate MRI has been greatly expanded from the traditional PCa diagnosis to also PCa screening, treatment and surveillance. Diagnostic prostate MRI has been relatively familiar in the community, particularly with the development of Prostate Imaging - Reporting and Data System (PI-RADS). But, on the other hand, the use of MRI in the emerging clinical practice of PCa MRgRT, which is substantially different from that in PCa diagnosis, has been so far sparsely presented in the medical literature. This review attempts to give a comprehensive overview of MRI acquisition techniques currently used in the clinical workflows of PCa MRgRT, from treatment planning to online treatment guidance, in order to promote MRI practice and research for PCa MRgRT. In particular, the major differences in the MRI acquisition of PCa MRgRT from that of diagnostic prostate MRI are demonstrated and explained. Limitations in the current MRI acquisition for PCa MRgRT are analyzed. The future developments of MRI in the PCa MRgRT are also discussed.

[MRI-guided minimally invasive treatment of prostate cancer]

CLINICAL/METHODOLOGICAL ISSUE

Multiparametric magnetic resonance imaging (mpMRI) of the prostate plays a crucial role in the diagnosis and local staging of primary prostate cancer.

STANDARD RADIOLOGICAL METHODS

Image-guided biopsy techniques such as MRI-ultrasound fusion not only allow guidance for targeted tissue sampling of index lesions for diagnostic confirmation, but also improve the detection of clinically significant prostate cancer.

METHODOLOGICAL INNOVATIONS

Minimally invasive, focal therapies of localized prostate cancer complement the treatment spectrum, especially for low- and intermediate-risk patients.

PERFORMANCE

In patients of low and intermediate risk, MR-guided, minimally invasive therapies could enable local tumor control, improved functional outcomes and possible subsequent therapy escalation. Further study results related to multimodal approaches and the application of artificial intelligence (AI) by machine and deep learning algorithms will help to leverage the full potential of focal therapies for prostate cancer in the upcoming era of precision medicine.

ACHIEVEMENTS

Completion of ongoing randomized trials comparing each minimally invasive therapy approach with established whole-gland procedures is needed before minimally invasive therapies can be implemented into existing treatment guidelines.

PRACTICAL RECOMMENDATIONS

This review article highlights minimally invasive therapies of prostate cancer and the key role of mpMRI for planning and conducting these therapies.

Triggers and oncologic outcome of salvage radical prostatectomy, salvage radiotherapy and active surveillance after focal therapy of prostate cancer

PURPOSE

Due to the tissue preserving approach of focal therapy (FT), local cancer relapse can occur. Uncertainty exists regarding triggers and outcome of salvage strategies.

METHODS

Patients with biopsy-proven prostate cancer (PCa) after FT for localized PCa from 2011 to 2020 at eight tertiary referral hospitals in Germany that underwent salvage radical prostatectomy (S-RP), salvage radiotherapy (S-RT) or active surveillance (AS) were reported. Prostate specific antigen (PSA) changes, suspicious lesions on mpMRI and histopathological findings on biopsy were analyzed. A multivariable regression model was created for adverse pathological findings (APF) at S-RP specimen. Kaplan-Meier curves were generated to determine oncological outcomes.

RESULTS

A total of 90 men were included. Cancer relapse after FT was detected at a median of 12 months (IQR 9-16). Of 50 men initially under AS 13 received S-RP or S-RT. In total, 44 men underwent S-RP and 13 S-RT. At cancer relapse 17 men (38.6%) in the S-RP group [S-RT n = 4 (30.8%); AS n = 3 (6%)] had ISUP > 2. APF (pT ≥ 3, ISUP ≥ 3, pN + or R1) were observed in 23 men (52.3%). A higher ISUP on biopsy was associated with APF [p = 0.006 (HR 2.32, 97.5% CI 1.35-4.59)] on univariable analysis. Progression-free survival was 80.4% after S-RP and 100% after S-RT at 3 years. Secondary therapy-free survival was 41.7% at 3 years in men undergoing AS. Metastasis-free survival was 80% at 5 years for the whole cohort.

CONCLUSION

With early detection of cancer relapse after FT S-RP and S-RT provide sufficient oncologic control at short to intermediate follow-up. After AS, a high secondary-therapy rate was observed.