Focal therapy for prostate cancer: revolution or evolution?

Migration in last decade to high-risk prostate cancer after radical prostatectomy

OBJECTIVE

There is controversy around prostate cancer (PCa) screening through the use of PSA, due to the risk of overtreatment. The current trend observed in various European and American studies is a decrease in the number of radical prostatectomy (RP) in low-risk PCa and an increase for intermediate or locally advanced diseases. The objective of this study was to observe the migration of the pathological stages from radical prostatectomy (RP) over 10 years in France through 2 French centers.

METHODS

It was a multicentric retrospective study, where all the RP realized in 2 French tertiary centers, in a laparoscopic or retropubic approach for each of the years 2005, 2010 and 2015 were included. Preoperative data (age, PSA, clinical stage, number of positive biopsies, Gleason biopsy score) and postoperative data (pTNM, pathological Gleason score (pGS)) were analyzed and compared.

RESULTS

In all, 1282 RP were realized (503 in 2005, 403 in 2010, 376 in 2015). Respectively between 2005, 2010, 2015 the average number of positive biopsy increased significantly from 2.30 vs. 2.88 vs. 5.3 (P=0.0001). The distribution of D'Amico's risk evolves with time: low-risk: 49.9 vs. 44.4 vs. 15.7% (P=0.0001); intermediate risk: 40.95 vs. 43.92 vs. 64.1% (P=0.0001) and high-risk: 9.15 vs. 11.66 vs. 20.2% (P=0.0001) between 2005, 2010 and 2015 respectively. pGS evolved to higher score with SG<7: 22.8 vs. 29.9 vs. 7.1% et SG≥7: 77.2 vs. 70.1 vs. 92.9% (P=0.001). Also, pTNM increased to non-organ-confined disease: pT2: 66.9 vs. 51.9 vs. 48.7%; pT3: 33.1 vs. 48.1 vs. 51.3% (P=0.0001).

CONCLUSION

This study showed a change in the management of PCa since new recommendations from medical authorities about PSA screening and evolving of conservative treatment. Number of RP increase for higher risk PCa. This change corresponds to better patient selection for RP: decrease for low-risk and increase for high-risk organ-confined disease.

LEVEL OF EVIDENCE

3.

Correlation of Peripheral Vein Tumour Marker Levels, Internal Iliac Vein Tumour Marker Levels and Radical Prostatectomy Specimens in Patients with Prostate Cancer and Borderline High Prostate-Specific Antigen: A Pilot Study

PURPOSE

To correlate prostate-specific antigen (PSA), free to total PSA percentage (fPSA%) and prostatic acid phosphatase (PAP) levels from peripheral and pelvic venous samples with prostatectomy specimens in patients with prostate adenocarcinoma and borderline elevation of PSA.

MATERIALS AND METHODS

In this prospective institutional review board approved study, 7 patients with biopsy proven prostate cancer had a venous sampling procedure prior to prostatectomy (mean 3.2 days, range 1-7). Venous samples were taken from a peripheral vein (PVS), the right internal iliac vein, a deep right internal iliac vein branch, left internal iliac vein and a deep left internal iliac vein branch. Venous sampling results were compared to tumour volume, laterality, stage and grade in prostatectomy surgical specimens.

RESULTS

Mean PVS PSA was 4.29, range 2.3-6 ng/ml. PSA and PAP values in PVS did not differ significantly from internal iliac or deep internal iliac vein samples (p > 0.05). fPSA% was significantly higher in internal iliac (p = 0.004) and deep internal iliac (p = 0.003) vein samples compared to PVS. One of 7 patients had unilateral tumour only. This patient, with left-sided tumour, had a fPSA% of 6, 6, 6, 14 and 12 in his peripheral, right internal iliac, deep right internal iliac branch, left internal iliac and deep left internal iliac branch samples respectively. There were no adverse events.

CONCLUSION

fPSA%, unlike total PSA or PAP, is significantly higher in pelvic vein compared to peripheral vein samples when prostate cancer is present. Larger studies including patients with higher PSA values are warranted to further investigate this counterintuitive finding.

Primary Zonal High Intensity Focused Ultrasound for Prostate Cancer: Results of a Prospective Phase IIa Feasibility Study

OBJECTIVES

To present the results of a prospective phase IIa study assessing the role of primary zonal High Intensity Focused Ultrasound (HIFU) for prostate cancer treatment.

METHODS

31 consecutive patients with unilateral organ confined prostate cancer primarily treated by zonal HIFU (from February 2007 to June 2011) were recruited into a single centre prospective phase IIa feasibility study. Complications were prospectively recorded and graded according to the Clavien-Dindo score. Postoperatively, patients were followed with serial serum PSA determinations and digital rectal examinations. An individual PSA nadir was identified in each patient. Followup also included whole gland biopsies performed in the event of a PSA rising>2.0 ng/mL above nadir value (Phoenix criteria).

RESULTS

At a median followup of 38 months, biochemical recurrence free survival was 100%, 89%, and 82.7% at 1, 2, and 3 years, respectively, with overall and cancer specific survival of 100%. The procedure was safe and well tolerated with no major adverse events. All patients were continent at their last followup and 55.2% (16/29) had erectile function sufficient for penetration.

CONCLUSION

Primary zonal HIFU is a valid focal therapy strategy, safe and feasible in day to day practice with good promising results [corrected].

Focal brachytherapy for selected low-risk prostate cancers: a pilot study

PURPOSE

To evaluate the feasibility and the early toxicity of focal brachytherapy in highly selected localized prostate cancer patients.

METHODS AND MATERIALS

Twenty-one patients underwent a focal brachytherapy between February 2010 and March 2012, representing 3.7% of the cases treated by our group during this period. Patient selection was based on (at least) two series of prostate biopsies and a high-resolution MRI. Only patients with very limited and localized tumors, according to strict criteria, were selected for the procedure. The technique used a real-time procedure with the implantation of free (125)I seeds and dynamic dose calculation. The prescribed dose for the focal volume was 145Gy.

RESULTS

The treated volume corresponded to a mean value of 34% of the total prostatic volume (range, 20-48%). For the focal volume, the mean D90 and V100 was 183.2Gy (range, 176-188Gy) and 99.3% (range, 98.8-100%), respectively. The technique was performed in an hour and a half. When compared with a previous cohort treated by whole-prostate brachytherapy, urinary toxicity (International Prostate Symptom Score) was borderline reduced (p = 0.04) at 6 months only, whereas the recovery of the International Index of Erectile Function 5 was better (p = 0.014). The International Continence Score was nil in almost all cases as well as rectal toxicity.

CONCLUSION

Focal treatment by brachytherapy is easily feasible with little acute toxicity. Further investigation is needed to assess the results in terms of tumor control and long-term toxicity.

Focal cryosurgical ablation of the prostate: a single institute's perspective

BACKGROUND

With the stage migration of prostate cancer witnessed in the late 1990's and early 2000's along with the persistent morbidities associated with prostatectomy and radiation therapy, the concept of focal prostate cancer treatment remains quite attractive. Herein we evaluate the tolerability and non-oncologic outcomes of a highly select cohort of men that underwent focal cryoablation of the prostate for the treatment of localized prostate cancer.

METHODS

Pre-operatively, erectile function was assessed by SHIM questionnaire while voiding symptoms were assessed by AUA symptom score. Twenty-six highly select patients (23 low-risk prostate cancer and 3 intermediate-risk prostate cancer) with documented minimal disease on saturation prostate biopsy underwent focal cryoablation of the prostate (24 hemi-ablation and 2 subtotal ablation). Subsequently, serum PSAs were obtained every 3 months for 2 years and then every 6 months thereafter. PSA failure was defined as an increase of 0.50 ng/ml over nadir. Mean follow-up was 19.1 months. Subjective assessment of erectile function and voiding was assessed post-operatively at each visit.

RESULTS

Based on our PSA failure definition, 11.5% (3 patients) of the cohort experienced biochemical failure. In two of the three patients, localized disease was detected on subsequent transrectal ultrasound guided biopsy. These two patients went on to have favorable PSA nadirs after undergoing conventional definitive therapy (one patient had external beam radiation and one patient had whole gland cryoablation). Within the study cohort, 27% (7 patients) reported new post-operative erectile dysfunction requiring therapy while no patients reported new post-operative urinary incontinence or worsening of voiding symptoms.

CONCLUSION

These preliminary results add to the expanding body of literature that the minimally invasive focal cryosurgical ablation of the prostate is a safe procedure with few side effects. The true extent of cancer control remains in question, but in highly select patients, favorable PSA kinetics have been demonstrated. If confirmed by further studies with long-term follow-up, this treatment approach could have a profound effect on prostate cancer management.

Is it possible to predict low-volume and insignificant prostate cancer by core needle biopsies?

In an attempt to minimize overtreatment of localized prostate cancer (PCa) active surveillance (AS) and minor invasive procedures have received increased attention. We investigated the accuracy of pre-operative findings in defining insignificant disease and distinguishing between unilateral/unifocal and bilateral/multifocal PCa. One-hundred and sixty patients undergoing radical prostatectomy were included. Histology reports from the biopsies and matching prostatectomies were compared. Three definitions of insignificant cancer were used: InsigE: tumour volume ≤0.5 mL; InsigW: tumour volume ≤1.3 mL; InsigM: tumour ≤5% of total prostate volume and prostate-specific antigen (PSA) ≤10 ng/mL. In all definitions, Gleason score (GS) was ≤6 and the tumour was organ confined. Biopsies alone performed poorly as a predictor of unifocal and unilateral cancer in the prostatectomy specimens with positive predictive values of 17.8% and 18.9% respectively. Inclusion of other clinical and biochemical parameters did not significantly increase the predictive value. However, the combination of GS ≤ 6, PSA ≤ 10 ng/mL and unifocal or unilateral cancer in biopsy cores resulted in a positive predictive value of 61.1%, 38.9% and 12.0%, respectively, for identifying InsigM, InsigW and InsigE in the prostate specimen. Conclusively, routine prostate biopsies cannot predict unifocal and unilateral PCa, and must be regarded insufficient to select patients for focal therapy. Although candidates for AS may be identified using standard biopsies, a considerable fraction of patients will be understaged. There is a need for more precise diagnostic tools to assess intraprostatic tumour growth.

Focal cryotherapy for clinically unilateral, low-intermediate risk prostate cancer in 73 men with a median follow-up of 3.7 years

BACKGROUND

Evolution of cryotherapy for prostate cancer is likely to result in parenchyma-sparing modifications adjacent to the urethra and neurovascular bundle. Results of initial series of focal therapy to minimize cryosurgery-related morbidity without compromising oncologic control have been encouraging, but limited in short-term outcomes.

OBJECTIVE

To retrospectively report (1) median 3.7-yr follow-up experience of primary focal cryotherapy for clinically unilateral prostate cancer with oncologic and functional outcomes, and (2) matched-pair analysis with contemporaneous patients undergoing radical prostatectomy (RP).

DESIGN, SETTING, AND PARTICIPANTS

Over 8.5 yr (September 2002 to March 2011), focal cryoablation (defined as ablation of one lobe) was performed in 73 carefully selected patients with biopsy-proven, clinically unilateral, low-intermediate risk prostate cancer. All patients underwent transrectal ultrasound (TRUS) and Doppler-guided sextant and targeted biopsies at entry.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Post-therapy follow-up included measuring prostate-specific antigen (PSA) level every 3-6 mo; TRUS biopsies at 6-12 mo and yearly, as indicated; and validated symptom questionnaires. Matched-pair analysis compared oncologic outcomes of focal cryotherapy and RP (matched for age, PSA, clinical stage, and biopsy Gleason score).

RESULTS AND LIMITATIONS

Complete follow-up was available in 70 patients (median follow-up: 3.7 yr; range: 1-8.5 yr). No patient died or developed metastases. Precryotherapy mean PSA was 5.9 ng/ml and Gleason score was 6 (n=30) or 7 (n=43). Postcryotherapy mean PSA was 1.6 ng/ml (70% reduction compared to precryotherapy; p<0.001). Of 48 patients undergoing postcryotherapy biopsy, 36 (75%) had negative biopsies; positive biopsy for cancer (n=12) occurred in the untreated contralateral (n=11) or treated ipsilateral lobe (n=1). Complete continence (no pads) and potency sufficient for intercourse were documented in 100% and 86% of patients, respectively. Matched-pair comparison of focal cryotherapy and RP revealed similar oncologic outcome, defined as needing salvage treatment.

CONCLUSIONS

Primary focal cryoablation for low-intermediate risk unilateral cancer affords encouraging oncologic and functional outcomes over a median 3.7-yr follow-up. Close surveillance with follow-up whole-gland biopsies is mandatory.

Inverse stage migration in patients undergoing radical prostatectomy: results of 8916 European patients treated within the last decade

OBJECTIVE

• To investigate the stage migration patterns during the last decade in European men treated with radical prostatectomy (RP).

PATIENTS AND METHODS

• Between 2000 and 2009, RP was performed in 8916 patients at a single European tertiary-care institution. • Age at diagnosis, clinical and pathological data were prospectively collected, and trends and proportions of preoperative and pathological findings were analysed over time.

RESULTS

• The median (mean) age of patients increased from 62 (62) to 63 (65) years between 2000 and 2009 (P < 0.001). • When patients were stratified based on their clinical findings according to the D'Amico risk groups for disease progression, the proportion of low-risk patients dropped from 66% in 2004 to 35% (P= 0.016) in the final year of the study period. • Similarly, histopathological evaluation of RP specimens showed a decrease of favourable disease (organ confinement and Gleason 3 + 3 grade) from 53 to 17% (P= 0.008). • This trend was accompanied by an increase in the number of patients with non-organ-confined prostate cancer (PCa) from 19% in 2003 to 33% in 2009 (P= 0.008). • The restriction of the analyses in the present study to a single tertiary-care centre could limit the generalizeability of the results.

CONCLUSIONS

• During the last decade, we observed an inverse stage migration trend in those European patients with PCa who were treated with RP. • The recorded increase in patients with non-organ-confined disease after RP could be related to changes in patient selection and the growing adoption of RP in multimodal treatment settings for locally advanced tumours as well as the availability of new treatment alternatives for low-risk disease.

Irreversible electroporation in the liver: contrast-enhanced inversion-recovery MR imaging approaches to differentiate reversibly electroporated penumbra from irreversibly electroporated ablation zones

PURPOSE

To evaluate the use of contrast material-enhanced magnetic resonance (MR) imaging with conventional T1-weighted gradient-recalled echo (GRE) and inversion-recovery (IR)-prepared GRE methods to quantitatively measure the size of irreversible electroporation (IRE) ablation zones in the liver in a rat model.

MATERIALS AND METHODS

All studies were approved by the institutional animal care and use committee and were performed in accordance with institutional guidelines. Seventeen adult male Sprague-Dawley rats were divided into four groups. Rats in groups 1-3 (n = 15 total) underwent IRE performed by using different IRE parameters after gadopentetate dimeglumine administration. Rats in group 4 (n = 2) underwent IRE ablation without prior gadopentetate dimeglumine injection to serve as control animals. MR imaging measurements (with conventional T1-weighted GRE and IR-prepared GRE methods) were performed 2 hours after IRE to predict the IRE ablation zones, which were correlated with pathology-confirmed necrosis areas 24 hours after IRE by using the Spearman correlation coefficient. Bland-Altman plots were also generated to investigate the agreement between MR imaging-measured ablation zones and reference standard histologic measurements of corresponding ablation zones.

RESULTS

The necrotic areas measured on the pathology images were well correlated with the hyperintense regions measured on T1-weighted GRE images (r = 0.891, P < .001) and normal tissue-nulled IR images (r = 0.874, P < .001); pathology measurements were also well correlated with the smaller hyperintense regions measured on those IR images with inversion times specifically selected to null signal from the peripheral penumbra surrounding the ablation zone (r = 0.939, P < .001). Bland-Altman plots indicated that these penumbra-nulled IR images provided more accurate predictions of IRE ablation zones, with T1-weighted GRE measurements tending to overestimate ablation zone sizes.

CONCLUSION

Contrast-enhanced MR imaging permits accurate depiction of ablated tissue zones after IRE procedures. IR-prepared contrast-enhanced MR imaging can be used to quantitatively measure IRE ablation zones in the liver.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100645/-/DC1.

Intensity-modulated radiotherapy for prostate cancer implementing molecular imaging with 18F-choline PET-CT to define a simultaneous integrated boost

PURPOSE

To report the own experience with 66 patients who received 18F-choline PET-CT (positron emission tomography-computed tomography) for treatment planning.

PATIENTS AND METHODS

Image acquisition followed 1 h after injection of 178-355 MBq (18)F-choline. An intraprostatic lesion (GTV(PET) [gross tumor volume]) was defined by a tumor-to-background SUV (standard uptake value) ratio > 2. A dose of 76 Gy was prescribed to the prostate in 2-Gy fractions, with a simultaneous integrated boost up to 80 Gy.

RESULTS

A boost volume could not be defined for a single patient. One, two and three or more lesions were found for 36 (55%), 22 (33%) and seven patients (11%). The lobe(s) with a positive biopsy correlated with a GTV(PET) in the same lobe in 63 cases (97%). GTV(PET) was additionally defined in 33 of 41 prostate lobes (80%) with only negative biopsies. GTV(PET), SUV(mean) and SUV(max) were found to be dependent on well-known prognostic risk factors, particularly T-stage and Gleason Score. In multivariate analysis, Gleason Score > 7 resulted as an independent factor for GTV(PET) > 8 cm(3) (hazard ratio 5.5; p = 0.02) and SUV(max) > 5 (hazard ratio 4.4; p = 0.04). Neoadjuvant hormonal treatment (NHT) did not affect SUV levels. The mean EUDs (equivalent uniform doses) to the rectum and bladder (55.9 Gy and 54.8 Gy) were comparable to patients (n = 18) who were treated in the same period without a boost (54.3 Gy and 55.6 Gy).

CONCLUSION

Treatment planning with (18)F-choline PET-CT allows the definition of an integrated boost in nearly all prostate cancer patients - including patients after NHT - without considerably affecting EUDs for the organs at risk. GTV(PET) and SUV levels were found to be dependent on prognostic risk factors, particularly Gleason Score.

[New perspectives in prostate cancer management]

The treatment of prostate cancer is experiencing important innovations. Hormone therapy includes a new class of drugs: LHRH antagonists, which induce a rapid, fast and sustained reduction of testosterone levels. Active surveillance enables to avoid an aggressive treatment without decreasing survival, provided that strict eligibility and follow-up criteria are applied. New imaging techniques and laboratory assays lead to early diagnosis of small size tumors. Lastly, focal therapy has the potential to target localized cancers without deterioration of surrounding structures. These concomitant improvements offer the clinician and the patient attractive options for prostate cancer management. However, they are not devoid of limitations and constraints. Thus, it is crucial to define the most appropriate patient's profile for each therapeutic option, taking into account the objective characteristics of the tumor and the psychological features of the patient.

Biopsy accuracy in identifying unilateral prostate cancer depends on prostate weight

OBJECTIVE

To evaluate the association between prostate weight and the diagnostic performance of routine biopsy schemes in detecting unilateral prostate cancer (PCa) that may be amenable to focal therapy.

METHODS AND MATERIALS

Retrospective analysis of patients undergoing radical prostatectomy at Duke University Medical Center from 1990 to 2007. The cohort was dichotomized according to prostate weight (≤40 and >40 g) and further divided by biopsy scheme: 6-9 (sextant) and 10-20 cores (extended). Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were calculated within each prostate weight group and compared between biopsy schemes.

RESULTS

A total of 859 patients were included in the study. Patients with prostates >40 g were generally older and had higher PSA levels (P < 0.0001 and P = 0.036, respectively). Unilateral disease was more common in prostates >40 g both on biopsy (69% vs. 60%, P = 0.009) and on final pathology (21% vs. 14%, P = 0.017) despite larger total tumor volume (6.1 vs. 4.8 cc, P < 0.001). Low grade PCa was also more common in larger glands (P = 0.003). Overall, extended biopsy schemes performed better than sextant but the benefit was statistically significant only in prostates >40 g.

CONCLUSIONS

Despite having higher tumor volumes, men with prostate weight >40 g were more likely to have unilateral PCa than those with smaller prostates. In prostates >40 g, increasing the number of cores harvested at biopsy increased the diagnostic performance for detecting cancer laterality. Therefore, our results suggest that the benefit of more extensive tissue sampling may be higher in larger prostates compared with smaller ones when selecting candidates for prostate hemiablation.