Salvage Cryoablation for Radiorecurrent Prostate Cancer: Initial Experience at a Regional Health Care System

Salvage Cryoablation for Recurrent Prostate Cancer Following Primary External Beam Radiotherapy or Primary Cryotherapy: A Propensity Score Matched Analysis of Mid-term Oncologic and Functional Outcomes

INTRODUCTION

Local prostate cancer recurrence following radiotherapy (XRT) or cryoablation (CRYO) may be addressed with salvage cryotherapy (SCT), although little is known about how the primary treatment modality affects SCT results. Oncologic and functional outcomes of patients who underwent SCT after primary XRT (XRT-SCT) or cryoablation (CRYO-SCT) were studied.

METHODS

Data was collected using the Duke Prostate Cancer database and the Cryo On-Line Data (COLD) registry. The primary outcome was biochemical progression-free survival (BPFS).  Urinary incontinence, rectourethral fistula, and erectile dysfunction were secondary outcomes. The Kaplan-Meier log-rank test and univariable/multivariable Cox proportional hazards (CPH) models were utilized to evaluate BPFS between groups.

RESULTS

419 XRT-SCT and 63 CRYO-SCT patients met inclusion criteria, that was reduced to 63 patients in each cohort after propensity matching. There was no difference in BPFS at 2 and 5 years both before (P = .5 and P = .7) and after matching (P = .6 and P = .3). On multivariable CPH, BPFS was comparable between treatment groups (CRYO-SCT, HR=1.1, [0.2-2.2]).  On the same analysis, BPFS was lower in D'Amico high-risk (HR 3.2, P < .01) and intermediate-risk (HR 1.95, P < .05) categories compared to low-risk. There was no significant difference in functional outcomes between cohorts.

CONCLUSION

Following primary cryotherapy, salvage cryoablation provides comparable intermediate oncological outcomes and functional outcomes compared to primary radiotherapy.

Systematic Review of Focal and Salvage Cryotherapy for Prostate Cancer

Cryotherapy is one of the recognised ablative modalities for both primary and salvage therapy for prostate cancer. It presents an alternative, less invasive treatment for an organ-confined disease, improved preservation of surrounding tissue and a more suitable option for patients who are unfit for radical prostatectomy. Nevertheless, the currently available literature is relatively too scarce to provide definite conclusions regarding the treatment outcomes in cryotherapy. The present study aimed to review current oncological and survival outcomes in cryotherapy for primary and recurrent prostate cancer. Furthermore, this study aimed to establish the complications and functional outcomes of cryotherapy for prostate cancer. A literature search was performed on the PubMed, Cochrane and Google Scholar databases. Current guidelines and recommendations from the European Association of Urology were also reviewed. The search keywords used included ‘Cryotherapy, Prostate Cancer’, ‘Cryoablation, Prostate Cancer’ and ’Cryosurgery, Focal Prostate Cancer’. Truncations and Boolean operators were used with the keywords. All relevant studies from after 2015, including abstracts and non-English research assessing oncological and functional outcomes and complications, were included. Twenty-six studies consisting of 11,228 patients were reviewed. Fifteen studies assessed the outcomes of primary cryotherapy, whereas 11 studies reported the outcomes in salvage therapy. The patient's age ranged 55-85 years, and the pre-procedural prostate-specific antigen (PSA) ranged 0.01-49.33 ng/mL. A total of 2031 patients were classified to be at low risk, 2,995 were at moderate risk and 253 were at high risk on the D’Amico prostate cancer risk classification system. Follow-ups ranged from 9.0 to 297.6 months. The disease-specific survival rate was 65.5%-100.0%, overall survival was 61.3%-99.1%, the PSA nadir was 0.01-2.63 ng/mL and the overall biochemical recurrence rate was 15.4%-62.0%. The complications included erectile dysfunction (3.7%-88.0%), urinary retention (2.13%-25.30%) and bladder neck stricture/stenosis (3.0%-16.7%). The functional assessment showed a mixture of improved, unchanged or worsened post-procedural outcomes in primary therapy. This systematic review did not find significant differences in the cancer-specific, overall and biochemical-free survival rate between the primary and salvage cryotherapy cohorts. The most common complications encountered in both cohorts were erectile dysfunction, urinary incontinence, lower urinary tract/bladder neck stricture and infection. More prospective and double-arm studies are critically needed to provide guidance on the careful selection of patient cohorts for cryotherapy, whether for curative or salvage intent.

Salvage re-irradiation using stereotactic body radiation therapy for locally recurrent prostate cancer: the impact of castration sensitivity on treatment outcomes

Background

Advances in imaging, biomaterials and precision radiotherapy provide new opportunities to salvage locally recurrent prostate cancer (PC). This study evaluates the efficacy and safety of re-irradiation using stereotactic body radiation therapy (SBRT). We hypothesized that patients with castrate-resistant PC (CRPC) would benefit less from local salvage.

Methods

A prospective clinical database was reviewed to extract 30 consecutive patients treated with prostate re-irradiation. Gallium prostate specific membrane antigen (PSMA) ligand positron emission tomography was performed following prostate-specific antigen failure in all patients and biopsy was obtained in 18 patients (60%). Re-irradiation was either focal (n = 13) or whole-gland (n = 17). Endo-rectal balloons were used in twenty-two patients and hydrogel spacers in eight patients. The median prescription dose was 5 fractions of 6.5 (range: 6–8) Gray (Gy).

Results

Median follow-up was 28 months. Failure occurred in 10 (out of 11) CRPC patients versus 6 (out of 19) castrate-sensitive patients (91% vs. 32%, p = 0.008) after a median of 13 and 23 months, respectively. Metastases occurred in 64% (n = 7) of CRPC patients versus 16% (n = 3) of castrate-sensitive patients (p = 0.007). Two patients experienced local in-field recurrence, thus local control was 93%. The 2 and 3-year recurrence-free survival were 84% and 79% for castrate-sensitive patients versus 18% and 9% for CRPC patients (p < 0.001), and 3-year metastasis-free survival was 90% versus 27% (p < 0.01) for castrate-sensitive and CRPC patients, respectively. Acute grade II and III genitourinary (GU) toxicity occurred in 27% and 3%, and late GU toxicity in 30% and 3%, respectively. No ≥ grade II acute gastrointestinal (GI) toxicity occurred, and only one patient (3%) developed late grade II toxicity.

Conclusions

Early delivery of salvage SBRT for local recurrence is associated with excellent 3-year disease control and acceptable toxicity in the castrate-sensitive phenotype. PSMA imaging for detection of local recurrence and the use of precision radiotherapy with rectal protective devices should be further investigated as a novel salvage strategy for radio-recurrent PC.

Functional Outcomes after Local Salvage Therapies for Radiation-Recurrent Prostate Cancer Patients: A Systematic Review

PURPOSE

To assess the rate and severity of functional outcomes after salvage therapy for radiation recurrent prostate cancer.

METHODS

This systematic review of the MEDLINE/PubMed database yielded 35 studies, evaluating salvage radical prostatectomy (RP), brachytherapy (BT), high-intensity focal ultrasound (HIFU) and cryotherapy (CT) after failure of primary radiation therapy. Data on pre- and post-salvage rates and severity of functional outcomes (urinary incontinence, erectile dysfunction, and lower urinary tract symptoms) were collected from each study.

RESULTS

The rates of severe urinary incontinence ranged from 28-88%, 4.5-42%, 0-6.5%, 2.4-8% post salvage RP, HIFU, CT and BT, respectively. The rates of erectile dysfunction were relatively high reaching as much as 90%, 94.6%, 100%, 62% following RP, HIFU, CT and BT, respectively. Nonetheless, the high pre-salvage rates of ED preclude accurate estimation of the effect of salvage therapy. There was an increase in the median IPSS following salvage HIFU, BT and CT ranging from 2.5-3.4, 3.5-12, and 2, respectively. Extended follow-up showed a return-to-baseline IPSS in a salvage BT study. The reported data suffer from selection, reporting, publication and period of study biases, making inter-study comparisons inappropriate.

CONCLUSIONS

local salvage therapies for radiation recurrent PCa affect continence, lower urinary tract symptoms and sexual functions. The use of local salvage therapies may be warranted in the setting of local disease control, but each individual decision must be made with the informed patient in a shared decision working process.