Salvage therapy for radiorecurrent prostate cancer

Development and internal validation of multivariable prediction models for biochemical failure after MRI-guided focal salvage high-dose-rate brachytherapy for radiorecurrent prostate cancer

Background and purpose

Magnetic resonance-guided focal salvage high-dose-rate brachytherapy (FS-HDR-BT) for radiorecurrent prostate cancer (PCa) shows low toxicity rates. However, biochemical failure (BF) after treatment occurs frequently. We developed two prediction models for BF (Phoenix definition) with the aim of enhancing patient counselling before FS-HDR-BT and during follow-up.

Materials and methods

A prospective cohort of 150 radiorecurrent PCa patients treated with FS-HDR-BT between 2013 and 2020 was used for model development and internal validation. Multivariable Cox Proportional Hazards regression was applied. For model 1, only pre-salvage variables were included as candidate predictors. For model 2, additional (post-)salvage characteristics were tested. After calibration, nomograms and webtools were constructed. Finally, three risk groups were identified.

Results

Sixty-one patients (41%) experienced BF. At baseline (model 1), age, gross tumour volume, pre-salvage PSA, and pre-salvage PSA doubling time (PSADT) were predictive of BF. During follow-up (model 2), age, pre-salvage PSA and PSADT, seminal vesicle involvement, post-salvage time to PSA nadir, and percentage PSA reduction were predictive of BF. The adjusted C-statistics were 0.73 (95% CI: 0.66-0.81) and 0.84 (95% CI: 0.78-0.90), respectively, with acceptable calibration. Estimated 2-year biochemical disease-free survival for the low-, intermediate-, and high-risk groups were 84%, 70%, and 31% (model 1), and 100%, 71%, and 5% (model 2).

Conclusion

Two models are provided for prediction of BF in patients with radiorecurrent PCa treated with FS-HDR-BT. Based on pre- and post-salvage characteristics, we are able to identify patients with a high risk of BF. These findings can aid patient counselling for FS-HDR-BT.

High-dose-rate brachytherapy for prostate cancer: Rationale, current applications, and clinical outcome

Background

High‐dose‐rate brachytherapy (HDR BRT) has been enjoying rapid acceptance as a treatment modality offered to selected prostate cancer patients devoid of risk group, employed either in monotherapy setting or combined with external beam radiation therapy (EBRT) and is currently one of the most active clinical research areas.

Recent findings

This review encompasses all the current evidence to support the use of HDR BRT in various clinical scenario and shines light to the HDR BRT rationale, as an ultimately conformal dose delivery method enabling safe dose escalation to the prostate.

Conclusion

Valid long‐term data, both in regard to the oncologic outcomes and toxicity profile, support the current clinical indication spectrum of HDR BRT. At the same time, this serves as solid, rigid ground for emerging therapeutic applications, allowing the technique to remain in the spotlight alongside stereotactic radiosurgery.

Challenge and Outcome for the Prostate Squamous Cell Carcinoma Which Developed 8 Years after Low-Dose-Rate Brachytherapy Approached by a Combined Multimodal Treatment with High-Dose-Rate Interstitial Brachytherapy, External Beam Radiation Therapy, and Chemotherapy

Prostate squamous cell carcinoma (pSCC) rarely develops as a secondary cancer after treatment with low-dose-rate brachytherapy (LDR-BT). There is no established effective treatment for the disease condition. Herein, we present a 78-year-old man who developed pSCC 8 years after LDR-BT. He was subsequently selected to receive a combined multimodal treatment with high-dose-rate interstitial brachytherapy (HDR-ISBT), external beam radiation therapy, and chemotherapy for his pSCC. Eleven months later, he displayed no biochemical failure nor clinical radiographic recurrence. However, MRI detected a newly developed prostatic-rectal fistula (grade 4), and a colostomy was performed to relieve pain and inflammation. To our knowledge, this is the first report to perform a combined multimodal treatment with HDR-ISBT for pSCC suspected as a secondary cancer due to LDR-BT.

Focal MRI-Guided Salvage High-Dose-Rate Brachytherapy in Patients With Radiorecurrent Prostate Cancer

Introduction:

Whole-gland salvage treatment of radiorecurrent prostate cancer has a high rate of severe toxicity. The standard of care in case of a biochemical recurrence is androgen deprivation treatment, which is associated with morbidity and negative effects on quality of life. A salvage treatment with acceptable toxicity might postpone the start of androgen deprivation treatment, might have a positive influence on the patients’ quality of life, and might even be curative. Here, toxicity and biochemical outcome are described after magnetic resonance imaging–guided focal salvage high-dose-rate brachytherapy in patients with radiorecurrent prostate cancer.

Materials and Methods:

Seventeen patients with pathologically proven locally recurrent prostate cancer were treated with focal high-dose-rate brachytherapy in a single 19-Gy fraction using magnetic resonance imaging for treatment guidance. Primary radiotherapy consisted of external beam radiotherapy or low-dose-rate brachytherapy. Tumors were delineated with Ga-68–prostate-specific membrane antigen or F18-choline positron emission tomography in combination with multiparametric magnetic resonance imaging. All patients had a prostate-specific antigen level of less than 10 ng/mL at the time of recurrence and a prostate-specific antigen doubling time of ≥12 months. Toxicity was measured by using the Common Terminology Criteria for Adverse Events version 4.

Results:

Eight of 17 patients had follow-up interval of at least 1 year. At a median follow-up interval of 10 months (range 3-40 months), 1 patient experienced a biochemical recurrence according to the Phoenix criteria, and prostate-specific membrane antigen testing revealed that this was due to a distant nodal metastasis. One patient had a grade 3 urethral stricture at 2 years after treatment.

Conclusion:

Focal salvage high-dose-rate brachytherapy in patients with radiorecurrent prostate cancer showed grade 3 toxicity in 1 of 17 patients and a distant nodal metastasis in another patient. Whether this treatment option leads to cure in a subset of patients or whether it can successfully postpone androgen deprivation treatment needs further investigation.

High-dose-rate brachytherapy as salvage modality for locally recurrent prostate cancer after definitive radiotherapy : A systematic review

PURPOSE

To review the current status of interstitial high-dose-rate brachytherapy as a salvage modality (sHDR BRT) for locally recurrent prostate cancer after definitive radiotherapy (RT).

MATERIALS AND METHODS

A literature search was performed in PubMed using "high-dose-rate, brachytherapy, prostate cancer, salvage" as search terms. In all, 51 search results published between 2000 and 2016 were identified. Data tables were generated and summary descriptions created. The main outcome parameters used were biochemical control (BC) and toxicity scores.

RESULTS

Eleven publications reported clinical outcome and toxicity with follow-up ranging from 4-191 months. A variety of dose and fractionation schedules were described, including 19.0 Gy in 2 fractions up to 42.0 Gy in 6 fractions. The 5‑year BC ranged from 18-77%. Late grade 3 genitourinary and gastrointestinal toxicity was 0-32% and 0-5.1%, respectively.

CONCLUSIONS

sHDR BRT appears as safe and effective salvage modality for the reirradiation of locally recurrent prostate cancer after definitive RT.

The feasibility and safety of repeat cryosurgical ablation of localized prostate cancer

BACKGROUND

The aim of the study was to assess the morbidity and efficacy of repeat cryoablation (CA) in the treatment of localized prostate cancer.

METHODS

Twenty-seven patients with median age of 71 years (range 48-80) who underwent repeat CA between April 2003 and April 2011 at a single institution were included. The median initial prostate-specific antigens (PSA) and Gleason values were 6.2 ng/ml (range 4-23.6) and 7 (range 6-9), respectively. Twenty-four patients underwent two CA treatments, and three patients underwent three CA treatments. Pre- and perioperative parameters and oncological and functional outcomes were evaluated.

RESULTS

No intraoperative complications occurred. After the first CA, PSA was undetectable in 10 patients, and the median nadir PSA value was 0.65 ng/ml (range 0.1-4.9). After the second CA, 4 patients had undetectable PSA, and the median nadir PSA value was 1.25 ng/ml (range 0.2-7.9). For patients who underwent a third CA treatment, no patients had undetectable PSA, and the subsequent median nadir PSA value was 1.6 ng/ml (range 0.4-4.5). Two patients had incontinence (1 pad per day) following repeat CA. One patient had urinary retention after the third CA treatment, and one had urethral stricture. The mean hospitalization and follow-up periods were 1 day (range 0-2) and 51.5 months (range 11-96), respectively.

CONCLUSIONS

Repeat CA successfully reduced PSA levels, and complications were modest. We conclude that repeat CA is a feasible, safe, and effective treatment option for localized prostate cancer.

Synthesis and characterization of multifunctional hybrid-polymeric nanoparticles for drug delivery and multimodal imaging of cancer

In this study, multifunctional hybrid-polymeric nanoparticles were prepared for the treatment of cultured multicellular tumor spheroids (MCTS) of the PANC-1 and MIA PaCa-2 pancreatic carcinoma cell lines. To synthesize the hybrid-polymeric nanoparticles, the poly lactic-co-glycolic acid core of the particles was loaded with Rhodamine 6G dye and the chemotherapeutic agent, Paclitaxel, was incorporated into the outer phospholipid layer. The surface of the nanoparticles was coated with gadolinium chelates for magnetic resonance imaging applications. This engineered nanoparticle formulation was found to be suitable for use in guided imaging therapy. Specifically, we investigated the size-dependent therapeutic response and the uptake of nanoparticles that were 65 nm, 85 nm, and 110 nm in size in the MCTS of the two pancreatic cancer cell lines used. After 24 hours of treatment, the MCTS of both PANC-1 and MIA PaCa-2 cell lines showed an average increase in the uptake of 18.4% for both 65 nm and 85 nm nanoparticles and 24.8% for 110 nm nanoparticles. Furthermore, the studies on therapeutic effects showed that particle size had a slight influence on the overall effectiveness of the formulation. In the MCTS of the MIA PaCa-2 cell line, 65 nm nanoparticles were found to produce the greatest therapeutic effect, whereas 12.8% of cells were apoptotic of which 11.4% of cells were apoptotic for 85 nm nanoparticles and 9.79% for 110 nm nanoparticles. Finally, the study conducted in vivo revealed the importance of nanoparticle size selection for the effective delivery of drug formulations to the tumors. In agreement with our in vitro results, excellent uptake and retention were found in the tumors of MIA PaCa-2 tumor-bearing mice treated with 110 nm nanoparticles.