Evolution from active surveillance to focal therapy in the management of prostate cancer

Role of multiparametric MRI in long-term surveillance following focal laser ablation of prostate cancer

OBJECTIVE

Determine the multiparametric magnetic resonance imaging (mpMRI) appearance of the prostate following focal laser ablation (FLA) for PCa and to identify imaging characteristics associated with recurrent disease.

METHODS

Retrospective analysis of patients who underwent FLA for low-intermediate risk PCa between 2010 and 2014 was performed. Early (median 4 months) and late mpMRI (median 49 months) follow-up were qualitatively assessed for T₂-weighted, dynamic contrast enhanced (DCE) and diffusion weighted imaging (DWI) appearances and also compared to corresponding PSA values and biopsy results.

RESULTS

55 cancers were treated in 54 men (mean age 61.0 years). Early mpMRI was performed in 30 (54.5%) patients while late follow-up mpMRI in 42 (84%). Ill-defined scarring with and without atrophy at the treatment site were the most common appearances. In patients with paired MRI and biopsy, one of four patients with clinically significant PCa on biopsy (≥GG2 or≥6 mm GG1) showed hyperenhancement or restricted diffusion at early follow-up. At late follow-up, positive biopsies were seen in 5/8 (63%) cases with hyperenhancement and 5/6 (83%) cases with restricted diffusion at the treatment site. PSA change was not associated with biopsy results at either time point.

CONCLUSION

mpMRI is able to document the morphological and temporal changes following focal therapy. It has limited ability to detect recurrent disease in early months following treatment. Late-term mpMRI is sensitive at identifying patients with recurrent disease. Small sample size is, however, a limitation of the study.

ADVANCES IN KNOWLEDGE

Implementing MRI in follow-up after FT may be useful in predicting residual or recurrent PCa and therefore provide reliable outcome data.

Focal high-dose-rate brachytherapy for localized prostate cancer: toxicity and preliminary biochemical results

BACKGROUND

This study aimed to evaluate the outcomes and the toxicity of focal high-dose-rate (HDR) brachytherapy in selected localized prostate cancer patients.

METHODS

Fifty patients were treated with focal high-dose-rate brachytherapy between March 2013 and November 2017, representing 5% of the cases treated by our group during this period. Only patients with very limited and localized tumors, according to strict criteria, were selected for the procedure. The prescribed dose for the focal volume was 24 Gy.

RESULTS

The treated volume corresponded to a mean value of 32% of the total prostatic volume. The mean focal D₉₀ in our series was 23 Gy (range 16-26 Gy). The mean initial IPSS was 8.2 (range 0-26), at 6 months 7.5 (range 0-23), and at 24 months 6.7 (range 0-18). No acute or late urinary retention was seen. When the ICIQ-SF score was 0 at the end of treatment, it remained nil thereafter at 1 and 2 years for all patients. No intraoperative or perioperative complications occurred. No rectal toxicity was reported after treatment. Of the total patients identified as potent, only three patients had a very slight decrease of the mean IIEF5. The mean initial PSA was 6.9 ng/mL (range 1.9-13.4). At the last follow-up visit, the mean PSA was 3 ng/ml (range 0.48-8.11).

CONCLUSION

HDR focal brachytherapy in selected patients with low intermediate-risk prostate cancer could achieve the same satisfactory results in terms of relapse-free survival as conventional whole prostate brachytherapy with less toxicity.

Association and regulation of protein factors of field effect in prostate tissues

Field effect or field cancerization denotes the presence of molecular aberrations in structurally intact cells residing in histologically normal tissues adjacent to solid tumors. Currently, the etiology of prostate field‑effect formation is unknown and there is a prominent lack of knowledge of the underlying cellular and molecular pathways. We have previously identified an upregulated expression of several protein factors representative of prostate field effect, i.e., early growth response-1 (EGR‑1), platelet-derived growth factor‑A (PDGF‑A), macrophage inhibitory cytokine‑1 (MIC‑1), and fatty acid synthase (FASN) in tissues at a distance of 1 cm from the visible margin of intracapsule prostate adenocarcinomas. We have hypothesized that the transcription factor EGR‑1 could be a key regulator of prostate field‑effect formation by controlling the expression of PDGF‑A, MIC‑1, and FASN. Taking advantage of our extensive quantitative immunofluorescence data specific for EGR‑1, PDGF‑A, MIC‑1, and FASN generated in disease‑free, tumor‑adjacent, and cancerous human prostate tissues, we chose comprehensive correlation as our major approach to test this hypothesis. Despite the static nature and sample heterogeneity of association studies, we show here that sophisticated data generation, such as by spectral image acquisition, linear unmixing, and digital quantitative imaging, can provide meaningful indications of molecular regulations in a physiologically relevant in situ environment. Our data suggest that EGR‑1 acts as a key regulator of prostate field effect through induction of pro‑proliferative (PDGF‑A and FASN), and suppression of pro‑apoptotic (MIC‑1) factors. These findings were corroborated by computational promoter analyses and cell transfection experiments in non‑cancerous prostate epithelial cells with ectopically induced and suppressed EGR‑1 expression. Among several clinical applications, a detailed knowledge of pathways of field effect may lead to the development of targeted intervention strategies preventing progression from pre-malignancy to cancer.

From whole gland to hemigland to ultra-focal high-dose-rate prostate brachytherapy: A dosimetric analysis

PURPOSE

To assess the magnitude of dosimetric reductions of a focal and ultra-focal high-dose-rate (HDR) prostate brachytherapy treatment strategy relative to standard whole gland (WG) treatment.

METHODS AND MATERIALS

HDR brachytherapy plans for five patients treated with WG HDR monotherapy were optimized to assess different treatment strategies. Plans were generated to treat the hemigland (HG), one-third gland (1/3G), and one-sixth gland (1/6G), as well as to assess treating the WG with a boost to one of those sub-volumes (WG + HG, WG + 1/3G, WG + 1/6G). Dosimetric parameters analyzed included Target D90%, V100%, V150%, Bladder (B), Rectal (R), Urethral (U) D0.1, 1 and 2cc, Urethral V75%, and the V50% to the contralateral HG. Two-tailed t tests were used for comparison of means, and p-values less than 0.05 were considered statistically significant.

RESULTS

Target objectives (D90 > 100% and V100 > 97%) were met in all cases. Significant organs at risk dose reductions were achieved for all approaches compared with WG plans. 1/6G vs WG plans resulted in the greatest reduction in dose with a mean bladder D2cc 24.7 vs 64.8%, rectal D2cc 32.8 vs 65.3%, urethral D1cc 52.1 vs 103.8%, and V75 14.5 vs 75% (p < 0.05 for all comparisons).

CONCLUSION

Significant dose reductions to organs at risk can be achieved using HDR focal brachytherapy. The magnitude of the reductions achievable with treating progressively smaller sub-volumes suggests the potential to reduce morbidity, but the clinical impact on morbidity and tumor control remain to be investigated.

Inherently multimodal nanoparticle-driven tracking and real-time delineation of orthotopic prostate tumors and micrometastases

Prostate cancer is the most common cancer among men and the second cause of male cancer-related deaths. There are currently three critical needs in prostate cancer imaging to personalize cancer treatment: (1) accurate intraprostatic imaging for multiple foci and extra-capsular extent; (2) monitoring local and systemic treatment response and predicting recurrence; and (3) more sensitive imaging of occult prostate cancer bone metastases. Recently, our lab developed porphysomes, inherently multimodal, all-organic nanoparticles with flexible and robust radiochemistry. Herein, we validate the first in vivo application of (64)Cu-porphysomes in clinically relevant orthotopic prostate and bony metastatic cancer models. We demonstrate clear multimodal delineation of orthotopic tumors on both the macro- and the microscopic scales (using both PET and fluorescence) and sensitively detected small bony metastases (<2 mm). The unique and multifaceted properties of porphysomes offers a promising all-in-one prostate cancer imaging agent for tumor detection and treatment response/recurrence monitoring using both radionuclide- and photonic-based strategies.

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.

Performance characteristics of MR imaging in the evaluation of clinically low-risk prostate cancer: a prospective study

PURPOSE

To prospectively evaluate diagnostic performance of T2-weighted magnetic resonance (MR) imaging and MR spectroscopic imaging in detecting lesions stratified by pathologic volume and Gleason score in men with clinically determined low-risk prostate cancer.

MATERIALS AND METHODS

The institutional review board approved this prospective, HIPAA-compliant study. Written informed consent was obtained from 183 men with clinically low-risk prostate cancer (cT1-cT2a, Gleason score≤6 at biopsy, prostate-specific antigen [PSA] level<10 ng/mL [10 μg/L]) undergoing MR imaging before prostatectomy. By using a scale of 1-5 (score 1, definitely no tumor; score 5, definitely tumor), two radiologists independently scored likelihood of tumor per sextant on T2-weighted images. Two spectroscopists jointly recorded locations of lesions with metabolic features consistent with tumor on MR spectroscopic images. Whole-mount step-section histopathologic analysis constituted the reference standard. Diagnostic performance at sextant level (T2-weighted imaging) and detection sensitivities (T2-weighted imaging and MR spectroscopic imaging) for lesions of 0.5 cm3 or larger were calculated.

RESULTS

For T2-weighted imaging, areas under the receiver operating characteristic curves for sextant-level detection were 0.77 (reader 1) and 0.82 (reader 2). For lesions of ≥0.5 cm3 and, 1

CONCLUSION

In men with clinically low-risk prostate cancer, detection of lesions of <1 cm3 with T2-weighted imaging is significantly dependent on lesion Gleason score; detection of lesions of ≥1 cm3 is significantly better than detection of smaller lesions and is not affected by lesion Gleason score. The role of MR spectroscopic imaging alone in this population is limited.

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Key Words Collapse

MESH Headings

• Adult
• Aged
• Humans
• Image Enhancement/methods
• Image Interpretation, Computer-Assisted/methods
• Male
• Middle Aged
• Preoperative Care/methods
• Prospective Studies
• Prostatic Neoplasms/pathology
• Reproducibility of Results
• Risk Factors
• Sensitivity and Specificity

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Grants

• R01 CA076423 NCI NIH HHS

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Affiliation(s)

Hebert Alberto Vargas Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, Room C-278, New York, NY 10065, USA
Oguz Akin
Amita Shukla-Dave
Jingbo Zhang
Kristen L Zakian
Junting Zheng
Kent Kanao
Debra A Goldman
Chaya S Moskowitz
Victor E Reuter
James A Eastham
Peter T Scardino
Hedvig Hricak

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Advances in oncologic imaging: update on 5 common cancers

Imaging has become a pivotal component throughout a patient's encounter with cancer, from initial disease detection and characterization through treatment response assessment and posttreatment follow-up. Recent progress in imaging technology has presented new opportunities for improving clinical care. This article provides updates on the latest approaches to imaging of 5 common cancers: breast, lung, prostate, and colorectal cancers, and lymphoma.

Markers of field cancerization: proposed clinical applications in prostate biopsies

Field cancerization denotes the occurrence of genetic, epigenetic, and biochemical aberrations in structurally intact cells in histologically normal tissues adjacent to cancerous lesions. This paper tabulates markers of prostate field cancerization known to date and discusses their potential clinical value in the analysis of prostate biopsies, including diagnosis, monitoring progression during active surveillance, and assessing efficacy of presurgical neoadjuvant and focal therapeutic interventions.