Transatlantic Consensus Group on active surveillance and focal therapy for prostate cancer

Abstract

What's known on the subject? and What does the study add? Active surveillance for prostate cancer is gaining increasing acceptance for low risk prostate cancer. Focal therapy is an emerging tissue preservation strategy that aims for treat only areas of cancer. Early phase trials have shown that side-effects can be significantly reduced using focal therapy. There is significant uncertainty in both active surveillance and focal therapy. This consensus group paper provides a road-map for clinical practice and research for both tissue-preserving strategies in the areas of patient population, tools for risk stratification and cancer localisation, treatment interventions as well as comparators and outcome measures in future comparative trials.

Objective: To reach consensus on key issues for clinical practice and future research in active surveillance and focal therapy in managing localized prostate cancer.

Patients and methods: A group of expert urologists, oncologists, radiologists, pathologists and computer scientists from North America and Europe met to discuss issues in patient population, interventions, comparators and outcome measures to use in both tissue-preserving strategies of active surveillance and focal therapy. Break-out sessions were formed to provide agreement or highlight areas of disagreement on individual topics which were then collated by a writing group into statements that formed the basis of this report and agreed upon by the whole Transatlantic Consensus Group.

Results: The Transatlantic group propose that emerging diagnostic tools such as precision imaging and transperineal prostate mapping biopsy can improve prostate cancer care. These tools should be integrated into prostate cancer management and research so that better risk stratification and more effective treatment allocation can be applied. The group envisaged a process of care in which active surveillance, focal therapy, and radical treatments lie on a continuum of complementary therapies for men with a range of disease grades and burdens, rather than being applied in the mutually exclusive and competitive way they are now.

Conclusion: The changing landscape of prostate cancer epidemiology requires the medical community to re-evaluate the entire prostate cancer diagnostic and treatment pathway in order to minimize harms resulting from over-diagnosis and over-treatment. Precise risk stratification at every point in this pathway is required alongside paradigm shifts in our thinking about what constitutes cancer in the prostate.

FIG. 1

Images showing the value of multi-parametric MRI for identifying the dominant lesion in a 58-year-old man with a preoperative PSA level of 11.9 ng/mL, in whom surgical pathology showed pT2b prostate cancer of Gleason score 8 (4 + 4). (A) T2-weighted image; (B) apparent diffusion coefficient (ADC) map; (C) dynamic contrast-enhanced T1-weighted image; and (D) colour-coded map showing peak enhancement. Marked differences in T2 signal, ADC values, and contrast enhancement can be seen between the dominant lesion (Gleason score 8; long arrows) at the right apex and a smaller lesion (Gleason score 6; short arrows) on the left side.

FIG. 2

In a 57-year-old man with a PSA level of 4.87 ng/mL diagnosed with low-risk prostate cancer (Gleason 3 + 3, 1/12 cores positive), multi-parametric MRI showed a clinically significant lesion: a 1 × 1 × 0.6-cm (0.5-mL by planimetry) focal area of low T2-signal intensity (A) within the right peripheral zone at the mid-gland level, abutting the lateral aspect of the prostatic capsule for a length of 1 cm without evidence of extracapsular extension. The lesion shows early arterial enhancement (B) and markedly restricted diffusion (C) in keeping with a carcinoma. No other clinically significant lesions are seen on MRI.

FIG. 3

The same man shown in Fig. 2 underwent 3-D TPM biopsy, with a total of 69 biopsies taken from 20 zones. Clinically significant cancer was confirmed in the right peripheral zone as shown on multiparametric MRI. Two smaller low-grade areas found in the contralateral lobe did not show enhancement or diffusion patterns that are associated with clinically significant cancer on MRI.

FIG. 4

The same man shown in Figs 2 and 3 underwent focal therapy using day-case TRUS-guided high-intensity focused ultrasound. Only the index (measurable) lesion on imaging was ablated. He was fully dry (leak-free, pad-free) after the procedure and had erections sufficient for penetrative sex at 6 weeks.