Secondary chemoprevention of localized prostate cancer by short-term androgen deprivation to select indolent tumors suitable for active surveillance: a prospective pilot phase II study

Randomized, Open-Label Phase 2 Study of Apalutamide plus Androgen Deprivation Therapy versus Apalutamide Monotherapy versus Androgen Deprivation Monotherapy in Patients with Biochemically Recurrent Prostate Cancer

Purpose. This randomized phase 2 study sought to assess the treatment effect of a finite duration of apalutamide with and without androgen deprivation therapy (ADT) in biochemically recurrent prostate cancer (BCR PC). Materials and Methods. Patients with BCR PC after primary definitive therapy and prostate-specific antigen (PSA) doubling time ≤12 months were randomized to open-label apalutamide (240 mg/d) alone, apalutamide plus ADT, or ADT alone (1 : 1:1 ratio) for 12 months followed by a 12-month observation period (NCT01790126). Mean changes from baseline in Functional Assessment of Cancer Therapy-Prostate (FACT-P) at 12 months (primary endpoint) and other prespecified assessments of health-related quality of life (HRQoL), PSA nadir, time to PSA progression, time to testosterone recovery, recovered testosterone >150 ng/dL without PSA progression at 24 months, and molecular markers were evaluated. Results. In 90 enrolled patients (apalutamide plus ADT (n = 31), apalutamide (n = 29), ADT (n = 30)), FACT-P at 12 months was not significantly different between apalutamide, ADT and apalutamide, and ADT groups. Addition of apalutamide to ADT prolonged time to PSA progression but this change did not reach statistical significance (hazard ratio (HR): 0.56, 95% confidence interval (CI): 0.23–1.36, $P=0.196$ ); time to testosterone recovery was similar in the ADT-containing groups. In apalutamide plus ADT, apalutamide, and ADT groups, 37.9%, 37.0%, and 19.2% of patients, respectively, had testosterone >150 ng/dL at 24 months without confirmed PSA progression. Of the few biomarkers expressed in blood, EPHA3 was significantly associated with shorter time to PSA progression ( $P=0.02$ ) in the overall population. Conclusions. HRQoL was similar in patients treated with apalutamide alone, ADT alone, or their combination, although apalutamide plus ADT did not demonstrate statistically significant noninferiority in change from baseline in overall HRQoL. The aggregated efficacy and safety outcomes support further evaluation of apalutamide plus ADT in BCR PC.

A Feasibility Study of the Therapeutic Response and Durability of Short-term Androgen-targeted Therapy in Early Prostate Cancer Managed with Surveillance: The Therapeutics in Active Prostate Surveillance (TAPS01) Study

Background

Active surveillance (AS) is a preferred management option for men with prostate cancer with favourable prognosis. However, nearly half of men on AS switch to treatment within 5 years, so therapeutic strategies to prevent or delay disease progression could be considered. The androgen receptor is the pre-eminent oncogenic driver in prostate cancer.

Objective

To explore image-based tumour responses and the patient impact of short-duration androgen-targeted therapy (ATT) to abrogate disease progression during AS.

Design, setting, and participants

Men on AS with Cambridge Prognostic Group 1 & 2 (low and favourable intermediate risk) prostate cancer and lesions visible on magnetic resonance imaging (MRI) were recruited to an open-label, single-centre, phase 2 feasibility study of short-term ATT (the TAPS01 study).

Intervention

Apalutamide 240 mg was administered for 90 days.

Outcome measurements and statistical analysis

MRI-measured tumour volume (TV), gland volume (GV), and the TV/GV ratio were calculated at baseline, at day 90 (end of treatment), and at 6- and 18-month follow-up. Quality of life metrics were measured at day 0, day 90, and 6 weeks after ATT.

Results and limitations

Eleven patients (40% of eligible men approached) agreed to participate, of whom nine completed treatment. At day 90, the median percentage reduction was −38.2% (range −51.8% to −23.5%) for GV, −54.2% (range −74.1% to −13.8%) for TV, and −27.2% (range −61.5% to −7.5%) for TV/GV (all p < 0.0001). At 6 mo, while GV had returned to baseline (p = 0.95) both TV (−31.9%; p = 0.0007) and TV/GV (−28.7%; p = 0.0009) remained significantly reduced. This reduction was sustained at 18 months (TV −18%, TV/GV −23.8%; p = 0.01). European Organization for Research and Treatment of Cancer QoL core 30-item questionnaire scores for global, physical, role, and social functioning decreased during treatment, but all were recovering by 6 weeks. EQ-VAS scores were unchanged compared to baseline.

Conclusions

TAPS01 has demonstrated feasibility and patient tolerability for short-term ATT in men on AS. Our data suggest a selective and durable antitumour effect in the short term and support a larger-scale randomised trial.

Patient summary

We investigated the feasibility of short-term treatment with an androgen inhibitor to prevent or delay disease progression for men on active surveillance for prostate cancer. Results for a small group of patients show that 90-day treatment led to a sustained decrease in tumour volume over 18 months. The findings warrant a larger clinical trial for this approach, which could allow patients to delay or even avoid longer-term active treatments.

Contemporary clinicopathological characteristics of pT0 prostate cancer at radical prostatectomy: A population-based study

BACKGROUND

The incidence of pT0 prostate cancer (CaP) at radical prostatectomy (RP) is extremely rare. We performed the first population-based analysis of pT0 CaP at RP.

METHODS

Within the Surveillance, Epidemiology, and End Results database (2004-2015), we tested for clinical and pathological characteristics according to pT0 vs. non-pT0 CaP and included a multivariable logistic regression model.

RESULTS

pT0 was identified in 358 (0.2%) out of 160,532 clinically localized RP patients. The majority of pT0 patients presented with initial prostate-specific antigen (PSA) <10 ng/ml (82.4%), harboured biopsy Gleason score (GS) 6 (69.8%) and cT1 disease (78.1%). Nonetheless, pT0 was identified in 13 (3.6%) patients with PSA ≥20 ng/ml, in 69 (19.3%) patients with biopsy GS ≥7 and in 78 (21.8%) patients with ≥cT2 disease. In a subset of patients with available number of biopsy cores, pT0 was identified in 34 (33.3%) patients with ≥2 positive biopsy cores. Age, race, marital status, hospital region, population density, PSA, as well as number of biopsy cores did not discriminate between pT0 and non-pT0 cases. Analyses according to annual rates (2004-2015) of pT0 did not vary between the years (0.2%-1.6%, estimated annual percent change: -1.6%, P = 0.3). Neither did the rates vary according to geographic region.

CONCLUSIONS

pT0 at RP is very rare. Even though, most pT0 patients have low PSA, low clinical stage, low biopsy GS, and only one positive biopsy core, those with more aggressive characteristics can still harbour pT0 at RP.

Focal Therapy for Prostate Cancer: Pending Questions

Focal therapy (FT) represents a potential shift in clinical practice by featuring a tissue-sparing approach for prostate cancer (PCa) treatment. It stands midway between active surveillance (AS) and more aggressive options like radical prostatectomy (RP) or radiotherapy. The field has enormously evolved in the last few years but there are still pending questions to answer in the future. The manuscript overlooks FT in terms of indications, available energies, situation of tumor microenvironment, follow-up, re-interventions, and the future of this approach for PCa.

Short-term enzalutamide treatment for the potential remission of active surveillance or intermediate-risk prostate cancer: a case study, review, and the need for a clinical trial

Active surveillance (AS) is a widely recognized and utilized option by which prostate cancer patients with less aggressive tumors on diagnosis defer immediate traditional conventional therapy (surgery, radiation) and undergo close monitoring by a physician for any clinical or pathologic changes. The juxtaposition of low- to intermediate-risk elderly patients between effective and conventional treatment with associated risks and monitoring without the opportunity for relief of anxiety and other psychological problems can be significant. Minimal and safe treatment over 6 months with the hope of eliminating the existing disease is of significant interest to prostate cancer patients. Unfortunately, dietary supplements have failed to improve and have sometimes even contributed to disease progression. In addition, the use of multiple medications is not always appropriate or safe. In this case study, we administered low doses of enzalutamide (80 mg/day–120 mg/day) in an AS patient during a 6 month period. Results showed a significant reduction in tumor size, as evidenced by magnetic resonance imaging and color Doppler, as well as a an undetectable level of prostate specific antigen during, and immediately following treatment. The use of an oral second-generation androgen-receptor signaling inhibitor was shown to be of benefit to patients unwilling to pursue AS and conventional treatment. Administration of enzalutamide did not reduce testosterone levels, but helped maintain good quality of life, was more cost effective at low doses, and was previously shown to be heart healthy and efficacious during early stages of castration-resistant prostate cancer. Although we do not advocate enzalutamide as a treatment approach in these situations, we believe that a clinical trial to evaluate short-term low-dose treatment using enzalutamide is warranted.