Overtreatment and Underutilization of Watchful Waiting in Men With Limited Life Expectancy: An Analysis of the Michigan Urological Surgery Improvement Collaborative Registry

Using Competing Risk of Mortality to Inform the Transition from Prostate Cancer Active Surveillance to Watchful Waiting

BACKGROUND

For men on active surveillance (AS) for prostate cancer (PCa), disease progression and age-related changes in health may influence decisions about pursuing curative treatment.

OBJECTIVE

To evaluate the predicted PCa and non-PCa mortality at the time of reclassification among men on AS, to identify clinical criteria for considering a transition from AS to watchful waiting (WW).

DESIGN, SETTING, AND PARTICIPANTS

Patients enrolled in a large AS program who experienced biopsy grade reclassification (Gleason grade increase) were retrospectively examined. All patients who had complete documentation of medical comorbidities at reclassification were included.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A validated model was used to assess 10- and 15-yr untreated PCa and non-PCa mortalities based on patient comorbidities and PCa clinical characteristics. We compared the ratio of predicted PCa mortality with predicted non-PCa mortality ("predicted mortality ratio") and divided patients into four risk tiers based on this ratio: (1) tier 1 (ratio: >0.33), (2) tier 2 (ratio 0.33-0.20), (3) tier 3 (ratio 0.20-0.10), and (4) tier 4 (ratio <0.10).

RESULTS AND LIMITATIONS

Of the 344 men who were reclassified, 98 (28%) were in risk tier 1, 85 (25%) in tier 2, 93 (27%) in tier 3, and 68 (20%) in tier 4 for 10-yr mortality. Fifteen-year risk tiers were distributed similarly. The 23 (6.7%) men who met the "transition triad" (age >75 yr, Charlson Comorbidity Index >3, and grade group ≤2) had a 14-fold higher non-PCa mortality risk and a lower predicted mortality ratio than those who did not (0.07 vs 0.23, p < 0.001). The primary limitations of our study included its retrospective nature and the use of predicted mortalities.

CONCLUSIONS

At reclassification, nearly half of patients had a more than five-fold and one in five patients had a more than ten-fold higher risk of non-PCa death than patients having a risk of untreated PCa death. Despite a more significant cancer diagnosis, a transition to WW for older men with multiple comorbidities and grade group <3 PCa should be considered.

PATIENT SUMMARY

Men with favorable-risk prostate cancer and life expectancy of >10 yr are often enrolled in active surveillance, which entails delay of curative treatment until there is evidence of more aggressive disease. We examined a group of men on active surveillance who developed more aggressive disease, and found, nevertheless, that the majority of these men continued to have a dramatically higher risk of death from non-prostate cancer causes than from prostate cancer based on a risk prediction tool. For men older than 75 yr, who have multiple medical conditions and who do not have higher-grade cancer, it may be reasonable to reconsider the need for curative treatment given the low risk of death from prostate cancer compared with the risk of death from other causes.

Impact of Decipher Biopsy testing on clinical outcomes in localized prostate cancer in a prospective statewide collaborative

BACKGROUND

Decipher Biopsy is a commercially available gene expression classifier used in risk stratification of newly diagnosed prostate cancer (PCa). Currently, there are no prospective data evaluating its clinical utility. We seek to assess the clinical utility of Decipher Biopsy in localized PCa patients.

METHODS

A multi-institutional study of 855 men who underwent Decipher Biopsy testing between February 2015 and October 2019. All patients were tracked through the prospective Michigan Urological Surgery Improvement Collaborative and linked to the Decipher Genomics Resource Information Database (GRID^®; NCT02609269). Patient matching was performed by an independent third-party (ArborMetrix Inc.) using two or more unique identifiers. Cumulative incidence curves for time to treatment (TTT) and time to failure (TTF) were constructed using Kaplan-Meier estimates. Multivariable Cox proportional hazard models were used to evaluate the independent association of high-risk Decipher scores with the conversion from AS to radical therapy and treatment failure (biochemical failure or receipt of salvage therapy).

RESULTS AND LIMITATIONS

Eight hundred fifty-five patients underwent Decipher Biopsy testing during the study period. Of the 855 men, 264 proceeded to AS (31%), and 454 (53%) received radical therapy. In men electing AS, after adjusting for NCCN risk group, age, PSA, prostate volume, body mass index, and percent positive cores, a high-risk Decipher score was independently associated with shorter TTT (HR 2.51, 95% CI 1.52-4.13 p < 0.001). Similarly, in patients that underwent radical therapy, a high-risk Decipher score was independently associated with TTF (HR 2.98, 95% CI 1.22-7.29, p = 0.01) on multivariable analysis. Follow-up time was a limitation.

CONCLUSION

In a prospective statewide registry, high-risk Decipher Biopsy score was strongly and independently associated with conversion from AS to definitive treatment and treatment failure. These real-world data support the clinical utility of Decipher Biopsy. An ongoing phase 3 randomized trial (NCT04396808) will provide level 1 evidence of the clinical impact of Decipher biopsy testing.

Active surveillance for prostate cancer: selection criteria, guidelines, and outcomes

INTRODUCTION

Active surveillance (AS) has been widely adopted for the management of men with low-risk prostate cancer. However, there is still a lack of consensus surrounding the optimal approach for monitoring men in AS protocols. While conservative management aims to reduce the burden of invasive testing without compromising oncological safety, inadequate assessment can result in misclassification and unintended over- or undertreatment, leading to increased patient morbidity, cost, and undue risk. No universally accepted AS protocol exists, although numerous strategies have been developed in an attempt to optimize the management of clinically localized disease. Variability in selection criteria, reclassification, triggers for definitive treatment, and follow-up exists between guidelines and institutions for AS. In this review, we summarize the landscape of AS by providing an overview of the existing AS protocols, guidelines, and their published outcomes.

METHODS

A comprehensive electronic search was performed to identify representative studies and guidelines pertaining to AS selection criteria and outcomes.

CONCLUSION

While AS is a safe and increasingly utilized treatment modality for lower-risk forms of PCa, ongoing research is needed to optimize patient selection as well as surveillance protocols along with improved implementation across practices. Further, assessment of companion risk assessment tools, such as mpMRI and tissue-based biomarkers, is also needed and will require rigorous prospective study.