Understanding the Uptake and Challenges of Genetic Testing Guidelines for Prostate Cancer Patients

Expert Perspectives on Controversies in Metastatic Castration-Resistant Prostate Cancer Management: Narrative Review and Report of the First US Prostate Cancer Conference Part 2

Background

Management strategies for metastatic castration-resistant prostate cancer (mCRPC) have rapidly shifted in recent years. As novel imaging and therapeutic approaches have made their way to the clinic, providers are encountering increasingly challenging clinical scenarios, with limited guidance from the current literature.

Materials and Methods

The US Prostate Cancer Conference (USPCC) is a multidisciplinary meeting of prostate cancer experts intended to address the many challenges of prostate cancer management. At the first annual USPCC meeting, areas of controversy and consensus were identified during a 2-day meeting that included expert presentations, full-panel discussions, and postdiscussion responses to questions developed by the USPCC cochairs and session moderators.

Results

This narrative review covers the USPCC expert discussion and perspectives relevant to mCRPC, including neuroendocrine/aggressive-variant prostate cancer (NEPC/AVPC). Areas of broad agreement identified among USPCC experts include the benefits of poly (ADP-ribose) polymerase (PARP) inhibitors for patients with BRCA1/2 mutations, the use of radioligand therapy in patients with prostate-specific membrane antigen (PSMA)-positive mCRPC, and the need for clinical trials that address real-world clinical questions, including the performance of novel therapies when compared with modern standard-of-care treatment. Ongoing areas of controversy and uncertainty included the appropriateness of PARP inhibitors in patients with non-BRCA1/2 mutations, the optimal definition of PSMA positivity, and systemic therapies for patients with NEPC/AVPC after progression on platinum-based therapies.

Conclusions

The first annual USPCC meeting identified several areas of controversy in the management of mCRPC, highlighting the urgent need for clinical trials designed to facilitate treatment selection and sequencing in this heterogeneous disease state.

Germline Mutations and Ancestry in Prostate Cancer

PURPOSE OF REVIEW

Prostate cancer is the most frequently diagnosed non-cutaneous malignancy of men in the USA; notably, the incidence is higher among men of African, followed by European and Asian ancestry. Germline mutations and, in particular, mutations in DNA damage repair genes (DDRGs) have been implicated in the pathogenesis of prostate cancer. This review intends to discuss the implication of ancestry on prostate cancer, specifically in regard to lack of diversity in genomic and genetic databases and the ability of providers to properly counsel patients on the significance of cancer genetic results.

RECENT FINDINGS

Ancestral differences in prostate cancer-associated DDRG germline mutations are increasingly recognized. Guidelines for treatment by the National Comprehensive Cancer Network® (NCCN®) support germline testing in certain patients, and a myriad of genetic testing panels for DDRG mutations are now available in clinical practice. However, the consensus among providers on what genes and mutations to include in the genetic tests has evolved from experience from men of European ancestry (EA). Gaps in ancestry-informed clinical practice exist in genetic risk assessment, implementation of screening, counseling, guiding recommendations, treatment, and clinical trial enrollment. The lack of diversity in tumor genomic and genetic databases may hinder ancestry-specific disease-predisposing alterations from being discovered and targeted in prostate cancer and, therefore, impede the ability of providers to accurately counsel patients on the significance of cancer genetic test results.

Characterizing Referrals for Prostate Cancer Genetic Services in a Safety-Net Hospital

PURPOSE

Little is known about the uptake of germline genetic testing for patients with prostate cancer after 2018 guideline changes. This study characterizes genetic service referral patterns and predictors of referrals among patients with prostate cancer.

METHODS

A retrospective cohort study using electronic health record data was conducted at an urban safety-net hospital. Individuals diagnosed with prostate cancer between January 2011 and March 2020 were eligible. The primary outcome was referral to genetic services after diagnosis. Using multivariable logistic regression, we identified patient characteristics associated with referrals. Interrupted time series analysis using a segmented Poisson regression examined whether guideline changes resulted in higher rates of referral after implementation.

RESULTS

The cohort included 1,877 patients. Mean age was 65 years; 44% identified as Black, 32% White; and 17% Hispanic or Latino. The predominant insurance type was Medicaid (34%) followed by Medicare or private insurance (25% each). Most were diagnosed with local disease (65%), while 3% had regional and 9% had metastatic disease. Of the 1,877 patients, 163 (9%) had at least one referral to genetics. In multivariable models, higher age was negatively associated with referral (odds ratio [OR], 0.96; 95% CI, 0.94 to 0.98), while having regional (OR, 4.51; 95% CI, 2.44 to 8.34) or metastatic disease (OR, 4.64; 95% CI, 2.98 to 7.24) versus local only disease at diagnosis was significantly associated with referral. The time series analysis demonstrated a 138% rise in referrals 1 year after guideline implementation (relative risk, 3.992; 97.5% CI, 2.20 to 7.24; P < .001).

CONCLUSION

Referrals to genetic services increased after guideline implementation. The strongest predictor of referral was clinical stage, suggesting opportunities to raise awareness about guideline eligibility for patients with advanced local or regional disease who may benefit from genetic services.

Psychosocial factors impacting barriers and motivators to cancer genetic testing

BACKGROUND

Only a small proportion of patients who qualify for clinical genetic testing for cancer susceptibility get testing. Many patient-level barriers contribute to low uptake. In this study, we examined self-reported patient barriers and motivators for cancer genetic testing.

METHODS

A survey comprised of both new and existing measures related to barriers and motivators to genetic testing was emailed to patients with a diagnosis of cancer at a large academic medical center. Patients who self-reported receiving a genetic test were included in these analyses (n = 376). Responses about emotions following testing as well as barriers and motivators prior to getting testing were examined. Group differences in barriers and motivators by patient demographic characteristics were examined.

RESULTS

Being assigned female at birth was associated with increased emotional, insurance, and family concerns as well as increased health benefits compared to patients assigned male at birth. Younger respondents had significantly higher emotional and family concerns compared to older respondents. Recently diagnosed respondents expressed fewer concerns about insurance implications and emotional concerns. Those with a BRCA-related cancer had higher scores on social and interpersonal concerns scale than those with other cancers. Participants with higher depression scores indicated increased emotional, social and interpersonal, and family concerns.

CONCLUSIONS

Self-reported depression emerged as the most consistent factor influencing report of barriers to genetic testing. By incorporating mental health resources into clinical practice, oncologists may better identify those patients who might need more assistance following through with a referral for genetic testing and the response afterwards.