The veteran was diagnosed with PCa at age 67 years at a non-VA clinic. The urology consult note reported a sudden increase of his PSA level to 5.9. A prostate needle biopsy was performed. The Gleason score was 3 + 3 = 6 in 2 of 12, with < 1% PCa involvement and focal highgrade prostatic intraepithelial neoplasia. The patient was asymptomatic, and his cancer was identified by needle biopsy due to elevated PSA. His clinical stage was T1c. According to AUA and NCCN guidelines, the patient was categorized as low risk, defined as Gleason Score ≤ 6, PSA < 10 ng/mL, and clinical stage up to T2a.3,4 Additionally, the veteran met 3 criteria for the NCCN very low-risk category (stage T1c, < 3 positive biopsy cores and ≤ 50% cancer in any core). However, because he was initially diagnosed at a non-VA clinic, his PSA density (the remaining criterion) was not available to the VA urologist. Therefore, the low-risk category was assumed for molecular test interpretation.
The non-VA urologist recommended active surveillance. The VA urologist agreed that active surveillance was an appropriate treatment recommendation at this time. However, the veteran and his family members remained concerned that his PCa might be more aggressive due to his BRCA2 mutation, and they worried that active surveillance would result in a worse outcome. Their concern was exacerbated by the veteran’s comorbidities, which could have potential implications on the timing of surgical options. The patient expressed these concerns to his VA primary care physician, who then referred him to the VA Genomic Medicine Services.
Genetic Consult
The genetic counselor scheduled a telegenetics consult and conducted an assessment of the veteran, which included a review of his medical history, mutation status, and relevant family history. The family history was consistent with hereditary breast/ovarian cancer. However, the primary reason the veteran underwent genetic testing was the diagnosis of breast cancer in a male. The genetic counselor provided the patient with information relevant to his mutation carrier status, including that men with BRCA2 mutations are at increased risk of developing more aggressive PCa, have higher rates of lymph node involvement, and greater mortality compared with men without BRCA2 mutations. The veteran was informed that there were no published guidelines that suggest PCa in BRCA2 carriers should be treated differently from sporadic PCa.
Tumor Testing Strategy
Although the veteran was comfortable with active surveillance at the time of consultation, he was concerned that, given his comorbidities, it would be better to pursue surgery sooner. The veteran asked the genetic counselor for more information about his prognosis given his BRCA2 status. The genetic counselor discussed possible use of tumor gene expression profiling and informed him about 2 active studies within the VA that are evaluating the clinical utility of gene expression tests for PCa risk stratification (Oncotype DX at Genomic Health and Prolaris at Myriad Genetic Laboratories). The veteran expressed an interest in having his biopsy tissue tested by both assays. Tumor biopsy tissue was obtained and sent to both Genomic Health and Myriad Genetics for testing. Neither test incorporated the veteran’s other health conditions or his BRCA mutation status into risk stratification results or the patient report.
Test Results
The Oncotype DX GPS result for this NCCN low-risk patient was 31 (Figure 1). This score corresponds to a likelihood of favorable pathology at radical prostatectomy of 71% (95% confidence interval [CI]: 63%-78%). Favorable pathology is defined as freedom from highgrade (Gleason score > 4+3) and/or nonorgan-confined (pT3) disease. This GPS result was consistent with the range of risk expected for NCCN low-risk patients based on the validation cohorts for the assay. The estimate of likelihood of favorable pathology would be modified if the PSA density result were available and if it placed the patient in the NCCN very low-risk category.
The Prolaris report demonstrated a score of 0.4 (Figure 2). This puts the veteran in the 94th percentile of contemporary U.S. men who are AUA low risk. The CCP score makes his cancer more aggressive than most AUA low-risk men, and the projected 10-year disease-specific mortality is 3%. In conjunction with the patient’s BRCA2 status, he may benefit from definitive intervention. If active surveillance is chosen, careful and regular follow-up for disease progression is mandated.
Interpretation of Genomic Testing in PCa
For both tests, the results are derived from 2-tiered calculations. For Oncotype DX, the gene expression measurement yields the GPS, which is then integrated with the patient’s clinical and pathologic information to yield the likelihood of favorable pathology. Although the Oncotype DX GPS is an independent measure of disease aggressiveness, on the patient report, the GPS is combined with the NCCN clinical risk group to provide a likelihood of favorable pathology. Therefore, 2 patients with the same GPS but different levels of clinical risk will have different likelihoods of favorable pathology.
The Prolaris test provides the Prolaris CCP score as well as the percentile group of patients with a lower score within the same risk category. Also, the Prolaris test yields a numerical 10-year PCa-specific mortality risk. The Prolaris score has been shown to impact therapeutic decisions in patients with newly diagnosed PCa.20
