Best of AUA 2014: Prostate Cancer

July 9, 2014

Michael C. Gong, MD, PhD, presents the take home messages on prostate cancer from the AUA annual meeting in Orlando, FL, including new findings about enzalutamide (XTANDI).

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After a median follow-up of 8.1 years in a large active surveillance cohort, about 40% of men had undergone delayed therapy and 1.5% had died from prostate cancer; the risk of dying from causes other than prostate cancer was nearly 10-fold higher. Similar results were reported in another large series that had a median follow-up of almost 5 years, and the investigators also reported PSA density was a predictor of progression.

• The U.S. validation study of the 4Kscore test showed it improved the detection rate of high-grade cancer on biopsy compared to a clinical algorithm built on PSA, age, digital rectal exam, and prior biopsy.

Related - Dr. J. Brantley Thrasher lists his top AUA 2014 prostate cancer abstracts

• Addition of urinary TMPRSS2:ERG to other risk models significantly increased detection of prostate cancer and high-grade disease.

• A multicenter validation trial showed that a multiplex epigenetic assay for detecting DNA-methylation events independently predicted the absence of prostate cancer in a repeat biopsy; the assay had a negative predictive value of 90%.

• A genetic risk score incorporating multiple prostate cancer risk-associated single-nucleotide polymorphisms was independently associated with prostate cancer and high-grade disease.

• Studies investigating cell cycle progression score reported associations with biochemical recurrence, metastatic disease, and disease-specific mortality.

• A physician-led quality improvement collaborative in Michigan found a 30-day hospital admission rate of 1% in a series of 3,911 prostate biopsies, of which 92% were for post-biopsy infection. The infection rate was 0.9% when the treating physician used antibiotic prophylaxis per AUA guidelines and 3.8% for non-concordant physicians.

• In a study of an active surveillance cohort, 24% of rectal swab cultures obtained prior to repeat prostate biopsy were positive for fluoroquinolone-resistant bacteria; diabetes was a risk factor for resistance.

• In a study including 1,012 men, use of magnetic resonance imaging (MRI)/ultrasound fusion-guided biopsy with 12-core biopsy led to more frequent upgrading to high-grade disease than 12-core biopsy alone, especially among men with PSA >10 ng/mL; setting a PSA threshold of 5.4 ng/mL resulted in capturing 95% of upgraded cancers and would potentially have avoided 36% of MRIs.

 

Next: Multiparametric MRI, metformin use

More on Prostate Cancer

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Risk for other cancers rises after prostate cancer RT

 

• Non-visible tumor on multiparametric MRI does not predict low-risk disease; in a group of 177 men with nonvisible tumor who underwent radical prostatectomy (RP), 28% had pathologic upgrading and 57% had a high tumor volume (>0.5 cc).

• A study correlating multiparametric MRI with whole-mount pathology found the imaging technique missed 26% of high-grade lesions.

Related - Upfront chemo plus ADT dramatically improves survival

• The finding of an 18% discordance rate between the nodule with the largest tumor volume versus the lesion with the highest Gleason score/stage adds to evidence that prostate cancer is a multifocal disease and indicates that nondominant lesions that are high grade may have potential for metastasis.

• In epidemiologic studies, metformin use was associated with a decreased risk of prostate cancer and statin use was associated with a decreased risk of prostate cancer-specific death; while the risk of biochemical recurrence after prostatectomy was higher among patients with diabetes than patients without diabetes (31% vs. 13%), it was reduced to only 15% among men using a statin and metformin.

• Two large series of RP patients found Gleason grade 3 tumors had limited metastatic risk.

• One study provided an updated timeline on outcomes for men with intermediate- and high-risk disease; with median follow-up of 10 years, median time to BCR was 3 years, median time from BCR to metastasis was 3 years, and median time from metastasis to death was 4 years.

• In men with high-risk prostate cancer who underwent RP, the cancer-specific mortality rate was significantly higher for those with a BCR time <36 months versus >36 months (19% vs. 4%).

• In a study of men with pathologic node-positive disease at RP, 15% developed visceral/bone metastases at a median of 32 months post surgery. Tumor burden at RP was associated with the risk of metastasis and time to onset. Despite lymph node positivity, the 10-year cancer-specific survival rate was 70%.

 

Next: PREVAIL results, studies of HIFU, sipuleucel-T

 

• Two studies reported that African-American race was associated with increased risk of higher grade disease at RP, suggesting there may be a need for more stringent criteria for African-American men to be candidates for active surveillance.

• A study comparing matched groups of patients treated by high-intensity focused ultrasound (HIFU) and RP found the HIFU group had a higher 7-year rate of salvage external beam radiation therapy (38% vs. 22%), but found no difference between groups in need for palliative androgen deprivation therapy (ADT); a second study comparing intermediate-risk HIFU-treated patients with a matched group of radiation-treated patients found the rate of palliative ADT was lower in the HIFU group (15% vs. 42%).

• Results of the phase III PREVAIL trial showed enzalutamide (XTANDI) started after progression on ADT in chemotherapy-naïve men delayed disease progression, risk of death, and time to chemotherapy compared to placebo.

• Sipuleucel-T (Provenge)-induced IgG responses against PSA correlate with overall survival.

• Trained dogs detected prostate volatile organic compounds in urinary samples with nearly 100% accuracy.UT

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