Identification of Genes with Rare Loss of Function Variants Associated with Aggressive Prostate Cancer and Survival

BACKGROUND

Prostate cancer (PrCa) is a substantial cause of mortality among men globally. Rare germline mutations in BRCA2 have been validated robustly as increasing risk of aggressive forms with a poorer prognosis; however, evidence remains less definitive for other genes.

OBJECTIVE

To detect genes associated with PrCa aggressiveness, through a pooled analysis of rare variant sequencing data from six previously reported studies in the UK Genetic Prostate Cancer Study (UKGPCS).

DESIGN, SETTING, AND PARTICIPANTS

We accumulated a cohort of 6805 PrCa cases, in which a set of ten candidate genes had been sequenced in all samples.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We examined the association between rare putative loss of function (pLOF) variants in each gene and aggressive classification (defined as any of death from PrCa, metastatic disease, stage T4, or both stage T3 and Gleason score ≥8). Secondary analyses examined staging phenotypes individually. Cox proportional hazards modelling and Kaplan-Meier survival analyses were used to further examine the relationship between mutation status and survival.

RESULTS AND LIMITATIONS

We observed associations between PrCa aggressiveness and pLOF mutations in ATM, BRCA2, MSH2, and NBN (odds ratio = 2.67-18.9). These four genes and MLH1 were additionally associated with one or more secondary analysis phenotype. Carriers of germline mutations in these genes experienced shorter PrCa-specific survival (hazard ratio = 2.15, 95% confidence interval 1.79-2.59, p = 4 × 10-16) than noncarriers.

CONCLUSIONS

This study provides further support that rare pLOF variants in specific genes are likely to increase aggressive PrCa risk and may help define the panel of informative genes for screening and treatment considerations.

PATIENT SUMMARY

By combining data from several previous studies, we have been able to enhance knowledge regarding genes in which inherited mutations would be expected to increase the risk of more aggressive PrCa. This may, in the future, aid in the identification of men at an elevated risk of dying from PrCa.

Metabolomic profile of prostate cancer-specific survival among 1812 Finnish men

BACKGROUND

Abnormal metabolism and perturbations in metabolic pathways play significant roles in the development and progression of prostate cancer; however, comprehensive metabolomic analyses of human data are lacking and needed to elucidate the interrelationships.

METHODS

We examined the serum metabolome in relation to prostate cancer survival in a cohort of 1812 cases in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Using an ultrahigh-performance LC-MS/MS platform, we identified 961 known metabolites in prospectively collected serum. Median survival time from diagnosis to prostate cancer-specific death (N=472) was 6.6 years (interquartile range=2.9-11.1 years). Cox proportional hazards regression models estimated hazard ratios and 95% confidence intervals of the associations between the serum metabolites (in quartiles) and prostate cancer death, adjusted for age at baseline and diagnosis, disease stage, and Gleason sum. In order to calculate risk scores, we first randomly divided the metabolomic data into a discovery set (70%) and validated in a replication set (30%).

RESULTS

Overall, 49 metabolites were associated with prostate cancer survival after Bonferroni correction. Notably, higher levels of the phospholipid choline, amino acid glutamate, long-chain polyunsaturated fatty acid (n6) arachidonate (20:4n6), and glutamyl amino acids gamma-glutamylglutamate, gamma-glutamylglycine, and gamma-glutamylleucine were associated with increased risk of prostate cancer-specific mortality (fourth versus first quartile HRs=2.07-2.14; P-values <5.2×10^-5). By contrast, the ascorbate/aldarate metabolite oxalate, xenobiotics S-carboxymethyl-L-cysteine, fibrinogen cleavage peptides ADpSGEGDFXAEGGGVR and fibrinopeptide B (1-12) were related to reduced disease-specific mortality (fourth versus first quartile HRs=0.82-0.84; P-value <5.2×10^-5). Further adjustment for years from blood collection to cancer diagnosis, body mass index, smoking intensity and duration, and serum total and high-density lipoprotein cholesterol did not alter the results. Participants with a higher metabolic score based on the discovery set had an elevated risk of prostate cancer-specific mortality in the replication set (fourth versus first quartile, HR=3.9, P-value for trend<0.0001).

CONCLUSIONS

The metabolic traits identified in this study, including for choline, glutamate, arachidonate, gamma-glutamyl amino acids, fibrinopeptides, and endocannabinoid and redox pathways and their composite risk score, corroborate our previous analysis of fatal prostate cancer and provide novel insights and potential leads regarding the molecular basis of prostate cancer progression and mortality.

Event-free survival after 68 Ga-PSMA-11 PET/CT in recurrent hormone-sensitive prostate cancer (HSPC) patients eligible for salvage therapy

Background/aim

Prostate-specific-membrane-antigen/positron emission tomography (PSMA-PET) detects with high accuracy disease-recurrence, leading to changes in the management of biochemically-recurrent (BCR) prostate cancer (PCa). However, data regarding the oncological outcomes of patients who performed PSMA-PET are needed. The aim of this study was to evaluate the incidence of clinically relevant events during follow-up in patients who performed PSMA-PET for BCR after radical treatment.

Materials and methods

This analysis included consecutive, hormone-sensitive, hormone-free, recurrent PCa patients (HSPC) enrolled through a prospective study. All patients were eligible for salvage therapy, having at least 24 months of follow-up after PSMA-PET. The primary endpoint was the Event-Free Survival (EFS), defined as the time between the PSMA-PET and the date of event/last follow-up. The Kaplan–Meier method was used to estimate the EFS curves. EFS was also investigated by Cox proportional hazards regression. Events were defined as death, radiological progression, or PSA recurrence after therapy.

Results

One-hundred and seventy-six (n = 176) patients were analyzed (median PSA 0.62 [IQR: 0.43–1.00] ng/mL; median follow-up of 35.4 [IQR: 26.5–40.3] months). The EFS was 78.8% at 1 year, 65.2% (2 years), and 52.2% (3 years). Patients experiencing events during study follow-up had a significantly higher median PSA (0.81 [IQR: 0.53–1.28] vs 0.51 [IQR: 0.36–0.80] ng/mL) and a lower PSA doubling time (PSAdt) (5.4 [IQR: 3.7–11.6] vs 12.7 [IQR: 6.6–24.3] months) (p < 0.001) compared to event-free patients. The Kaplan–Meier curves showed that PSA > 0.5 ng/mL, PSAdt ≤ 6 months, and a positive PSMA-PET result were associated with a higher event rate (p < 0.01). No significant differences of event rates were observed in patients who received changes in therapy management after PSMA-PET vs. patients who did not receive therapy changes. Finally, PSA > 0.5 ng/mL and PSAdt ≤ 6 months were statistically significant event-predictors in multivariate model (p < 0.001).

Conclusion

Low PSA and long PSAdt were significant predictors of longer EFS. A lower incidence of events was observed in patients having negative PSMA-PET, since longer EFS was significantly more probable in case of a negative scan.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-022-05741-9.

Does Protocol Make a Difference? Comparison of Two Prostate Cancer Active Surveillance Cohorts: A Non-protocol-based Follow-up and a Protocol-based Contemporary Follow-up

Background

Active surveillance (AS) is the preferred option for initial management for low-risk prostate cancer (PC). Although many AS protocols exist, there is little evidence to support one over another.

Objective

To assess whether there is difference in overall (OS), prostate cancer–specific (CSS), metastasis-free (MFS), or treatment-free (TFS) survival between a strict (Prostate cancer Research International: Active Surveillance [PRIAS]) and a loose (European Randomized study of Screening for Prostate Cancer [ERSPC]) AS protocol.

Design, setting, and participants

This study included two cohorts of men (n = 518) with low-risk, localized, Gleason score ≤7 PC. The ERSPC cohort included 241 men followed for 9.5 yr (median) with a non–protocol-based follow-up. The PRIAS cohort included 277 men followed for 5 yr (median) with a strict protocol.

Outcome measurements and statistical analysis

OS, CSS, MFS, and TFS were compared by the Kaplan-Meier method, competing risk analysis, and Cox proportional hazard regression.

Results and limitations

As expected, due to the difference in median follow-up time between the cohorts, a difference in the absolute number of events was seen. However, no difference in any of the survival outcomes was evident in the Kaplan-Meier or competing risks analysis. Furthermore, in Cox proportional hazard regression analysis, cohort (ERSPC vs PRIAS) was not associated with any of the outcomes. Results are limited by the retrospective study design, limited statistical power, and inability to match the cohorts for predictive factors.

Conclusions

There was no difference in survival outcomes between a non–protocol-based follow-up and a protocol-based contemporary AS follow-up of patients with low-risk PC. However, a longer follow-up is needed.

Patient summary

We compared survival outcomes of two cohorts of patients with low-risk prostate cancer: a strict and a loose follow-up protocol. We found no differences in survival measures between the cohorts.

PSA, stage, grade and prostate cancer specific mortality in Asian American patients relative to Caucasians according to the United States Census Bureau race definitions

Background

The United States Census Bureau recommends distinguishing between “Asians” vs. “Native Hawaiians or Other Pacific Islanders” (NHOPI). We tested for prognostic differences according to this stratification in patients with prostate cancer (PCa) of all stages.

Methods

Descriptive statistics, time-trend analyses, Kaplan–Meier plots and multivariate Cox regression models were used to test for differences at diagnosis, as well as for cancer specific mortality (CSM) according to the Census Bureau’s definition in either non-metastatic or metastatic patients vs. 1:4 propensity score (PS)-matched Caucasian controls, identified within the Surveillance, Epidemiology and End Results database (2004–2016).

Results

Of all 380,705 PCa patients, NHOPI accounted for 1877 (0.5%) vs. 23,343 (6.1%) remaining Asians vs. 93.4% Caucasians. NHOPI invariably harbored worse PCa characteristics at diagnosis. The rates of PSA ≥ 20 ng/ml, Gleason ≥ 8, T3/T4, N1- and M1 stages were highest for NHOPI, followed by Asians, followed by Caucasians (PSA ≥ 20: 18.4 vs. 14.8 vs. 10.2%, Gleason ≥ 8: 24.9 vs. 22.1, vs. 15.9%, T3/T4: 5.5 vs. 4.2 vs. 3.5%, N1: 4.4 vs. 2.8, vs. 2.7%, M1: 8.3 vs. 4.9 vs. 3.9%). Despite the worst PCa characteristics at diagnosis, NHOPI did not exhibit worse CSM than Caucasians. Moreover, despite worse PCa characteristics, Asians exhibited more favorable CSM than Caucasians in comparisons that focussed on non-metastatic and on metastatic patients.

Conclusions

Our observations corroborate the validity of the distinction between NHOPI and Asian patients according to the Census Bureau’s recommendation, since these two groups show differences in PSA, grade and stage characteristics at diagnosis in addition to exhibiting differences in CSM even after PS matching and multivariate adjustment.

Survival and mortality of elderly men with localized prostate cancer managed with primary androgen deprivation therapy or by primary observation

BACKGROUND

Androgen deprivation therapy (ADT) remains a primary treatment for localized prostate cancer (PCa) even though there is no evidence that its use is beneficial in the absence of curative treatment.

METHODS

Men aged ≥70 years (n = 16,534) diagnosed with localized PCa from 1985 to 2014 and managed either with primary observation or ADT in the absence of curative treatment were included. The cases were identified from the population-based Finnish Cancer Registry. We estimated the standardized mortality ratios (SMR) for overall mortality by treatment group. We determined the relative risk (RR) of PCa-specific mortality (PCSM) and other-cause mortality between the two treatment groups. Survival was determined using the life table method. Two age groups (70-79 years and ≥ 80 years) and three calendar time cohorts (1985-1994, 1995-2004, and 2005-2014) were compared following adjustment of propensity score matching between the treatment groups with four covariates (age, year of diagnosis, educational level, and hospital district). Follow-up continued until death or until December 31, 2015.

RESULTS

Patients in the observation group had lower overall SMRs than those in the ADT group in both age cohorts over the entire study period. PCSM was higher in men aged 70-79 years undergoing primary ADT compared to those managed by observation only (RR: 1.70, 95% confidence interval [CI]: 1.29-2.23 [1985-1994]; RR 1.55, 95% CI: 1.35-1.84 [1995-2004]; and RR 2.71, 95% CI: 2.08-3.53 [2005-2014]); p = 0.005 for periodic trend. A similar trend over time was also observed in men aged > 80 years; (p for age-period interaction = 0.237). Overall survival was also higher among men in their 70's managed by observation compared to those undergoing ADT.

CONCLUSIONS

Primary ADT within four months period from diagnosis is not associated with improved long-term overall survival or decreased PCSM compared to primary conservative management for men with localized PCa. However, this observational study's conclusions should be weighted with confounding factors related to cancer aggressiveness and comorbidities.

Aspirin Use and Lethal Prostate Cancer in the Health Professionals Follow-up Study

BACKGROUND

Aspirin use probably protects against some malignancies but its effects on lethal prostate cancer (PC) are unclear.

OBJECTIVE

To investigate the association between regular aspirin use and lethal PC.

DESIGN, SETTING, AND PARTICIPANTS

Participants were aged 40-75 yr at baseline in 1986 and have been followed with biennial questionnaires. The risk analysis includes 49 409 men. The survival analysis includes 5980 PC patients without metastatic disease at diagnosis.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We used Cox proportional hazards regression to examine the association between current, past, or never regular aspirin use (≥2 d/wk) in relation to lethal (metastatic or fatal) PC. We also examined years of use among current users and years since stopping among past users. In the risk analysis, aspirin was updated throughout follow-up. In the survival analysis, aspirin use after diagnosis was assessed.

RESULTS AND LIMITATIONS

Some 29% of participants used aspirin regularly at baseline, which increased to 60% by 2010. In the risk analysis, 804 men were diagnosed with lethal PC. Current regular aspirin was associated with a lower risk of lethal prostate cancer (hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.66-0.96) compared to never users. In the survival analysis, 451 of the men diagnosed with nonmetastatic PC later developed lethal disease. Current postdiagnostic aspirin was associated with a lower risk of lethal PC (HR 0.80, 95% CI 0.64-1.00) and overall mortality (HR 0.79, 95% CI 0.69-0.90). When restricted to highly screened men, the risk analysis associations were stronger and survival analysis associations remained statistically significant. Reverse causation and residual confounding remain concerns, as demonstrated by the attenuated results in sensitivity analyses.

CONCLUSIONS

Regular aspirin use was associated with a lower risk of lethal PC. Postdiagnostic use was associated with better survival after diagnosis.

PATIENT SUMMARY

We found that it may be advisable for prostate cancer patients to take aspirin to improve their survival for both prostate cancer mortality and other mortality outcomes.

Survival after initiation of androgen deprivation therapy for prostate cancer of Australian men

OBJECTIVE

To examine duration of use and survival rates of Australian males who initiated androgen deprivation therapy for prostate cancer, including survival rates stratified by the type of the initial androgen deprivation therapy and age at initiation.

METHOD

Cohort study using Australian Government Department of Veterans' Affairs (DVA) data. Males aged 50 and over initiating androgen deprivation therapy (2008-2010) were included in the cohort. Time to death or end of study (31 Dec 2012), duration of therapy and 1 to 5-year relative survival rates stratified by type of initial therapy and age were presented.

RESULTS

Of the androgen deprivation therapy initiators (n=3,611, mean age 84), 92% survived 1 year with the relative survival rate decreasing to 79% at 3 years and to 57% at 5 years. Survival outcomes stratified by the type of initial therapy showed slightly higher rates amongst those initiated on gonadotropin releasing hormone analogues or on combined androgen blockage compared to those initiated on anti-androgens. Age specific rates were similar amongst the younger groups (under 80 years old) at each single point of time and were slightly higher than in those aged 80 years and over for some points of time. Fifty percent of patients received androgen deprivation therapy for extended periods (30 months).

CONCLUSIONS

The 1-year relative survival of veterans was high and similar to that of the general Australian population with prostate cancer. Factors such as tumour stage and grade (not available in the data) could explain differences in survival based on the type of the initial therapy.