An Updated Evaluation of Atrazine-Cancer Incidence Associations among Pesticide Applicators in the Agricultural Health Study Cohort

BACKGROUND

Atrazine is a common agricultural herbicide in the United States. Few epidemiologic studies have evaluated cancer risks. Previous analyses within the Agricultural Health Study (AHS) have found some evidence of associations with cancer at some sites.

OBJECTIVE

We updated exposure information, incident cases, and follow-up time to assess the associations between atrazine use and cancer at specific sites in the AHS.

METHODS

Information about lifetime pesticide use was reported at enrollment (1993-1997) and follow-up (1999-2005). Among 53,562 pesticide applicators in North Carolina and Iowa, we identified 8,915 incident cases through cancer registry linkages through 2014 (North Carolina)/2017 (Iowa). We used Poisson regression to evaluate the association between ever/never and intensity-weighted lifetime days of atrazine use and incident cancer risk controlling for several confounders. We also evaluated lagged exposures and age-stratified risk.

RESULTS

Approximately 71.2% of applicators reported ever using atrazine, which was associated with lung cancer [rate ratios  ( RR ) = 1.24 ; 95% confidence interval (CI): 1.04, 1.46]. Aggressive prostate cancer risk was increased in the highest quartile (RR Q 4 = 1.20 ; 95% CI: 0.95, 1.52; p -trend = 0.19 ), particularly among those < 60 years old (RR Q 4 = 3.04 ; 95% CI: 1.61, 5.75; p -trend < 0.001 ; p -interaction = 0.04 ). Among applicators < 50 years of age, ever-atrazine use was associated with non-Hodgkin lymphoma (NHL) (RR = 2.43 ; 95% CI: 1.10, 5.38; p -interaction = 0.60 ). For soft tissue sarcoma, there was an elevated risk in the highest tertile of exposure (RR T 3 : 2.54; 95% CI: 0.97, 6.62; p -trend = 0.31 ). In analyses with exposure lagged by 25 years, there was an elevated risk of pharyngeal (RR T 3 = 3.04 ; 95% CI: 1.45, 6.36; p -trend = 0.07 ) and kidney (RR Q 4 = 1.62 ; 95% CI: 1.15, 2.29; p -trend < 0.005 ) cancers.

DISCUSSION

We observed suggestive associations with some malignancies in overall, age-specific, and lagged analyses. Associations with aggressive prostate cancer and NHL were apparent among those diagnosed at younger ages and with cancers of the pharynx and kidney, and soft tissue sarcomas were observed in lagged analyses. Further work is needed to confirm these observed associations and elucidate potential underlying mechanisms. https://doi.org/10.1289/EHP13684.

Obesity and prostate cancer screening, incidence, and mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

BACKGROUND

Though obesity, measured by body mass index (BMI), is an established risk factor for several cancer sites, there is conflicting evidence on whether obesity increases prostate cancer risk or mortality and, if it does, whether it increases risk directly or indirectly by affecting prostate cancer screening efficacy.

METHODS

We examined associations between BMI and prostate cancer screening outcomes, incidence, and mortality in men randomly assigned to the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (n = 36 756) between 1993 and 2001. Participants received annual screening with the prostate-specific antigen test and digital rectal exam. Associations between baseline BMI and screening outcomes were assessed via multinomial logistic regression, and associations with prostate cancer incidence and mortality were assessed via Cox proportional hazards regression.

RESULTS

Individuals with higher BMI were less likely to screen positive via the prostate-specific antigen test and/or digital rectal exam and more likely to have an inadequate screen (all Ptrend < .01). Higher BMI was inversely associated with prostate cancer incidence (per 5 kg/m2 BMI increase: hazard ratio [HR] = 0.94, 95% confidence interval [CI] = 0.91 to 0.97), including incidence of early stage (HR = 0.94, 95% CI = 0.90 to 0.97) and advanced-stage (HR = 0.91, 95% CI = 0.82 to 1.02) disease, but positively associated with prostate cancer mortality (HR = 1.21, 95% CI = 1.06 to 1.37). The association with mortality was not modified by screening outcome (Pinteraction = .13).

CONCLUSIONS

Within this screened population, individuals with higher BMI had lower risk of prostate cancer diagnosis but higher risk of prostate cancer mortality. As higher BMI was not positively associated with advanced-stage prostate cancer risk, the increased mortality is unlikely to be due to delayed prostate cancer detection.

Joint associations between established genetic susceptibility loci, pesticide exposures, and risk of prostate cancer

More than 200 genetic variants have been independently associated with prostate cancer risk. Studies among farmers have also observed increased prostate cancer risk associated with exposure to specific organophosphate (fonofos, terbufos, malathion, dimethoate) and organochlorine (aldrin, chlordane) insecticides. We examined the joint associations between these pesticides, established prostate cancer loci, and prostate cancer risk among 1,162 cases (588 aggressive) and 2,206 frequency-matched controls nested in the Agricultural Health Study cohort. History of lifetime pesticide use was combined with a polygenic risk score (PRS) generated using 256 established prostate cancer risk variants. Logistic regression models estimated the joint associations of the pesticides, the PRS, and the 256 individual genetic variants with risk of total and aggressive prostate cancer. Likelihood ratio tests assessed multiplicative interaction. We observed interaction between ever use of fonofos and the PRS in relation to total and aggressive prostate cancer risk. Compared to the reference group (never use, PRS < median), men with ever use of fonofos and PRS > median had elevated risks of total (OR 1.35 [1.06-1.73], p-interaction = 0.03) and aggressive (OR 1.49 [1.09-2.04], p-interaction = 0.19) prostate cancer. There was also suggestion of interaction between pesticides and individual genetic variants occurring in regions associated with DNA damage response (CDH3, EMSY genes) and with variants related to altered androgen receptor-driven transcriptional programs critical for prostate cancer. Our study provides evidence that men with greater genetic susceptibility to prostate cancer may be at higher risk if they are also exposed to pesticides and suggests potential mechanisms by which pesticides may increase prostate cancer risk.

Circulating insulin-like growth factors and risks of overall, aggressive and early-onset prostate cancer: a collaborative analysis of 20 prospective studies and Mendelian randomization analysis

BACKGROUND

Previous studies had limited power to assess the associations of circulating insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) with clinically relevant prostate cancer as a primary endpoint, and the association of genetically predicted IGF-I with aggressive prostate cancer is not known. We aimed to investigate the associations of IGF-I, IGF-II, IGFBP-1, IGFBP-2 and IGFBP-3 concentrations with overall, aggressive and early-onset prostate cancer.

METHODS

Prospective analysis of biomarkers using the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group dataset (up to 20 studies, 17 009 prostate cancer cases, including 2332 aggressive cases). Odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer were estimated using conditional logistic regression. For IGF-I, two-sample Mendelian randomization (MR) analysis was undertaken using instruments identified using UK Biobank (158 444 men) and outcome data from PRACTICAL (up to 85 554 cases, including 15 167 aggressive cases). Additionally, we used colocalization to rule out confounding by linkage disequilibrium.

RESULTS

In observational analyses, IGF-I was positively associated with risks of overall (OR per 1 SD = 1.09: 95% CI 1.07, 1.11), aggressive (1.09: 1.03, 1.16) and possibly early-onset disease (1.11: 1.00, 1.24); associations were similar in MR analyses (OR per 1 SD = 1.07: 1.00, 1.15; 1.10: 1.01, 1.20; and 1.13; 0.98, 1.30, respectively). Colocalization also indicated a shared signal for IGF-I and prostate cancer (PP4: 99%). Men with higher IGF-II (1.06: 1.02, 1.11) and IGFBP-3 (1.08: 1.04, 1.11) had higher risks of overall prostate cancer, whereas higher IGFBP-1 was associated with a lower risk (0.95: 0.91, 0.99); these associations were attenuated following adjustment for IGF-I.

CONCLUSIONS

These findings support the role of IGF-I in the development of prostate cancer, including for aggressive disease.

Association of Frequent Aspirin Use With Ovarian Cancer Risk According to Genetic Susceptibility

Importance

Frequent aspirin use is associated with reduced ovarian cancer risk, but it is unknown whether genetic factors modify this association. Understanding effect modifiers is important given that any use of aspirin for ovarian cancer chemoprevention will likely need to focus on specific higher-risk subgroups.

Objective

To evaluate whether the association between frequent aspirin use and ovarian cancer is modified by a polygenic score (PGS) for nonmucinous ovarian cancer.

Design, Setting, and Participants

We pooled individual-level data from 8 population-based case-control studies from the Ovarian Cancer Association Consortium conducted in the US, UK, and Australia between 1995 and 2009. We included case patients and control participants with both genetic data and data on frequent aspirin use. Case patients with mucinous ovarian cancer were excluded. Data were analyzed between November 1, 2021, and July 31, 2022.

Exposures

Frequent aspirin use, defined as daily or almost daily use for 6 months or longer.

Main Outcomes and Measures

The main outcome was nonmucinous epithelial ovarian cancer. We used logistic regression to estimate odds ratios (ORs) and 95% CIs and likelihood ratio tests to investigate effect modification by the PGS.

Results

There were 4476 case patients with nonmucinous ovarian cancer and 6659 control participants included in this analysis. At study enrollment, the median (IQR) age was 58 (50-66) years for case patients and 57 (49-65) years for control participants. Case patients and control participants self-reported that they were Black (122 [3%] vs 218 [3%]), White (3995 [89%] vs 5851 [88%]), or of other race and ethnicity (348 [8%] vs 580 [9%]; race and ethnicity were unknown for 11 [0%] vs 10 [0%]). There were 575 case patients (13%) and 1030 control participants (15%) who reported frequent aspirin use. The 13% reduction in ovarian cancer risk associated with frequent aspirin use (OR, 0.87 [95% CI, 0.76-0.99]) was not modified by the PGS. Consistent ORs were observed among individuals with a PGS less than (0.85 [0.70-1.02]) and greater than (0.86 [0.74-1.01]) the median. Results were similar by histotype.

Conclusions and Relevance

The findings of this study suggest that genetic susceptibility to ovarian cancer based on currently identified common genetic variants does not appear to modify the protective association between frequent aspirin use and ovarian cancer risk. Future work should continue to explore the role of aspirin use for ovarian cancer prevention among individuals who are at higher risk for ovarian cancer.

Applying recommended definition of aggressive prostate cancer: a validation study using high-quality data from the Cancer Registry of Norway

BACKGROUND

The Prostate Cancer Cohort Consortium (PC3) Working Group proposed a definition for aggressive prostate cancer (PC) for aetiologic epidemiologic research. We aimed to validate this definition as well as a second approach utilising only information on stage at diagnosis.

METHODS

First primary PCs diagnosed 2004 - 2009 in the population-based Janus Serum Bank (JSB) cohort were identified by linkage to the population-based Cancer Registry of Norway (CRN) (n = 3568). The CRN and Norwegian Prostate Cancer Registry provided clinicopathological data for these cases. Approach 1 classified PC as aggressive if it was clinically T4, or N1, or M1, or had a Gleason score ≥8 at diagnosis (as proposed). Approach 2 classified PC as aggressive if CRN stage at diagnosis was 'regional spread' or 'distant metastases'. Both approaches were validated by calculating the sensitivity and positive predictive value (PPV) against PC-death within 10 years of diagnosis.

RESULTS

Overall, 555 died from PC within 10 years. Approach 1 classified 24.7% of cases as aggressive and 13.6% were unclassified due to missing information. Approach 2 classified 19.6% as aggressive and 29% were unclassified. Sensitivity was highest for Approach 1 (0.76, 95% CI: 0.72 - 0.80 vs 0.69, 95% CI: 0.64 - 0.73), while PPVs were similar for both approaches (0.43, 95% CI: 0.40 - 0.46 and 0.40, 95% CI: 0.36 - 0.44). We observed similarly high sensitivity and higher PPVs than those reported by the PC3 Working Group.

CONCLUSIONS

The proposed definition of aggressive PC was applicable and valid in the JSB cohort. Stage at diagnosis can be useful if data on cTNM or Gleason score is unavailable.

Modification of the Association Between Frequent Aspirin Use and Ovarian Cancer Risk: A Meta-Analysis Using Individual-Level Data From Two Ovarian Cancer Consortia

PURPOSE

Frequent aspirin use has been associated with reduced ovarian cancer risk, but no study has comprehensively assessed for effect modification. We leveraged harmonized, individual-level data from 17 studies to examine the association between frequent aspirin use and ovarian cancer risk, overall and across subgroups of women with other ovarian cancer risk factors.

METHODS

Nine cohort studies from the Ovarian Cancer Cohort Consortium (n = 2,600 cases) and eight case-control studies from the Ovarian Cancer Association Consortium (n = 5,726 cases) were included. We used Cox regression and logistic regression to assess study-specific associations between frequent aspirin use (≥ 6 days/week) and ovarian cancer risk and combined study-specific estimates using random-effects meta-analysis. We conducted analyses within subgroups defined by individual ovarian cancer risk factors (endometriosis, obesity, family history of breast/ovarian cancer, nulliparity, oral contraceptive use, and tubal ligation) and by number of risk factors (0, 1, and ≥ 2).

RESULTS

Overall, frequent aspirin use was associated with a 13% reduction in ovarian cancer risk (95% CI, 6 to 20), with no significant heterogeneity by study design (P = .48) or histotype (P = .60). Although no association was observed among women with endometriosis, consistent risk reductions were observed among all other subgroups defined by ovarian cancer risk factors (relative risks ranging from 0.79 to 0.93, all P-heterogeneity > .05), including women with ≥ 2 risk factors (relative risk, 0.81; 95% CI, 0.73 to 0.90).

CONCLUSION

This study, the largest to-date on aspirin use and ovarian cancer, provides evidence that frequent aspirin use is associated with lower ovarian cancer risk regardless of the presence of most other ovarian cancer risk factors. Risk reductions were also observed among women with multiple risk factors, providing proof of principle that chemoprevention programs with frequent aspirin use could target higher-risk subgroups.

Circulating free testosterone and risk of aggressive prostate cancer: Prospective and Mendelian randomisation analyses in international consortia

Previous studies had limited power to assess the associations of testosterone with aggressive disease as a primary endpoint. Further, the association of genetically predicted testosterone with aggressive disease is not known. We investigated the associations of calculated free and measured total testosterone and sex hormone-binding globulin (SHBG) with aggressive, overall and early-onset prostate cancer. In blood-based analyses, odds ratios (OR) and 95% confidence intervals (CI) for prostate cancer were estimated using conditional logistic regression from prospective analysis of biomarker concentrations in the Endogenous Hormones, Nutritional Biomarkers and Prostate Cancer Collaborative Group (up to 25 studies, 14 944 cases and 36 752 controls, including 1870 aggressive prostate cancers). In Mendelian randomisation (MR) analyses, using instruments identified using UK Biobank (up to 194 453 men) and outcome data from PRACTICAL (up to 79 148 cases and 61 106 controls, including 15 167 aggressive cancers), ORs were estimated using the inverse-variance weighted method. Free testosterone was associated with aggressive disease in MR analyses (OR per 1 SD = 1.23, 95% CI = 1.08-1.40). In blood-based analyses there was no association with aggressive disease overall, but there was heterogeneity by age at blood collection (OR for men aged <60 years 1.14, CI = 1.02-1.28; Phet  = .0003: inverse association for older ages). Associations for free testosterone were positive for overall prostate cancer (MR: 1.20, 1.08-1.34; blood-based: 1.03, 1.01-1.05) and early-onset prostate cancer (MR: 1.37, 1.09-1.73; blood-based: 1.08, 0.98-1.19). SHBG and total testosterone were inversely associated with overall prostate cancer in blood-based analyses, with null associations in MR analysis. Our results support free testosterone, rather than total testosterone, in the development of prostate cancer, including aggressive subgroups.

Analgesic use and circulating estrogens, androgens, and their metabolites in the Women's Health Initiative Observational Study

Though studies have observed inverse associations between use of analgesics (aspirin, non-aspirin nonsteroidal anti-inflammatory drugs [NSAIDs], and acetaminophen) and the risk of several cancers, the potential biological mechanisms underlying these associations are unclear. We investigated the relationship between analgesic use and serum concentrations of estrogens, androgens, and their metabolites among postmenopausal women to provide insights on whether analgesic use might influence endogenous hormone levels, which could in turn influence hormone-related cancer risk. The study included 1,860 postmenopausal women from two case-control studies nested within the Women's Health Initiative Observational Study. Analgesic use was reported at study baseline. Fifteen estrogens and estrogen metabolites and twelve androgens and androgen metabolites were quantified in baseline serum by liquid chromatography-tandem mass spectrometry. Linear regression with inverse probability weighting, stratified by menopausal hormone therapy (MHT) use, was used to estimate adjusted geometric mean concentrations of each hormone by analgesic use. Among women not currently using MHT (n=951), low-dose aspirin (<100 mg) use was associated with a higher serum concentration of estrone, estradiol, and 2,4, and 16 hydroxylated metabolites. Use of regular-dose aspirin ( {greater than or equal to} 100 mg), non-aspirin NSAIDs, and acetaminophen were not associated with serum concentrations of estrogens, androgens, or their metabolites. This study highlights the importance of examining aspirin use by dose and suggests that low-dose aspirin may influence endogenous estrogen concentrations.

Recommended Definitions of Aggressive Prostate Cancer for Etiologic Epidemiologic Research

BACKGROUND

In the era of widespread prostate-specific antigen testing, it is important to focus etiologic research on the outcome of aggressive prostate cancer, but studies have defined this outcome differently. We aimed to develop an evidence-based consensus definition of aggressive prostate cancer using clinical features at diagnosis for etiologic epidemiologic research.

METHODS

Among prostate cancer cases diagnosed in 2007 in the National Cancer Institute's Surveillance, Epidemiology, and End Results-18 database with follow-up through 2017, we compared the performance of categorizations of aggressive prostate cancer in discriminating fatal prostate cancer within 10 years of diagnosis, placing the most emphasis on sensitivity and positive predictive value (PPV).

RESULTS

In our case population (n = 55 900), 3073 men died of prostate cancer within 10 years. Among 12 definitions that included TNM staging and Gleason score, sensitivities ranged from 0.64 to 0.89 and PPVs ranged from 0.09 to 0.23. We propose defining aggressive prostate cancer as diagnosis of category T4 or N1 or M1 or Gleason score of 8 or greater prostate cancer, because this definition had one of the higher PPVs (0.23, 95% confidence interval = 0.22 to 0.24) and reasonable sensitivity (0.66, 95% confidence interval = 0.64 to 0.67) for prostate cancer death within 10 years. Results were similar across sensitivity analyses.

CONCLUSIONS

We recommend that etiologic epidemiologic studies of prostate cancer report results for this definition of aggressive prostate cancer. We also recommend that studies separately report results for advanced category (T4 or N1 or M1), high-grade (Gleason score ≥8), and fatal prostate cancer. Use of this comprehensive set of endpoints will facilitate comparison of results from different studies and help elucidate prostate cancer etiology.

Aspirin Use and Prostate Cancer among African-American Men in the Southern Community Cohort Study

BACKGROUND

The association of aspirin use with prostate cancer has been investigated, but few studies included African-American men. Here, we analyzed the relationship of aspirin intake with prostate cancer risk and mortality among African-American men in the Southern Community Cohort Study (SCCS).

METHODS

SCCS recruited 22,426 African-American men between 2002 and 2009. Aspirin use was assessed at enrollment. Our exposures of interest were any aspirin use (regular strength, low-dose or baby aspirin, or half tablets of aspirin) and regular strength aspirin. Each exposure variable was compared with nonusers. Associations between aspirin use and prostate cancer risk and mortality were examined with Cox proportional hazards models.

RESULTS

At enrollment, 5,486 men (25.1%) reported taking any aspirin and 2,634 men (12.1%) reported regular strength aspirin use. During follow-up (median, 13 years), 1,058 men developed prostate cancer, including 103 prostate cancer-specific deaths. Aspirin use was not associated with prostate cancer development [adjusted HR, 1.07; 95% confidence interval (CI), 0.92-1.25 for any aspirin use and HR, 0.97; 95% CI, 0.78-1.19 for regular strength aspirin], but was suggestively associated with reduced prostate cancer mortality (HR, 0.66; 95% CI, 0.39-1.14 for any aspirin use and HR, 0.41; 95% CI, 0.17-1.00 for regular strength aspirin).

CONCLUSIONS

Aspirin use at enrollment was tentatively associated with reduced prostate cancer mortality, but not risk, among African-American men in SCCS.

IMPACT

Prospective SCCS data suggest that aspirin use may help prevent lethal prostate cancer among this high-risk group of men.

Associations between daily aspirin use and cancer risk across strata of major cancer risk factors in two large U.S. cohorts

PURPOSE

Daily aspirin use has been shown to reduce risk of colorectal, and possibly other, cancers, but it is unknown if these benefits are consistent across subgroups of people with differing cancer risk factors. We investigated whether age, body mass index (BMI), smoking status, physical inactivity, and family history of cancer modify the effect of daily aspirin use on colorectal, ovarian, breast, endometrial and aggressive prostate cancer risk.

METHODS

We pooled 423,495 individuals from two prospective, U.S.-based studies: the NIH-AARP Diet and Health Study (1995-2011) and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (1993-2009). Using Cox proportional hazards regression, we examined associations between daily aspirin use (≥ 5 days/week) and risk of colorectal, ovarian, breast, endometrial, and aggressive prostate cancer, overall and across strata of risk factors.

RESULTS

Daily aspirin use was associated with a 15% reduction in colorectal cancer risk (hazard ratio [HR]: 0.85, 95% confidence interval [CI] 0.80-0.89). Risk reductions were generally consistent across strata of risk factors but attenuated with increasing BMI (p-interaction = 0.16). For ovarian cancer, there was no significant association overall (HR: 0.93, 95% CI 0.80-1.08) but reduced risk among obese women (HR: 0.73, 95% CI 0.52-0.98, p-interaction = 0.12). Weak or null associations were observed for breast, endometrial, and aggressive prostate cancer, with no strong effect modification observed.

CONCLUSIONS

Daily aspirin use appears to reduce colorectal cancer risk regardless of other risk factors, though the potential modifying effect of BMI warrants further investigation and may need to be considered in risk-benefit calculations for aspirin use.

Aspirin use and ovarian cancer risk using extended follow-up of the PLCO Cancer Screening Trial

OBJECTIVE

Frequent use of aspirin has been associated with reduced ovarian cancer risk in observational studies, but it is unclear if only daily, low-dose aspirin confers a protective benefit. We examined associations between patterns of aspirin use and ovarian cancer risk among postmenopausal women in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial.

METHODS

Participants were enrolled in PLCO between 1993 and 2001 and followed for cancer outcomes through 2014. Detailed data on aspirin use (e.g., dose, frequency and duration) were ascertained via the supplemental questionnaire (SQX) administered in 2006-2007. We used Cox proportional hazards regression to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between aspirin use (defined as use ≥once/week) and incident ovarian cancer. We conducted analyses among all women in the study sample and stratified by age at the time of the SQX.

RESULTS

There were 41,633 women included in this analysis, of whom 223 developed incident ovarian cancer. Overall, aspirin use was not significantly associated with ovarian cancer risk (HR: 0.93, 95% CI: 0.72-1.21). Among women <70 years, there was suggestion of an inverse association for daily use of aspirin (HR: 0.65, 95% CI: 0.40-1.05), low-dose aspirin (HR: 0.79, 95% CI: 0.51-1.24) and daily use of low-dose aspirin (HR: 0.64, 95% CI: 0.38-1.09).

CONCLUSIONS

These findings suggest a potential modest effect of daily, low-dose aspirin in reducing ovarian cancer risk. However, effect estimates were imprecise given the small number of events, and further research will be needed to confirm and extend these findings.

Abstract A02: Modification of the association between daily aspirin use and ovarian cancer risk by potentially modifiable risk factors

Purpose: Daily aspirin use has been associated with a 10-20% reduced risk of ovarian cancer in case-control and cohort studies. However, it is unknown whether certain subgroups of women are more likely to benefit from potential chemoprevention through daily aspirin. We determined whether the association between aspirin use and ovarian cancer varies by other ovarian cancer risk factors, including age, body mass index (BMI), duration of oral contraceptive use, and duration of menopausal hormone use.

Methods: This study included women from the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening Trial. Women were enrolled between 1993-2001 and followed for cancer outcomes through 2009. Aspirin use and ovarian cancer risk factors were reported at baseline. Cox proportional hazards regression was used to examine associations between daily aspirin use and ovarian cancer risk. Analyses were conducted overall and stratified by baseline age (50-59, 60-69, ≥70), BMI (&lt;25, 25-29, ≥30 kg/m2), duration of oral contraceptive use (none, ≤5 years, &gt;5 years of use), and duration of menopausal hormone use (none, ≤5 years, &gt;5 years of use). All models were adjusted for these risk factors, as well as race (white, non-white), study arm (intervention, control), and number of live births (0, 1, 2, 3, ≥4). Statistical interaction was tested via likelihood ratio tests.

Results: There were 60,713 women included in this study, of whom 364 developed epithelial ovarian cancer. Overall, compared to nonuse or infrequent use, a reduced risk of ovarian cancer was suggested with daily aspirin use (hazard ratio [HR]: 0.79, 95% confidence interval [CI]: 0.61-1.03). The association appeared stronger among women with BMI ≥30 kg/m2 (HR: 0.61, 95% CI: 0.36-1.13) compared to women with BMI &lt;25 kg/m2 (HR: 0.95, 95% CI: 0.64-1.41) or 25-29 kg/m2 (HR: 0.87, 95% CI: 0.55-1.38, p-interaction=0.48). The association remained inverse and did not vary quantitatively or statistically by baseline age (p-interaction=0.96), duration of oral contraceptive use (p-interaction=0.85), or duration of menopausal hormone use (p-interaction=0.95).

Conclusion: Consistent with prior studies, women who used daily aspirin had a lower risk of developing ovarian cancer. The association was not modified by other ovarian cancer risk factors, with the possible exception of BMI. We plan to similarly evaluate modification of the associations between aspirin use and risk of other cancers with potential inflammatory etiologies (e.g., colorectal) and will evaluate this in multiple cohorts. To determine whether aspirin is an effective form of chemoprevention in certain subgroups, ongoing research will likely need to pool data across studies or leverage other large-scale resources.

Citation Format: Lauren M. Hurwitz, Kara A. Michels, Britton Trabert. Modification of the association between daily aspirin use and ovarian cancer risk by potentially modifiable risk factors [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr A02.

Abstract 4667: Associations between daily aspirin use and cancer risk across strata of major cancer risk factors in two large U.S. cohorts

Purpose: Daily low-dose aspirin is recommended for certain individuals for prevention of cardiovascular disease and colorectal cancer. However, there are known risks associated with aspirin use. Identifying subgroups of individuals most likely to benefit from aspirin for cancer prevention would help to tailor risk-benefit calculations to maximize benefits and minimize risks. We investigated whether associations between daily aspirin use and risk of several cancers vary by other cancer risk factors, including age, body mass index (BMI), smoking status, physical inactivity, and family history of cancer.

Methods: We pooled 423,495 individuals from two prospective, U.S.-based studies: the NIH-AARP Diet and Health Study (1995-2011), a population-based cohort study, and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (1993-2009), a multicenter randomized controlled trial. Daily aspirin use was self-reported at baseline and defined as use ≥5 days/week. Our main outcome measures were incident colorectal, ovarian, breast, endometrial, and aggressive prostate cancers. We used multivariable Cox proportional hazards regression to examine associations between daily aspirin use and risk of each cancer, overall and across strata of risk factors.

Results: Compared with non-use and non-daily use, daily aspirin use was associated with a 15% reduction in colorectal cancer risk (hazard ratio [HR]: 0.85, 95% confidence interval [CI]: 0.80-0.89). Risk reductions were generally consistent across strata of other risk factors but attenuated with increasing BMI (p-interaction=0.16). For ovarian cancer, there was no significant association overall (HR: 0.93, 95% CI: 0.80-1.08) but a reduced risk among obese women (HR: 0.73, 95% CI: 0.52-0.98, p-interaction=0.12). We observed suggestive modest risk reductions for breast (HR: 0.96, 95% CI: 0.91-1.00) and aggressive prostate (HR: 0.95, 95% CI: 0.90-1.00) cancer and a null association for endometrial cancer (HR: 0.96, 95% CI: 0.86-1.07), with no strong effect modification observed.

Conclusions: Daily aspirin use was associated with reduced colorectal cancer risk across strata of cancer risk factors. The magnitude of the benefit varied by BMI for colorectal cancer and was restricted to obese women for ovarian cancer. The potential modifying effect of BMI warrants further investigation and may need to be considered in risk-benefit calculations for aspirin use.

Citation Format: Lauren M. Hurwitz, Kara A. Michels, Michael B. Cook, Ruth M. Pfeiffer, Britton Trabert. Associations between daily aspirin use and cancer risk across strata of major cancer risk factors in two large U.S. cohorts [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4667.

Use of Aspirin and Statins in Relation to Inflammation in Benign Prostate Tissue in the Placebo Arm of the Prostate Cancer Prevention Trial

Aspirin and statin use may lower the risk of advanced/fatal prostate cancer, possibly by reducing intraprostatic inflammation. To test this hypothesis, we investigated the association of aspirin and statin use with the presence and extent of intraprostatic inflammation, and the abundance of specific immune cell types, in benign prostate tissue from a subset of men from the placebo arm of the Prostate Cancer Prevention Trial. Men were classified as aspirin or statin users if they reported use at baseline or during the 7-year trial. Presence and extent of inflammation were assessed, and markers of specific immune cell types (CD4, CD8, FoxP3, CD68, and c-KIT) were scored, in slides from end-of-study prostate biopsies taken irrespective of clinical indication, per trial protocol. Logistic regression was used to estimate associations between medication use and inflammation measures, adjusted for potential confounders. Of 357 men included, 61% reported aspirin use and 32% reported statin use. Prevalence and extent of inflammation were not associated with medication use. However, aspirin users were more likely to have low FoxP3, a T regulatory cell marker [OR, 5.60; 95% confidence interval (CI), 1.16-27.07], and statin users were more likely to have low CD68, a macrophage marker (OR, 1.63; 95% CI, 0.81-3.27). If confirmed, these results suggest that these medications may alter the immune milieu of the prostate, which could potentially mediate effects of these medications on advanced/fatal prostate cancer risk.

Overall and abdominal obesity and prostate cancer risk in a West African population: An analysis of the Ghana Prostate Study

Obesity has been associated with an increased risk of advanced prostate cancer. However, most studies have been conducted among North American and European populations. Prostate cancer mortality appears elevated in West Africa, yet risk factors for prostate cancer in this region are unknown. We thus examined the relationship between obesity and prostate cancer using a case-control study conducted in Accra, Ghana in 2004 to 2012. Cases and controls were drawn from a population-based sample of 1037 men screened for prostate cancer, yielding 73 cases and 964 controls. An additional 493 incident cases were recruited from the Korle-Bu Teaching Hospital. Anthropometric measurements were taken at enrollment. We used logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR) and prostate cancer, adjusting for potential confounders. The mean BMI was 25.1 kg/m² for cases and 24.3 kg/m² for controls. After adjustment, men with BMI ≥ 30 kg/m² had an increased risk of prostate cancer relative to men with BMI < 25 kg/m² (OR 1.86, 95% CI 1.11-3.13). Elevated WC (OR 1.76, 95% CI 1.24-2.51) and WHR (OR 1.46, 95% CI 0.99-2.16) were also associated with prostate cancer. Associations were not modified by smoking status and were evident for low- and high-grade disease. These findings indicate that overall and abdominal obesity are positively associated with prostate cancer among men in Ghana, implicating obesity as a potentially modifiable risk factor for prostate cancer in this region.

A prospective analysis of health-related quality of life in intermediate and high-risk prostate cancer patients managed with intensity modulated radiation therapy, with vs. without hormonal therapy

INTRODUCTION

Combined radiotherapy and hormonal treatment are recommended for intermediate- and high-risk prostate cancer (CaP). This study compared the long-term effects on health-related quality of life (HRQoL) of intermediate- and high-risk CaP patients managed with radiation therapy (RT) with vs. without hormone therapy (HT).

METHODS

Patients with intermediate- and high-risk CaP enrolled in the Center for Prostate Disease Research diagnosed from 2007 to 2017 were included. EPIC and SF-36 questionnaires were completed and HRQoL scores were compared for patients receiving RT vs. RT + HT at baseline (pretreatment), 6, 12, 24, 36, 48, and 60 months after CaP diagnosis. Longitudinal patterns of change in HRQoL were modeled using linear regression models, adjusting for baseline HRQoL, age at CaP diagnosis, race, comorbidities, National Comprehensive Cancer Network (NCCN) risk stratum, time to treatment, and follow-up time.

RESULTS

Of 164 patients, 93 (56.7%) received RT alone and 71 (43.3%) received RT + HT. Both groups reported comparable baseline HRQoL. Patients receiving RT+HT were more likely to be NCCN high risk as compared to those receiving only RT. The RT + HT patients experienced worse sexual function, hormonal function, and hormonal bother than those who only received RT; however, HRQoL recovered over time for the RT + HT group. No significant differences were observed between groups in urinary and bowel domains or SF-36 mental and physical scores.

CONCLUSION

Combined RT + HT treatment was associated with temporary lower scores in sexual and hormonal HRQoL compared with RT only. Intermediate- and high-risk CaP patients should be counseled about the possible declines in HRQoL associated with HT.

A prospective study of health-related quality of life outcomes among men treated for intermediate- and high-risk prostate cancer: the impact of primary and secondary therapies

INTRODUCTION

To assess the impact of primary and secondary therapies for high- and intermediate-risk prostate cancer on health-related quality of life (HRQoL).

MATERIALS AND METHODS

A prospective study was initiated in 2007 at Center for Prostate Disease Research Multicenter National Database sites. Longitudinal patterns in HRQoL from baseline (pre-treatment) to 5 years post-diagnosis were examined for patients with high- and intermediate-risk prostate cancer, treated by radical prostatectomy (RP) or external beam radiation therapy (EBRT). Change in HRQoL was modeled using linear regression models fit with generalized estimating equations. The probability of maintaining HRQoL was compared between patients receiving RP only versus RP with secondary treatment.

RESULTS

Of 445 men with high- and intermediate-risk prostate cancer, 228 underwent RP and 143 had EBRT± androgen deprivation therapy (ADT). Fifty received secondary therapy (EBRT and/or ADT or chemotherapy) after RP. RP patients showed a greater decline over time in sexual function and bother and urinary function compared to EBRT±ADT patients. Patients who had secondary therapy after RP were less likely to maintain their HRQoL compared to those who had RP alone. These differences were most pronounced for sexual and hormonal function.

CONCLUSIONS

Prostate cancer patients experience significant declines in HRQoL after primary therapy. Additional secondary therapy after RP, in the form of EBRT and/or ADT, appears to be responsible for further deterioration in HRQoL outcomes.

Aspirin and Non-Aspirin NSAID Use and Prostate Cancer Incidence, Mortality, and Case Fatality in the Atherosclerosis Risk in Communities Study

BACKGROUND

NSAIDs appear to moderately reduce prostate cancer risk. However, evidence is limited on whether NSAIDs protect against prostate cancer mortality (death from prostate cancer among men without a cancer history) and case fatality (death from prostate cancer among men with prostate cancer), and whether benefits are consistent in white and black men. This study investigated associations of aspirin and non-aspirin (NA) NSAID use with prostate cancer incidence, mortality, and case fatality in a population-based cohort of white and black men.

METHODS

We included 6,594 men (5,060 white and 1,534 black) from the Atherosclerosis Risk in Communities study without a cancer history at enrollment from 1987 to 1989. NSAID use was assessed at four study visits (1987-1998). Cancer outcomes were ascertained through 2012. Cox proportional hazards regression was used to estimate adjusted HRs, overall and by race.

RESULTS

Aspirin use was not associated with prostate cancer incidence. However, aspirin use was inversely associated with prostate cancer mortality [HR, 0.59; 95% confidence interval (CI), 0.36-0.96]. This association was consistent among white and black men and appeared restricted to men using aspirin daily and/or for cardiovascular disease prevention. Aspirin use was inversely associated with case fatality (HR, 0.45; 95% CI, 0.22-0.94). NA-NSAID use was not associated with these endpoints.

CONCLUSIONS

Aspirin use was inversely associated with prostate cancer mortality and case fatality among white and black men.

IMPACT

If confirmed by additional studies, benefits of aspirin for preventing prostate cancer mortality may need to be factored into risk-benefit calculations of men considering an aspirin regimen.

Abstract 4947: Aspirin use and risk of lethal prostate cancer in the Atherosclerosis Risk in Communities cohort

Background: Aspirin is commonly used to treat pain and inflammation, and is recommended for some individuals for prevention of cardiovascular disease (CVD) and colorectal cancer. Observational studies suggest that aspirin use may also lower risk of prostate cancer. However, there is limited evidence on whether aspirin may protect against lethal prostate cancer in particular, and on whether benefits are consistent in black and white men. This study sought to determine the association between aspirin use and risk of total and lethal prostate cancer, overall and by race, among men in the Atherosclerosis Risk in Communities (ARIC) cohort.

Methods: The ARIC study enrolled individuals from four U.S. communities in 1987-89. This analysis was restricted to white and black men from this cohort who had non-missing data on aspirin use and were cancer-free at baseline. Aspirin use was assessed at four study visits (V1: 1987-89, V2: 1990-92, V3: 1993-95, V4: 1996-98). Indication for aspirin use was reported at V4. Cancer outcomes were ascertained through 2012. Cox proportional hazards regression was used to estimate cause-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for total incident prostate cancer and lethal prostate cancer, defined as cancer that was advanced at diagnosis or fatal during follow-up. Models were adjusted for race, study center, year of birth, education, and family history of prostate cancer (time-fixed), and smoking status, body mass index, use of statins, diabetes, and coronary heart disease (time-varying). Stratified models and likelihood ratio tests were used to test for effect modification by race.

Results: There were 6,594 men (5,060 white, 1,534 black) included in this analysis. Aspirin use was reported by 29%, 33%, 37% and 44% of men at V1, V2, V3, and V4, respectively. Through the end of 2012, 817 total incident prostate cancers, including 97 lethal prostate cancers, were diagnosed. Aspirin use was not associated with risk of total prostate cancer (HR 1.06, 95% CI 0.91-1.23). However, aspirin use was inversely associated with risk of lethal prostate cancer (HR 0.58, 95% CI 0.35-0.95). This association was consistent among both white men (HR 0.64, 95% CI 0.36-1.13) and black men (HR 0.47, 95% CI 0.16-1.35, p-interaction=0.45). When looked at by indication for use, the inverse association with lethal prostate cancer appeared to be only among men who reported using aspirin regularly for CVD prevention (HR 0.63, 95% CI 0.27-1.50).

Conclusions: Aspirin use was inversely associated with lethal prostate cancer, but not total prostate cancer, in this study population. The association was not modified by race and was possibly restricted to men who used aspirin regularly for CVD prevention. Support: NHLBI, NCI, NPCR

Citation Format: Lauren M. Hurwitz, Corinne E. Joshu, John R. Barber, Anna E. Prizment, Mara Z. Vitolins, Miranda R. Jones, Aaron R. Folsom, Misop Han, Elizabeth A. Platz. Aspirin use and risk of lethal prostate cancer in the Atherosclerosis Risk in Communities cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4947.

Longitudinal regret after treatment for low- and intermediate-risk prostate cancer

BACKGROUND

Prostate cancer patients diagnosed with low- and intermediate-risk disease have several treatment options. Decisional regret after treatment is a concern, especially when poor oncologic outcomes or declines in health-related quality of life (HRQoL) occur. This study assessed determinants of longitudinal decisional regret in prostate cancer patients attending a multidisciplinary clinic and treated with radical prostatectomy (RP), external beam radiation therapy (EBRT), brachytherapy (BT), or active surveillance (AS).

METHODS

Patients newly diagnosed with prostate cancer at the Walter Reed National Military Medical Center who attended a multidisciplinary clinic were enrolled into a prospective study from 2006 to 2014. The Decision Regret Scale was administered at 6, 12, 24, and 36 months posttreatment. HRQoL was also assessed at regular intervals using the Expanded Prostate Cancer Index Composite and 36-item RAND Medical Outcomes Study Short Form questionnaires. Adjusted probabilities of reporting regret were estimated via multivariable logistic regression fitted with generalized estimating equations.

RESULTS

A total of 652 patients met the inclusion criteria (395 RP, 141 EBRT, 41 BT, 75 AS). Decisional regret was consistently low after all of these treatments. In multivariable models, only African American race (odds ratio, 1.67; 95% confidence interval, 1.12-2.47) was associated with greater regret across time. Age and control preference were marginally associated with regret. Regret scores were similar between RP patients who did and did not experience biochemical recurrence. Declines in HRQoL were weakly correlated with greater decisional regret.

CONCLUSION

In the context of a multidisciplinary clinic, decisional regret did not differ significantly between treatment groups but was greater in African Americans and those reporting poorer HRQoL. Cancer 2017;123:4252-4258. © 2017 American Cancer Society.

Prospective quality-of-life outcomes for low-risk prostate cancer: Active surveillance versus radical prostatectomy

BACKGROUND

For patients with low-risk prostate cancer (PCa), active surveillance (AS) may produce oncologic outcomes comparable to those achieved with radical prostatectomy (RP). Health-related quality-of-life (HRQoL) outcomes are important to consider, yet few studies have examined HRQoL among patients with PCa who were managed with AS. In this study, the authors compared longitudinal HRQoL in a prospective, racially diverse, and contemporary cohort of patients who underwent RP or AS for low-risk PCa.

METHODS

Beginning in 2007, HRQoL data from validated questionnaires (the Expanded Prostate Cancer Index Composite and the 36-item RAND Medical Outcomes Study short-form survey) were collected by the Center for Prostate Disease Research in a multicenter national database. Patients aged ≤75 years who were diagnosed with low-risk PCa and elected RP or AS for initial disease management were followed for 3 years. Mean scores were estimated using generalized estimating equations adjusting for baseline HRQoL, demographic characteristics, and clinical patient characteristics.

RESULTS

Of the patients with low-risk PCa, 228 underwent RP, and 77 underwent AS. Multivariable analysis revealed that patients in the RP group had significantly worse sexual function, sexual bother, and urinary function at all time points compared with patients in the AS group. Differences in mental health between groups were below the threshold for clinical significance at 1 year.

CONCLUSIONS

In this study, no differences in mental health outcomes were observed, but urinary and sexual HRQoL were worse for patients who underwent RP compared with those who underwent AS for up to 3 years. These data offer support for the management of low-risk PCa with AS as a means for postponing the morbidity associated with RP without concomitant declines in mental health.

Telomere length as a risk factor for hereditary prostate cancer

BACKGROUND

Telomeres are repetitive nucleotide sequences that stabilize the ends of chromosomes. Critically short telomeres are thought to contribute to cancer development by increasing chromosomal instability. We hypothesized that shorter leukocyte telomere length, a surrogate for inherited prostate cell telomere length, would be associated with increased risk of prostate cancer in hereditary prostate cancer (HPC) families.

METHODS

One hundred twelve affected and 63 unaffected men from 28 families were drawn from the Johns Hopkins HPC family database. Relative mean telomere length was measured in isolated peripheral leukocyte DNA by quantitative PCR. Conditional logistic regression was used to estimate the association between quartile of age-adjusted telomere length and prostate cancer.

RESULTS

Men in the shortest quartile of telomere length did not have increased odds of prostate cancer compared to men in the other three quartiles (OR = 0.84, 95% CI: 0.32-2.20, P = 0.73). However, when the analysis was restricted to affected men with blood drawn before or within a year of diagnosis (N = 39) and all unaffected men, shorter telomere length was moderately associated with increased odds of prostate cancer (OR = 3.55, 95% CI: 0.82-15.43, P = 0.09).

CONCLUSIONS

Though we found no association overall, shorter leukocyte telomere length may be associated with increased odds of prostate cancer when measured in pre-diagnostic samples. Further prospective research is warranted exploring the utility of telomere length as a prostate cancer biomarker.

Practical injection-rate CT perfusion imaging: deconvolution-derived hemodynamics in a case of stroke

Previously reported methods of dynamic, contrast-enhanced, CT perfusion imaging in acute stroke have been promising but substantially limited by their dependence on very rapid rates of injection (typically 10-20 ml/s in an arm vein). Newly available deconvolution software permits the use of lower rates of injection (e. g., 3-4 ml/s), and rapidly provides maps of cerebral blood flow, cerebral blood volume and mean transit time. We report the potential of CT perfusion imaging performed with an injection rate of 4 ml/s to provide information on the extent of hemodynamic abnormality, and to help distinguish viable from nonviable ischemic tissue. The slower injection rates permitted by deconvolution analysis substantially enhance the practicality of CT perfusion imaging for studying stroke.

Can prenylcysteines be exploited as ligands for mammalian multidrug-resistance transporters?

The overexpression of specific transport proteins in the membrane of many cancer cells renders these cells resistant to many therapeutic drugs. Some lipid-modified cysteine compounds inhibit one drug-transporting protein, indicating the potential of developing such compounds as therapeutic agents.

Regulation of extracellular calcium entry in endothelial cells: role of intracellular calcium pool

We have investigated the role of the intracellular Ca2+ pool in regulating Ca2+ entry into vascular endothelial cells. The intracellular Ca2+ pool was mobilized using either thapsigargin (TG) or 2',5'-di(tert-butyl)-1,4-benzohydroquinone (BHQ), inhibitors of the endoplasmic reticulum Ca(2+)-adenosinetriphosphatase (ATPase). Mobilization of intracellular Ca2+ stores with either inhibitor depleted intracellular Ca2+ and greatly reduced subsequent mobilization of the inositol 1,4,5-trisphosphate (IP3)-sensitive intracellular Ca2+ pool by bradykinin. However, bradykinin-induced mobilization of the IP3-sensitive intracellular Ca2+ pool only partially reduced the subsequent response of cells to TG and BHQ. Mobilization of the intracellular Ca2+ pool by either TG or BHQ led to a concentration-dependent elevation of cytosolic Ca2+ concentrations ([Ca2+]i) without initiating inositol polyphosphate formation. In contrast to the rapidly developing, transient rise in Ca2+ concentration initiated by bradykinin, maximal concentrations of TG and BHQ stimulated a slowly developing, prolonged elevation of [Ca2+]i that required extracellular Ca2+ and could be blocked by extracellular Ni2+. Extracellular Ca2+ entered the cell through an activated cation entry pathway, since bradykinin, TG, and BHQ stimulated Mn2+ and 45Ca2+ entry. Bradykinin-stimulated 45Ca2+ uptake reached a peak within 2 min, whereas 45Ca2+ influx initiated by TG or BHQ continued for at least 8 min. Importantly, the [Ca2+]i response after low concentrations of BHQ was more transient than that seen after TG. The return of [Ca2+]i to basal values after low concentrations of BHQ was associated with reversal of Ca(2+)-ATPase inhibition and refilling of the IP3-sensitive Ca2+ pool. The continued elevation of [Ca2+]i and prolonged Ca2+ entry seen with TG was associated with continued Ca(2+)-ATPase inhibition and an empty IP3-sensitive Ca2+ pool. We conclude that mobilization of intracellular Ca2+ stores induces Ca2+ entry in endothelial cells which continues until the intracellular Ca2+ pool is refilled.