Abstract 439: Physical activity among male cancer survivors during the COVID-19 pandemic

Introduction: The COVID-19 pandemic has greatly disrupted the lives of cancer survivors. Beyond being at increased risk for COVID-19 infection and severe complications, cancer survivors may be at higher risk of other consequential health outcomes compared to those without a history of cancer. Engagement in physical activity has been shown to positively affect cancer survivorship outcomes, and as such, it is important to assess physical activity habits during the pandemic of cancer survivors.

Aim: To investigate the individual-level physical activity among male cancer survivors during the COVID-19 pandemic and compare to men without cancer.

Methods: Participants of the Health Professionals Follow-up Study, enrolled since 1986, were asked to self-report health behaviors during the pandemic on three web-based questionnaires administered during the COVID-19 pandemic (baseline COVID: October 2020, first follow-up: January 2021, second follow-up: April 2021). Physical activity measures were analyzed descriptively between cancer survivors and individuals without a history of cancer. Outcomes were recoded dichotomously to reflect either: healthful (i.e., higher engagement since pandemic) vs unchanged/unhealthful behavior or high vs low engagement in an activity. Logistic regression models were employed to assess association with cancer survivor status and were adjusted for covariates such as age, race, pre-pandemic BMI, pre-pandemic physical activity, and other health information, as appropriate.

Results: Of 4,416 men who completed the baseline COVID-19 questionnaire, 962 were cancer survivors (after excluding those with non-melanoma skin cancer). Of all eligible men (median age: 78 years) reporting on physical activity, over 50% walked for at least 2-3 hours per week, over 10% used a stationary bike for at least 1 hour per week, 14% engaged in yoga for at least 1 hour per week, and nearly 20% engaged in vigorous activity for at least 1 hour per week. Further, 42% engaged in high (1+ times per day) levels of mindfulness and 24% engaged in high (1+ times per day) levels of yoga. Engagement in vigorous physical activity was significantly lower among cancer survivors compared to individuals without a history of cancer (Chi-square p = 0.01).

Conclusion: Our findings suggest older men had high engagement in physical activity during the COVID-19 pandemic, with vigorous physical activity engagement significantly lower in cancer survivors.

Citation Format: Colleen B. McGrath, Alaina H. Shreves, Konrad Stopsack, Lilian Cheung, Ann Fisher, Sarah Markt, Lorelei A. Mucci. Physical activity among male cancer survivors during the COVID-19 pandemic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 439.

Abstract 38: Racial disparities in prostate cancer mortality rates explained by differences in dietary and lifestyle factors

Introduction: Black men have 2.1 times higher prostate cancer mortality rates than White men in the United States, yet the reasons for this disparity remain unclear. Several dietary and lifestyle factors may influence the risk of developing lethal prostate cancer. This study evaluated to what extent differences in the prevalence of modifiable risk factors by race could explain racial disparities in prostate cancer mortality.

Methods: Our study utilized data from the Health Professionals Follow-up Study (HPFS, N=51,529 men, 1986-2016) and the National Health and Nutrition Examination Study (NHANES, 2000-2010). First, we used data from NHANES to estimate the prevalence of three factors among Black and White men: smoking, vitamin D, and coffee. Then, using HPFS, we generated relative risk estimates for lethal prostate cancer for each factor. To estimate the relative prostate cancer burden associated with these risk factors, we calculated the population attributable fraction (PAF) for each factor by self-identified race, defined as the reduction in mortality that would be achieved if the population had been entirely unexposed, compared with the current exposure pattern. We then calculated the difference in the PAF between Black and white men to estimate the difference in mortality reduction between the two groups if all men had been entirely unexposed, assuming causality of risk factors and no effect modification by race.

Results: There were notable differences in the prevalence of several risk factors by race. For example, Black men had significantly lower levels of vitamin D[MLA1], were less likely to drink coffee, and had a higher prevalence of smoking compared to white men. We estimated that eliminating these risk factors among Black men could lead to a reduction in prostate cancer mortality that is 4-14% larger compared to eliminating these risk factors among white men.

Conclusions: Modifiable lifestyle and dietary factors are potentially responsible for a proportion of the racial disparity in prostate cancer mortality. Our future work will expand the modifiable factors as well as incorporating more contemporary comparisons of the prevalence of these factors to predict future disparities in prostate cancer.

Citation Format: Emily Rencsok, Michelle Sodipo, Travis Gerke, Konrad Stopsack, Lorelei Mucci. Racial disparities in prostate cancer mortality rates explained by differences in dietary and lifestyle factors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 38.

Abstract 440: Diet and supplement use changes among male cancer survivors during the COVID-19 pandemic

Introduction: The COVID-19 pandemic has disrupted the lives of cancer survivors who may be at higher risk than people without cancer of other adverse health outcomes. For many individuals, a cancer diagnosis leads to lower physical activity and change in mental health status. Modifiable health behaviors, such as consumption of a healthy diet, can positively affect cancer survivorship outcomes.

Aim: To investigate the individual-level changes in diet and supplement use among male cancer survivors during the COVID-19 pandemic and compared to men without cancer.

Methods: Participants of the Health Professionals Follow-up Study, enrolled since 1986, were asked to self-report health behaviors during the pandemic on three web-based questionnaires administered during the COVID-19 pandemic (baseline COVID: October 2020, first follow-up: January 2021, second follow-up: April 2021). Diet and supplement use were analyzed descriptively between cancer survivors and individuals without a history of cancer. Further, outcomes were dichotomized to reflect whether a change was healthful or unchanged/unhealthful; for example, lower fast food consumption was classified as a healthful change. To assess the associations between cancer survivors and other men, logistic regression was used, adjusting for age, race, pre-pandemic body mass index, pre-pandemic physical activity, and other health information.

Results: Of 4,416 men who completed the baseline COVID-19 questionnaire, 962 were cancer survivors (after excluding those with non-melanoma skin cancer). Across all eligible men (median age: 78 years), there were considerable proportions of men engaging in healthful changes following the start of the pandemic in intake of fast food (19% decreased), sugary drinks (14% decreased), fresh fruit (26% increased), fresh vegetables (19% increased), fish (13% increased), and red meat (12% decreased) consumption. Similar changes in diet were reported on the second follow-up questionnaire. For most foods, a similar percentage of cancer survivors and individuals without a history of cancer increased healthy eating. Findings from multivariable logistic regression models were reflective of higher odds of cancer survivors to engage in a healthful diet change for unhealthy food categories (i.e., less fast food, less frozen food), though none of which were statistically significant. There was little change in supplement use during the pandemic, except for 6% who started use of vitamin D supplements between the baseline and first follow-up questionnaire.

Conclusion: Our findings suggest that older men engaged in healthful diet changes during the COVID-19 pandemic, without noticeable differences among cancer survivors.

Citation Format: Alaina H. Shreves, Colleen B. McGrath, Konrad Stopsack, Lilian Cheung, Ann Fisher, Edward Giovannucci, Sarah Markt, Eric Rimm, Lorelei Mucci. Diet and supplement use changes among male cancer survivors during the COVID-19 pandemic [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 440.

Abstract 822: Can the genetic risk of prostate cancer be attenuated by a healthy lifestyle

Introduction: Inherited genetic factors contribute significantly to prostate cancer risk and explains 58% of the variability in prostate cancer incidence. It is unclear if the increased genetic risk of prostate cancer, including progression to lethal disease, can be offset by adherence to a healthy lifestyle.

Methods: Using a validated polygenic risk score (PRS) for overall prostate cancer, we quantified the genetic risk of prostate cancer in 10,443 men in the Health Professionals Follow-up Study for whom genotype data was available. We applied a validated lifestyle score for lethal prostate cancer (including healthy weight, vigorous physical activity, not smoking, and high consumption of tomatoes, fatty fish, and reduced intake of processed meat) and examined the incidence of overall and lethal (metastatic disease or prostate cancer-specific death) prostate cancer from the date of blood (1993-1999) or cheek collection (2005-2006) through 2014 (2016 for lethal disease). Multivariable Cox proportional hazards models were used to estimate the risk of overall and lethal prostate cancer by joint categories of genetic risk (PRS quartiles) and a time-varying lifestyle score (1-2: least healthy, 3: moderate healthy, and 4-6: most healthy). Both unweighted and inverse probability weighted (IPW) models (to account for possible bias arising from the genotype sampling design) were applied. Lifetime cumulative incidence was estimated using regression standardization.

Results: We observed 2,111 prostate cancer and 238 lethal prostate cancer events during a median follow-up of 18 and 22 years, respectively. The PRS enabled risk stratification for both overall and lethal prostate cancer, with men in the highest genetic risk quartile having a 5.4-fold increased risk of overall prostate cancer (HRipw = 5.39, 95% CI = 4.59-6.33) and a 3.5-fold increased risk of lethal prostate cancer (HRipw = 3.53, 95% CI = 2.34-5.32) compared with men in the lowest genetic risk quartile. Among men in the highest genetic risk quartile, adhering to a healthy lifestyle was significantly associated with a decreased risk of lethal prostate cancer (HRipw = 0.54, 95% CI = 0.31-0.94) compared with the least healthy lifestyle. Adhering to healthy lifestyle was not associated with a decreased risk of overall prostate cancer (HRipw = 1.01, 95% CI = 0.84-1.22). In the group of men with highest genetic risk, having a healthy lifestyle at study entry was associated with a lifetime cumulative incidence of lethal prostate cancer of 3%, lower than for men having the least healthy lifestyle (6%) and similar to the population average (3%).

Conclusion: In this large prospective cohort of US men, inherited genetic factors increased the risk of both overall and lethal prostate cancer. The associated decreased risk of aggressive disease in those with a favorable lifestyle may suggest that the excess genetic risk of lethal prostate cancer could be offset by adhering to a healthy lifestyle.

Citation Format: Anna Plym, Yiwen Zhang, Konrad Stopsack, Bénédicte Delcoigne, Adam S. Kibel, Edward Giovannucci, Kathryn L. Penney, Lorelei A. Mucci. Can the genetic risk of prostate cancer be attenuated by a healthy lifestyle [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 822.

Abstract 339: Mechanisms of resistance to poly (ADP-ribose) polymerase inhibitors in prostate cancer

Background: Poly (ADP-ribose) polymerase inhibitors (PARPi) have demonstrated promise in treating cancers with DNA damage repair (DDR) gene abnormalities. As a result, olaparib and more recently, rucaparib have been given Breakthrough Therapy designation by the FDA for use in metastatic castration resistant prostate cancer (mCRPC) with BRCA1/2 and ATM mutations. One of the problems encountered with PARPi is drug resistance which generally limits drug efficacy. Mechanistic studies on PARPi resistance have shown one of the main mechanisms of acquired resistance to be a reversion mutation of BRCA1/2. However, this is likely more applicable to cancers in which impaired BRCA1/2 function is due to a mutation rather than in prostate cancer (PC) where BRCA2 tends to be frequently deleted. Therefore, we hypothesize that mechanisms of resistance to PARPi in PC may involve alternative molecular mechanisms rather than a reversion mutation.

Methods: We used human castration-resistant PC cell lines that harbor genomic deletions of BRCA2, PC-3 and LnCaP-Abl, and performed cell viability (MTT) assays to determine the inhibitory growth (IG) concentrations of these cell lines with talazoparib and olaparib. We cultured parental PC-3 cells in sublethal concentrations (IG 50% and IG 90%) of talazoparib-supplemented media to develop talazoparib-resistant cells. RNA sequencing followed by gene-set enrichment analysis (GSEA) of hallmark gene sets was performed on the talazoparib-resistant PC-3 cells to understand the underlying molecular mechanisms.

Results: We observed that the talazoparib-resistant PC-3 cells exhibited significantly enhanced cell growth compared to parental cells when cultured in the IG 90% concentration of olaparib. However, interestingly, the talazoparib-resistant cells grew much slower in 2D compared to parental PC-3 cells when cultured in the PARPi-free media. Our transcriptomic analysis showed significant enrichment of various inflammatory response pathways, including TNF-α and IFNα/γ signaling pathways, in the talazoparib-resistant cells and even in the parental PC-3 cells transiently treated with talazoparib.

Conclusion: We hypothesize that resistance to PARPi in PC may be related to upregulation of inflammatory signaling. Therefore, further exploration of TNF-α and IFNα/γ and their role in PARPi resistance mechanisms may lead to the identification of targets that allow for overcoming PARPi resistance in PC.

Citation Format: Mohammad Atiq, Goutam Chakraborty, Subhiksha Nandakumar, Ying Z. Mazzu, Konrad Stopsack, Yuki Yoshikawa, Nabeela Khan, Gwo-Shu Mary Lee, Philip W. Kantoff. Mechanisms of resistance to poly (ADP-ribose) polymerase inhibitors in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 339.

Blastocystis sp. subtype 2 detection during recurrence of gastrointestinal and urticarial symptoms

Blastocystis is a common unicellular intestinal parasite in humans. Its clinical relevance is still subject to discussion with numerous conflicting reports on its ability to cause disease. A remarkable genetic heterogeneity among isolates suggests an association between distinct subtypes (STs) and pathogenicity, although a clear correlation between symptoms and subtype is lacking. Here, we report on a clinical case which possibly links Blastocystis sp. ST2 infection with the simultaneous occurrence of gastrointestinal illness and generalized chronic urticaria. Despite repeated chemotherapy with different antimicrobial drugs, both the gastrointestinal and cutaneous disorders reoccurred after short symptom-free intervals. Eradication of the parasite and permanent resolution of the patient's medical condition was finally achieved with the combined application of metronidazole and paromomycin.