Interactions between oxidative stress and senescence in cancer: Mechanisms, therapeutic implications, and future perspectives

BACKGROUND

Recently, numerous studies have reported the interaction between senescence and oxidative stress in cancer. However, there is a lack of a comprehensive understanding of the precise mechanisms involved.

AIM

Therefore, our review aims to summarize the current findings and elucidate by presenting specific mechanisms that encompass functional pathways, target genes, and related aspects.

METHODS

Pubmed and Web of Science databases were retrieved to search studies about the interaction between senescence and oxidative stress in cancer. Relevant publications in the reference list of enrolled studies were also checked.

RESULTS

In carcinogenesis, oxidative stress-induced cellular senescence acts as a barrier against the transformation of stimulated cells into cancer cells. However, the senescence-associated secretory phenotype (SASP) is positively linked to tumorigenesis. In the cancer progression stage, targeting specific genes or pathways that promote oxidative stress-induced cellular senescence can suppress cancer progression. In terms of treatment, many current clinical therapies combine with novel drugs to overcome resistance and reduce side effects by attenuating oxidative stress-induced senescence. Notably, emerging drugs control cancer development by enhancing oxidative stress-induced senescence. These studies highlight the complacted effects of the interplay between oxidative stress and senescence at different cancer stages and among distinct cell populations. Future research should focus on characterizing the roles of distinct senescent cell types in various tumor stages and identifying the specific components of SASP.

CONCLUDSION

We've summarized the mechanisms of senescence and oxidative stress in cancer and provided illustrative figures to guide future research in this area.

Psychological Determinants of Physician Variation in End-of-Life Treatment Intensity: A Systematic Review and Meta-Synthesis

BACKGROUND

Physicians treating similar patients in similar care-delivery contexts vary in the intensity of life-extending care provided to their patients at the end-of-life. Physician psychological propensities are an important potential determinant of this variability, but the pertinent literature has yet to be synthesized.

OBJECTIVE

Conduct a review of qualitative studies to explicate whether and how psychological propensities could result in some physicians providing more intensive treatment than others.

METHODS

Systematic searches were conducted in five major electronic databases-MEDLINE ALL (Ovid), Embase (Elsevier), CINAHL (EBSCO), PsycINFO (Ovid), and Cochrane CENTRAL (Wiley)-to identify eligible studies (earliest available date to August 2021). Eligibility criteria included examination of a physician psychological factor as relating to end-of-life care intensity in advanced life-limiting illness. Findings from individual studies were pooled and synthesized using thematic analysis, which identified common, prevalent themes across findings.

RESULTS

The search identified 5623 references, of which 28 were included in the final synthesis. Seven psychological propensities were identified as influencing physician judgments regarding whether and when to withhold or de-escalate life-extending treatments resulting in higher treatment intensity: (1) professional identity as someone who extends lifespan, (2) mortality aversion, (3) communication avoidance, (4) conflict avoidance, (5) personal values favoring life extension, (6) decisional avoidance, and (7) over-optimism.

CONCLUSIONS

Psychological propensities could influence physician judgments regarding whether and when to de-escalate life-extending treatments. Future work should examine how individual and environmental factors combine to create such propensities, and how addressing these propensities could reduce physician-attributed variation in end-of-life care intensity.

Chemotherapy for metastatic colon cancer: No effect on survival when the dose is reduced due to side effects

BACKGROUND

5-Fluorouracil (5FU), Folinic acid (FA), and Oxaliplatin (FOLFOX) or 5FU, FA, and Irinotecan (FOLFIRI) are standard regimens for palliative chemotherapy of metastatic colon cancer. Since data showing the influence of dose reduction in palliative treatment are rare, the objective of this single center, retrospective study was to further characterize the influence of dose reduction on efficacy of these therapeutic regimens.

METHODS

One hundred nine patients, diagnosed with stage IV colon cancer between 2004 and 2012 and receiving palliative first-line chemotherapy with either FOLFOX or FOLFIRI regimens in our outpatient clinic were analyzed for treatment efficacy. Patients who received dose reductions due to side effects usually received doses of 80% or lower of per protocol dose. Survival data were obtained from the Regensburg Tumor Registry. Survival analysis was performed using Kaplan-Meier statistical analysis and multivariable analysis.

RESULTS

A dose reduction due to side effects was necessary in 46 (42%) patients. Dose reduction was independent of age. Major reasons for dose reduction were neutropenia (30%) followed by polyneuropathy (16%) and diarrhea (14%). Dosage was more often reduced in patients receiving FOLFOX based therapy. Comparison of patients with dose reduction versus patients with full dosage showed no significant difference on overall survival (p = 0.430). Subgroup analysis revealed dose reduction in patients with N2 stage disease was associated with improved survival. Patients who underwent dose reduction received more cycles of chemotherapy (13.7 vs. 10.8 cycles) and cumulative dosage was similar in both groups.

CONCLUSION

Contrary to our expectations, the need to reduce chemotherapy dosage due to side effects does not indicate a worse prognosis in our retrospective analysis. We believe this can in part be explained by better adaption to interindividual pharmacokinetics and longer time of treatment.

"Rather one more chemo than one less…": Oncologists and Oncology Nurses' Reasons for Aggressive Treatment of Young Adults with Advanced Cancer

BACKGROUND

Empirical research demonstrates that there is a tendency to administer tumor-directed therapy to patients with advanced cancer close to death, especially if they are young. The aim of this qualitative study was to understand oncologists' treatment decisions and oncology nurses' perception of these decisions in young adult patients and to investigate the extent to which young age was a factor in cancer treatment decisions.

MATERIALS AND METHODS

We conducted 29 face-to-face interviews with oncologists and oncology nurses at the Department of Hematology and Oncology at the University Hospital in Munich, Germany. The interviews were analyzed according to the grounded theory approach.

RESULTS

Oncologists and nurses reported that decisions about limiting cancer treatment with young adult patients are the most challenging and stressful in clinical practice. Apart from using young age as a proxy for patient's medical fitness, oncologists' decisions in favor of more aggressive treatment of younger patients were mainly guided by ethical reasons such as patient preferences and the perceptions of injustice associated with dying at a young age, as well as by psychological reasons, such as identification and emotional entanglement.

CONCLUSION

"Struggling" together with the patient against the injustice of dying young for a longer lifetime is an important factor driving aggressive treatment in young adult patients. However, oncologists might run a risk of neglecting other ethical aspects, such as a principle of nonmaleficence, that might even result in life-shortening adverse events.

IMPLICATIONS FOR PRACTICE

This study identifies two ethical and one psychological reasons for patients' overtreatment: 1) patients' preference for further treatment; 2) oncologists' perception of un-fairness of dying young; and 3) identification and emotional entanglement with patient. These findings emphasize the need for oncologists' awareness of the reasons guiding their treatment decisions - a sole focus on patients' preferences and on the fighting against the unfairness of dying young might lead to neglecting obligations of non-maleficence. Self-reflection, the balance of empathy and professional distance as well as timely end of life discussions and involvement of psycho-oncologists are needed in the care of young cancer patients.

Planning Ahead: Using the Theory of Planned Behavior to Predict Older Adults’ Intentions to Use Hospice if Faced With Terminal Illness

Hospice is underutilized in the United States, and many patients enroll for short periods of times. The purpose of this cross-sectional study was to identify significant predictors of intentions to use hospice in community-dwelling older adults. The Theory of Planned Behavior informed the selection of predictors. Data were collected from 146 White older adults ( M age = 69.5; 69% females). Multiple linear regression analyses showed that higher hospice knowledge, normative beliefs that support hospice utilization, higher perceived control to use hospice, and preferences for end-of-life care that favor comfort and quality of life over living as long as possible were significant predictors of intentions to use hospice. In spite of being a sample of mostly highly educated older adults, almost half did not know about funding for hospice. These results provide better understanding of where to focus interventions to educate older adults about hospice, ideally in advance of a crisis.

The Role of the Advanced Practice Nurse in Geriatric Oncology Care

OBJECTIVES

To describe how the Advanced Practice Nurse (APN) is uniquely suited to meet the needs of older adults throughout the continuum of cancer, to explore the progress that APNs have made in gero-oncology care, and make suggestions for future directions.

DATA SOURCE

Google Scholar, PubMed, and CINAHL. Search terms included: "gero-oncology," "geriatric oncology," "Advanced Practice Nurse," "Nurse Practitioner," "older adult," "elderly," and "cancer."

CONCLUSION

Over the last decade, APNs have made advances in caring for older adults with cancer by playing a role in prevention, screening, and diagnosis; through evidence-based gero-oncology care during cancer treatment; and in designing tailored survivorship care models. APNs must combat ageism in treatment choice for older adults, standardize comprehensive geriatric assessments, and focus on providing person-centered care, specifically during care transitions.

IMPLICATIONS FOR NURSING PRACTICE

APNs are well-positioned to help understand the complex relationship between risk factors, geriatric syndromes, and frailty and translate research into practice. Palliative care must expand beyond specialty providers and shift toward APNs with a focus on early advanced care planning. Finally, APNs should continue to establish multidisciplinary survivorship models across care settings, with a focus on primary care.