Exercise Training and Natural Killer Cells in Cancer Survivors: Current Evidence and Research Gaps Based on a Systematic Review and Meta-analysis

Exercise: a non-drug strategy of NK cell activation

Natural killer (NK) cells are a critical component of the innate immune system and one of the immune cells most sensitive to exercise. So far, it is widely believed that moderate exercise can significantly enhance the proliferation and activity of NK cells, strengthening immune function. However, the impact of exercise on NK cells is a dynamic and complex process. In addition to the type of exercise, the frequency, intensity, and duration of exercise are also key factors. This article not only briefly summarizes the activation mechanisms of NK cells but also delves into the potential importance of exercise as a non-pharmacological strategy in modulating NK cell activity and enhancing the immune system. Emerging studies have indicated that the timing and regularity of exercise bouts might also influence NK cell responses. Moreover, the interaction between exercise and other components of the immune system, such as cytokines and chemokines, could further modulate the functionality of NK cells. The above research is of crucial significance for achieving a deeper understanding of the intricate connection between exercise and NK cell function, as well as the development of effective health promotion strategies. In addition, further research is needed to investigate the effects of long-term exercise on NK cell function and the interaction between exercise and NK cell-mediated immune responses. Translating these research findings into precisely tailored exercise programs for specific populations, taking into account factors like age, health status, and genetic predisposition, could potentially offer unprecedented prospects for further advancements in this burgeoning field of study.

Unraveling the role of exercise in cancer suppression: insights from a mathematical model

Recent experimental studies have shown that physical exercise has the potential to suppress tumor progression. Such suppression has been reported to be mediated by the exercise-induced activation of natural killer (NK) cells through the release of IL-6, a cytokine. Aimed at shedding light on how exercise-induced NK cell activation helps in the suppression of cancer, we developed a coarse-grained mathematical model based on a system of ordinary differential equations describing the interaction between IL-6, NK-cells, and tumor cells. The model is then used to study how exercise duration and exercise intensity affect tumor suppression. Our results show that increasing exercise intensity or increasing exercise duration leads to greater and sustained tumor suppression. Furthermore, multi-bout exercise patterns hold promise for improving cancer treatment strategies by adjusting exercise intensity and frequency. Thus, the proposed mathematical model provides insights into the role of exercise in tumor suppression and can be instrumental in guiding future experimental studies, potentially leading to more effective exercise interventions.

Construction and verification of rehabilitation nursing program for shoulder and neck discomfort after thyroid cancer surgery: A pilot randomized controlled trial

BACKGROUND

To develop a nursing program for the prevention and rehabilitation of shoulder and neck discomfort after thyroid cancer surgery based on the empowerment theory, and to evaluate the application effect of the program.

METHODS

The prevention and rehabilitation nursing program for shoulder and neck discomfort after thyroid cancer surgery was established by literature review and the Delphi method. Between July 2022 and January 2023, a total of 62 postoperative thyroid cancer patients were recruited and randomly allocated to either the intervention group (n = 31) or the control group (n = 31) in this randomized controlled trial. Comparisons of shoulder and neck function, self-efficacy, and quality of life between the 2 groups were performed using a 2-sample independent t test, Wilcoxon rank-sum test, and repeated-measures analysis of variance.

RESULTS

At the end of the study, the control group and intervention group were 30 cases each completed the study. After the intervention, the self-efficacy score of the intervention group was higher than the control group (P < .05), and the score of emotional function, cognitive function, and overall health dimension of the intervention group was higher than the control group (P < .05). The pain dimension score of the intervention group was lower than the control group (P < .05). There were significant differences in the group and time effects of the total shoulder joint scores between the 2 groups (P < .05).

CONCLUSION

This study demonstrated that the shoulder and neck rehabilitation nursing program can alleviate the symptoms of shoulder and neck discomfort and improve patients' self-efficacy and quality of life.

Perioperative Immunosuppressive Factors during Cancer Surgery: An Updated Review

Surgical excision of the primary tumor represents the most frequent and curative procedure for solid malignancies. Compelling evidence suggests that, despite its beneficial effects, surgery may impair immunosurveillance by triggering an immunosuppressive inflammatory stress response and favor recurrence by stimulating minimal residual disease. In addition, many factors interfere with the immune effectors before and after cancer procedures, such as malnutrition, anemia, or subsequent transfusion. Thus, the perioperative period plays a key role in determining oncological outcomes and represents a short phase to circumvent anesthetic and surgical deleterious factors by supporting the immune system through the use of synergistic pharmacological and non-pharmacological approaches. In line with this, accumulating studies indicate that anesthetic agents could drive both protumor or antitumor signaling pathways during or after cancer surgery. While preclinical investigations focusing on anesthetics' impact on the behavior of cancer cells are quite convincing, limited clinical trials studying the consequences on survival and recurrences remain inconclusive. Herein, we highlight the main factors occurring during the perioperative period of cancer surgery and their potential impact on immunomodulation and cancer progression. We also discuss patient management prior to and during surgery, taking into consideration the latest advances in the literature.

Effects of chronic stress on cancer development and the therapeutic prospects of adrenergic signaling regulation

Long-term chronic stress is an important factor in the poor prognosis of cancer patients. Chronic stress reduces the tissue infiltration of immune cells in the tumor microenvironment (TME) by continuously activating the adrenergic signaling, inhibits antitumor immune response and tumor cell apoptosis while also inducing epithelial-mesenchymal transition (EMT) and tumor angiogenesis, promoting tumor invasion and metastasis. This review first summarizes how adrenergic signaling activates intracellular signaling by binding different adrenergic receptor (AR) heterodimers. Then, we focused on reviewing adrenergic signaling to regulate multiple functions of immune cells, including cell differentiation, migration, and cytokine secretion. In addition, the article discusses the mechanisms by which adrenergic signaling exerts pro-tumorigenic effects by acting directly on the tumor itself. It also highlights the use of adrenergic receptor modulators in cancer therapy, with particular emphasis on their potential role in immunotherapy. Finally, the article reviews the beneficial effects of stress intervention measures on cancer treatment. We think that enhancing the body's antitumor response by adjusting adrenergic signaling can enhance the efficacy of cancer treatment.

The effect of physical exercise on anticancer immunity

Regular physical activity is associated with lower cancer incidence and mortality, as well as with a lower rate of tumour recurrence. The epidemiological evidence is supported by preclinical studies in animal models showing that regular exercise delays the progression of cancer, including highly aggressive malignancies. Although the mechanisms underlying the antitumorigenic effects of exercise remain to be defined, an improvement in cancer immunosurveillance is likely important, with different immune cell subtypes stimulated by exercise to infiltrate tumours. There is also evidence that immune cells from blood collected after an exercise bout could be used as adoptive cell therapy for cancer. In this Perspective, we address the importance of muscular activity for maintaining a healthy immune system and discuss the effects of a single bout of exercise (that is, 'acute' exercise) and those of 'regular' exercise (that is, repeated bouts) on anticancer immunity, including tumour infiltrates. We also address the postulated mechanisms and the clinical implications of this emerging area of research.

Role of Prehabilitation and Rehabilitation on Functional Recovery and Quality of Life in Thyroid Cancer Patients: A Comprehensive Review

BACKGROUND

This narrative review aims to provide a comprehensive overview of the current prehabilitation and rehabilitation strategies for thyroid cancer survivors to optimize functional outcomes and enhance their quality of life.

METHODS

The review follows the SANRA quality criteria and includes an extensive literature search conducted in PubMed/Medline, Web of Science, and Scopus.

RESULTS

The review emphasizes the role of a comprehensive rehabilitation approach in targeting the different domains that generate disability in thyroid cancer patients. In this context, physical activity, range of motion exercises, myofascial release, joint mobilization, and postural exercises are crucial for improving functional outcomes and reducing treatment-related discomfort and disability. Moreover, tailored rehabilitative management addressing dysphonia and dysphagia might have a positive impact on the quality of life of these patients. Despite these considerations, several barriers still affect the implementation of a multimodal rehabilitative approach in common clinical practice. Thus, sustainable and effective strategies like digital innovation and patient-centered approaches are strongly needed in order to implement the rehabilitative treatment framework of these subjects.

CONCLUSIONS

This narrative review provides valuable insights into the current prehabilitation and rehabilitation strategies to treat thyroid cancer survivors, addressing physical, psychological, and vocational needs to optimize functional outcomes and enhance their quality of life.

Effects of exercise on immune cells with tumor-specific activity in breast cancer patients and survivors: a systematic review and meta-analysis

Exercise is effective for improving the physical and psychological health of breast cancer patients. However, there is still controversy around its role on the immune system. Therefore, this systematic review and meta-analysis is aimed to evaluate the effect of chronic exercise on the number and activity of the immune cells that can contribute to anti-tumor immune responses, such as natural killers (NK) cells, CD + 4, or CD + 8. The main hypothesis of this study was that exercise could improve the immune system or, at least, there will not be a reduction in the number or activity of immune cells because of exercise. The search was conducted in the PubMed and Web of Science databases. Out of 244 studies reviewed, 10 studies met the inclusion criteria. The studies included in the meta-analyses showed mixed results and no significant (p > 0.05) positive or negative effects of exercise interventions in women with breast cancer. Therefore, the current evidence indicates that exercise does not significantly improve or reduce the immune system; thus, the prescription of exercise must not be discouraged due to the effects on the number and activity of immune system cells, but should be recommended due to the well-known benefits in quality of life, physical function or fatigue, and the absence of negative effects on the immune system. Further studies are needed to evaluate the effects according to the type of exercise, the type of cancer, or the timing of the intervention.

Differential Impact of Exercises on Quality-of-Life Improvement in Breast Cancer Survivors: A Network Meta-Analysis of Randomized Controlled Trials

This study aimed to assess the effectiveness of various exercise interventions in enhancing the quality of life for breast cancer survivors. To achieve this, randomized controlled trials were identified from major electronic databases, focusing on the relationship between exercise and quality of life in breast cancer survivors. The primary outcome was the impact of exercise on quality of life 12 weeks after the intervention, with a secondary outcome comparing dropout rates between intervention groups and a regular care control group. The study protocol was registered with INPLASY (INPLASY202340007). A network meta-analysis of nine randomized controlled trials involving 725 participants was conducted, examining aerobic and strength training, aerobic activity, yoga, and strength exercise. Results showed that aerobic and strength training was the most effective intervention, significantly improving the quality of life of breast cancer survivors (1.31; 95% confidence interval: 0.49 to 2.12). Aerobic activity had a borderline effect (0.83; 0.03 to 1.63), while no exercise interventions were associated with an increased dropout risk compared to the control group (regular care). The study concluded that concurrent aerobic and strength training can improve breast cancer survivors' quality of life after 12 weeks of intervention without increasing dropout risk compared to regular care.

Acute exercise induces distinct quantitative and phenotypical T cell profiles in men with prostate cancer

Background

Reduced testosterone levels can influence immune system function, particularly T cells. Exercise during cancer reduces treatment-related side effects and provide a stimulus to mobilize and redistribute immune cells. However, it is unclear how conventional and unconventional T cells (UTC) respond to acute exercise in prostate cancer survivors compared to healthy controls.

Methods

Age-matched prostate cancer survivors on androgen deprivation therapy (ADT) and those without ADT (PCa) along with non-cancer controls (CON) completed ∼45 min of intermittent cycling with 3 min at 60% of peak power interspersed by 1.5 min of rest. Fresh, unstimulated immune cell populations and intracellular perforin were assessed before (baseline), immediately following (0 h), 2 h, and 24 h post-exercise.

Results

At 0 h, conventional T cell counts increased by 45%-64% with no differences between groups. T cell frequency decreased by -3.5% for CD3+ and -4.5% for CD4+ cells relative to base at 0 h with CD8+ cells experiencing a delayed decrease of -4.5% at 2 h with no group differences. Compared to CON, the frequency of CD8+CD57+ cells was -18.1% lower in ADT. Despite a potential decrease in maturity, ADT increased CD8+perforin+ GMFI. CD3+Vα7.2+CD161+ counts, but not frequencies, increased by 69% post-exercise while CD3+CD56+ cell counts increased by 127% and were preferentially mobilized (+1.7%) immediately following the acute cycling bout. There were no UTC group differences. Cell counts and frequencies returned to baseline by 24 h.

Conclusion

Following acute exercise, prostate cancer survivors demonstrate normal T cell and UTC responses that were comparable to CON. Independent of exercise, ADT is associated with lower CD8+ cell maturity (CD57) and perforin frequency that suggests a less mature phenotype. However, higher perforin GMFI may attenuate these changes, with the functional implications of this yet to be determined.

The effects of exercise training for eight weeks on immune cell characteristics among breast cancer survivors

Methods

This study examined the effects of exercise training for 8 weeks on blood immune cell characteristics among 20 breast cancer survivors (age 56 ± 6 years, Body Mass Index 25.4 ± 3.0 kg m2) within two years of treatment. Participants were randomly allocated to a partly-supervised or a remotely-supported exercise group (n = 10 each). The partly supervised group undertook 2 supervised (laboratory-based treadmill walking and cycling) and 1 unsupervised session per week (outdoor walking) progressing from 35 to 50 min and 55% to 70% V˙O2max. The remotely-supported group received weekly exercise/outdoor walking targets (progressing from 105 to 150 min per week 55% to 70% V˙O2max) via weekly telephone calls discussing data from a fitness tracker. Immune cell counts were assessed using flow cytometry: CD4+ and CD8+ T cells (Naïve, NA; Central memory, CM; and Effector cells, EM and EMRA; using CD27/CD45RA), Stem cell-like memory T cells (TSCMs; using CD95/CD127), B cells (plasmablasts, memory, immature and naïve cells using CD19/CD27/CD38/CD10) and Natural Killer cells (effector and regulatory cells, using CD56/CD16). T cell function was assessed by unstimulated HLA-DR expression or interferon gamma (IFN-γ) production with Enzyme-linked ImmunoSpot assays following stimulation with virus or tumour-associated antigens.

Results

Total leukocyte counts, lymphocytes, monocytes and neutrophils did not change with training (p > 0.425). Most CD4+ and CD8+ T cell subtypes, including TSCMs, and B cell and NK cell subtypes did not change (p > 0.127). However, across groups combined, the CD4+ EMRA T cell count was lower after training (cells/µl: 18 ± 33 vs. 12 ± 22, p = 0.028) and these cells were less activated on a per cell basis (HLA-DR median fluorescence intensity: 463 ± 138 vs. 420 ± 77, p = 0.018). Furthermore, the partly-supervised group showed a significant decrease in the CD4+/CD8+ ratio (3.90 ± 2.98 vs. 2.54 ± 1.29, p = 0.006) and a significant increase of regulatory NK cells (cells/µl: 16 ± 8 vs. 21 ± 10, p = 0.011). T cell IFN-γ production did not change with exercise training (p > 0.515).

Discussion

In summary, most immune cell characteristics are relatively stable with 8 weeks of exercise training among breast cancer survivors. The lower counts and activation of CD4+ EMRA T cells, might reflect an anti-immunosenescence effect of exercise.

Effects of Tai Chi on patients with moderate to severe COPD in stable phase

This study was designed to investigate the effects of Tai Chi training on moderate to severe Chronic obstructive pulmonary disease (COPD) in the stable phase. This was a 2-arm randomized clinical trial. A total of 226 COPD patients with moderate to severe in the stable phase were allocated to either the control group or the observation group. The observation of the frequency of acute exacerbation for both groups lasted for at least 52 weeks follow-up. Changes in lung function and symptom scores of health-related quality of life (St George's Respiratory Questionnaire score) were also compared between the 2 groups. The accompanying anxiety and depressive symptoms of the patients were evaluated using the Self-Rating Depression Scale and Self-Rating Anxiety Scale prior to the procedure and 52 weeks later. Patients with moderate to severe COPD in China were divided into the Tai Chi group (n = 116) or control group (n = 110). After excluding 10 patients who fell off, 108 patients were enrolled in each group. Evidently, the matched group had higher exacerbation rate than the Tai Chi group (P < .05). Both groups showed no significant improvement in lung function (P > .05) but showed significant improvement in morbidity of acute exacerbation and quality of life (P < .05) compared with their former performance. Compared with regular therapy, Tai Chi also improved health-related quality of life (P < .05). The Self-Rating Anxiety Scale and Self-Rating Depression Scale scores of the 2 groups of patients after treatment and 52-week after treatment showed a notable decrease (P < .05). Overall, Tai Chi treatment was well tolerated. For moderate to severe COPD patients, regular treatment with Tai Chi can not only improve their health-related quality of life but also reduce the exacerbation rate compared with regular treatment alone. Tai Chi is recommended for COPD rehabilitation.

Recent Findings in Physical Exercise for Cancer Survivors

In recent years, the number of cancer survivors has been increasing each year due to advances in the early diagnosis and treatment of cancer. Cancer survivors present a variety of physical and psychological complications due to cancer and its treatment. Physical exercise is an effective nonpharmacological treatment for complications in cancer survivors. Furthermore, recent evidence has shown that physical exercise improves the prognosis of cancer survivors. The benefits of physical exercise have been widely reported, and guidelines for physical exercise for cancer survivors have been published. These guidelines recommend that cancer survivors engage in moderate- or vigorous-intensity aerobic exercises and/or resistance training. However, many cancer survivors have a poor commitment to physical exercise. In the future, it is necessary to promote physical exercise among cancer survivors through outpatient rehabilitation and community support.

Physical Exercise and the Hallmarks of Breast Cancer: A Narrative Review

Growing evidence suggests that, among the different molecular/cellular pathophysiological mechanisms associated with cancer, there are 14 hallmarks that play a major role, including: (i) sustaining proliferative signaling, (ii) evading growth suppressors, (iii) activating invasion and metastasis, (iv) enabling replicative immortality, (v) inducing angiogenesis, (vi) resisting cell death, (vii) reprogramming energy metabolism, (viii) evading immune destruction, (ix) genome instability and mutations, (x) tumor-promoting inflammation, (xi) unlocking phenotypic plasticity, (xii) nonmutational epigenetic reprogramming, (xiii) polymorphic microbiomes, and (xiv) senescent cells. These hallmarks are also associated with the development of breast cancer, which represents the most prevalent tumor type in the world. The present narrative review aims to describe, for the first time, the effects of physical activity/exercise on these hallmarks. In summary, an active lifestyle, and particularly regular physical exercise, provides beneficial effects on all major hallmarks associated with breast cancer, and might therefore help to counteract the progression of the disease or its associated burden.

Distinct distribution patterns of exercise-induced natural killer cell mobilisation into the circulation and tumor tissue of patients with prostate cancer

The mobilization and activation of natural killer (NK) cells have been proposed as key mechanisms promoting anti oncogenic effects of physical exercise. Although mouse models have proven that physical exercise recruits NK cells to tumor tissue and inhibits tumor growth, this preclinical finding has not been transferred to the clinical setting yet. In this first-in-human study, we found that physical exercise mobilizes and redistributes NK cells, especially those with a cytotoxic phenotype, in line with preclinical models. However, physical exercise did not increase NK cell tumor infiltrates. Future studies should carefully distinguish between acute and chronic exercise modalities and should be encouraged to investigate more immune responsive tumor entities.