Brief review: pain management for cancer survivors: challenges and opportunities

The Mediating Effect of Perceived Injustice and Pain Catastrophizing in the Relationship of Pain on Fatigue and Sleep in Breast Cancer Survivors: A Cross-Sectional Study

OBJECTIVE

Multidimensional aspects of pain have raised awareness about cognitive appraisals, such as perceived injustice (PI) and pain catastrophizing (PC). It has been demonstrated that they play an important role in patients' pain experience. However, the mediating effect of these appraisals has not been investigated in breast cancer survivors (BCS), nor have they been related to fatigue and sleep.

METHODS

Cross-sectional data from 128 BCS were analysed by structural path analysis with the aim to examine the mediating effect of PI and PC in the relationship of pain on fatigue and sleep.

RESULTS

The indirect mediating effects of PI on fatigue (CSI*PI = 0.21; P < 0.01 and VAS*PI = 1.19; P < 0.01) and sleep (CSI*PI = 0.31; P < 0.01 and VAS*PI = 1.74; P < 0.01) were found significant for both pain measures (Central Sensitization Inventory (CSI) and Visual Analogue Scale (VAS)). PC, on the other hand, only mediated the relationship between pain measured by VAS and fatigue (VAS*PC = 0.80; P = 0.03). Positive associations were found, indicating that higher pain levels are positively correlated with PI and PC, which go hand in hand with higher levels of fatigue and sleep problems.

CONCLUSION

PI is an important mediator in the relationship of pain on fatigue and sleep, while PC is a mediator on fatigue after cancer treatment. These findings highlight that both appraisals are understudied and open new perspectives regarding treatment strategies in BCS.

Pain Assessment and Management in Intensive Care Unit: Nurses' Practices, Perceived Influencing Factors, and Educational Needs

Background:

Critically ill patients and those mechanically ventilated or unable to communicate may not be able to report any pain they experience. Consequently, pain assessment and management (PAM) is challenging and underestimated in intensive care units (ICUs), where patients suffer alteration of consciousness, sedation, invasive procedures and mechanical ventilation.

Aim:

This study aimed to investigate ICU nurses’ PAM practices, their perceptions of influencing factors, and their related educational needs.

Methods:

A descriptive cross-sectional design was employed, using a valid self-reported questionnaire.

Results:

Among the sample of 171 nurses, 55% were male and 83% held a bachelor’s degree. 60% reported performing pain assessment for patients able to report pain and 50% for those unable to do so. Almost 40% of participants reported that pain management plans and scores were not discussed in medical rounds. Workload and lack of guidelines were reported as the most common barriers to PAM, while the most common enablers were perceived to be prescribing analgesia and considering pain a priority. Nurses recognized the need for education regarding pain, especially the physiological (50%) and psychological (47%) consequences of untreated pain.

Conclusion:

Nurses’ reported performance of pain assessment for ICU patients remains suboptimal. Therefore, healthcare professionals, organizations, nursing schools, and policymakers should work together to improve nurses’ PAM knowledge and practices.

Circadian regulation of chemotherapy-induced peripheral neuropathic pain and the underlying transcriptomic landscape

Growing evidence demonstrates circadian rhythms of pain hypersensitivity in various chronic disorders. In chemotherapy-induced peripheral neuropathy (CIPN), agents such as paclitaxel are known to elicit chronic neuropathic pain in cancer patients and seriously compromise their quality of life. Here, we report that the mechanical threshold for allodynia in paclitaxel-treated rats exhibited a robust circadian oscillation, reaching the nadir during the daytime (inactive phase). Using Per2::LucSV circadian reporter mice expressing a PER2::LUC fusion protein, we isolated dorsal root ganglia (DRG), the primary sensory cell body for peripheral nerve injury generated hypersensitivity, and monitored ex vivo reporter bioluminescence. We observed strong circadian reporter rhythms in DRG neurons which are highly entrainable by external cues. Paclitaxel treatment significantly lengthened DRG circadian periods, with little effects on the amplitude of oscillation. We further observed the core protein BMAL1 and PER2 in DRG neurons and satellite cells. Using DRG and dorsal horn (DH; another key structure for CIPN pain response) tissues from vehicle and paclitaxel treated rats, we performed RNA-sequencing and identified diurnal expression of core clock genes as well as clock-controlled genes in both sites. Interestingly, 20.1% and 30.4% of diurnal differentially expressed genes (DEGs) overlapped with paclitaxel-induced DEGs in the DRG and the DH respectively. In contrast, paclitaxel-induced DEGs displayed only a modest overlap between daytime and nighttime (Zeitgeber Time 8 and 20). Furthermore, paclitaxel treatment induced de novo diurnal DEGs, suggesting reciprocal interaction of circadian rhythms and chemotherapy. Our study therefore demonstrates a circadian oscillation of CIPN and its underlying transcriptomic landscape.

Nrf2 activation ameliorates mechanical allodynia in paclitaxel-induced neuropathic pain

Paclitaxel-induced neuropathic pain (PINP) is refractory to currently used analgesics. Previous studies show a pivotal role of oxidative stress in PINP. Because the nuclear factor erythroid-2-related factor 2 (Nrf2) has been considered as the critical regulator of endogenous antioxidant defense, we here explored whether activation of Nrf2 could attenuate PINP. A rat model of PINP was established by intraperitoneal injection of paclitaxel (2 mg/kg) every other day with a final cumulative dose of 8 mg/kg. Hind paw withdrawal thresholds (PWTs) in response to von Frey filament stimuli were used to assess mechanical allodynia. We showed that a single dose of Nrf2 activator, oltipraz (10, 50, and 100 mg/kg), dose-dependently attenuated established mechanical allodynia, whereas repeated injection of oltipraz (100 mg· kg-1· d-1, i.p. from d 14 to d 18) almost abolished the mechanical allodynia in PINP rats. The antinociceptive effect of oltipraz was blocked by pre-injection of Nrf2 inhibitor trigonelline (20 mg/kg, i.p.). Early treatment with oltipraz (100 mg· kg-1· d-1, i.p. from d 0 to d 6) failed to prevent the development of the PINP, but delayed its onset. Western blot and immunofluorescence analysis revealed that the expression levels of Nrf2 and HO-1 were significantly upregulated in the spinal cord of PINP rats. Repeated injection of oltipraz caused further elevation of the expression levels of Nrf2 and HO-1 in the spinal cord of PINP rats, which was reversed by pre-injection of trigonelline. These results demonstrate that oltipraz ameliorates PINP via activating Nrf2/HO-1-signaling pathway in the spinal cord.

Losartan, an Angiotensin II Type 1 Receptor Antagonist, Alleviates Mechanical Hyperalgesia in a Rat Model of Chemotherapy-Induced Neuropathic Pain by Inhibiting Inflammatory Cytokines in the Dorsal Root Ganglia

Chemotherapy-induced peripheral neuropathy (CIPN) adversely impacts quality of life and a challenge to treat with existing drugs used for neuropathic pain. Losartan, an angiotensin II type 1 receptor (AT1R) antagonist widely used to treat hypertension, has been reported to have analgesic effects in several pain models. In this study, we assessed losartan's analgesic effect on paclitaxel-induced neuropathic pain (PINP) in rats and its mechanism of action in dorsal root ganglion (DRG). Rats received intraperitoneal injections of 2 mg/kg paclitaxel on days 0, 2, 4, and 6 and received single or multiple intraperitoneal injections of losartan potassium dissolved in phosphate-buffered saline at various times. The mechanical thresholds, protein levels of inflammatory cytokines, and cellular location of AT1R and interleukin 1β (IL-1β) in the DRG were assessed with behavioral testing, Western blotting, and immunohistochemistry, respectively. Data were analyzed by two-way repeated-measures analysis of variance for the behavioral test or the Mann-Whitney U test for the Western blot analysis and immunohistochemistry. Single and multiple injections of losartan ameliorated PINP, and losartan delayed the development of PINP. Paclitaxel significantly increased, and losartan subsequently decreased, the expression levels of inflammatory cytokines, including IL-1β and tumor necrosis factor α (TNF-α), in the lumbar DRG. AT1R and IL-1β were expressed in both neurons and satellite cells and losartan decreased the intensity of IL-1β in the DRG. Losartan ameliorates PINP by decreasing inflammatory cytokines including IL-1β and TNF-α in the DRG. Our findings provide a new or add-on therapy for CIPN patients.

Cancer Pain Management at Oncology Units: Comparing Knowledge, Attitudes and Perceived Barriers Between Physicians and Nurses

Pain is a major symptom that causes suffering among patients diagnosed with cancer. Identifying physicians' and nurses' knowledge, attitudes, and their perceived barriers of cancer pain management is considered an essential step in improving cancer pain relief. The purposes of this study are to compare physicians' and nurses' knowledge and attitudes toward cancer pain management (CPM) and describe their perceived barriers to CPM at oncology units. A descriptive cross-sectional design was utilized to obtain data through self-report questionnaire. The total number of sample size was 207 participants (72 physicians and 135 nurses). Findings revealed that both physicians and nurses had fair knowledge and attitudes toward CPM. Physicians had significantly higher knowledge and better attitudes than nurses (62.3 vs. 51.5%, respectively). Physicians were knowledgeable about pharmacological pain management and opioid addiction but had negative attitudes toward pain assessment. Nurses' knowledge was better in regard of CPM guidelines, while they had poor knowledge about pharmacological pain management and opioid addiction. Physicians and nurses perceived knowledge deficit, lack of pain assessment, opioid unavailability, and lack of psychological interventions as the most common barriers to CPM. It is recommended to integrate recent evidence-based guidelines about CPM in oncology units that aim to improve practice. Offering continuing education courses in hospitals guided by pain teams is another essential recommendation for effective CPM.

Challenges and concerns of persistent opioid use in cancer patients

INTRODUCTION

As a result of advancements in the diagnosis and treatment of cancer, two-thirds of individuals suffering with cancer survive more than 5 years after diagnosis, resulting in a large proportion of patients with chronic cancer pain alone or associated with chronic noncancer pain. There is a paucity of literature in reference to diagnosis and management of chronic cancer pain, specifically in relation to persistent opioid use, its effectiveness, and adverse consequences. Areas covered: This review covers the prevalence of chronic cancer pain and its association with multiple comorbidities, persistent opioid use and related consequences, and challenges in managing persistent chronic cancer pain patients. In addition, discussion includes therapeutic opioid use, effectiveness of opioid therapy, assessment of risk of persistent opioid use, and guidance for responsible, persistent opioid prescribing for chronic cancer pain patients. Expert commentary: Despite extensive availability of opioids and related common adverse consequences, including the potential for escalating use, abuse, and deaths, greater awareness is needed to counteract the present atmosphere and appropriately manage patients with chronic cancer pain. Chronic cancer pain is a complex biopsychosocial phenomenon with multiple comorbidities. Opioid therapy has become extremely complex with negative connotations related to escalating abuse and related deaths.

Tempol Ameliorates and Prevents Mechanical Hyperalgesia in a Rat Model of Chemotherapy-Induced Neuropathic Pain

Chemotherapy-induced neuropathic pain is difficult to treat and prevent. Tempol decreases cellular superoxide radical levels and oxidative stress. The aims of our study were to investigate the analgesic and preventive effects of tempol on paclitaxel-induced neuropathic pain in rats and to identify the associated mechanisms of action. Neuropathic pain was induced with intraperitoneally injected paclitaxel on four alternate days in male Sprague-Dawley rats. Tempol was administered systemically as a single injection and a continuous infusion before or after the injection of paclitaxel. The mechanical threshold for allodynia, protein levels, and free radical levels were measured using von Frey filaments, Western blotting, and live cell imaging, respectively. After the rats developed neuropathic pain behavior, a single intraperitoneal injection and continuous infusion of tempol ameliorated paclitaxel-induced mechanical allodynia. Systemic infusion of tempol in the early phase of the development of pain behavior prevented the development of paclitaxel-induced pain behavior. Paclitaxel increased the levels of phosphorylated protein kinase C, phosphorylated nuclear factor κB, phosphodiesterase 4D (PDE4D), IL-1β, and monocyte chemoattractant protein-1 in the lumbar dorsal root ganglia; however, tempol decreased these levels. Paclitaxel also increased superoxide levels in a culture of primary dorsal root ganglion cells and tempol decreased these levels. In conclusion, tempol alleviates and prevents chemotherapy-induced neuropathic pain in rats by reducing the levels of inflammatory cytokines and free radicals in dorsal root ganglia.

Advancing breast cancer survivorship among African-American women

Advances have occurred in breast cancer survivorship but, for many African-American women, challenges and gaps in relevant information remain. This article identifies opportunities to address disparities in breast cancer survival and quality of life, and thereby to increase breast cancer survivorship among African-American women. For breast cancer survivors, common side effects, lasting for long periods after cancer treatment, include fatigue, loss of strength, difficulty sleeping, and sexual dysfunction. For addressing physical and mental health concerns, a variety of interventions have been evaluated, including exercise and weight training, dietary interventions, yoga and mindfulness-based stress reduction, and support groups or group therapy. Obesity has been associated with breast cancer recurrence and poorer survival. Relative to white survivors, African-American breast cancer survivors are more likely to be obese and less likely to engage in physical activity, although exercise improves overall quality of life and cancer-related fatigue. Considerable information exists about the effectiveness of such interventions for alleviating distress and improving quality of life among breast cancer survivors, but few studies have focused specifically on African-American women with a breast cancer diagnosis. Studies have identified a number of personal factors that are associated with resilience, increased quality of life, and positive adaptation to a breast cancer diagnosis. There is a need for a better understanding of breast cancer survivorship among African-American women. Additional evaluations of interventions for improving the quality of life and survival of African-American breast cancer survivors are desirable.