Iatrogenic painful neuropathic complications of surgery in cancer

Racial Differences in Pain, Nutrition, and Oxidative Stress

Investigating the disproportionate rates of chronic pain and their related comorbidities between Black and non-Hispanic White (White) individuals is a growing area of interest, both in the healthcare community and in general society. Researchers have identified racial differences in chronic pain prevalence and severity, but still very little is known about the mechanisms underlying them. Current explanations for these differences have primarily focused on socioeconomic status and unequal healthcare between races as causal factors. Whereas these factors are informative, a racial gap still exists between Black and White individuals when these factors are controlled for. One potential cause of this racial gap in chronic pain is the differences in nutrition and dietary intake between groups. Certain foods play a key role in the inflammatory and oxidative stress pathways in the human body and could potentially influence the severity of the pain experience. Here, we review the previous literature on the surrounding topics and propose a potential mechanism to explain racial differences in the chronic pain population, based on established racial differences in diet and oxidative stress.

Cancer and Peripheral Nerve Disease

Patients with cancer may experience neuropathy at any stage of malignancy, ranging from symptoms that are the earliest signs of cancer to side effects of treatment. Peripheral nerves are affected most commonly in a symmetric, stocking-glove pattern. Sensory neuronopathies, plexopathies, and radiculopathies may also be seen. The most common type of neuropathy in patients with cancer is related to chemotherapy, and recently peripheral nerve complications have been described as an effect of immune checkpoint inhibitors too. Other causes include paraneoplastic syndromes, direct tumor infiltration, and radiation. Treatment focuses on addressing the underlying cancer and management of neuropathic pain.

Pain in Platin-Induced Neuropathies: A Systematic Review and Meta-Analysis

Introduction

Platin-induced peripheral neuropathy (PIPN) is a common cause of PN in cancer patients. The aim of this paper is to systematically review the current literature regarding PIPN, with a particular focus on epidemiological and clinical characteristics of painful PIPN, and to discuss relevant management strategies.

Methods

A systematic computer-based literature search was conducted on the PubMed database.

Results

This search strategy resulted in the identification of 353 articles. After the eligibility assessment, 282 articles were excluded. An additional 24 papers were identified by scanning the reference lists. In total, 95 papers met the inclusion criteria and were used for this review. The prevalence of neuropathic symptoms due to acute toxicity of oxaliplatin was estimated at 84.6%, whereas PN established after chemotherapy with platins was estimated at 74.9%. Specifically regarding pain, the reported prevalence of pain due to acute toxicity of oxaliplatin was estimated at 55.6%, whereas the reported prevalence of chronic peripheral neuropathic pain in PIPN was estimated at 49.2%.

Conclusion

Peripheral neuropathy is a common complication in patients receiving platins and can be particularly painful. There is significant heterogeneity among studies regarding the method for diagnosing peripheral neuropathy. Nerve conduction studies are the gold standard and should be performed in patients receiving platins and complaining of neuropathic symptoms post-treatment.

Painful Peripheral Neuropathy and Cancer

Peripheral neuropathy (PN) is very prevalent in cancer patients and a leading cause of pain related to cancer. However, the underlying pathophysiological mechanisms vary significantly. Peripheral neuropathy can be a direct or an indirect complication of cancer or cancer-related treatment, or a pre-existing comorbidity not related to cancer. PN might also occur as a paraneoplastic neurological syndrome. Such syndromes are immune-mediated manifestations that usually precede the diagnosis of cancer or cancer’s relapse. Pain is very prevalent in paraneoplastic peripheral neuropathies and, therefore, merits attention.

Review of the complications associated with treatment of oropharyngeal cancer: a guide for the dental practitioner

OBJECTIVES

Oropharyngeal cancer (OPC) is the sixth most common cancer worldwide. Focus on risk factors, improved diagnostic methods and effective management strategies have made it possible to successfully treat OPC. However, the 5-year survival rate has not improved for several years due to multiple treatment complications, tissue morbidity, loss of function, and diminished quality of life. Survivors are faced with complications like oral mucositis, hyposalivation, osteoradionecrosis, tissue fibrosis, morbidity from jaw resection, disfigurement, and loss of function that further diminish quality of life. The aim of this review is to highlight major complications associated with treatment of OPC via a literature search and review of available options for identification and management of these complications.

DATA SOURCES

Relevant publications on oral complications of OPC therapy were thoroughly reviewed from the literature published between the years 1988 and 2012. We evaluated reported incidence, prevalence, and risk factors for oral complications of chemotherapy and radiotherapy for OPC. The authors conducted an electronic search using English language databases, namely PubMed Plus, Medline (Pre-Medline and Medline), Cochrane Database of Systematic Reviews (evidence-based medicine), Dentistry & Oral Sciences Source, A ccessScience, Embase, Evidence-Based Medicine Reviews Multifile, Google Scholar, ISI Journal Citation Reports, and Ovid Multi-Database.

CONCLUSION

We identified the most common complications associated with the treatment of oral cancers. Based on the information gathered, there is evidence that survival of OPC extends beyond eradication of the diseased tissue. Understanding the potential treatment complications and utilizing available resources to prevent and minimize them are important. Caring for OPC survivors should be a multidisciplinary team approach involving the dentist, oncologist, internist, and social worker to improve the currently stagnant 5-year survival rate of OPC. More emphasis on improved quality of life after elimination of the cancer will ultimately improve OPC survivorship.

Postoperative occipital neuralgia with and without C2 nerve root transection during atlantoaxial screw fixation: a post-hoc comparative outcome study of prospectively collected data

BACKGROUND CONTEXT

Although routine transection of the C2 nerve root during atlantoaxial segmental screw fixation has been recommended by some surgeons, it remains controversial and to our knowledge no comparative studies have been performed to determine whether transection or preservation of the C2 nerve root affects patient-derived sensory outcomes.

PURPOSE

The purpose of this study is to specifically analyze patient-derived sensory outcomes over time in patients with intentional C2 nerve root transection during atlantoaxial segmental screw fixation compared with those without transection.

STUDY DESIGN

This is a post-hoc comparative analysis of prospectively collected patient-derived outcome data.

PATIENT SAMPLE

The sample consists of 24 consecutive patients who underwent intentional bilateral transection of the C2 nerve root during posterior atlantoaxial segmental screw fixation (transection group) and subsequent 41 consecutive patients without transection (preservation group).

OUTCOME MEASURES

A visual analog scale (VAS) score was used for occipital neuralgia as the primary outcome measure and VAS score for neck pain, neck disability index score and Japanese Orthopedic Association score for cervical myelopathy and recovery rate, with bone union rate as the secondary outcome measure.

METHODS

Patient-derived outcomes including change in VAS score for occipital neuralgia over time were statistically compared between the two groups. This study was not supported by any financial sources and there is no topic-specific conflict of interest related to the authors of this study.

RESULTS

Seven (29%) of the 24 patients in the transection group experienced increased neuralgic pain at 1 month after surgery either because of newly developed occipital neuralgia or aggravation of preexisting occipital neuralgia. Four of the seven patients required almost daily medication even at the final follow-up (44 and 80 months). On the other hand, only four (10%) of 41 patients in the preservation group had increased neuralgic pain at 1 month after surgery, and at ≥ 1 year, no patients had increased neuralgic pain. The difference in the prevalence of increased neuralgic pain between the two groups was statistically significant at all time points (3, 6, 12, and 24 months postoperatively) except at 1 month postoperatively. The intensity of neuralgic pain, which preoperatively had not been significantly different between the two groups, was significantly higher in the transection group at the final follow-up.

CONCLUSIONS

C2 nerve root transection is not a benign procedure and, in our experience, more than a quarter of the patients experience increased neuralgic pain following C2 nerve root transection. Because the prevalence and intensity of postoperative neuralgia was significantly higher with C2 nerve root transection than with its preservation, we recommend against routine C2 nerve root transection when performing atlantoaxial segmental screw fixation.

What made her give up her breasts: a qualitative study on decisional considerations for contralateral prophylactic mastectomy among breast cancer survivors undergoing BRCA1/2 genetic testing

OBJECTIVE

This qualitative study retrospectively examined the experience and psychological impact of contralateral prophylactic mastectomy (CPM) among Southern Chinese females with unilateral breast cancer history who underwent BRCA1/2 genetic testing. Limited knowledge is available on this topic especially among Asians; therefore, the aim of this study was to acquire insight from Chinese females' subjective perspectives.

METHODS

A total of 12 semi-structured in-depth interviews, with 11 female BRCA1/BRCA 2 mutated gene carriers and 1 non-carrier with a history of one-sided breast cancer and genetic testing performed by the Hong Kong Hereditary Breast Cancer Family Registry, who subsequently underwent CPM, were assessed using thematic analysis and a Stage Conceptual Model. Breast cancer history, procedures conducted, cosmetic satisfaction, pain, body image and sexuality issues, and cancer risk perception were discussed. Retrieval of medical records using a prospective database was also performed.

RESULTS

All participants opted for prophylaxis due to their reservations concerning the efficacy of surveillance and worries of recurrent breast cancer risk. Most participants were satisfied with the overall results and their decision. One-fourth expressed different extents of regrets. Psychological relief and decreased breast cancer risk were stated as major benefits. Spouses' reactions and support were crucial for post-surgery sexual satisfaction and long-term adjustment.

CONCLUSIONS

Our findings indicate that thorough education on cancer risk and realistic expectations of surgery outcomes are crucial for positive adjustment after CPM. Appropriate genetic counseling and pre-and post-surgery psychological counseling were necessary. This study adds valuable contextual insights into the experiences of living with breast cancer fear and the importance of involving spouses when counseling these patients.

Intrathecal lidocaine pretreatment attenuates immediate neuropathic pain by modulating Nav1.3 expression and decreasing spinal microglial activation

Background

Intrathecal lidocaine reverses tactile allodynia after nerve injury, but whether neuropathic pain is attenuated by intrathecal lidocaine pretreatment is uncertain.

Methods

Sixty six adult male Sprague-Dawley rats were divided into three treatment groups: (1) sham (Group S), which underwent removal of the L₆ transverse process; (2) ligated (Group L), which underwent left L₅ spinal nerve ligation (SNL); and (3) pretreated (Group P), which underwent L₅ SNL and was pretreated with intrathecal 2% lidocaine (50 μl). Neuropathic pain was assessed based on behavioral responses to thermal and mechanical stimuli. Expression of sodium channels (Nav_1.3 and Nav_1.8) in injured dorsal root ganglia and microglial proliferation/activation in the spinal cord were measured on post-operative days 3 (POD₃) and 7 (POD₇).

Results

Group L presented abnormal behavioral responses indicative of mechanical allodynia and thermal hyperalgesia, exhibited up-regulation of Nav_1.3 and down-regulation of Nav_1.8, and showed increased microglial activation. Compared with ligation only, pretreatment with intrathecal lidocaine before nerve injury (Group P), as measured on POD₃, palliated both mechanical allodynia (p < 0.01) and thermal hyperalgesia (p < 0.001), attenuated Nav_1.3 up-regulation (p = 0.003), and mitigated spinal microglial activation (p = 0.026) by inhibiting phosphorylation (activation) of p38 MAP kinase (p = 0.034). p38 activation was also suppressed on POD₇ (p = 0.002).

Conclusions

Intrathecal lidocaine prior to SNL blunts the response to noxious stimuli by attenuating Nav_1.3 up-regulation and suppressing activation of spinal microglia. Although its effects are limited to 3 days, intrathecal lidocaine pretreatment can alleviate acute SNL-induced neuropathic pain.

The prevalence and impact of pain among Taiwanese oncology outpatients

The purpose of this study was to report the prevalence and impact of pain among Taiwanese oncology outpatients who had experienced moderate pain. Ninety-two cancer outpatients in two teaching hospitals in the Taipei area of Taiwan were enrolled in a descriptive cross-sectional study. Outpatients aged ≥18 years who had been prescribed opioid analgesics for cancer-related pain completed the Brief Pain Inventory-Chinese questionnaire. Results of this study highlighted an important issue: undertreatment of cancer pain in the Taiwanese outpatients. Patients in this study reported that in the preceding 24 hours they had experienced a mean worst pain of 6.91 (SD 2.06, range 0-10). The average pain intensity in the preceding 24 hours was 5.21 (SD 1.69, range 0-10). Around 50% of the patients had pain most of the time and 25% of the patients had pain all of the time. In the preceding 24 hours the average pain relief experienced was 62.6% (SD 22.2%, range 0%-100%). Only 10.9% of patients experienced good pain relief (defined as 90%-100% of pain relief in the past 24 hours), whereas 45.7% experienced poor pain relief (defined as 0%-60% of pain relief in the past 24 hours). The mean pain interference with the patients' daily activities was 5.69 (SD 2.33, range 0-10). The findings of this study indicate the need for better programmatic efforts to improve relief of cancer pain in Taiwanese outpatients.

Treatment of pain in children after limb-sparing surgery: an institution's 26-year experience

A significant proportion of patients report long-term pain that is ≥5 on a 0-10 intensity scale after limb-sparing surgery for malignancies of the long bones. Patients experience several distinct types of pain after limb-sparing surgery which constitute a complex clinical entity. This retrospective study examined 26 years of experience in a pediatric institution (1981-2007) in pain management as long as 6 months after limb-sparing surgery and reviewed the historical evolution of pain interventions. One hundred fifty patients underwent 151 limb-salvage surgeries for bone cancer of the extremities in this series. Pain treatment increased progressively in complexity. Therapies included opioids, nonsteroidal antiinflammatory drugs, acetaminophen-opioid combinations, postoperative continuous epidural infusion, anticonvulsants and tricyclic antidepressants for neuropathic pain, local anesthetic wound catheters, and continuous peripheral nerve block catheters. Management of pain after limb-sparing surgery has evolved over the 26 years of this review. It currently relies on multiple "layers" of pharmacologic and nonpharmacologic strategies to address the complex mixed nociceptive and neuropathic mechanisms of pain in this patient population.

Painful peripheral neuropathies

Peripheral neuropathies are a heterogeneous group of diseases affecting peripheral nerves. The causes are multiple: hereditary, metabolic, infectious, inflammatory, toxic, traumatic. The temporal profile includes acute, subacute and chronic conditions. The majority of peripheral neuropathies cause mainly muscle weakness and sensory loss, positive sensory symptoms and sometimes pain. When pain is present, however, it is usually extremely intense and among the most disabling symptoms for the patients. In addition, the neurological origin of the pain is often missed and patients receive inadequate or delayed specific treatment. Independently of the disease causing the peripheral nerve injury, pain originating from axonal pathology or ganglionopathy privileges neuropathies affecting smaller fibres, a clinical observation that points towards abnormal activity within nociceptive afferents as a main generator of pain. Natural activation of blood vessels or perineurial nociceptive network by pathology also causes intense pain. Pain of this kind, i.e. nerve trunk pain, is among the heralding symptoms of inflammatory or ischemic mononeuropathy and for its intensity represents itself a medical emergency. Neuropathic pain quality rekindles the psychophysical experience of peripheral nerves intraneural microstimulation i.e. a combination of large and small fibres sensation temporally distorted compared to physiological perception evoked by natural stimuli. Pins and needles, burning, cramping mixed with numbness, and tingling are the wording most used by patients. Nociceptive pain instead is most often described as aching, deep and dull. Good command of peripheral nerve anatomy and pathophysiology allows timely recognition of the different pain components and targeted treatment, selected according to intensity, type and temporal profile of the pain.

Endothelin-1-induced pain and hyperalgesia: a review of pathophysiology, clinical manifestations and future therapeutic options

Pain in patients with metastatic cancer contributes to increased suffering in those already burdened by their advancing illness. The causes of this pain are unknown, but are likely to involve the action of tumour-associated mediators and their receptors. In recent years, several chemical mediators have increasingly come to the forefront in the pathophysiology of cancer pain. One such mediator, endothelin-1 (ET-1), is a peptide of 21 amino acids that was initially shown to be a potent vasoconstrictor. Extensive research has revealed that members of the ET family are indeed produced by several epithelial cancerous tumours, in which they act as autocrine and/or paracrine growth factors. Several preclinical and clinical studies of various malignancies have suggested that the ET axis may represent an interesting contributor to tumour progression. In addition, evidence is accumulating to suggest that ET-1 may contribute to pain states both in humans and in other animals. ET-1 both stimulates nociceptors and sensitises them to painful stimuli. Selective stimulation of ET receptors has been implicated as a cause of inflammatory, neuropathic and tumoural pain. ET-1-induced pain-related behaviour seems to be mediated either solely by one receptor type or via both endothelin-A receptors (ETAR) and endothelin-B receptors (ETBR). Whereas stimulation of ETAR on nociceptors always elicits a pain response, stimulation of ETBR may cause analgesia or elicit a pain response, depending on the conditions. The administration of ETAR antagonists in the receptive fields of these nociceptors has been shown to ameliorate pain-related behaviours in animals, as well as in some patients with advanced metastatic prostate cancer. The identification of tumour-associated mediators that might directly or indirectly cause pain in patients with metastatic disease, such as ET-1, should lead to improved, targeted analgesia for patients with advanced cancer. In this review, we will describe the current status of the role of ET-1 in different types of painful syndromes, with special emphasis on its role in the pathophysiology of cancer pain. Finally, potential new treatment options that are based on the role of the ET axis in the pathophysiology of cancer are elaborated.

Orofacial pain and neurosensory disorders and dysfunction in cancer patients

Orofacial pain and altered nerve sensation may be the initial sign of oropharyngeal or nasopharyngeal cancer. This article focuses on the most common orofacial pain conditions and neurosensory alterations that affect cancer patients, such as neuropathic pain, muscle spasm or contractures, mucositis, and increased or decreased sensory discrimination in the affected area. The various pharmacotherapeutic modalities for cancer pain management ranging from non steroidal anti-inflammatory drugs (NSAIDs) for mild pain to opioids for severe pain are discussed in detail.

Barriers to pain management in the rehabilitation of the surgical oncology patient

Virtually every surgical oncology patient faces pain, and it can become a major barrier to rehabilitation and quality of life. Pain must be assessed as to its severity, etiology (somatic, visceral, or neuropathic), causation (directly from malignancy or from treatment side effects), and its impact on daily function. Treatments can include physical modalities, exercise, opioids, adjuvant medications, and interventional techniques. Barriers to treatment may include side effects, finances, and attitudes. New technologies in medication delivery systems, intrathecal pumps, injections, and surgery have greatly strengthened the armamentarium available to manage pain.

Some cases of severe post-mastectomy pain syndrome may be caused by an axillary haematoma

Post-mastectomy pain syndrome (PMPS) is experienced by 20-65% of patients who undergo breast surgery for cancer. The etiology of this chronic neuropathic pain syndrome is unclear and most likely multi-factorial. Symptoms may be mild, not requiring treatment, or severe, considerably restricting quality of life. The effectiveness of available pharmacological and pain management therapies is unknown. Certainly, some women remain under-treated with poor pain control. We report three women undergoing wide local excision for cancer of the breast and block dissection of axillary lymph nodes who subsequently developed severe PMPS. In these cases the symptoms were completely relieved by the aspiration or formal drainage of an encapsulated haematoma in the axilla. The removal of a minimal amount of blood brought instant improvement suggesting that pressure within the haematoma could be an etiological factor. An axillary haematoma, which may not be clinically obvious, should be considered as a possible cause of PMPS.