The development of brain metastases in patients with different therapeutic strategies for metastatic renal cell cancer.

A diagnosis of brain metastasis (BM) significantly affects quality of life in patients with metastatic renal cell cancer (mRCC). Although systemic treatments have shown efficacy in mRCC, active surveillance (AS) is still commonly used in clinical practice. In this single-center cohort study, we assessed the impact of different initial treatment strategies for metastatic RCC (mRCC) on the development of BM. All consecutive patients diagnosed with mRCC between 2011 and 2022 were included at the Erasmus MC Cancer Institute, the Netherlands, and a subgroup of patients with BM was selected. In total, 381 patients with mRCC (ECM, BM, or both) were identified. Forty-six patients had BM of whom 39 had metachronous BM (diagnosed ≥1 month after ECM). Twenty-five (64.1%) of these 39 patients with metachronous BM had received prior systemic treatment for ECM and 14 (35.9%) patients were treatment naive at BM diagnosis. The median BM-free survival since ECM diagnosis was significantly longer (p = .02) in previously treated patients (29.0 [IQR 12.6-57.0] months) compared to treatment naive patients (6.8 [IQR 1.0-7.0] months). In conclusion, patients with mRCC who received systemic treatment for ECM prior to BM diagnosis had a longer BM-free survival as compared to treatment naïve patients. These results emphasize the need for careful evaluation of treatment strategies, and especially AS, for patients with mRCC.

Prognostic Role of Ventricular Size and Its Dynamics in Patients With Leptomeningeal Metastasis From Solid Tumors.

BACKGROUND AND OBJECTIVES: Hydrocephalus is a common radiologic sign in patients with leptomeningeal metastasis (LM) from solid tumors which can be assessed using the Evans index (EI). Here, we explored the prognostic value of ventricular size in LM. METHODS: We identified patients with LM from solid tumors by chart review at 3 academic hospitals to explore the prognostic associations of the EI at diagnosis, first follow-up, and progression. RESULTS: We included 113 patients. The median age was 58.3 years (interquartile range [IQR] 46.1-65.8), 41 patients (36%) were male, and 72 patients (64%) were female. The most frequent cancers were lung cancer (n = 39), breast cancer (n = 36), and melanoma (n = 23). The median EI at baseline was 0.28 (IQR 0.26-0.31); the EI value was 0.27 or more in 67 patients (59%) and 0.30 or more in 37 patients (33%). Among patients with MRI follow-up, the EI increased by 0.01 or more in 16 of 31 patients (52%), including 8 of 30 patients (30%) without and 10 of 17 patients (59%) with LM progression at first follow-up. At LM progression, an increase of EI of 0.01 or more was noted in 18 of 34 patients (53%). The median survival was 2.9 months (IQR 1-7.2). Patients with a baseline EI below 0.27 had a longer survival than those with an EI of 0.27 or more (5.3 months, IQR 2.4-10.8, vs 1.3 months, IQR 0.6-4.1) (HR 1.70, 95% CI 1.135-2.534, p = 0.0099). The median survival was 3.7 months (IQR 1.4-8.3) with an EI below 0.30 vs 1.8 months (IQR 0.8-4.1) with an EI of 0.30 or more (HR 1.40, 95% CI 0.935-1.243, p = 0.1113). Among patients with follow-up scans available, the overall survival was 9.4 months (IQR 5.6-21.0) for patients with stable or decreased EI at first follow-up as opposed to 5.6 months (IQR 2.5-10.5) for those with an increase in the EI (HR 1.08, 95% CI 0.937-1.243; p = 0.300). DISCUSSION: The EI at baseline is prognostic in LM. An increase of EI during follow-up may be associated with inferior LM progression-free survival. Independent validation cohorts with larger sample size and evaluation of confounding factors will help to better define the clinical utility of EI assessments in LM.

Impact of Novel Treatments in Patients with Melanoma Brain Metastasis: Real-World Data.

BACKGROUND: Melanoma brain metastasis (MBM) is associated with poor outcome, but targeted therapies (TTs) and immune checkpoint inhibitors (ICIs) have revolutionized treatment over the past decade. We assessed the impact of these treatments in a real-world setting. METHODS: A single-center cohort study was performed at a large, tertiary referral center for melanoma (Erasmus MC, Rotterdam, the Netherlands). Overall survival (OS) was assessed before and after 2015, after which TTs and ICIs were increasingly prescribed. RESULTS: There were 430 patients with MBM included; 152 pre-2015 and 278 post-2015. Median OS improved from 4.4 to 6.9 months (HR 0.67, p < 0.001) after 2015. TTs and ICIs prior to MBM diagnosis were associated with poorer median OS as compared to no prior systemic treatment (TTs: 2.0 vs. 10.9 and ICIs: 4.2 vs. 7.9 months, p < 0.001). ICIs directly after MBM diagnosis were associated with improved median OS as compared to no direct ICIs (21.5 vs. 4.2 months, p < 0.001). Stereotactic radiotherapy (SRT; HR 0.49, p = 0.013) and ICIs (HR 0.32, p < 0.001) were independently associated with improved OS. CONCLUSION: After 2015, OS significantly improved for patients with MBM, especially with SRT and ICIs. Demonstrating a large survival benefit, ICIs should be considered first after MBM diagnosis, if clinically feasible.

A mechanistic understanding of the relationship between skin innervation and chemotherapy-induced neuropathic pain.

Neuropathic pain is a frequent complication of chemotherapy-induced peripheral neurotoxicity (CIPN). Chemotherapy-induced peripheral neuropathies may serve as a model to study mechanisms of neuropathic pain, since several other common causes of peripheral neuropathy like painful diabetic neuropathy may be due to both neuropathic and non-neuropathic pain mechanisms like ischemia and inflammation. Experimental studies are ideally suited to study changes in morphology, phenotype and electrophysiologic characteristics of primary afferent neurons that are affected by chemotherapy and to correlate these changes to behaviors reflective of evoked pain, mainly hyperalgesia and allodynia. However, hyperalgesia and allodynia may only represent one aspect of human pain, i.e., the sensory-discriminative component, while patients with CIPN often describe their pain using words like annoying, tiring and dreadful, which are affective-emotional descriptors that cannot be tested in experimental animals. To understand why some patients with CIPN develop neuropathic pain and others not, and which are the components of neuropathic pain that they are experiencing, experimental and clinical pain research should be combined. Emerging evidence suggests that changes in subsets of primary afferent nerve fibers may contribute to specific aspects of neuropathic pain in both preclinical models and in patients with CIPN. In addition, the role of cutaneous neuroimmune interactions is considered. Since obtaining dorsal root ganglia and peripheral nerves in patients is problematic, analyses performed on skin biopsies from preclinical models as well as patients provide an opportunity to study changes in primary afferent nerve fibers and to associate these changes to human pain. In addition, other biomarkers of small fiber damage in CIPN, like corneal confocal microscope and quantitative sensory testing, may be considered.

Detection of Aneuploidy in Cerebrospinal Fluid from Patients with Breast Cancer Can Improve Diagnosis of Leptomeningeal Metastases.

PURPOSE: Detection of leptomeningeal metastasis is hampered by limited sensitivities of currently used techniques: MRI and cytology of cerebrospinal fluid (CSF). Detection of cell-free tumor DNA in CSF has been proposed as a tumor-specific candidate to detect leptomeningeal metastasis at an earlier stage. The aim of this study was to investigate mutation and aneuploidy status in CSF-derived cell-free DNA (cfDNA) of patients with breast cancer with a clinical suspicion of leptomeningeal metastasis. EXPERIMENTAL DESIGN: cfDNA was isolated from stored remnant CSF and analyzed by targeted next-generation sequencing (NGS; n = 30) and the modified fast aneuploidy screening test-sequencing system (mFAST-SeqS; n = 121). The latter method employs selective amplification of long interspaced nuclear elements sequences that are present throughout the genome and allow for fast and cheap detection of aneuploidy. We compared these results with the gold standard to diagnose leptomeningeal metastasis: cytology. RESULTS: Leptomeningeal metastasis was cytology proven in 13 of 121 patients. Low DNA yields resulted in insufficient molecular coverage of NGS for the majority of samples (success rate, 8/30). The mFAST-SeqS method, successful in 112 of 121 (93%) samples, detected genome-wide aneuploidy in 24 patients. Ten of these patients had cytology-proven leptomeningeal metastasis; 8 additional patients were either concurrently diagnosed with central nervous system metastases by radiological means or developed these soon after the lumbar puncture. The remaining six cases were suspected of leptomeningeal metastasis, but could not be confirmed by cytology or imaging. Aneuploidy was associated with development of leptomeningeal metastasis and significantly worse overall survival. CONCLUSIONS: Aneuploidy in CSF-derived cfDNA may provide a promising biomarker to improve timely detection of leptomeningeal metastasis.

Prognostic validation and clinical implications of the EANO ESMO classification of leptomeningeal metastasis from solid tumors.

BACKGROUND: The EANO ESMO guidelines have proposed a classification of leptomeningeal metastases (LM) from solid cancers based on clinical, magnetic resonance imaging (MRI), and cerebrospinal fluid (CSF) cytology presentation. MRI patterns are classified as linear, nodular, both, or neither. Type I LM is defined by positive CSF cytology (confirmed LM) whereas type II LM is defined by typical clinical and MRI signs (probable or possible LM). Here we explored the clinical utility of these LM subtypes. PATIENTS AND METHODS: We retrospectively assembled data from 254 patients with newly diagnosed LM from solid tumors. Survival curves were derived using the Kaplan-Meier method and compared by Log-rank test. RESULTS: Median age at LM diagnosis was 56 years. Typical clinical LM features were noted in 225 patients (89%); 13 patients (5%) were clinically asymptomatic. Tumor cells in the CSF were observed in 186 patients (73%) whereas the CSF was equivocal in 24 patients (9.5%) and negative in 44 patients (17.5%). Patients with confirmed LM had inferior outcome compared with patients with probable or possible LM (P = 0.006). Type I patients had inferior outcome than type II patients (P = 0.002). Nodular disease on MRI was a negative prognostic factor in type II LM (P = 0.014), but not in type I LM. Administration of either intrathecal pharmacotherapy (P = 0.020) or systemic pharmacotherapy (P = 0.0004) was associated with improved outcome in type I LM, but not in type II LM. CONCLUSION: The EANO ESMO LM subtypes are highly prognostic and should be considered for stratification and overall design of clinical trials.

Pain-related changes in cutaneous innervation of patients suffering from bortezomib-induced, diabetic or chronic idiopathic axonal polyneuropathy.

Consistent associations between the severity of neuropathic pain and cutaneous innervation have not been described. We collected demographic and clinical data, McGill Pain Questionnaires (MPQ) and skin biopsies processed for PGP9.5 and CGRP immunohistochemistry from patients with bortezomib-induced peripheral neuropathy (BiPN; n = 22), painful diabetic neuropathy (PDN; n = 16), chronic idiopathic axonal polyneuropathy (CIAP; n = 16) and 17 age-matched healthy volunteers. Duration of neuropathic symptoms was significantly shorter in patients with BiPN in comparison with PDN and CIAP patients. BiPN was characterized by a significant increase in epidermal axonal swellings and upper dermis nerve fiber densities (UDNFD) and a decrease in subepidermal nerve fiber densities (SENFD) of PGP9.5-positive fibers and of PGP9.5 containing structures that did not show CGRP labeling, presumably non-peptidergic fibers. In PDN and CIAP patients, intraepidermal nerve fiber densities (IENFD) and SENFD of PGP9.5-positive and of non-peptidergic fibers were decreased in comparison with healthy volunteers. Significant unadjusted associations between IENFD and SENFD of CGRP-positive, i.e. peptidergic, fibers and the MPQ sensory-discriminative, as well as between UDNFD of PGP9.5-positive fibers and the MPQ evaluative/affective component of neuropathic pain, were found in BiPN and CIAP patients. No significant associations were found in PDN patients. Cutaneous innervation changes in BiPN confirm characteristic features of early, whereas those in CIAP and PDN are in line with late forms of neuropathic pathology. Our results allude to a distinct role for non-peptidergic nociceptors in BiPN and CIAP patients. The lack of significant associations in PDN may be caused by mixed ischemic and purely neuropathic pain pathology.

Opioid responsiveness of nociceptive versus mixed pain in clinical cancer patients.

OBJECTIVE: To investigate whether clinical cancer patients with mixed nociceptive-neuropathic pain are less responsive to opioids than patients with nociceptive pain. BACKGROUND: Pain is common in advanced cancer patients. Pain driven by neuropathic mechanisms is considered to be resistant to opioids. This hypothesis is mainly based on animal studies and single-dose opioid studies in humans but has not been confirmed in clinical practice. METHODS: Data were prospectively collected from 240 clinical cancer pain patients using opioids. Multiple linear regression was used for assessing the associations between the logarithm of the morphine equivalent dose (MED) at three days after admission (T = 3d) relative to admission (T = 0d) (logRMED) and type of pain (nociceptive versus mixed pain), corrected for gender, age, primary cancer site and use of non-opioid and adjuvant analgesics. As secondary outcome measures, associations between logMED and logPFent (fentanyl plasma level) at T = 3d and type of pain were assessed. RESULTS: Pain intensity between T = 0d and T = 3d was significantly and evenly reduced in patients with nociceptive pain (n = 173) and mixed pain (n = 67). Median (interquartile range) MED was 20 (10-52) and 20 (20-80) mg (T = 0d), 40 (10-67) and 40 (20-100) mg (T = 3d), median PFent (T = 3d) was 1.59 (0.58-3.19) and 1.38 (0.54-4.39) ng/ml, none of them significantly different, in patients with nociceptive and mixed pain, respectively. Neither logRMED, logMED (T = 3d), or logPFent (T = 3d) was significantly associated with type of pain, after correction for confounding factors. CONCLUSIONS: We conclude that, at least in clinical cancer patients, mixed pain is as responsive to opioids as nociceptive pain.

Pain Experience is Somatotopically Organized and Overlaps with Pain Anticipation in the Human Cerebellum.

Many fMRI studies have shown activity in the cerebellum after peripheral nociceptive stimulation. We investigated whether the areas in the cerebellum that were activated after nociceptive thumb stimulation were separate from those after nociceptive toe stimulation. In an additional experiment, we investigated the same for the anticipation of a nociceptive stimulation on the thumb or toe. For his purpose, we used fMRI after an electrical stimulation of the thumb and toe in 19 adult healthy volunteers. Following nociceptive stimulation, different areas were activated by stimulation on the thumb (lobule VI ipsilaterally and Crus II mainly contralaterally) and toe (lobules VIII-IX and IV-V bilaterally and lobule VI contralaterally), i.e., were somatotopically organized. Cerebellar areas innervated non-somatotopically by both toe and thumb stimulation were the posterior vermis and Crus I, bilaterally. In the anticipation experiment, similar results were found. However, here, the somatotopically activated areas were relatively small for thumb and negligible for toe stimulation, while the largest area was innervated non-somatotopically and consisted mainly of Crus I and lobule VI bilaterally. These findings indicate that nociceptive stimulation and anticipation of nociceptive stimulation are at least partly processed by the same areas in the cerebellum. This was confirmed by an additional conjunction analysis. Based on our findings, we hypothesize that input that is organized in a somatotopical manner reflects direct input from the spinal cord, while non-somatotopically activated parts of the cerebellum receive their information indirectly through cortical and subcortical connections, possibly involved in processing contextual emotional states, like the expectation of pain.

The reduction of intraepidermal P2X3 nerve fiber density correlates with behavioral hyperalgesia in a rat model of nerve injury-induced pain.

Skin biopsies from patients with neuropathic pain often show changes in epidermal innervation, although it remains to be elucidated to what extent such changes can be linked to a particular subgroup of nerve fibers and how these changes are correlated with pain intensity. Here, we investigated to what extent behavioral signs of hyperalgesia are correlated with immunohistochemical changes of peptidergic and non-peptidergic epidermal nerve fibers in a rat model of nerve injury-induced pain. Rats subjected to unilateral partial ligation of the sciatic nerve developed significant mechanical and thermal hyperalgesia as tested by the withdrawal responses of the ipsilateral footpad to von Frey hairs and hotplate stimulation. At day 14, epidermal nerve fiber density and total epidermal nerve fiber length/mm2 were significantly and consistently reduced compared to the contralateral side, following testing and re-testing by two blinded observers. The expression of calcitonin gene-related peptide, a marker for peptidergic nerve fibers, was not significantly changed on the ipsilateral side. In contrast, the expression of the P2X3 receptor, a marker for non-peptidergic nerve fibers, was not only significantly reduced but could also be correlated with behavioral hyperalgesia. When labeling both peptidergic and non-peptidergic nerve fibers with the pan-neuronal marker PGP9.5, the expression was significantly reduced, albeit without a significant correlation with behavioral hyperalgesia. In conjunction, our data suggest that the pathology of the P2X3 epidermal nerve fibers can be selectively linked to neuropathy, highlighting the possibility that it is the degeneration of these fibers that drives hyperalgesia.

Pharmacological Treatment of Pain in Cancer Patients: The Role of Adjuvant Analgesics, a Systematic Review.

CONTEXT: In patients with cancer, pain is one of the most feared and burdensome symptoms. Adjuvant analgesics are an important cornerstone on which treatment of pain in patients with cancer is based. OBJECTIVES: To update our guidelines for the treatment of pain in patients with cancer, we performed a systematic review on the use of adjuvant analgesics in pain in cancer. METHODS: A systematic search of the literature was performed searching for articles that studied the effect of (1) antidepressants, (2) anti-epileptics, (3) N-methyl-d-aspartate (NMDA) receptor antagonists, and (4) other adjuvant analgesics in patients with cancer pain and described their effects on pain intensity and/or side effects. RESULTS: Based on the keywords and after reading the full papers, we could include 12 papers on anticonvulsants, 10 papers on antidepressants, four on NMDA receptor antagonists, and 10 papers on other adjuvant analgesics. The methodological quality of the included papers was graded as low to very low. Overall, there was a low quality of evidence that gabapentin, pregabalin, amitriptyline, and venlafaxine were effective in reducing pain intensity in patients with cancer pain. There was insufficient evidence on the effectiveness of lamotrigine, levetiracetam, NMDA antagonists, cannabinoids, corticosteroids, and local anesthetics on reducing pain intensity in patients with cancer pain. CONCLUSION: The quality of currently available evidence on the effectiveness of adjuvant analgesics in the treatment of cancer pain is low. The treatment of pain associated with cancer should be tailored to the patient's personal preferences.

Spinal autofluorescent flavoprotein imaging in a rat model of nerve injury-induced pain and the effect of spinal cord stimulation.

Nerve injury may cause neuropathic pain, which involves hyperexcitability of spinal dorsal horn neurons. The mechanisms of action of spinal cord stimulation (SCS), an established treatment for intractable neuropathic pain, are only partially understood. We used Autofluorescent Flavoprotein Imaging (AFI) to study changes in spinal dorsal horn metabolic activity. In the Seltzer model of nerve-injury induced pain, hypersensitivity was confirmed using the von Frey and hotplate test. 14 Days after nerve-injury, rats were anesthetized, a bipolar electrode was placed around the affected sciatic nerve and the spinal cord was exposed by a laminectomy at T13. AFI recordings were obtained in neuropathic rats and a control group of naïve rats following 10 seconds of electrical stimulation of the sciatic nerve at C-fiber strength, or following non-noxious palpation. Neuropathic rats were then treated with 30 minutes of SCS or sham stimulation and AFI recordings were obtained for up to 60 minutes after cessation of SCS/sham. Although AFI responses to noxious electrical stimulation were similar in neuropathic and naïve rats, only neuropathic rats demonstrated an AFI-response to palpation. Secondly, an immediate, short-lasting, but strong reduction in AFI intensity and area of excitation occurred following SCS, but not following sham stimulation. Our data confirm that AFI can be used to directly visualize changes in spinal metabolic activity following nerve injury and they imply that SCS acts through rapid modulation of nociceptive processing at the spinal level.

Spinal distribution of c-Fos activated neurons expressing enkephalin in acute and chronic pain models.

The endogenous opioid enkephalin is known to inhibit spinal nociceptive transmission. Here we investigated activation of spinal enkephalinergic neurons by determining the proportions of c-Fos expressing (activated) spinal neurons that were enkephalinergic after different acute and chronic peripheral nociceptive stimuli. The number of c-Fos-activated neurons in the dorsal horn was increased after hind paw injection of capsaicin, formalin or complete Freund's adjuvant (CFA, 1.5 hrs - 4 days). The numbers of these neurons that were enkephalinergic increased after paraformaldehyde, and at 20 hrs, but not 1.5 hrs or 4 days post-CFA as compared to saline. In the spared nerve injury (SNI) model of neuropathic pain, c-Fos expression was increased acutely (2 hrs) and chronically (2 weeks), and a greater number of these were enkephalinergic in the nerve-injured animals acutely compared to controls (sham-SNI). Combining all acute (=2 hrs) versus chronic (≥20 hrs) treatment groups, there was a significant decrease in the percentage of activated neurons that were enkephalinergic in superficial layers, but a significant increase in the deeper layers of the dorsal horn in the chronic treatment group. It is concluded that the overall percentage of c-Fos activated neurons that contained enkephalin was not significantly different between acute and chronic pain phases. However, the shift in localization of these neurons within the spinal dorsal horn indicates a noxious stimulus directed activation pattern.

Neuropathic pain and pharmacological treatment.

Neuropathic pain is a serious chronic condition strongly affecting quality of life, which can be relieved but cannot be cured. Apart from symptomatic management, treatment should focus on the underlying disorder. The estimated prevalence is at least 1% to 5% of the general population. Neuropathic pain is characterized both by spontaneous and evoked pain. A diagnosis of neuropathic pain can usually be established based solely on history and neurological examination. Ancillary investigations may include EMG and computerized tomography/magnetic resonance imaging scans, depending on the localization of the suspected lesion. A limited number of agents, primarily directed at symptom control, are currently approved for use in neuropathic pain. A mechanism-based approach to pharmacological intervention supports the use of polypharmacy in neuropathic pain.

The evidence for pharmacologic treatment of neuropathic cancer pain: beneficial and adverse effects.

CONTEXT: The prevalence of neuropathic pain in patients with cancer pain has been estimated to be around 40%. Neuropathic pain may be caused by tumor invasion and is considered as mixed nociceptive-neuropathic pain, or caused by an anticancer treatment and considered as purely neuropathic pain. The use of adjuvant analgesics in patients with cancer is usually extrapolated from their efficacy in nononcological neuropathic pain syndromes. OBJECTIVES: In this systematic review, we sought to evaluate the evidence for the beneficial and adverse effects of pharmacologic treatment of neuropathic cancer pain. METHODS: A systematic review of the literature in PubMed and Embase was performed. Primary outcome measures were absolute risk benefit (ARB), defined as the number of patients with a defined degree of pain relief divided by the total number of patients in the treatment group, and absolute risk harm (ARH), defined as the fraction of patients who dropped out as a result of adverse effects. RESULTS: We identified 30 articles that fulfilled our inclusion criteria. Overall, ARB of antidepressants, anticonvulsants, other adjuvant analgesics, or opioids greatly outweighed ARH. There were no significant differences in ARB or ARH between the four groups of medication or between patients with mixed vs. purely neuropathic pain. Because of the low methodological quality of the studies, we could not draw conclusions about the true treatment effect size of the four groups of medications. CONCLUSION: Once a diagnosis of neuropathic pain has been established in patients with cancer, antidepressants, anticonvulsants, or other adjuvant analgesics should be considered in addition to or instead of opioids.