title: A systematic review of clinical outcomes for patients diagnosed with skin cancer spinal metastases.
abstract: OBJECT Surgical procedures and/or adjuvant therapies are effective modalities for the treatment of symptomatic spinal metastases. However, clinical results specific to the skin cancer spinal metastasis cohort are generally lacking. The purpose of this study was to systematically review the literature for treatments, clinical outcomes, and survival following the diagnosis of a skin cancer spinal metastasis and evaluate prognostic factors in the context of spinal skin cancer metastases stratified by tumor subtype. METHODS The authors performed a literature review using PubMed, Embase, CINAHL, and Web of Science to identify articles since 1950 that reported survival, clinical outcomes, and/or prognostic factors for the skin cancer patient population with spinal metastases. The methodological quality of reviews was assessed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) tool. RESULTS Sixty-five studies met the preset criteria and were included in the analysis. Of these studies, a total of 25, 40, 25, and 12 studies included patients who underwent some form of surgery, radiotherapy, chemotherapy, or observation alone, respectively. Sixty-three of the 65 included studies were retrospective in nature (Class of Evidence [CoE] IV), and the 2 prospective studies were CoE II. Based on the studies analyzed, the median overall survival for a patient with a spinal metastasis from a primary skin malignancy is 4.0 months; survival by tumor subtype is 12.5 months for patients with basal cell carcinoma (BCC), 4.0 months for those with melanoma, 4.0 months for those with squamous cell carcinoma, 3.0 months for those with pilomatrix carcinoma, and 1.5 months for those with Merkel cell carcinoma (p < 0.0001). The overall percentage of known continued disease progression after spine metastasis diagnosis was 40.1% (n = 244/608, range 25.0%-88.9%), the rate of known recurrence of the primary skin cancer lesion was 3.5% (n = 21/608, range 0.2%-100.0%), and the rate of known spine metastasis recurrence despite treatment for all skin malignancies was 2.8% (n = 17/608, range 0.0%-33.3%). Age greater than 65 years, sacral spinal involvement, presence of a neurological deficit, and nonambulatory status were associated with decreased survival in patients diagnosed with a primary skin cancer spinal metastasis. All other clinical or prognostic parameters were of low or insufficient strength. CONCLUSIONS Patients diagnosed with a primary skin cancer metastasis to the spine have poor overall survival with the exception of those with BCC. The median duration of survival for patients who received surgical intervention alone, medical management (chemotherapy and/or radiation) alone, or the combination of therapies was similar across interventions. Age, spinal region, and neurological status may be associated with poor survival following surgery.
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: C Rory
authors.initials: CR
authors.lastname: Goodwin
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Eric W
authors.initials: EW
authors.lastname: Sankey
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Ann
authors.initials: A
authors.lastname: Liu
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Elder
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Thomas
authors.initials: T
authors.lastname: Kosztowski
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Sheng-Fu L
authors.initials: SF
authors.lastname: Lo
authors.affiliation: Division of Spine, Department of Orthopaedics, University of British Columbia and Vancouver General Hospital, Vancouver, British Columbia, Canada; and.
authors.forename: Charles G
authors.initials: CG
authors.lastname: Fisher
authors.affiliation: Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota.
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Clarke
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Ziya L
authors.initials: ZL
authors.lastname: Gokaslan
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland;
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sciubba
mesh_terms: D000367:Age Factors; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000556:secondary / Q000628:therapy*; D003131:Combined Modality Therapy; D006801:Humans; D008545:Melanoma / Q000401:mortality / Q000556:secondary / Q000628:therapy*; D011379:Prognosis; D012878:Skin Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D013125:Spinal Neoplasms / Q000401:mortality / Q000556:secondary / Q000628:therapy*
keywords: BCC = basal cell carcinoma; CoE = Class of Evidence; IQR = interquartile range; MCC = Merkel cell carcinoma; MESCC = metastatic epidural spinal cord compression; Merkel cell carcinoma; SCC = squamous cell carcinoma; basal cell carcinoma; melanoma; oncology; pilomatrix carcinoma; skin cancer; spine metastasis; squamous cell carcinoma; survival