Epidemiology of spinal metastases, metastatic epidural spinal cord compression and pathologic vertebral compression fractures in patients with solid tumors: A systematic review

Abstract

Introduction: Spinal metastases (SM) are a frequent complication of cancer and may lead to pathologic vertebral compression fractures (pVCF) and/or metastatic epidural spinal cord compression (MESCC). Based on autopsy studies, it is estimated that about one third of all cancer patients will develop SM. These data may not provide a correct estimation of the incidence in clinical practice.

Objective: This systematic review (SR) aims to provide a more accurate estimation of the incidence of SM, MESCC and pVCF in a clinical setting.

Methods: We performed a SR of papers regarding epidemiology of SM, pVCF, and MESCC in patients with solid tumors conform PRISMA guidelines. A search was conducted in the PubMed and Web of Science database using the terms epidemiology, prevalence, incidence, global burden of disease, cost of disease, spinal metastas*, metastatic epidural spinal cord compression, pathologic fracture, vertebral compression fracture, vertebral metastas* and spinal neoplasms. Papers published between 1975 and august 2021 were included. Quality was evaluated by the STROBE criteria.

Results: While 56 studies were included, none of them reports the actual definition used for MESCC and pVCF, inevitably introducing heterogenity. The overall cumulative incidence of SM and MESCC is 15.67% and 2.84% respectively in patients with a solid tumor. We calculated a mean cumulative incidence in patients with SM of 9.56% (95% CI 5.70%-13.42%) for MESCC and 12.63% (95% CI 7.00%-18.25%) for pVCF. Studies show an important delay between onset of symptoms and diagnosis.

Conclusions: While the overall cumulative incidence for clinically diagnosed SM in patients with a solid tumor is 15.67%, autopsy studies reveal that SM are present in 30% by the time they die, suggesting underdiagnosing of SM. Approximately 1 out of 10 patients with SM will develop MESCC and another 12.6% will develop a pVCF. Understanding these epidemiologic data, should increase awareness for first symptoms, allowing early diagnosis and subsequent treatment, thus improving overall outcome.

Keywords: CA, carcinoma; CI, confidence interval; Epidemiology; HCC, hepatocellular carcinoma; LOL, length of life; MESCC, metastastic epidural spinal cord compression; MRI, magnetic resonance imaging; Metastatic epidural spinal cord compression; OR, odds ratio; Oncology; PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses; Pathologic vertebral compression fracture; QOL, quality of life; RCT, randomized controlled trial; SINS, spinal instability neoplastic score; SM, spinal metastases; SR, systematic review; SRE, skeletal related event; ST, solid tumor; STROBE, Strengthening the reporting of observational studies in epidemiology; Spinal metastases; WHO, World Health Organization; pVCF, pathologic vertebral compression fractures; rMESCC, subclinical radiographic MESCC.

Fig. 1

PRISMA flow diagram of the literature search and selection of papers.

Fig. 2

Cohort studies: Incidence of SM and MESCC in relation to study period during the past two decades (2000–2020). Study period was defined by end date of study period. Size of any given circle represents study size.

Fig. 3

Cumulative incidence of spinal metastases (SM), Metastatic Epidural Spinal Cord Compression (MESCC) and pathologic Vertebral Compression Fractures (pVCF). CA = carcinoma, ST = solid tumor. Solid bars represent the mean values and error bars represent the 95% CI. While some higher values are not shown in the graphs due to axis limits, these values are included in both mean and 95% CI error bars and can be found in Table 1, Table 2.