Extent of resection of epidermoid tumors and risk of recurrence: case report and meta-analysis

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Intracranial epidermoid tumors are slow-growing, histologically benign tumors of epithelial cellular origin that can be symptomatic because of their size and mass effect. Neurosurgical resection, while the treatment of choice, can be quite challenging due to locations where these lesions commonly occur and their association with critical neurovascular structures. As such, subtotal resection (STR) rather than gross-total resection (GTR) can often be performed, rendering residual and recurrent tumor potentially problematic. The authors present a case of a 28-year-old man who underwent STR followed by aggressive repeat resection for regrowth, and they report the results of the largest meta-analysis to date of epidermoid tumors to compare recurrence rates for STR and GTR.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>The authors conducted a systemic review of PubMed, Web of Science, and the Cochrane Collaboration following the PRISMA guidelines. They then conducted a proportional meta-analysis to compare the pooled recurrence rates between STR and GTR in the included studies. The authors developed fixed- and mixed-effect models to estimate the pooled proportions of recurrence among patients undergoing STR or GTR. They also investigated the relationship between recurrence rate and follow-up time in the previous studies using linear regression and natural cubic spline models.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Overall, 27 studies with 691 patients met the inclusion criteria; of these, 293 (42%) underwent STR and 398 (58%) received GTR. The average recurrence rate for all procedures was 11%. The proportional meta-analysis showed that the pooled recurrence rate after STR (21%) was 7 times greater than the rate after GTR (3%). The average recurrence rate for studies with longer follow-up durations (≥ 4.4 years) (17.4%) was significantly higher than the average recurrence rate for studies with shorter follow-up durations (&lt; 4.4 years) (5.7%). The cutoff point of 4.4 years was selected based on the significant relationship between the recurrence rate of both STR and GTR and follow-up durations in the included studies (p = 0.008).</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>STR is associated with a significantly higher rate of epidermoid tumor recurrence compared to GTR. Attempts at GTR should be made during the initial surgery with efforts to optimize success. Surgical expertise, as well as the use of adjuncts, such as intraoperative MRI and neuromonitoring, may increase the likelihood of completing a safe GTR and decreasing the long-term risk of recurrence. The most common surgical complications were transient cranial nerve palsies, occurring equally in STR and GTR cases when reported. In all postoperative epidermoid tumor cases, but particularly following STR, close follow-up with serial MRI, even years after surgery, is recommended.</jats:p></jats:sec>

Role of the apparent diffusion coefficient as a predictive factor for tumor recurrence in patients with intracranial epidermoid tumor

“…Although there are no established treatment guidelines, maximal safe surgical resection is generally conducted, and reoperation is often considered for recurrent cases. Due to its benign nature and pathologic simplicity, many studies related to intracranial epidermoid tumors focus on surgical techniques, cranial nerve function preservation, and recurrence after surgery [2,5,8,12,[18][19][20][21]. The EOR was shown to be a signi cant prognostic factor for recurrence in these studies, but there are no known preoperative factors that can predict tumor behavior.…”

“…There have been many debates about the optimum extent of resection in intracranial epidermoid tumors [2,5,8,25]. The proliferation of strati ed squamous epithelium is considered to be the cause of tumor recurrence, leading to accumulation of acellular debris such as keratin, protein, and lipid [1,8,9]. Considering the pathogenesis of this tumor, many studies have revealed that complete excision, including of the tumor capsule, reduces the risk of recurrence compared with STR [2,5,8].…”

“…The proliferation of strati ed squamous epithelium is considered to be the cause of tumor recurrence, leading to accumulation of acellular debris such as keratin, protein, and lipid [1,8,9]. Considering the pathogenesis of this tumor, many studies have revealed that complete excision, including of the tumor capsule, reduces the risk of recurrence compared with STR [2,5,8]. Our case series con rms that patients treated with total resection showed lower recurrence rates than those treated with non-total resection (P = 0.036).…”

“…A recent meta-analysis reported that the recurrence rate of intracranial epidermoid tumors is roughly one in ten patients, and some studies showed no recurrence even after subtotal resection [8]. However, several studies included in that meta-analysis obtained follow-up imaging only when symptoms occurred and did not perform MRI annually, which might make their interpretation problematic [2,19,26].…”

“…Although they have a benign nature with slow growth rates, surgical resection is generally conducted if they cause neurologic de cits due to compression of neural structures. However, there are risks of surgical morbidity and recurrence because the tumor capsule adherent to the adjacent critical neurovascular structures makes it di cult to surgically eradicate the tumor [1,2,4,8].…”