Elsevier

Oral Oncology

Volume 51, Issue 11, November 2015, Pages 976-981
Oral Oncology

Review
Elective versus therapeutic neck dissection in node-negative oral cancer: Evidence from five randomized controlled trials

https://doi.org/10.1016/j.oraloncology.2015.08.009Get rights and content

Highlights

  • This study may provide paramount evidence for surgeons to make treatment plan of OSCC.

  • All the included studies are RCTS.

  • This study’s sample size is probably the largest by now.

Summary

The aim of this study was to compare the outcomes of elective neck dissection (END) with that of a more conservative approach comprising of observation plus therapeutic neck dissection for nodal relapse (OBS), by conducting a meta-analysis of randomized controlled trials (RCTs) that compare these two surgical approaches in patients. RCTs conducted prior to May 2015 were identified from electronic databases such as MEDLINE EMBASE and Cochrane Library. Reference lists within the retrieved articles were used as secondary reference sources. Disease-free survival (DFS) and overall survival (OS) were the primary outcome measures. Five RCTs with a combined subject population of 779 patients were included. Meta-analysis of these 5 RCTs showed that DFS in END group was higher than that in the OBS group with a significant inter-group difference (Risk Ratio [RR]:1.33; 95% Confidence Interval [CI] 1.06, 1.66); P = 0.01; five trials, 779 participants]. However, there was a significant statistical heterogeneity among the studies (I-squared = 56%, P = 0.06). Four studies had reported on OS. Meta-analysis of these 4 RCTs revealed a higher OS in the END group as compared to that that in the OBS group with a significant inter-group difference (RR: 1.18; 95% CI 1.07, 1.29); P = 0.0009; four trials, 708 participants]. The statistical heterogeneity of these 4 studies is small (I-squared = 14%, P = 0.32). The results of this meta-analysis suggest that END at the time of resection of the primary tumor confers a DFS and OS benefit in patients with clinically node-negative oral cancer.

Introduction

Oral cancer is the sixth most common cancer in the world and accounts for nearly 3% of all cancer cases [1]. The most common tumor in the oral cavity is oral squamous cell carcinoma (OSCC), an aggressive cancer frequently associated with poor prognosis. Surgery is still the preferred treatment [2], [3], [4]. Neck dissection plays an important role in the treatment of OSCC and is an indispensable part of many OSCC treatments [4]. However, iatrogenic injury to the anatomically contiguous vital structures in the neck, either during surgery or that resulting from postoperative complications, is a risk. Although OSCC is a locally aggressive disease with a strong tendency for loco-regional metastasis, some patients with clinically node-negative (cN0) OSCC do not actually have cancer cells in the cervical lymphatic tissue. In such cases, elective neck dissection could potentially result in avoidable morbidity and its associated costs such as prolonged hospital stay. Conversely, cN0 patients with actual micro metastases, but, in whom, neck dissection is not included in the management plan, may experience increased mortality [5]. In other words, there is no greater controversy related to the management of oral cancers than that surrounding the choice of treatment strategy for OSCC, especially in cN0 patients [6], [7], [8], [9], [10].

Treatment of early stage cN0 OSCC has been a contentious issue since the past 50 years. Surgery is still the preferred treatment in these cN0 OSCC patients. The two main surgical strategies for addressing the neck involvement include: (1) a conservative approach consisting of observation with therapeutic neck dissection only in the event of nodal relapse; (2) Elective neck dissection at the time of the excision of the primary tumor. Proponents of elective neck dissection cite decreased relapse rates and better disease-free survival (DFS) as well as overall survival (OS) [10], [11], [12], [13], [14], [15]. However, some studies found no statistically significant difference with respect to DFS or OS between the two strategies [6], [7], [16]. Results from a few randomized controlled trials (RCTs) and retrospective studies have largely been inconclusive. Although the elective neck dissection approach may improve DFS and/or OS, the observation approach has the potential advantage of avoiding an additional surgical procedure in more than 70% of patients. Furthermore, neck dissection could increase treatment costs including that of treatment and complications. These considerations have resulted in variability in global practices.

The purpose of this research is to compare the outcomes of elective neck dissection (END) with those of a conservative surgical strategy comprising of observation followed by therapeutic neck dissection in the event of nodal relapse (OBS), in cN0 OSCC, by conducting a meta-analysis of the RCTs that have compared these two approaches.

Section snippets

Inclusion criteria

Studies were included if they met all the following inclusion criteria: (a) patients diagnosed with cN0 OSCC without any treatment before surgery; (b) patients treated with oral surgical excision of the primary tumor with or without neck dissection; (c) reported clinical outcomes of END and OBS; (d) reported outcome measures included OS or DFS; (e) randomized controlled trials without limitations on publication status; (f) something about summary data being available for the outcomes of

Search findings

A total of 827 records were retrieved on database search and 12 additional records were identified after reviewing the reference lists of retrieved articles. After deleting the duplications, 814 papers were left. 792 papers were excluded as being irrelevant to OSCC or survival, or due to the lack of prognostic data. The remaining 22 articles were further assessed for eligibility and another 17 articles were eventually excluded. 14 articles were excluded because of the retrospective study

Discussion

The proponents of the treatment strategy that includes elective neck dissection cite lower relapse rates and better prognosis as benefits of this strategy [10], [11], [12], [15]. However, some researchers disagree with this assertion [6], [16]. Retrospective studies have not been helpful in resolving the lack of consensus on this subject [10], [16], [20], [21]. Although some RCTs have sought to address this issue, the evidence backing the comparative advantage of elective neck dissection is

Conflict of interest statement

None declared.

References (22)

  • A.K. D’Cruz et al.

    Elective versus therapeutic neck dissection in node-negative oral cancer

    New Engl J Med

    (2015)
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