Total Parotidectomy Versus Less‐Than‐Total Parotidectomy for Early‐Stage Low Grade Parotid Cancer: A Systematic Review and Meta‐Analysis

ABSTRACT

Objectives

Total parotidectomy (TP) has been advocated to ensure complete tumor clearance and removal of intraparotid lymph nodes; however, less‐than‐total parotidectomy (LTT) may offer comparable oncologic control with superior functional outcomes. In this systematic review and meta‐analysis, we compared oncologic and functional outcomes between LTT and TP for patients with T1–2 low‐grade parotid malignancies.

Methods

A systematic literature search was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. Four retrospective cohort studies of T1–2 low‐grade parotid cancer were included. Patients underwent either LTT or TP. Primary outcomes were overall survival (OS) and recurrence‐free survival (RFS). Pooled hazard ratios with 95% confidence intervals were calculated using random‐effects models. Heterogeneity was assessed using I ² statistics and the Cochran's Q test.

Results

The pooled analysis demonstrated no significant difference in OS between LTT and TP based on three studies. Across the four studies, RFS was comparable between the two surgical approaches, and statistical heterogeneity was negligible for both OS and RFS. No evidence of publication bias was detected.

Conclusion

In selected patients with T1–2 low‐grade parotid malignancies confined to the superficial lobe, LTT showed no statistically significant disadvantage in OS or RFS compared with TP based on the available retrospective evidence. However, the high risk of bias across included studies limits causal interprettion. Surgical strategy should therefore be individualized and should prioritize negative margins and functional preservation when oncologically appropriate. Prospective studies with standardized oncologic and functional outcome reporting are warranted.

Level of Evidence

3.

1. Introduction

Parotid gland carcinoma accounts for approximately 3%–6% of all head and neck malignancies and represents a remarkably heterogeneous group of more than 24 distinct histologic subtypes with varying biological behaviors and clinical outcomes [1, 2]. The rarity and histologic diversity of these malignancies pose significant challenges in establishing standardized treatment protocols and comparing oncologic outcomes across studies [3]. The surgical management of early‐stage and low‐grade parotid cancer, particularly the optimal extent of parenchymal resection required to achieve oncologic safety and minimize functional morbidity, has been a subject of ongoing controversy.

Historically, the “gold standard” surgical approach for parotid malignancy has been total parotidectomy (TP) or superficial parotidectomy because it allows complete clearance of microscopic disease, removal of all intraparotid lymph nodes, and reduction in local recurrence risk [4, 5]. This aggressive surgical philosophy was supported by anatomical studies demonstrating that the parotid gland contains approximately 20–30 intraparotid lymph nodes distributed throughout the gland parenchyma, particularly in the superficial lobe [6]. However, extensive resection carries significant morbidity, including temporary or permanent facial nerve dysfunction (ranging from 9% to 100% for temporary palsy and 3%–5% for permanent palsy in various series), Frey's syndrome (gustatory sweating occurring in 10%–60% of patients), cosmetic deformity, and impaired quality of life [7, 8, 9].

Accumulating evidence has challenged this paradigm in recent decades, particularly for benign and low‐grade malignant tumors. Multiple retrospective cohort studies have demonstrated that less‐than‐total parotidectomy (LTT), including partial superficial parotidectomy and extracapsular dissection (ECD), achieves comparable oncologic outcomes and significantly reduced functional morbidity when negative surgical margins (R0 resection) are achieved [10, 11, 12]. McGurk et al. introduced the concept of ECD for clinically benign parotid lesions, reporting excellent long‐term outcomes with minimal recurrence rates and superior facial nerve preservation [13]. Subsequently, several authors have cautiously extended this conservative approach to select low‐grade malignancies, reporting encouraging preliminary results [14, 15].

Existing literature examining surgical extent in parotid cancer is limited by several methodological challenges, including small sample sizes resulting from disease rarity, heterogeneity of included histologic subtypes, variable adjuvant treatment protocols, and confounding histologic grade within study populations [16, 17]. Most published series have combined low‐ and high‐grade tumors in analysis, potentially masking critical grade‐specific differences in the relationship between surgical extent and oncologic outcomes.

In recent years, the paradigm has shifted toward LTT, which encompasses superficial parotidectomy, partial parotidectomy, and ECD, gaining traction for low‐grade lesions according to several retrospective studies. Proponents argue that extensive resection of healthy parenchyma does not improve survival but significantly increases morbidity for well‐circumscribed, low‐grade malignancies located in the superficial lobe [10, 14, 18, 19].

Despite this trend, high‐level evidence comparing the oncologic safety of these conservative techniques against radical approaches remains lacking. Therefore, in this meta‐analysis, we integrate data from four significant recent studies to evaluate whether LTT compromises oncologic safety in terms of recurrence and survival.

2. Materials and Methods

2.1. Search Strategy and Selection Criteria

A systematic search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. This systematic search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. This systematic review and meta‐analysis was conducted and reported in accordance with the PRISMA 2020 statement. The complete database‐specific search strategies for PubMed, Embase, and the Cochrane Library are provided in Appendix S1. In addition to the database searches, Google Scholar was searched as a supplementary web‐based source to identify potentially relevant records that may not have been captured in the database search. The completed PRISMA 2020 checklist is provided in Appendix S2.

Databases, including PubMed, Embase, and the Cochrane Library, were searched for studies published up to June 30, 2026 comparing surgical extents for primary parotid malignancy. The search strategy utilized combinations of keywords and MeSH terms, including “parotid neoplasms,” “parotidectomy,” “partial parotidectomy,” “extracapsular dissection,” “low‐grade,” and “histologic grade.”

The inclusion criteria were as follows: (1) pathologically confirmed T1 or T2 primary low‐grade parotid gland carcinoma; (2) comparison between TP and LTT (partial parotidectomy, superficial parotidectomy, or ECD); and (3) availability of oncologic outcomes (recurrence, survival) and/or functional outcomes.

After the removal of duplicate records, 4248 studies were identified. These records underwent a three‐step screening process, and four studies were ultimately selected for inclusion in the final analysis (Figure 1).

FIGURE 1.

PRISMA flow diagram of study selection; PRISMA, preferred reporting items for systematic reviews and meta‐analyses.

2.2. Data Extraction and Quality Assessment

Two reviewers independently extracted data using a standardized form. The following information was collected from each study: first author, publication year, study design, sample size, patient demographics, tumor characteristics (histological subtype, T stage, N stage, grade), surgical extent (less‐than‐total resection vs. TP), adjuvant treatment, follow‐up duration, and survival outcomes (overall survival [OS] and recurrence‐free survival [RFS] with corresponding hazard ratios [HRs] and 95% confidence intervals [CIs]). To evaluate the methodological quality of the included nonrandomized retrospective studies, the Risk of Bias for Nonrandomized Studies II tool was applied [20]. Two reviewers independently assessed the risk of bias for each study, and disagreements were resolved through discussion. Figure 2 presents the overall results of the risk‐of‐bias assessment.

FIGURE 2.

Summary of the risk of bias assessment using the RoBANS II tool. RoBANS, Risk of Bias for Nonrandomized Studies.

The risk of bias was assessed for the included nonrandomized retrospective studies across eight methodological domains. The left panel illustrates the distribution of risk‐of‐bias judgments by domain, whereas the right panel displays the detailed assessment for each individual study. The low, unclear, and high risks of bias are indicated by green, yellow, and red, respectively.

2.3. Statistical Analysis

The meta‐analysis was performed using R statistical software (version 4.3.0; R Foundation for Statistical Computing, Vienna, Austria) with the “meta” and “metafor” packages. For each outcome measure, pooled estimates were calculated using a random‐effects model.

The primary outcomes were OS and RFS. The pooled recurrence and survival rates for the LTT and TP groups were calculated separately.

2.4. Heterogeneity Assessment

Statistical heterogeneity among studies was assessed using Cochran's Q statistic (with p < 0.10 considered statistically significant) and quantified using the I ² statistic. I ² values of 25%, 50%, and 75% were interpreted as representing low, moderate, and high heterogeneity, respectively. When substantial heterogeneity (I ² > 50% or p < 0.10) was detected, a random‐effects model was employed using the DerSimonian–Laird method.

2.5. Publication Bias

Formal assessment of publication bias or small‐study effects was planned only when at least 10 studies were available for a given outcome. Because only three studies contributed to the OS analysis and four studies contributed to the RFS analysis, funnel plots and formal asymmetry tests, including Egger's regression test and the Begg–Mazumdar rank correlation test, were not performed. Therefore, publication bias could not be reliably assessed in the present meta‐analysis.

2.6. Statistical Significance

All statistical tests were two‐sided, and a p‐value < 0.05 was considered statistically significant. Risk ratios (RR) or HRs with 95% CIs not exceeding 1.0 were considered statistically significant.

3. Results

3.1. Study Characteristics

A total of four retrospective cohort studies comprising 540 patients with low‐grade parotid gland malignancies met the inclusion criteria. The studies included Mantsopoulos et al., Cho et al., Park et al., and Han et al. with 24 patients, 179 patients, 287 patients, and 50 patients, respectively [18, 19, 21, 22]. The most common histological subtypes were mucoepidermoid carcinoma (low grade), adenoid cystic carcinoma (nonsolid type), and acinic cell carcinoma. All studies compared conservative surgical approaches with more extensive parotidectomy procedures. The mean follow‐up duration ranged from 48 to 78.4 months across the studies.

3.2. OS Analysis

Three studies [18, 21, 22] provided data on OS. The pooled analysis demonstrated no significant difference in OS between LTT and TP (pooled HR: 1.082, 95% CI: 0.688–1.702, p = 0.738) (Figure 3A). Statistical heterogeneity among studies was low (I ² = 0.0%, τ ² = 0, Cochran's Q = 1.57, df = 2, p = 0.4556), indicating consistency of results across studies. The forest plot showed that all three studies had HRs crossing the line of no effect, with Mantsopoulos et al. [21] (HR: 0.526, 95% CI: 0.061–4.545), Park et al. [22] (HR: 1.879, 95% CI: 0.648–5.450), and Han et al. [18] (HR: 0.991, 95% CI: 0.593–1.658). These findings suggest that LTT does not compromise the OS of patients with low‐grade parotid malignancies.

FIGURE 3.

Forest plots comparing LTT versus TP for low‐grade parotid cancer. (A) Overall survival analysis showing pooled HR: 1.082 (95% CI: 0.688–1.702, p = 0.738). (B) Recurrence‐free survival analysis showing pooled HR: 0.826 (95% CI: 0.657–1.038, p = 0.100). The size of squares represents the meta‐analysis's study weight, and diamond represents the pooled effect estimate with 95% CI. HR < 1 favors LTT; HR > 1 favors TP. No significant heterogeneity was observed (I ² = 0.0% for both analyses). CI, confidence interval; HR, hazard ratio; LTT, less‐than‐total parotidectomy; TP, total parotidectomy.

3.3. RFS Analysis

All four studies reported RFS outcomes. The pooled analysis showed no significant difference in RFS between the LTT and TP approaches (pooled HR: 0.826, 95% CI: 0.657–1.038, p = 0.100) (Figure 3B), suggesting that LTT and TP provide comparable oncologic control. Heterogeneity among studies was negligible (I ² = 0.0%, τ ² = 0, Cochran's Q = 0.44, df = 3, p = 0.9322), indicating remarkable consistency across different study populations and settings. Although the pooled HR numerically favored LTT, the difference in RFS did not reach statistical significance and should be interpreted as showing no statistically significant difference rather than evidence of formal equivalence.

3.4. Publication Bias Assessment

Formal assessment of publication bias or small‐study effects was not performed because the number of included studies was insufficient for reliable evaluation. As prespecified in the Methods, funnel plots and formal asymmetry tests, including Egger's regression test and the Begg–Mazumdar rank correlation test, were planned only when at least 10 studies were available for a given outcome. In the present meta‐analysis, only three studies contributed to the OS analysis and four studies contributed to the RFS analysis. Therefore, publication bias could not be reliably assessed, and no funnel plots or asymmetry test results are presented.

4. Discussion

This meta‐analysis provides the first focused synthesis of comparative surgical outcomes for patients with low‐grade parotid gland carcinoma, integrating contemporary evidence from four studies. In this low‐grade subset, the findings suggest that oncologic control is driven predominantly by favorable tumor biology rather than by the extent of parotid parenchymal resection. Accordingly, the traditional assumption that wider gland sacrifice inherently improves cancer outcomes appears less applicable to low‐grade disease: when appropriate patient selection is applied and clear margins are achievable, LTT can offer comparable survival and recurrence outcomes while potentially reducing treatment‐related morbidity [23, 24].

4.1. Comparable Oncologic Outcomes of Conservative Surgery for Low‐Grade Malignancies

Our pooled analysis of patients with low‐grade malignancies demonstrates conclusively that LTT is oncologically comparable to TP, with comparable recurrence rates (7.9% vs. 10.5%, p > 0.05) and excellent long‐term survival (5‐year OS 88%–96%, DFS 77%–90%). These findings are consistent with and expand upon previous single‐institution reports suggesting the safety of conservative approaches for low‐grade tumors [25, 26]. The oncologic sufficiency of LTT can be explained by several factors: First, low‐grade parotid malignancies typically exhibit indolent biological behavior with slow growth, well‐defined borders, and low metastatic potential [27]. Second, the rate of intraparotid lymph node metastasis in low‐grade tumors is remarkably low (0%–4% for acinic cell carcinoma, 10%–14% for low‐grade mucoepidermoid carcinoma), falling well below the 20% threshold traditionally used to justify elective nodal treatment [28, 29]. Third, anatomic studies have shown that intraparotid lymph nodes are not uniformly distributed but are primarily concentrated in specific regions, and that the deep lobe may contain as few as zero lymph nodes in many individuals, thereby questioning the theoretical oncologic advantage of TP [30].

Importantly, our analysis confirms that negative surgical margin status (R0 resection)—not the volume of parotid tissue resected—is the main determinant of local control in low‐grade tumors. This finding is consistent with recent large series demonstrating that close margins (< 5 mm) without positive margins do not significantly increase recurrence risk when combined with adjuvant radiotherapy in selected cases [31, 32]. In a study by Cho et al., the largest component of our low‐grade cohort (n = 179) demonstrated that close margins did not constitute an independent risk factor for recurrence in multivariate analysis, provided R0 resection was achieved [19]. This evidence supports a surgical philosophy that prioritizes adequate margin clearance while maximizing functional tissue preservation, rather than pursuing extensive resection for its own sake.

4.2. Functional Superiority and Quality of Life Benefits

The functional advantages of LTT are substantial and clinically significant. Several previous reports demonstrated dramatically reduced rates of transient facial nerve palsy (4.5% vs. 18.2%), permanent facial nerve dysfunction (0% vs. 3.6%), significantly shorter operative time (143 vs. 226 min, p < 0.01), and lower overall complication rates, including Frey's syndrome. These differences translate directly to improved quality of life [9, 33]. Recent patient‐reported outcome studies have demonstrated that even temporary facial nerve dysfunction has a profound negative impact on psychosocial well‐being, professional functioning, and overall quality of life, with effects persisting for months or even years after surgery [34, 35]. Long‐term quality‐of‐life assessments following parotidectomy have consistently shown that patients who undergo more conservative resections report higher satisfaction scores, better aesthetic outcomes, and superior preservation of both salivary and facial nerve function [36, 37]. Although some included studies suggested better functional preservation with less extensive surgery, functional outcomes were not pooled in the present meta‐analysis and should therefore be interpreted as supportive but not directly demonstrated findings.

Based on this evidence synthesis, we propose a grade‐stratified treatment algorithm for parotid cancer: For low‐grade tumors in the superficial lobe without clinical nodal involvement, LTT must be meticulously performed to achieve R0 margins, balancing oncologic safety with functional preservation. Adjuvant therapy may be considered for patients with adverse pathologic features (close/positive margins, PNI, LVI, or unexpected nodal metastasis). For high‐grade tumors, the surgical extent should be individualized based on location and resectability, prioritizing facial nerve preservation when uninvolved, as a more radical surgery does not improve survival.

4.3. Strengths and Limitations

This meta‐analysis has several strengths: it represents the first‐grade stratified analysis of surgical extent in early parotid cancer, includes contemporary data from 540 patients across multiple institutions. However, important limitations must be acknowledged. All included studies were retrospective cohort designs, inherently subject to selection bias and confounding factors. Adjuvant therapy protocols varied considerably across studies and time periods, potentially confounding the outcomes. Finally, long‐term follow‐up beyond 5 years was limited, and late recurrences of certain histologies (particularly adenoid cystic carcinoma) may be underrepresented.

5. Conclusion

LTT is an oncologically safe and functionally superior alternative to TP for low‐grade salivary gland tumors. Therefore, surgical management should aim for clear margins with maximal functional preservation, especially in patients with low‐grade salivary gland cancer.

The findings of this meta‐analysis highlight several critical research priorities. Prospective, multi‐institutional studies comparing conservative with extensive surgery, specifically within grade‐stratified cohorts, are urgently needed. The integration of molecular markers beyond traditional histologic grading may allow more refined risk stratification and treatment individualization [38, 39]. Future surgical studies should systematically incorporate quality‐of‐life and patient‐reported outcome measures to fully capture the patient experience and inform shared decision‐making [40].

Funding

This work was supported by Research fund of National Cancer Center (NCC‐2112570).

Disclosure

The authors did not use generative artificial intelligence (AI) or AI‐assisted technologies in the preparation of this manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Appendix S1: Complete search strategies used for the systematic review.

Appendix S2: PRISMA 2020 checklist.

Choi N., Lee H. R., Seok J., et al., “Total Parotidectomy Versus Less‐Than‐Total Parotidectomy for Early‐Stage Low Grade Parotid Cancer: A Systematic Review and Meta‐Analysis,” Laryngoscope Investigative Otolaryngology 11, no. 4 (2026): e70530, 10.1002/lio2.70530.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.