Close surgical margin after conservative parotidectomy in early stage low-/intermediate-grade parotid carcinoma: Outcome of watch and wait policy

A Retrospective 8-Year Single Institutional Study in Germany Regarding Diagnosis, Treatment, and Outcome of Malignant Parotid Tumors

This study sought to comprehensively evaluate the diagnosis, therapeutic interventions, and outcomes of individuals afflicted with malignant parotid tumors at a tertiary care otolaryngology department in Heilbronn, Germany, spanning the years 2010-2018. The primary objective was to juxtapose this dataset with findings from analogous single and multicenter investigations. We conducted a meticulous analysis of electronic medical records pertaining to 45 patients subjected to primary parotid cancer treatment. The male-to-female ratio was 3:2, with an average age of 61 years. Predominant histological types included mucoepidermoid and squamous cell carcinomas, with ultrasound emerging as the predominant diagnostic modality (97.8% sensitivity). Intraoperative frozen sections exhibited a high level of sensitivity. Notably, lymph node metastasis was prevalent in T3 tumors, frequently located intraparotid and at Neck level II. Solely one patient exhibited distant metastases (pulmonary). All patients underwent parotidectomy, and 29% necessitated a secondary procedure due to positive resection margins. Postoperative complications encompassed facial nerve palsy, seromas, and salivary fistulas. Adjuvant radiotherapy (38%) was recommended for high-grade tumors, T3/T4 stage, N+, perineural invasion (PNI), and positive or uncertain surgical margins. Neck dissection was executed in 67% of instances, with 20% revealing occult lymph node metastases. Recurrence manifested in 22% of patients, primarily as locoregional recurrence (80%) and distant metastases (20%). The 3-year recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) rates stood at 72.1%, 91.9%, and 87.5%, respectively. Noteworthy factors influencing RFS included preoperative facial palsy, T stage, resection margins, and PNI. In summary, the management of parotid cancer involving surgical interventions, neck dissection, and radiotherapy in high-risk patients yielded commendable outcomes with minimal complications, showcasing survival rates exceeding 70%. Timely diagnosis at an early stage is imperative for achieving tumor-free margins and enhancing survival rates. More assertive therapeutic strategies are advocated for cases presenting with preoperative facial nerve palsy and PNI.

Adjuvant Radiation Therapy for Salivary Duct and Epithelial Myoepithelial Salivary Carcinoma

Salivary gland cancers are rare in general and salivary duct carcinoma and epithelial myoepithelial carcinomas are rare subtypes. This topic discussion will review the characteristics of these uncommon cancers. Additionally, it will briefly discuss available guidelines for salivary cancers and summarize author opinions on the role of adjuvant radiation therapy for these cases.

Comparison of Partial Versus Superficial or Total Parotidectomy for Superficial T1-2 Primary Parotid Cancers

OBJECTIVES

This study aimed to compare the oncological outcomes of partial versus superficial or total parotidectomy for superficial T1 or T2 primary parotid cancers and investigate their prognostic factors and recurrence patterns.

METHODS

The medical records of 77 patients with T1-2 primary parotid malignancies between May 2003 and March 2022 were retrospectively reviewed. Univariate and multivariate analyses were performed to evaluate the prognostic factors associated with overall survival, disease-free survival, and local and distant recurrence.

RESULTS

The average follow-up duration was 70.2 months (range, 12-202 months). The 5-year overall and disease-free survival rates were 88.7% and 77.1%, respectively. Twenty-two patients underwent partial parotidectomy, and 55 underwent superficial or total parotidectomy. There were no significant differences in the disease recurrence (P=0.320) and mortality rates (P=0.884) of the partial and superficial or total parotidectomy groups. The mean duration of surgery was shorter and the overall complication rates were significantly lower in the partial group than in the superficial or total parotidectomy group (P=0.049). Sixteen cases of recurrence occurred during the study period (20.8%). Univariate analyses showed that high-grade tumors (P=0.006), lymphovascular invasion (P=0.046), and regional lymph node metastasis (P=0.010) were significant risk factors for disease recurrence. Multivariate analysis identified regional lymph node metastasis as an independent prognostic factor for disease recurrence (P=0.027), and lymphovascular invasion as an independent prognostic factor for overall survival (P=0.033).

CONCLUSION

The conservative surgical approach of partial parotidectomy can yield oncological outcomes comparable to those of superficial or total parotidectomy with careful patient selection in T1-2 parotid cancers.

Milan system for reporting salivary gland cytology in diagnosis and surgery of parotid gland lesions

INTRODUCTION

A cytology report is always a challenge for both head and neck surgeons and cytopathologists to diagnose and manage parotid gland (PG) diseases, because of the various similar features between the lesions.

OBJECTIVES

The present study was conducted to assess our practice using the Milan System for Reporting Salivary Cytopathology (MSRSGC) and to evaluate the risk of malignancy (ROM) in different categories.

PATIENTS AND METHODS

The patients with parotid gland lesions were diagnosed by clinical examination, ultrasound, and FNAC under ultrasound guidance at our hospital from 1 May 2019 to 30 April 2021. The FNAC results were divided into six categories according to the Milan system. We calculated the ROM for each category of the Milan system based on histopathological follow-up.

RESULTS

This study included 204 patients. There were 115 men (56 %) aged 46-60 years. Pathology results were 33 cases for malignant and 182 cases for benign. The rate of malignancy for each category according to the MSRSGC were 23.1 % (non-neoplastic), 20 % (atypical), 50 % (neoplastic), 1 % (benign), 10.3 % (salivary neoplasm of uncertain neoplastic potential), 84.6 % (suspicious for malignancy), and 100 % (malignant) categories. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNAC with application of Milan system were respectively 90.9 %, 98.2 %, 90.9 %, 98.9 % and 97 %.

CONCLUSION

When the Milan system was applied, FNAC had a high efficacy, suggesting that MSRSGC can improve the communication between the cytopathologist and the surgeon. This system can allow the surgeon to decide the extent of the surgery.

Survival in Patients with Primary Parotid Gland Carcinoma after Surgery—Results of a Single-Centre Study

This study aims to analyse a single-centre cohort series of patients who underwent parotidectomy for primary malignant parotid tumours. A retrospective chart review of 64 consecutive patients treated from November 2010 to March 2022 was performed. Outcomes were analysed by Kaplan-Meier curves. Sixty-four patients with a primary parotid malignancy were included in the study, with one bilateral case in this cohort. Patients were classified as stage I–II in 39 cases and stage III–IV in 26 cases. The five-year overall survival (OS), disease-specific survival (DSS), local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 78.4%, 89%, 92.5%, and 87.1%, respectively. Univariate analysis showed that high-risk histology, stage IV disease, lymphovascular invasion, perineural invasion, node metastasis, skin involvement, facial nerve involvement, and positive or close margins were risk factors associated with poorer outcomes. At present, the best evidence suggests that radical surgery should be the standard approach, and adjuvant therapy, in terms of radiotherapy/chemoradiotherapy, is recommended in patients with risk factors.

Adjuvant radiotherapy in node-negative salivary malignancies of the parotid gland: A multi-institutional analysis

BACKGROUND AND PURPOSE

To determine the role of adjuvant radiotherapy (ART) in parotid gland cancer without nodal metastasis, we evaluated the survival outcomes, prognostic factors, and dose-response relationships in patients with node-negative parotid gland cancer patients.

MATERIALS AND METHODS

Patients who underwent curative parotidectomy and were pathologically diagnosed with parotid gland cancer without regional or distant metastases between 2004 and 2019 were reviewed. The benefit of ART in terms of locoregional control (LRC) and progression-free survival (PFS) were evaluated.

RESULTS

In total, 261 patients were included in the analysis. Of them, 45.2 % received ART. The median follow-up period was 66.8 months. Multivariate analysis revealed that histological grade and ART were independent prognostic factors for LRC and PFS (all p <.05). For patients with high-grade histology, ART was associated with a significant improvement in 5-year LRC (p =.005) and PFS (p =.009). Among patients with high-grade histology who completed RT, higher biologic effective dose (≥77 Gy10) significantly increased PFS (adjusted hazard ratio [HR], 0.10 per 1-Gy increase; 95 % confidence interval [CI], 0.02-0.58; p =.010). ART significantly improved LRC (p =.039) in patients with low-to-intermediate histological grade as well per multivariate analysis, and subgroup analyses revealed patients with T3-4 stage and close/positive resection margins (<1 mm) would benefit from ART.

CONCLUSION

ART should be strongly recommended for patients with node-negative parotid gland cancer with high-grade histology in terms of disease control and survival. In patients with low-to-intermediate-grade disease, those with high T stage and incomplete resection margin benefit with ART.

The impact of interval between surgery and postoperative radiotherapy in major salivary gland carcinoma

Background

Radiotherapy following primary operation is strongly recommended for salivary gland carcinomas (SGCs) with adverse features. The interval between surgery and the initiation of radiotherapy (SRT) varied and a prolonged SRT may cause failure of cancer treatment. However, the association of SRT with survival is unclear in major SGCs.

Methods

This retrospective study included a total of 346 patients who underwent radiotherapy after the primary operation from Fudan University Shanghai Cancer Center from 2005 to 2020. The best cutoff value of the SRT was determined by the maximum log-rank statistic method. The primary endpoint of the study was overall survival (OS). Correlations between variables and OS were conducted by the univariable analysis using the Log-rank method, and a multivariate Cox proportional hazards regression was performed to identify the independent prognostic factors associated with OS. The estimated survival rates were captured using the Kaplan-Meier method.

Results

With a median follow-up time of 70.31 months, the estimated 5-year OS, LRFS, and DMFS were 83.3%, 80.1%, and 75.9%, respectively. The cutoff value for SRT was 8.5 weeks, while age, T stage, N stage, perineural invasion (PNI), pathological aggression, chemotherapy, and SRT were associated with OS in the univariable analysis. The Cox regression analysis demonstrated that older age (P < 0.001), T3-4 tumors (P = 0.007), positive N stage (P < 0.001), pathological aggression (P = 0.014), and longer SRT (P = 0.009) were independent prognostic factors for major SGCs. Using the stratification model, we observed that delay in the SRT was associated with worse OS (P = 0.006) in the high-risk group, whereas no significant difference was observed in the low-risk subgroup (P = 0.61).

Conclusions

The delay in the initiation of postoperative radiotherapy may be a prognostic factor for patients with major SGCs. It was suggested that radiotherapy should be delivered within 8.5 weeks following the operation, especially for patients with ≥2 risk factors, including older age, high pathological aggression, T3-4 tumors, and positive N stage.

[Surgery for parotid gland cancer-controversial and proven aspects]

BACKGROUND

Due to the rarity of primary parotid malignancies, there are currently only limited clinical study data on the optimal surgical therapy. Parotid malignancies encompass a broad spectrum of more than 20 different histological subtypes with varying biology, which thus represents a challenge for even experienced pathologists and head and neck surgeons with proven expertise in salivary gland surgery.

OBJECTIVE

The aim of this review article is to provide an overview of the current literature on surgical therapy of the primary tumor and the cN0 neck as well as treatment of the facial nerve, and to shed light on the various controversial aspects of this topic.

RESULTS

In salivary gland oncology there is a trend towards safe (R0) but more conservative surgery. Currently, less-invasive surgical approaches could potentially be applied in a small subgroup with carefully selected caudally located and R0-resected "low-grade tumors" in stages T1-T2 and cN0 in relatively young patients with high compliance and more in the context of structured clinical studies. Elective neck dissection in the case of cN0 status should be carried out if risk factors for occult cervical lymph node metastasis (T3-T4a, "high-grade subtypes," advanced age, lymphangitic carcinomatosis) are present. In cases of small "low-grade parotid carcinomas," narrow resection margins or even microscopic tumor residues on the facial nerve can potentially be adequately compensated with adjuvant radiation therapy. However, due to the lack of solid data, the significance of the actual effect of the radiation in this situation should be viewed with great caution.

Evaluation of Surgical Margin Status in Patients With Salivary Gland Cancer

Importance

Salivary gland cancer comprises a diverse group of histologic types with different biological behavior. Owing to this heterogeneity, the association of margin status and postoperative adjuvant radiotherapy has been poorly studied.

Objective

To examine the association between surgical margin status and oncologic outcomes and the subsequent outcome of adjuvant radiotherapy in patients with salivary gland carcinomas.

Design, Setting, and Participants

This cohort study analyzed data from institutional records at Memorial Sloan Kettering Cancer Center from 1985 to 2015. Statistical analysis was completed on October 31, 2020. After exclusions, 837 patients with surgically treated salivary gland carcinoma were identified. Surgical margins and histologic characteristics identified from pathology reports were recorded, with margins classified as negative, close, and positive, and individual histologic types classified into 3 risk groups: low, intermediate, and high.

Exposures

The outcome of adjuvant radiotherapy was determined in patients with close margins with low- and intermediate-risk histologic type and overall pathologic stage I/II disease.

Main Outcomes and Measures

Disease-specific survival (DSS) and local recurrence-free survival (LRFS) outcomes were calculated using the Kaplan-Meier method. Multivariable analysis was performed using the Cox proportional hazards regression model. A planned subgroup analysis of patients with close margins was conducted.

Results

Among the 837 patients identified, 438 were women (52.3%); median age at surgery was 58 years (range, 6-98). A total of 399 tumors (47.7%) originated from major salivary glands, and 438 (52.3%) from minor salivary glands. Margin positivity rates were not different between minor and major salivary gland tumors. Positive surgical margins were identified in 252 patients (30.1%), with nasal cavity/paranasal sinuses and trachea/larynx subsites as the most common sites. Close margins were recorded in 203 patients (24.3%). Adjuvant radiotherapy was administered in 80.5% (103 of 128) of patients with major salivary gland cancer with positive margins, 58.8% (60 of 102) with close margins, and 30.7% (52 of 169) with negative margins and in 70.2% (87 of 124), 36.6% (37 of 101) , and 19.7% (42 of 213) patients with minor salivary gland cancer. With median follow up time of 57 months (range, 1-363 months), patients with positive margins had poorer DSS and LRFS. However, after controlling for overall stage, histologic risk group, and adjuvant radiotherapy, margin status was not a factor associated with poorer DSS or LRFS. In patients with close margins, low-risk and intermediate-risk histologic type, and overall pathologic stage I/II, patients who did not have adjuvant radiotherapy had comparable local control with those who received adjuvant radiotherapy.

Conclusions and Relevance

The findings of this cohort study suggest that patients with salivary gland cancer who have either close or positive surgical margins are at increased risk for poorer local control and survival. After controlling for tumor stage, histologic risk group, and the use of adjuvant radiotherapy, margin status was not an independent factor associated with poorer outcome. Subgroup analyses showed that care for patients with close margins with low-risk or intermediate-risk histologic type who have stage I/II cancers might be managed safely without adjuvant radiotherapy.

Management of Salivary Gland Malignancy: ASCO Guideline

PURPOSE

To provide evidence-based recommendations for practicing physicians and other healthcare providers on the management of salivary gland malignancy.

METHODS

ASCO convened an Expert Panel of medical oncology, surgical oncology, radiation oncology, neuroradiology, pathology, and patient advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2000 through 2020. Outcomes of interest included survival, diagnostic accuracy, disease recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 293 relevant studies to inform the evidence base for this guideline. Six main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate radiotherapy techniques, the role of systemic therapy, and follow-up evaluations.

RECOMMENDATIONS

When possible, evidence-based recommendations were developed to address the diagnosis and appropriate preoperative evaluations for patients with a salivary gland malignancy, therapeutic procedures, and appropriate treatment options in various salivary gland histologies.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Oncological outcomes of preoperatively unexpected malignant tumors of the parotid gland

PURPOSE

Unexpected parotid cancers are often encountered due to inaccuracies in the preoperative evaluation. This study aimed to examine the clinical characteristics and oncological outcomes of these cancers and to propose the appropriate management strategy.

METHODS

This is a multicenter case series study in which a total of 302 patients were diagnosed postoperatively with parotid cancers between 2003 and 2017. Of these, 85 cases without evidence of malignancy prior to surgery but identified as malignant on postoperative pathology were included.

RESULTS

Of 85 patients, 76 and 9 underwent superficial and total parotidectomy, respectively. A positive resection margin was present in 24.7% of the cases. Postoperative radiotherapy was administered to 43.6% of patients; 4.2% had a local recurrence, and no patients died of the disease. The 5-year overall and relapse-free survival rates were 100.0% and 95.2%, respectively. Patients who underwent piecemeal resection had significantly poorer oncologic outcomes. Age, sex, histologic grade, T stage, extracapsular extension, resection margin status, and postoperative radiotherapy did not affect recurrence and survival.

CONCLUSION

Preoperatively unexpected parotid cancers had excellent local control and overall survival despite positive or close resection margin, with or without postoperative radiotherapy. Therefore, patients with unexpected parotid malignancies may benefit from less aggressive postoperative management option.

Is There A Role for Limited Parotid Resections for Primary Malignant Parotid Tumors?

(1) Background: Lateral or total parotidectomy are the standard surgical treatments for malignant parotid tumors. However, some authors have proposed a more limited procedure. (2) Methods: We performed a review of the literature on this topic. Studies were included that met the following criteria: malignant parotid tumors, information about the extent of surgical resection, treated with less than a complete lateral lobectomy, and information on local control and/or survival. Nine articles fulfilled the inclusion criteria. (3) Results: Eight of the nine series reported favorable results for the more limited approaches. Most used them for small, mobile, low-grade cancers in the lateral parotid lobe. Most authors have used a limited partial lateral lobectomy for a presumed benign lesion. The remaining study analyzed pediatric patients treated with enucleation with poor local control. (4) Conclusions: There is weak evidence for recommending less extensive procedures than a lateral parotid lobectomy. In the unique case of a partial lateral parotidectomy performed for a tumor initially thought to be benign but pathologically proved to be malignant, close follow-up can be recommended for low grade T1 that has been excised with free margins and does not have adverse prognostic factors.

Comprehensive Analysis of Clinicopathologic Factors Predictive of an Unfavorable Prognosis in Patients With Acinic Cell Carcinoma of the Parotid Gland

Objectives.

In subset of patients, acinic cell carcinoma (AcCC) exhibits aggressive features such as recurrence, distant metastasis, and mortality. This study aimed to investigate clinicopathologic factors influencing patients’ prognosis and to identify adverse features predictive of an unfavorable prognosis.

Methods.

Between January 2000 and December 2016, 59 patients with AcCC were enrolled in this study.

Results.

The patients’ 5-year overall survival rate was 93.3%, and their 5-year recurrence-free survival rate was 80.5%. During the study period, recurrence occurred in 10 patients. The mean time to recurrence after surgery was 26 months (range, 5–60 months). During the study period, three patients died from the disease. Univariate analysis showed that sex, surgical extent, extranodal extension, T classification, and TNM stage were significantly associated with disease recurrence. Multivariate analysis showed that, among the clinicopathologic factors included in the analysis, only TNM stage displayed a statistically significant correlation with disease recurrence.

Conclusion.

Surgical treatment alone yielded good results for AcCC, and additional treatment did not affect the recurrence-free survival rate or the overall survival rate, even when the resection margin was less than 1 mm. Other pathologic factors did not show prognostic significance for disease recurrence or death.

Challenges with preoperative diagnosis of low/intermediate-grade carcinoma of the parotid gland: single-center study of 112 patients

BACKGROUND

The malignancy of parotid carcinoma varies, and accurate preoperative assessment of malignancy is important for selecting the appropriate treatment. However, the preoperative diagnosis of low/intermediate-grade carcinoma is difficult, and surgery may sometimes be performed without any prior knowledge of malignancy.

METHODS

The results of fine-needle aspiration cytology (FNA), imaging studies (MRI and US), physical examination, and frozen section biopsy (FSB) were evaluated in 112 patients with low/intermediate-grade parotid carcinoma.

RESULTS

The result of FNA was benign/inadequate specimen in 44.6% of the patients. In addition, the tumor was diagnosed as benign by MRI/US in 21.4% of the patients and 37.5% had no symptoms/signs of malignancy on physical examination. The rate of misdiagnosis as benign decreased when FNA was combined with imaging and physical findings. However, malignancy could not be diagnosed by FNA and FSB in 12.5% of the patients who were only found to have malignant tumors by the final pathological examination.

CONCLUSION

FNA shows a high misdiagnosis rate of malignancy in patients with low/intermediate-grade cancer. Therefore, it is necessary to carefully evaluate the findings of imaging studies and physical examination, and FSB should be conducted if such findings suggest the possibility of malignancy.

Intermediate-grade carcinoma of the parotid and the impact of adjuvant radiation

PURPOSE

To determine the influence of adjuvant radiotherapy on survival in surgically-managed early stage intermediate-grade mucoepidermoid and acinic cell carcinoma of the parotid.

MATERIALS AND METHODS

The National Cancer Database was reviewed between 2004 and 2015 to identify patients with intermediate-grade, early T-stage, node-negative parotid carcinoma who underwent parotidectomy ± radiotherapy.

RESULTS

There were 744 patients identified of which 81% had mucoepidermoid carcinoma and 19% had acinic cell carcinoma. Positive surgical margins were identified in 21% and adjuvant radiotherapy was administered in 38% of cases. Of the 159 patients with positive margins, 113 (71%) received adjuvant radiotherapy. Of the 585 patients with negative margins, 173 (30%) underwent adjuvant radiotherapy. In multivariable analysis, age (over 52 years: HR 5.19, 95%CI 2.33-11.57), insurance status (private insurance: HR 0.24 95%CI 0.13-0.43), and extent of parotidectomy (total parotidectomy: HR 2.02 95%CI 1.23-3.31) were significantly associated with overall survival, while adjuvant radiotherapy was not a significant predictive factor (HR 0.81, 95%CI 0.49-1.36). In patients with positive margin resections, however, adjuvant radiation was an independent predictor of improved survival when adjusted for age, insurance status, and extent of parotidectomy (HR 0.34, 95%CI 0.13-0.88). Conversely, in patients with negative margin resections, adjuvant radiation did not influence survival outcomes when adjusted for these covariates (HR 1.02, 95%CI 0.53-1.93).

CONCLUSIONS AND RELEVANCE

In patients with early stage intermediate-grade parotid carcinoma, adjuvant radiotherapy significantly and independently improves survival in those with post-operative positive margins. Adjuvant therapy, however, does not appear to improve survival outcomes in those with negative margin resections.

Close Margins and Adjuvant Radiotherapy in Acinic Cell Carcinoma of the Parotid Gland

Importance

The precise indications and oncologic effects of adjuvant radiotherapy in acinic cell carcinoma of the parotid gland are not well known, particularly in patients with negative, but close (≤1 mm), margins without other high-risk histopathologic factors.

Objective

To evaluate the oncologic outcomes of patients with acinic cell carcinoma of the parotid gland and the results of adjuvant therapy for those with close (≤1-mm) margins.

Design, Setting, and Participants

In a retrospective case series with medical record review at a single academic tertiary referral center, patients treated surgically from January 2000 to December 2014 for acinic cell carcinoma of the parotid gland were identified from an institutional database. All data analysis was performed in September 2017.

Exposures

All patients underwent parotidectomy with or without adjuvant radiotherapy or chemoradiotherapy.

Main Outcomes and Measures

The primary end point was locoregional control. Secondary end points included recurrence patterns and survival.

Results

Forty-five patients were identified in this case series (23 [51%] female), with a mean (SD) age of 47.1 (19.5) years. The median follow-up in surviving patients was 56.7 months (range, 18.5-204 months). Four patients (9%) experienced recurrence (1 local and 3 distant) at a median of 67.3 months (range, 12.7-136 months) after surgery. Thirteen patients (29%) had at least one high-risk histopathologic factor (advanced T category, nodal disease, lymphovascular or perineural invasion, high-grade, or positive margins). The remaining 32 patients (71%) without these high-risk factors had significantly improved disease-free survival (hazard ratio, 0.08; 95% CI, 0.01-0.71). Of patients without high-risk factors, those with close (≤1-mm) margins were significantly more likely to receive adjuvant radiotherapy (10 [56%] vs 1 [7%]; difference, 49%; 95% CI, 16%-82%), although this was not associated with disease control. At a median follow-up of 64.3 months (range, 33-204 months) in the 18 patients with close (≤1-mm) margins without other high-risk factors (10 with adjuvant radiotherapy and 8 without adjuvant therapy), only 1 patient (who had received adjuvant radiotherapy) experienced a recurrence, at 136 months after surgery.

Conclusions and Relevance

Patients with acinic cell carcinoma of the parotid gland whose only histopathologic risk factor is a close (≤1 mm) but negative margin do not appear to benefit from adjuvant radiotherapy. Recurrent disease is rare but may occur many years after initial treatment, and patients with acinic cell carcinoma could benefit from lifelong clinical surveillance.

Mucoepidermoid Carcinoma of the Parotid: Very Close Margins and Adjuvant Radiotherapy

BACKGROUND/AIMS

The importance of adjuvant radiotherapy in patients with close margin resections for mucoepidermoid carcinoma of the parotid gland remains unclear.

METHODS

Patients who underwent parotidectomy for mucoepidermoid carcinoma with or without adjuvant radiotherapy at a single academic tertiary care center from 2000 to 2014 were identified. Included patients had negative but close (≤2 mm) surgical margins without other high-risk histopathological factors including advanced T-stage, positive nodal disease, lymphovascular or perineural invasion, or high-grade histology.

RESULTS

Nineteen patients were identified, of whom 15 (79%) were observed postoperatively, while 4 (21%) underwent adjuvant radiotherapy. There were no significant differences in extent of parotidectomy, elective neck dissection, T staging, or tumor size between patients who were observed and those undergoing adjuvant radiation. There were no locoregional or distant recurrences in any patients at a mean follow up 74.3 months. Patients undergoing adjuvant radiation, however, had significantly more intermediate-grade as compared to low-grade histology (75% vs. 13%, difference 62%, 95% CI 4% to 100%).

CONCLUSIONS

Patients with negative but close (≤2 mm) surgical margins without other high-risk histopathological factors have excellent long-term locoregional control with surgery alone. The effects of adjuvant radiotherapy for those who have intermediate-grade disease remain uncertain.