Predictors of Nodal Metastasis in Parotid Malignancies: A National Cancer Data Base Study of 22,653 Patients

OBJECTIVE

(1) To identify predictors of nodal disease in parotid malignancies using various clinical and pathologic variables. (2) To examine the effect of nodal disease on overall survival (OS) in parotid cancers

STUDY DESIGN

Retrospective database review.

SETTING

National Cancer Data Base (1998-2012).

SUBJECTS AND METHODS

We identified all cases of primary parotid malignancies in the United States between 1998 and 2012 in the National Cancer Data Base. Eight histopathologies, constituting >80% of all cases, were examined for nodal metastasis and survival.

RESULTS

We identified 22,653 cases of primary parotid cancer. Eight major histologies were studied, with mucoepidermoid carcinoma (31%), acinic cell carcinoma (18%), adenocarcinoma (14%), and adenoid cystic carcinoma (9%) being most common. Regional nodal disease incidence was 24.4% overall and varied by histopathology. Salivary ductal carcinoma had the highest incidence of both nodal metastasis and occult lymph node metastasis. Overall, N0 patients lived significantly longer than N+ (5-year OS, 79% vs 40%; P < .001). Low-grade disease had significantly better survival than high-grade (5-year OS, 88% vs 69%; P < .001). Occult nodal disease was found in 10.2% and varied by histopathology.

CONCLUSION

Regional lymph node metastasis significantly decreases survival in many parotid malignancies. High-grade cancers had higher incidences of regional disease than did low grade. Adenocarcinoma had the highest mortality when regional disease was present. Incidence of occult disease varied by histology, but incidence was <10% for all low-grade disease. High T stage and grade are significant independent predictors of nodal disease for most histopathologies.

Adenoid cystic carcinoma of the head and neck--An update

This article provides an update on the current understanding of adenoid cystic carcinoma of the head and neck, including a review of its epidemiology, clinical behavior, pathology, molecular biology, diagnostic workup, treatment and prognosis. Adenoid cystic carcinoma is an uncommon salivary gland tumor that may arise in a wide variety of anatomical sites in the head and neck, often with an advanced stage at diagnosis. The clinical course is characterized by very late recurrences; consequently, clinical follow-up should extend at least >15 years. The optimal treatment is generally considered to be surgery with postoperative radiotherapy to optimize local disease control. Much effort has been invested into understanding the tumor's molecular biological processes, aiming to identify patients at high risk of recurrence, in hopes that they could benefit from other, still unproven treatment modalities such as chemotherapy or biological therapy.

Unexpected Detection of Parotid Gland Malignancy during Primary Extracapsular Dissection

Objective

To evaluate the oncologic and functional outcome in cases in which a false preoperative working hypothesis “benign parotid tumor” led to a primary extracapsular dissection being performed rather than a traditional, more radical surgical modality.

Study Design

Case series with chart review.

Setting

Academic tertiary referral center.

Subjects and Methods

The records of all patients treated for malignant tumors of the parotid gland between 2006 and 2012 were retrospectively studied. Patients were excluded from our study sample for insufficient data or if their histories indicated manifestation of malignant tumors without primary parotid origin (squamous cell carcinomas, lymphomas, melanomas), revision surgery, as well as concomitant or past malignant tumors. Consequently, a total of 29 patients with 30 primary malignant tumors of the parotid gland formed our study sample (14 men, 15 women; male:female ratio, 0.93:1; mean age, 55.4 years; range, 14-85 years).

Results

Of 30 cases, 22 had low-grade tumors. Further tumor cells were detected in only the histology specimens of the parotid in 3 of the 25 cases treated subsequently with completion parotidectomy. Five patients received adjuvant radiation. Five-year disease-specific survival was 100%; local disease control was 96.6%. Of 30 cases, 28 had House-Brackmann I after tumor treatment; the other 2 cases had a slight paralysis (House-Brackmann II).

Conclusion

Beginning with the “false” working hypothesis and performing an extracapsular dissection in unsuspected cases seems to have no adverse impact on patients’ survival and postoperative quality of life in cases in which definitive histology reveals malignancy.

Histologic grade as prognostic indicator for mucoepidermoid carcinoma: a population-level analysis of 2400 patients

BACKGROUND

Mucoepidermoid carcinoma (MEC) is an uncommon malignancy. To the best of our knowledge, this is the largest study investigating disease-specific survival (DSS) of parotid MEC and the first population-level study of the distribution of nodal metastases.

METHODS

Patients with MEC of the parotid gland were identified in the Surveillance, Epidemiology, and End Results (SEER) database (1988-2009).

RESULTS

We identified 2400 patients with MEC: 522 low grade, 1137 intermediate grade, and 741 high grade. Five-year DSS rates for low-grade, intermediate-grade, and high-grade MEC were 98.8%, 97.4%, and 67.0%, respectively (p < .001). Negative prognostic factors included high grade, increasing patient age, and tumor size, extraparenchymal extension, nodal metastases, and distant metastases. High-grade MEC was more likely to have lymph node metastases in levels I to III (34.0%) than low-grade (3.3%) and intermediate-grade MEC (8.1%; p < .001).

CONCLUSION

Grade influences the prognosis and distribution of nodal metastases. Results indicate that management guidelines should vary based on grade.