Stage/Grade Citation 19

Salivary Gland Neoplasms

Author: Michael M. Johns, MD
Editor(s): David J Terris, MD, Fellowship Codirector, Associate Professor, Department of Surgery, Division of Otolaryngology, Stanford University Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, Pharmacy, eMedicine; Erik Kass, MD, Chief, Department of Clinical Otolaryngology, NIH National Institute On Deafness and Other Communication Disorders; Christopher L Slack, MD, Consulting Staff, Otolaryngology-Facial Plastic Surgery, Lawnwood Regional Medical Center; and Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine
From:Emedicine.com (where images are viewable) at:
http://www.emedicine.com/ent/topic679.htm
Last Updated: July 25, 2003

(Excerpts)

Stage
Staging of malignant salivary gland tumors is important for predicting prognosis and for accurate comparison of treatment results. The American Joint Committee for Cancer Staging and End Result Reporting (AJCC) has published a TNM-based staging system for major salivary gland malignancies. The most recent edition, published in 1997, is summarized in Image 4.

This staging system has been developed on the basis of retrospective studies performed by Spiro, who correlated various tumor factors with the prognosis. The system includes tumor size, local extension of tumor, cervical lymph node metastases, and distant metastases. This method of staging has been shown to be correlated with survival. The 10-year determinant survival rate is 83% for stage I tumors, 76% for stage II tumors, and 32% for stage III tumors.

Histology
It is not surprising that the histologic diagnosis is correlated with biologic behavior. For this reason, dividing tumors into low-grade and high-grade categories is useful. Low-grade tumors include acinic cell carcinoma (ACCIC note: NOT always) and low-grade mucoepidermoid carcinoma. High-grade tumors include adenoid cystic carcinoma, high-grade mucoepidermoid carcinoma, carcinoma ex-pleomorphic adenoma, squamous cell carcinoma, and adenocarcinoma. Low-grade tumors have 10-year survival rates of 80-95%, while 10-year survival rates for high-grade tumors range from 25-50%.

Histopathologic diagnosis is often unavailable at the time of initial surgery, and grading usually cannot be performed with frozen-section analysis. Thus, histologic information is typically not available before surgery. However, histopathologic diagnosis and grade should be considered because they may affect the decision regarding further surgery, elective neck dissection, or adjuvant radiation therapy (see Image 5).

Lymph node metastases
The ocurrence of regional lymph node metastases is related to tumor histopathology and size. The highest rates of lymph node metastases occur with high-grade mucoepidermoid carcinoma (44% of cases), squamous cell carcinoma (36% of cases), adenocarcinoma (26% of cases), undifferentiated carcinoma (23% of cases), and carcinoma ex-pleomorphic adenoma (21% of cases). High-grade mucoepidermoid carcinoma and squamous cell carcinoma have high rates of occult lymph node metastases (16% and 40%, respectively).

Modified radical neck dissection is indicated in any patient with clinically positive neck nodes. First-echelon lymph nodes, which are exposed during parotidectomy, should be sampled if they appear suspicious, with further treatment based on pathology. Elective neck dissection generally is not required because of the low rate of regional failure with salivary gland malignancy. Limited neck dissection for the N0 neck may be appropriate in patients with a high probability of occult cervical metastases (eg, those with high-grade mucoepidermoid carcinoma, squamous cell carcinoma, or tumors larger than 4 cm).

Treatment of malignant salivary gland neoplasms
Primary treatment of malignant tumors of the salivary glands is surgery. This is often combined with postoperative radiation therapy, depending on specific tumor characteristics and stage. Extent of surgery is based on the size of the tumor, local extension, and neck metastases. The facial nerve is spared unless it is directly involved. Radiation therapy is recommended for all but small low-grade tumors.

Parotid gland
On the basis of the histologic classification and clinical stage, a useful management schema has been developed and is shown in Image 5. Four groups are identified. (Tumor, nodes, and metastases [TNM] stages are described in the Stage section.)

Group 1 includes T1 and T2 low-grade tumors (eg, low-grade mucoepidermoid carcinoma, acinic cell carcinoma). For these tumors, perform parotidectomy (superficial or total) with an adequate margin of normal tissue with preservation of the facial nerve. Inspect first-echelon nodes at the time of surgery and send suspicious nodes to pathology for evaluation. For complete excision without tumor spillage and no evidence of cervical metastases, radiation therapy is not performed.

Group 2 includes T1 and T2 tumors with high-grade features (eg, high-grade mucoepidermoid carcinoma, adenoid cystic carcinoma, squamous cell carcinoma, adenocarcinoma, carcinoma ex-pleomorphic adenoma). For these tumors, perform total parotidectomy, including first-echelon lymph nodes. Perform further neck dissection (modified radical neck dissection or selective neck dissection) for upper nodes confirmed to be positive on frozen sections or for clinically palpable cervical disease. Preserve the facial nerve unless it is directly infiltrated by tumor. In this case, the nerve is resected until the frozen section shows clear margins, and it is immediately reconstructed with cable grafting. Administer postoperative radiation therapy to the parotid region and the neck.

Group 3 includes any T3 tumor, any N+, and any recurrent tumors not in group 4. Tumors in this group generally require radical parotidectomy with sacrifice of the facial nerve in order to obtain sufficient tumor-free margins. Perform frozen sectioning of the facial nerve stump with continued excision until the margin is free. Immediately reconstruct the facial nerve with a cable graft. Perform neck dissection for positive nodal disease and treat the parotid bed and neck with postoperative radiation therapy.

Group 4 includes T4 tumors. Direct excision based on tumor size and location. Perform radical parotidectomy with excision of the involved structures (eg, facial nerve, mandible, mastoid tip, skin) as required to obtain tumor-free margins. Complex reconstruction, including free tissue transfer, is usually required to maximize functional restoration. Perform neck dissection for N+ disease and administer postoperative radiation therapy.

Submandibular gland
Submandibular salivary gland malignancies may be treated by a similar approach (see Image 5). For small, low-grade tumors (group 1), submandibular triangle excision is adequate without resection of cranial nerves.

For group 2 tumors, a wider resection of the submandibular triangle is required for clear margins. Sacrifice nerves only if they are directly involved with tumor. Frozen-section sampling of the epineurium of cranial nerves near the tumor mass may be performed, with the results directing further excision. Perform neck dissection for clinically positive disease. Postoperative radiation therapy is given.

Group 3 tumors commonly require sacrifice of the lingual and hypoglossal nerves to obtain clear margins. Perform selective or modified radical neck dissection and administer postoperative radiation therapy.

Group 4 tumors require wide surgical extirpation to fit the tumor extent. This may include mandible, floor of mouth, tongue, skin, and cranial nerves with appropriate reconstruction. Neck dissection and postoperative radiation therapy are added for these tumors.

Note: Images can be viewed at Emedicine website: http://www.emedicine.com/ent/topic679.htm




	Salivary Gland Neoplasms Author: Michael M. Johns, MD Editor(s): David J Terris, MD, Fellowship Codirector, Associate Professor, Department of Surgery, Division of Otolaryngology, Stanford University Medical Center; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, Pharmacy, eMedicine; Erik Kass, MD, Chief, Department of Clinical Otolaryngology, NIH National Institute On Deafness and Other Communication Disorders; Christopher L Slack, MD, Consulting Staff, Otolaryngology-Facial Plastic Surgery, Lawnwood Regional Medical Center; and Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine From:Emedicine.com (where images are viewable) at: http://www.emedicine.com/ent/topic679.htm Last Updated: July 25, 2003 (Excerpts) Stage Staging of malignant salivary gland tumors is important for predicting prognosis and for accurate comparison of treatment results. The American Joint Committee for Cancer Staging and End Result Reporting (AJCC) has published a TNM-based staging system for major salivary gland malignancies. The most recent edition, published in 1997, is summarized in Image 4. This staging system has been developed on the basis of retrospective studies performed by Spiro, who correlated various tumor factors with the prognosis. The system includes tumor size, local extension of tumor, cervical lymph node metastases, and distant metastases. This method of staging has been shown to be correlated with survival. The 10-year determinant survival rate is 83% for stage I tumors, 76% for stage II tumors, and 32% for stage III tumors. Histology It is not surprising that the histologic diagnosis is correlated with biologic behavior. For this reason, dividing tumors into low-grade and high-grade categories is useful. Low-grade tumors include acinic cell carcinoma (ACCIC note: NOT always) and low-grade mucoepidermoid carcinoma. High-grade tumors include adenoid cystic carcinoma, high-grade mucoepidermoid carcinoma, carcinoma ex-pleomorphic adenoma, squamous cell carcinoma, and adenocarcinoma. Low-grade tumors have 10-year survival rates of 80-95%, while 10-year survival rates for high-grade tumors range from 25-50%. Histopathologic diagnosis is often unavailable at the time of initial surgery, and grading usually cannot be performed with frozen-section analysis. Thus, histologic information is typically not available before surgery. However, histopathologic diagnosis and grade should be considered because they may affect the decision regarding further surgery, elective neck dissection, or adjuvant radiation therapy (see Image 5). Lymph node metastases The ocurrence of regional lymph node metastases is related to tumor histopathology and size. The highest rates of lymph node metastases occur with high-grade mucoepidermoid carcinoma (44% of cases), squamous cell carcinoma (36% of cases), adenocarcinoma (26% of cases), undifferentiated carcinoma (23% of cases), and carcinoma ex-pleomorphic adenoma (21% of cases). High-grade mucoepidermoid carcinoma and squamous cell carcinoma have high rates of occult lymph node metastases (16% and 40%, respectively). Modified radical neck dissection is indicated in any patient with clinically positive neck nodes. First-echelon lymph nodes, which are exposed during parotidectomy, should be sampled if they appear suspicious, with further treatment based on pathology. Elective neck dissection generally is not required because of the low rate of regional failure with salivary gland malignancy. Limited neck dissection for the N0 neck may be appropriate in patients with a high probability of occult cervical metastases (eg, those with high-grade mucoepidermoid carcinoma, squamous cell carcinoma, or tumors larger than 4 cm). Treatment of malignant salivary gland neoplasms Primary treatment of malignant tumors of the salivary glands is surgery. This is often combined with postoperative radiation therapy, depending on specific tumor characteristics and stage. Extent of surgery is based on the size of the tumor, local extension, and neck metastases. The facial nerve is spared unless it is directly involved. Radiation therapy is recommended for all but small low-grade tumors. Parotid gland On the basis of the histologic classification and clinical stage, a useful management schema has been developed and is shown in Image 5. Four groups are identified. (Tumor, nodes, and metastases [TNM] stages are described in the Stage section.) Group 1 includes T1 and T2 low-grade tumors (eg, low-grade mucoepidermoid carcinoma, acinic cell carcinoma). For these tumors, perform parotidectomy (superficial or total) with an adequate margin of normal tissue with preservation of the facial nerve. Inspect first-echelon nodes at the time of surgery and send suspicious nodes to pathology for evaluation. For complete excision without tumor spillage and no evidence of cervical metastases, radiation therapy is not performed. Group 2 includes T1 and T2 tumors with high-grade features (eg, high-grade mucoepidermoid carcinoma, adenoid cystic carcinoma, squamous cell carcinoma, adenocarcinoma, carcinoma ex-pleomorphic adenoma). For these tumors, perform total parotidectomy, including first-echelon lymph nodes. Perform further neck dissection (modified radical neck dissection or selective neck dissection) for upper nodes confirmed to be positive on frozen sections or for clinically palpable cervical disease. Preserve the facial nerve unless it is directly infiltrated by tumor. In this case, the nerve is resected until the frozen section shows clear margins, and it is immediately reconstructed with cable grafting. Administer postoperative radiation therapy to the parotid region and the neck. Group 3 includes any T3 tumor, any N+, and any recurrent tumors not in group 4. Tumors in this group generally require radical parotidectomy with sacrifice of the facial nerve in order to obtain sufficient tumor-free margins. Perform frozen sectioning of the facial nerve stump with continued excision until the margin is free. Immediately reconstruct the facial nerve with a cable graft. Perform neck dissection for positive nodal disease and treat the parotid bed and neck with postoperative radiation therapy. Group 4 includes T4 tumors. Direct excision based on tumor size and location. Perform radical parotidectomy with excision of the involved structures (eg, facial nerve, mandible, mastoid tip, skin) as required to obtain tumor-free margins. Complex reconstruction, including free tissue transfer, is usually required to maximize functional restoration. Perform neck dissection for N+ disease and administer postoperative radiation therapy. Submandibular gland Submandibular salivary gland malignancies may be treated by a similar approach (see Image 5). For small, low-grade tumors (group 1), submandibular triangle excision is adequate without resection of cranial nerves. For group 2 tumors, a wider resection of the submandibular triangle is required for clear margins. Sacrifice nerves only if they are directly involved with tumor. Frozen-section sampling of the epineurium of cranial nerves near the tumor mass may be performed, with the results directing further excision. Perform neck dissection for clinically positive disease. Postoperative radiation therapy is given. Group 3 tumors commonly require sacrifice of the lingual and hypoglossal nerves to obtain clear margins. Perform selective or modified radical neck dissection and administer postoperative radiation therapy. Group 4 tumors require wide surgical extirpation to fit the tumor extent. This may include mandible, floor of mouth, tongue, skin, and cranial nerves with appropriate reconstruction. Neck dissection and postoperative radiation therapy are added for these tumors. Note: Images can be viewed at Emedicine website: http://www.emedicine.com/ent/topic679.htm VIEW ENTIRE CITATION BACK TO STAGES AND GRADES PAGE BACK TO MAIN PAGE