Pablo Salivary gland tumors are relatively uncommon in this country. On average 100,000 people will be diagnosed with this disease each year in the United States. The prognosis for this type of cancer depends greatly on how early or late the disease is diagnosed. The stage and overall health of the individual being diagnosed also plays an important role. The five year survival rate for salivary cancer is 91% if the disease has not spread when the patient is diagnosed and 75% for those whose disease has affected the surrounding lymph nodes. If the tumor has metastasized to distant parts of the individual’s body, the survival rate is 39%.1
Etiology:
Becky
Þ Major and minor salivary glands are of an unknown origin.
Þ Dental x-rays may be implicated for both benign and malignant salivary gland tumors.
Þ It is thought that low-dose ionizing radiation can be considered for the cause of malignant salivary tumors.
Þ Exposure to hard wood dust has been thought to be linked to minor salivary gland adenocarcinomas.
Þ Gender doesn’t seem to play a big role in the incidence of malignant neoplasms.
Signs & Symptoms:
Adam Patients presenting with cancer of the salivary gland typically have had a painless, rapidly-growing mass for a number of years. A sudden change in its growth pattern is often what prompts the patient to seek medical attention.2 Additionally, up to 25% of patients also have facial nerve involvement, although only about 10% actually complain of it.2
Diagnostic Procedures:
Megan When diagnosing salivary gland cancer, a careful history physical exam are important, taking particular care to check for local fixation or regional adenopathy.2 Computed Tomography (CT) scans can be very useful in determining the extent of lesions, especially the deep lobe of the parotid gland.2 A magnetic resonance imaging (MRI) study can reveal excellent detail when imaging this region of the body.2 Also, if a cancer positive diagnosis is presumed, then an open biopsy is often performed so that excision of the gland can immediately follow.2
Histology:
Kevin Tsai
Most parotid masses are benign.2
Adenoid cystic carcinoma is the most common cancer in the submaxillary gland and in minor salivary glands
Most common malignant subtype of parotid tumor are
o Mucoepidermoid (children, 50% of all cases)
o Acinic cell carcinoma (usually occurs only in the parotid gland)
Lymph node drainage:
Erin Lymphatics drain from more laterally on the face, including parts of the eyelids, diagonally downward and posteriorly toward the parotid gland.3 The lymphatics from the frontal region of the scalp drain the same way. Parotid nodes are associated with the parotid glands, which drain down along the retromandibular vein to empty into the superficial lymphatics and nodes along the outer surface of the sternocleidomastoid muscle and into upper nodes of the deep cervical chain. Lymphatics from the parietal region of the scalp drain partly to the parotid nodes in front of the ear and partly to the retroauricular nodes in the back of the ear. These then drain into the upper deep cervical nodes
Metastatic spread:
Spencer Although the salivary glands are a smaller gland comprised of the parotid, submandibular, and sublingual glands, there still can be metastatic spread around local areas and lymph nodes.
33% of tumors that arise in the submandibular gland usually spread to the lower jaw area.2 This is probable due to the lymph drainage and local structures.
Many patients with malignant parotid cancer (up to 25%) can present with distant lymph node metastasis.2
There is also high incidence of lymph node involvement (44%) at presentation with submandibular malignancies.2
One of the biggest factors in metastatic spread with the salivary glands is the difference between high-grade tumors and intermediate to low-grade tumors. High-grade tumors have a much higher risk of lymph node metastasis at 49%, while intermediate to low grade tumors only carry about a 7% risk of spread.2
Grading:
Pablo Salivary gland tumor grade is based on the following:
Grade 1 well differentiated. Grow slowly and have good outcome.
Grade 2 moderately differentiated. Appearance and outlook between grade 1 and grade 3 tumors.
Grade 3 poorly differentiated. Look different from normal cells. Grow and spread quickly.4
Staging:
Becky
TNM system of the American Joint Committee on Cancer (AJCC). This system contains 3 key pieces of information:
T describes the size of the primary tumor and whether it has invaded into nearby organs or tissues.
N describes whether the cancer has spread to nearby (regional) lymph nodes (bean-sized collections of immune system cells located throughout the body).
M indicates whether the cancer has metastasized (spread) to other organs of the body (The most common site of distant salivary gland cancer spread is the lungs).
Numbers or letters appear after T, N, and M to provide more details about each of these factors:
The numbers 0 through 4 indicate increasing severity.
The letter X means "cannot be assessed" because the information is not available.
T groups for major salivary gland cancers
TX: The main (primary) tumor cannot be assessed; information not known.
T0: No evidence of a primary tumor.
T1: Tumor is 2 cm (about ¾ inch) across or smaller. It is not growing into nearby tissues.
T2: Tumor is larger than 2 cm but no larger than 4 cm (about 1½ inch) across. It is not growing into nearby tissues.
T3: Tumor is larger than 4 cm across and/or is growing into nearby soft tissues.
T4a: Tumor is any size and is growing into nearby structures such as the jaw bone, skin, ear canal, and/or facial nerve. This is known as moderately advanced disease.
T4b: Tumor is any size and is growing into nearby structures such as the base of the skull or other bones nearby, or it surrounds the carotid artery. This is known as very advanced disease.
N groups for major salivary gland cancers
NX: Nearby (regional) lymph nodes cannot be assessed; information not known.
N0: No spread to regional lymph nodes.
N1: The cancer has spread to 1 lymph node on the same side of the head or neck as the primary tumor. The lymph node is smaller than 3 cm (about 1¼ inch) across.
N2: This group includes 3 subgroups:
N2a: The cancer has spread to 1 lymph node on the same side as the primary tumor. The lymph node is larger than 3 cm but not larger than 6 cm (about 2½ inches) across.
N2b: The cancer has spread to more than 1 lymph node on the same side as the primary tumor; none of the lymph nodes are larger than 6 cm across.
N2c: The cancer has spread to 1 or more lymph nodes, none larger than 6 cm across, either on the side opposite the primary tumor or on both sides of the neck.
N3: The cancer has spread to a lymph node that is larger than 6 cm across.
M groups for major salivary gland cancers
M0: The cancer has not spread to tissues or organs far away from the salivary glands.
M1: The cancer has spread to tissues or organs far away from the salivary glands.5
Radiation side effects:
Adam The biggest issue for patients with cancers of the salivary glands is xerostomia. In some cases, this can be permanent, and patients will no longer be able to produce saliva.2 This is a major quality of life issue, and a very high priority is placed on avoiding this whenever possible.
Prognosis:
Megan Prognosis is impacted by several key markers:
Tumor grade2
Postsurgical residual disease2
Tumor size2
Facial nerve invasion2
Presence of positive cervical nodes2
Treatments:
Kevin Tsai
Surgical excision followed by radiation therapy is the standard.2
Postoperative irradiation is indicated for microscopic or macroscopic residual diseases, recurrent cancer, intermediate- and high-grade tumors, all adenoid cystic carcinomas, neural or perineural invasion, lymph node metastases, lymphatic or vascular invasion, and T3 to T4 malignancies.
Definitive radiation therapy is indicated for medically inoperable or unresectable cancer.
o Radiation therapy techniques
3-D CRT and IMRT
One technique uses unilateral anterior and posterior wedged-pair fields, using 4- to 6- MV photons
IMRT with 5-7 fields allow optimal coverage while sparing critical structures
Postsurgical patient with minimal residual disease, 55-60 Gy at 5 cm depth is given in daily fractions of 2 Gy.
Salivary gland tumors are relatively uncommon in this country. On average 100,000 people will be diagnosed with this disease each year in the United States. The prognosis for this type of cancer depends greatly on how early or late the disease is diagnosed. The stage and overall health of the individual being diagnosed also plays an important role.
The five year survival rate for salivary cancer is 91% if the disease has not spread when the patient is diagnosed and 75% for those whose disease has affected the surrounding lymph nodes. If the tumor has metastasized to distant parts of the individual’s body, the survival rate is 39%.1
Þ Major and minor salivary glands are of an unknown origin.
Þ Dental x-rays may be implicated for both benign and malignant salivary gland tumors.
Þ It is thought that low-dose ionizing radiation can be considered for the cause of malignant salivary tumors.
Þ Exposure to hard wood dust has been thought to be linked to minor salivary gland adenocarcinomas.
Þ Gender doesn’t seem to play a big role in the incidence of malignant neoplasms.
Patients presenting with cancer of the salivary gland typically have had a painless, rapidly-growing mass for a number of years. A sudden change in its growth pattern is often what prompts the patient to seek medical attention.2 Additionally, up to 25% of patients also have facial nerve involvement, although only about 10% actually complain of it.2
When diagnosing salivary gland cancer, a careful history physical exam are important, taking particular care to check for local fixation or regional adenopathy.2 Computed Tomography (CT) scans can be very useful in determining the extent of lesions, especially the deep lobe of the parotid gland.2 A magnetic resonance imaging (MRI) study can reveal excellent detail when imaging this region of the body.2 Also, if a cancer positive diagnosis is presumed, then an open biopsy is often performed so that excision of the gland can immediately follow.2
Lymphatics drain from more laterally on the face, including parts of the eyelids, diagonally downward and posteriorly toward the parotid gland.3 The lymphatics from the frontal region of the scalp drain the same way. Parotid nodes are associated with the parotid glands, which drain down along the retromandibular vein to empty into the superficial lymphatics and nodes along the outer surface of the sternocleidomastoid muscle and into upper nodes of the deep cervical chain. Lymphatics from the parietal region of the scalp drain partly to the parotid nodes in front of the ear and partly to the retroauricular nodes in the back of the ear. These then drain into the upper deep cervical nodes
Although the salivary glands are a smaller gland comprised of the parotid, submandibular, and sublingual glands, there still can be metastatic spread around local areas and lymph nodes.
One of the biggest factors in metastatic spread with the salivary glands is the difference between high-grade tumors and intermediate to low-grade tumors. High-grade tumors have a much higher risk of lymph node metastasis at 49%, while intermediate to low grade tumors only carry about a 7% risk of spread.2
TNM system of the American Joint Committee on Cancer (AJCC). This system contains 3 key pieces of information:
- T describes the size of the primary tumor and whether it has invaded into nearby organs or tissues.
- N describes whether the cancer has spread to nearby (regional) lymph nodes (bean-sized collections of immune system cells located throughout the body).
- M indicates whether the cancer has metastasized (spread) to other organs of the body (The most common site of distant salivary gland cancer spread is the lungs).
Numbers or letters appear after T, N, and M to provide more details about each of these factors:- The numbers 0 through 4 indicate increasing severity.
- The letter X means "cannot be assessed" because the information is not available.
T groups for major salivary gland cancersTX: The main (primary) tumor cannot be assessed; information not known.
T0: No evidence of a primary tumor.
T1: Tumor is 2 cm (about ¾ inch) across or smaller. It is not growing into nearby tissues.
T2: Tumor is larger than 2 cm but no larger than 4 cm (about 1½ inch) across. It is not growing into nearby tissues.
T3: Tumor is larger than 4 cm across and/or is growing into nearby soft tissues.
T4a: Tumor is any size and is growing into nearby structures such as the jaw bone, skin, ear canal, and/or facial nerve. This is known as moderately advanced disease.
T4b: Tumor is any size and is growing into nearby structures such as the base of the skull or other bones nearby, or it surrounds the carotid artery. This is known as very advanced disease.
N groups for major salivary gland cancers
NX: Nearby (regional) lymph nodes cannot be assessed; information not known.
N0: No spread to regional lymph nodes.
N1: The cancer has spread to 1 lymph node on the same side of the head or neck as the primary tumor. The lymph node is smaller than 3 cm (about 1¼ inch) across.
N2: This group includes 3 subgroups:
- N2a: The cancer has spread to 1 lymph node on the same side as the primary tumor. The lymph node is larger than 3 cm but not larger than 6 cm (about 2½ inches) across.
- N2b: The cancer has spread to more than 1 lymph node on the same side as the primary tumor; none of the lymph nodes are larger than 6 cm across.
- N2c: The cancer has spread to 1 or more lymph nodes, none larger than 6 cm across, either on the side opposite the primary tumor or on both sides of the neck.
N3: The cancer has spread to a lymph node that is larger than 6 cm across.M groups for major salivary gland cancers
M0: The cancer has not spread to tissues or organs far away from the salivary glands.
M1: The cancer has spread to tissues or organs far away from the salivary glands.5
The biggest issue for patients with cancers of the salivary glands is xerostomia. In some cases, this can be permanent, and patients will no longer be able to produce saliva.2 This is a major quality of life issue, and a very high priority is placed on avoiding this whenever possible.
Prognosis is impacted by several key markers:
Ear (middle) 5500cGy – Serous oitis6
Oral Cavity & Pharynx 6000cGy – Ulceration
Salivary Glands 5000cGy – Xerostomia
Spinal Cord 4500cGy – Myelitis/necrosis
Brain 5000-6000cGy – Infarction, necrosis
Lens 1000cGy – Cataract
Optic Chiasm 4500cGy – Blindness
Optic Nerve 5000cGy – Blindness
Retina 4500cGy - Blindness
Thyroid 4500cGy – Reduced hormone production
Larynx 70000cGy – Necrosis
1. Cancer.net. Web site. http://www.cancer.net/cancer-types/salivary-gland-cancer/statistics. Accessed Jun 5, 2013.
2. Chao KS, Perez CA, Brady LW. Radiation Oncology Management Decisions. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2011.
3. Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby Inc; 2010:732
4. American Cancer Society. Web site. http://www.cancer.org/cancer/salivaryglandcancer/detailedguide/salivary-gland-cancer-what-is-salivary-gland-cancer. Accessed Jun 5, 2013.
5. Salivary gland cancer. Cancer.org Web site. http://www.cancer.org/cancer/salivaryglandcancer/detailedguide/salivary-gland-cancer-staging. 2012. Accessed June 4, 2013.
6. Washington CM, Leaver D. Principles and Practice of Radiation Therapy. 3rd ed. St. Louis, MO: Mosby Inc; 2010:81-82.
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