Site:
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Parotid
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Histology:
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Mucoepidermoid Carcinoma, Adenoid Cystic Carcinoma, Acinic
Cell Carcinoma, Adenocarcinoma, Squamous Cell Carcinoma, Carcinoma
ex-Pleomorphic Adenoma, Or Benign Mixed (Pleomorphic) Adenoma.
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Stage:
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All Stages
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- DIAGNOSTIC EVALUATION
- DEFINITIVE TREATMENT
- RECONSTRUCTION
- POSTOPERATIVE RADIATION
- ADJUVANT TREATMENT
- FOLLOW UP
- BIBLIOGRAPHY
I.DIAGNOSTIC EVALUATION:
Clinical Evaluation:
- A complete history and physical
With particular reference to a previous history of skin cancers. Head neck
examination should focus on the extent of disease involvement in the parotid,
parapharyngeal space and neck, presence of trismus, status of facial nerve
function and presence of hypesthesia or anesthesia of the skin of face
or neck, any otologic findings and assessment of the patient's dentition.
- FNA
If the parotid mass is mobile, discrete and confined to the superficial
lobe, no pre-operative FNA is necessary unless the patient's medical condition
is such that a general anesthetic would be very risky and a priority needs
to be established. FNA is useful when a parotid tumor is likely to be metastatic
in nature (e.g. from the skin or from other organs). Some surgeons feel
that FNA is useful in counseling the patient and planning treatment when
malignancy is suspected. If the patient has wide-spread metastatic disease
and a tissue diagnosis is necessary in order to institute treatment or
if the mass is unresectable, an FNA will help in directing palliative therapy.
Imaging Studies and Laboratory Tests:
- Routine preoperative studies dictated by institutional guidelines.
- Chest radiographs, AP and lateral.
To evaluate for acute or chronic pulmonary disease and metastases.
Abnormal findings on chest x-ray with suspicions lesions may need further
imaging including a chest CT.
Is indicated if the tumor extends beyond the superficial lobe, a deep
lobe tumor is suspected or extension into the deep lobe is appreciated
and the patient has trismus. In patients with large tumors it is useful
to assess the medial extent of the tumor, its relationship to the mandible,
the temporal bone and the cervical spine.
- MRI
Is indicated if facial nerve function is affected in order to better visualize
the fallopian canal.
- Panorex
Is useful if there are teeth present in order to help with the dental evaluation
Consultations:
- Dental Exam is appropriate to assess status of teeth if radiation
therapy may be a part of the treatment plan.
- Radiotherapy: In anticipation of possible postoperative radiation.
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Neck:
N0: Neck dissection is not indicated regardless
of the histology unless clinically suspicious nodes are present.
N+: If nodes are present, the type of neck dissection
is determined by the level of nodal involvement and the likelihood of using
postoperative radiotherapy. Again, all gross disease in the neck must be
resected.
II. DEFINITIVE TREATMENT:
Primary tumor:
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A superficial parotidectomy is the minimal surgical
procedure, but the final extent of the resection is determined by
the extent of the disease not the histology. All gross disease should
be removed.
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If the tumor is encasing the facial nerve, the nerve
should be resected and a nerve graft used, otherwise, the facial
nerve can be spared, as long as there is a clearly identifiable plane
between the tumor and the nerve
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If the nerve is nonfunctioning preoperatively, grafting
is appropriate if the involved portion of the nerve is resected with
clear margins.
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III. RECONSTRUCTION:
A free flap or a myocutaneous flap is necessary if bone is exposed or
extensive soft tissue and skin are removed. For smaller defects with no
bone exposed a local/regional flap or a skin graft may be sufficient.
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IV. POSTOPERATIVE RADIATION:
If the tumor is an adenoma (pleomorphic, monomorphic, Warthin's) removed
with clear margins, no further therapy is indicated.
If a T1 - T2 malignant tumor of low grade histology is removed with clear
margins postoperative radiation is not indicated.
Most commonly radiation therapy is employed for malignant tumors that
are removed with very close margins due to their proximity to the facial
nerve,
tumors with extensive soft tissue/bone invasion (e.g. facial skin, masseter,
pterygoids, mandible, infratemporal fossa), malignant tumors of the deep
lobe that can not be excised with generous margins, tumors that exhibit
extensive perineural or intravascular invasion, and tumors associated with
multiple
lymph node metastases.
Timing:
Radiation is initiated within a reasonable period after healing has occurred.
Total dose and fractionation:
These are determined by the clinical and pathological findings. The usual
range is 50 - 70 Gy in daily fractions of 1.8 to 2.0 Gy in 5 to 8 weeks.
This includes a brachytherapy boost when indicated by specific pathological
findings.
A nerve graft is not a contraindication to postoperative radiation.
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V.ADJUVANT TREATMENT:
Adjunctive chemotherapy has no proven effect on salivary
gland tumor. Neutron therapy may be considered for recurrent or unresectable
local/regional disease. Isolated bone metastasis may respond to localized
radiation with relief of pain. Solitary pulmonary metastasis of adenoid
cystic carcinoma should be evaluated for resection.
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VI.FOLLOW UP:
Follow-up appointments are scheduled on an individual basis
determined by the risk of recurrence, to deal with morbidity from treatment
(i.e. xerostomia, trismus, as well as wound care), to provide social and
psychological support, and to deal with comorbidity not directly related
to the cancer itself.
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Periodic examinations by the head and neck surgeon may
be necessary during radiation therapy in patients experiencing difficulty
with nutritional intake, or pain control.
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Periodic examinations by the radiation oncologist and
a dentist in patients that received radiation therapy
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After all treatment is completed a general formula which
is modified according to the individual patient's characteristics is:
1st year post treatment: 1-3 months
2nd year post treatment: 2-4 months
3rd year post treatment: 3- 6 months
4th and 5th years: 4- 6 months
After 5 years: Every 12 months
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Chest radiographs, yearly.
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Liver enzymes, yearly.
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VII. BIBLIOGRAPHY:
Spiro RH and Huvos AG. Stage means more than grade in adenoid
cystic carcinoma. Am J Surg 164: 623-628, 1992.
Armstrong JG, Harrison LB, Spiro RH, Fass DE, Strong EW,
and Fuks ZY. Malignant tumors of the major salivary gland origin. Arch
Otolaryngol Head Neck Surgery 116: 290-293, 1990.
Harrison LB, Armstrong JG, Spiro RH, Fass DE, and Strong
EW. Postoperative radiation therapy for major salivary gland malignancies.
J Surg Oncol 45: 52-55, 1990.
Johns ME. Parotid cancer: a rational basis for treatment.
Head Neck Surg 4:132-141, 1980.
Frankenthaler RA. Prognostic variables in parotid gland
cancer. Arch Otolaryngol Head Neck Surg. 117:1251-1256, 1991
Kane WS. Primary parotid malignancies. Arch Otolaryngol
Head Neck Surg. 117:307-315, 1991.
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