Salivary gland tumors
clinical presentation of parotid gland tumors
-symptomatic parotid mass -localized pain and swelling -facial palsy and rapid growth -facial nerve involvement is highly suggestive of a malignancy
what are the presenting symptoms of parotid gland lesions?
-symptomatic parotid mass -localized pain and swelling -facial palsy and rapid growth facial nerve invovlement - malignancye
what are the chronic side effects of parotid gland RT?
-telengiectasia -hyper or hypopigmentation -serous otitis media -loss of hearing -osteoradionecrosis
when is RT used for parotid gland lesion
-to enhance local control -recommended for T3-T4 lesions -recommended for incomplete resection, bone involvement, perineural invasion -high grade lesions RT is always done post op
what is the average age of incidence for salivary gland tumors?
55 for malignant lesions 40 for benign lesions
what dose is needed for parotid lesions?
60-70Gy
what is the RT dose for salivary gland tumors?
60-75Gy in 30-35 post op dose of 60-63Gy
what is the most effective detection method for diagnosis?
a fine needle aspiration biopsy
what salivary gland has the highest incidence?
parotid gland (80-90% of salivary gland tumors)
which yeilds a better prognosis, submandibular or parotid lesions?
parotid lesions
are tumors of the salivary glands common or rare?
rare 3-4% of all cancers in the head and neck
hematogenous spread of parotid lesions
to lung and bone range from 13% for acinic and 41% adenocystic carcinoma
what is the optimal treatment for salivary gland tumors?
total resection with generous margins for sparing facial nerves since local recurrence is high
pleomorphic adenocarcinoma
this is a malignant transformation within a benign tumor
chronic reactions for parotid gland lesions
*skin* -erythema -desquamation (dry and moist) *ear* -serous otitis media -loss of hearing *facial nerve* -paralysis varies in degree trismus osteoradionecrosis
acute reactions for the parotid gland
*skin* discuss the reactions *edema* causing pain within the first 24 *mucosa* -xerostomia -altered tase sensation (temporary) -dental caries *ear* partial hearing loss *facial nerve* varying degree of paralysis
lymphatic spread of Parotid gland lesions
-20-25% have lymphatic involvement at the time of diagnosis -*jugulodigastric* and then to the *deep cervical nodes* -pre-auricular nodes from the the skin overlaying the parotid, this is not a common route of spread, even though they lie right over top of the parotid, this is not how the parotid gland drains
Radiation Therapy characteristics
-Mv photons or electrons -CT simulation for treatment planning -bolus -immobilization with neck extended -ensure to include the whole parotid bed, middle and external ear -careful to preserve contralateral eye and underlying brain from high dose -small feilds of 8x6cm, 5-6cm in depth -dose of *60-75Gy in 30-35* -post op dose of 60-63Gy -mixed beam RT is not commonly used anymore (photons and electrons) RT doesn't work well for parotid tumors
what are the most common histologies/pathologies of salivary gland tumors?
-adenoid cystic -mucoepidermoid -adenocarcinoma
natural history of salivary gland tumors
-an asymptomatic mass lasting for 4-8 months -local invasion is the initial route of spread, dependant on location and histological type, parotid tumors result in fixation to structure in 20% of cases -skin invasion is more often seen in parotid tumors 10% compared with 3% in submandibular tumors -cervical neck nodes may be seen in up to 44% of cases, varies with histological types -distant mets to the lungs and bone are most common, occasionally to the liver -distant mets are common and range from 13-44% this depends on the pathology of the tumor
surgery for parotid gland lesions
-can be used for benign and malignant lesions -surgery is the go to treatment for most patients, surgical excision is followed by RT for unfavourable prognostic indicators -surgery is a good option because these tumors are usually relatively radioreistant -with surgery we can attempt to spar the facial nerve -elective neck node dissections are used -surgery is used most or low grade tumors surgery is the primary choice for benign and malignant, will use surgery for every stage, it is the first thing
what is the role of the salivary glands?
-digestion -tooth protection
treatment of Salivary gland tumors
-surgical biopsy and excision followed by radical post op RT is the treatment of choice for most malignant tumors (IMRT) -low grade carcinomas that can be adequately removed need no further treatment
what pathology of salivary gland tumor has the highest incidence of cervical node involvement?
-high grade mucoepidermoid tumors (44% metastatic behaviour) -adenoid cystic carcinoma (41%)
what are the indications for radical RT?
-inadequate surgical excision -high grade malignancy -lymphomas (if a lymphoma arises from a salivary gland)
when is radiation therapy used for salivary gland tumors?
-inadequate surgical excision -high grade tumors when there perineural involvement of the facial, trigeminal, hypoglossal, and lingual nerves IMRT is effective because you can treat the proximal nerve to the brainstem with sparing the contralateral salivary gland, the eyes, and the temporal bones and brainstem itself
local spread from the parotid Gland
-it can infiltrate the whole gland -it can invade the 7th cranial nerve (facial nerve) which can cause motor problems with the muscles of facial expressions and sensory issues related to taste of the anterior 2/3 of the tongue, there can also be parasympathetic issues with the lacrimal, submandibular and sublingual glands -the spread can travel on the nerve sheath causing, swelling in the parotid area, local pain, facial palsy, tenderness, and the growth can be rapid -late invasion of the base of the skull, parapharyngeal space can encroach on other cranial nerves and can cause lock jaw (trismus) and severe pain 20% are fixed due to infiltration -skin invasion -can infiltrate whole gland
what is the lymphatic drainage of the parotid gland
-jugulodigastric node (upper deep cervical chain) -middle deep cervical chain -lower deep cervical chain -supraclavicular nodes
what are the 3 main salivary glands?
-parotid gland -submandibular gland -sublingual gland
etiology
-previous RT exposure (20 year latency period) -skin cancer of the face - *mostly unknown* -risk factors such as dental radiographs have been implicated for both benign and malignant tumors -some nutritional factors such as low vitamin A and C increases incidence -workers in various occupation with experience to hardwood dust, hair dressers radiation induce malignancies have been associated with early RT treatments for benign conditions (Acne, tinea capitis, infected tonsils) these malignancies have been associated with atomic bomb survivors
what are the indications for palliative RT?
-relieve pain and fungation in advanced disease when patients are unsuitable for radical RT -the site of disease when there is distant mets
what are the acute RT reactions for parotid gland lesions?
-skin reaction -edema -xerostomia -altered tast sensation -partial hearing loss -varying degrees of facial nerve paralysis
what are the prognostic indicators of parotid gland lesions?
-tumor type and grade -tumor site and extent -tumor involvement of surgical margins, in surgery they try to spare the facial nerve, so this can result in positive margins -oncogene expression is an independent prognostic factor -regional node mets
epidemiology
-tumors of the salivary glands are uncommon and comprise <3% of all new cancers of the head and neck region -parotid gland is the most common (80-90%), submandibular gland (10%) and sublingual (1%) -tumors of minor salivary glands (2-3%) up in the aerodigestive tract -of these tumors more than 66% are benign and the rest are malignant -M:F is 1:1 -8 fold increase in breast cancer with females that have had a salivary gland tumor -benign tumors are more likely in females -average age is 55 years for malignant disease and 40 years old for benign disease dont see a lot of them, but when you do they are in the parotid gland
Radiation therapy for parotid gland tumors
-used to enhance local control -is recommended for T3-T4 tumors -recommended for incomplete resection, bone involvement, perineural invasion, high grade cancer and recurrent cancer -primary neutron therapy may lead to superior local control rates compared to primary photon therapy for advanced, inoperable and recurrent cancers -use of conventional RT along with hyperthermia has been reported to have similar efficacy in this patient population
what techniques of RT are used for parotid gland lesions?
1) conventional -unilateral anterior and posterior wedged pair feilds using cobalt or low energy linac, this can also be done with electron beam 2) 3D conformal RT -geometrically shaped beams of uniform intensity 3) *IMRT planning is most commonly used * -most conformal RT technique -5-7 inverse field IMRT allows ecellent coverage of the tumor with sparing of mandible, cochlea, spinal cord, brain, and oropharynx compared to 3D conformal
how are parotid gland lesions diagnosed?
1) history and physical exam 2) CT with contrast 3) MRI, so evaluate size and extent, if there is benign or malignant characteristics, location in relation to facial nerve and to see if surgery is possible 4) biopsy, if there is a superficial lesion surgery can be used, if it is a deep lesion a total parotidectomy can be used to reduce the risk of seeding and recurrence. a fine needle aspiration is used for recurrent or inoperable lesions where RT will be the primary modality
are CT and MRI commonly used for the detection and diagnosis for salivary gland tumors?
NO they are not effective in differentiating between benign and malignant salivary gland tumors
are incisional and excisional biopsies performed for diagnosis?
NO, NEVER EVEN IF THERE IS A FIRE there is risk of recurrence, injury to facial nerve and subsequent surgical morbidity
salivary gland TNM staging
T1: <2cm without extraparenchymal extension T2: 2-4cm without extraparenchymal extension T3: >4cm and or extraparenchymal extension T4a: skin, mandible, ear canal, facial nerve T4b: skull, pterygoid plates, carotid artery you have to be able to visually see the extraparenchymal extension N0: no lymph node involvement N1: ipsilateral single node <3cm N2a: ipsilateral single node 3-6cm` N2b: ipsilateral multiple nodes <6cm N2c: bilateral or contralateral lymph nodes <6cm N3: >6cm nodes
what histology of salivary gland tumors yeilds the worst prognosis?
adenoid cystic carcinoma
what is the most common pathology of minor salivary gland tumors?
adenoid cystic carcinoma
what is the most common pathology of submandibular gland tumors?
adenoid cystic carcinoma
chemo for parotid gland lesions
adjuvant chemo has not been considered useful
clinical presentation of malignant salivary gland tumors
an asymptomatic mass that does go away -rapid growth rate -pain -facial nerve palsy -childhood occurrence -skin involvement -cervical adenopathy malignant tumors are characterized by rapid growth or a sudden growth spurt, they are firm, nodular, and can be fixed to adjacent tissue, often with a poorly defined periphery. eventually the overlying skin or mucosa may become ulcerated or the adjacent tissues may become invaded
what is the conventional technique for parotid RT?
anterior and posterior wedged pair
acinic cell cancer
derives from cells of the terminal ducts and intercalated ducts of the glands
what is the M:F ratio for salivary gland tumors?
essentially 1:1 with slight male predominance
chemo for parotid gland tumors
has a palliative role with *chlorambucil* *5-Fu* "dont worry about chemo" -Brian
what is the prognosis of salivary gland tumors?
high grade : 20-25% 5ys low grade: 80-90% 5ys stage 1: 90% 10ys
survival for salivary gland tumors
high grade: 20-25% 5 year survival low grade: 80-90% 5 year survival stage I = 90% 10 year survival the survival of patients with submandibular cancer is inferior to that of the parotid cancers the poorest prognosis is associated with adenoid cystic carcinoma
when is surgery used for parotid gland lesions?
it is used no matter what usually the best option because parotid gland lesions are usually radioreistant surgical excision followed by RT
are salivary gland tumors mostly malignant or benign?
more than 60% are benign and 15-30% are malignant tumors of the minor salivary gland are mostly malignant (65-85%)
adnenoid cystic carcinoma
most common in minor salivaary glands followed by the submandibular gland
minor salivary gland tumors
mostly malignant account for 2-3% of all H&N cancer
what is the most common pathology of parotid gland tumors?
mucoepidermoid
does RT work well for parotid tumors?
no
Pathology
salivary gland tumors may be graded as low, mixed, and high (particularly for mucoepidermoid tumors) there are many pathologies 1) *muco-epidermoid* 35% is most common for the parotid gland 2) *adenoid cystic carcinoma* 25% is the most common in minor salivary glands and submandibular gland 3) *adenocarcinoma* 25% 4) *pleomorphic adenocarcinoma* or mixed malignant tumors, this is a malignant transformation within a benign tumor 5) *acinic cell cancer* derived from cells of th terminal ducts and intercalated ducts of the glands 6) *squamous cell* and *anaplastic* do occur occasionally
stage groupings for salivary gland lesions
stage 1: T1 N0 M0 Stage II: T2 N0 M0 Stage III: T3 N0 M0 T1-T3 N1 M0 Stage IVa: T4a, T4b N0, N1 M0 T1-T4a N2 M0 Stage IVb: T4b any N M0 any T N3 M0 Stage IVc: any T any N M1
what are the conventional RT field borders for paortid tumors?
sup: zygomatic arch, including surgical scar. base of skull should be included if there is perineural invasion ant: anterior border of the massester muscles Post: behind the mastoid process inf: top of the thyroid cartilage
Where is the parotid gland located?
superficially and partly posterior to the ramus of the mandible it is superficial to the massester muscle
what is the largest salivary gland?
the parotid gland
how does the incidence of major salivary gland lesions in women affect their likelihood to get other cancers?
they have a higher incidence rate of breast cancer that is 8X higher than the rest of the healthy population
Radiation treatment volumes for salivary gland tumors
treatment volume includes the parotid bed and the ipsilateral upper neck nodes. the entire parotid and surgical bed is included superior border: zygomatic arch including surgical scar, if patient has perineural involvement, the base of the skull should be included anterior border: anterior border of masseter muscle posterior border: behind mastoid process inferior border: top of thyroid cartilage
clinical presention of minor salivary gland tumors?
vary because of their diverse locations, most are intraoral and a painless lump is the most common presenting symptom
