malinant salivary gland tumours dr.shaji thomas additional professor,regional cancer centre...

REGIONAL CANCER CENTRE, TRIVANDRUM Life beyond cancer

MALIGNANT SALIVARY GLAND TUMOURS

DR. SHAJI THOMAS MS,MChAdditional Professor

Division of Surgical Oncology


Introduction

• Tumours of the salivary glands account for only 5% of H&N cancers and 0.3% of all cancers

• Diverse histopathology

• Proportion of malignant and benign varies with the gland of origin.


Malignant Neoplasms-subtypes

Mucoepidermoid Carcinoma

Adenoid Cystic Carcinoma

Carcinoma ex-pleomorphic adenoma

Acinic Cell Carcinoma

Adenocarcinoma

Squamous Cell Carcinoma

Undifferentiated Carcinoma

Sarcoma

Lymphoma


Mucoepidermoid Carcinoma

• Most common type

• 80-90% occur in the parotid gland

• More common in females

• Highest prevalence in 5th decade of life

• Characterized histologically by a mixed population of cells, mucin-

producing cells, epithelial cells, and intermediate cells.


Mucoepidermoid Carcinoma• Mucoepidermoid cancer is histologically classified into low and high

grade. A higher grade correlates with a poorer outcome

• Low-grade tumors have a higher percentage of mucinous cells

• Epithelial cells predominate in high-grade.

• The presence of four or more mitotic figures per 10 high-power fields, neural invasion, necrosis, intracystic component <20%, and cellular anaplasia indicate high-grade behavior.



• Adenoid cystic carcinoma is the most common malignancy of the

Submandibular gland

• Adenoid cystic carcinoma is characterized by slow growth,

neurotropism, local recurrence, and distant metastasis.

• Exhibits a predilection for neurotropic spread, often leading to

recurrences at the skull base after surgical and radiation treatment



• Three distinct histologic patterns, cribriform, tubular, or solid, although the histologic patterns may coexist in the same tumor

• The cribiform pattern has a glandular architecture and is reported to have the best prognosis.

• The solid pattern is more epithelial in nature and is associated with a poorer prognosis.

• The tubular pattern has a clinical prognosis of intermediate nature between the other two patterns.


Acinic Cell Carcinoma

• This tumor has a low-grade behavior and has the best survival rate of

any salivary malignancy

• Parotid gland was the most common site of origin


Carcinoma ex-Pleomorphic Adenoma

• Malignant degeneration can occur in 3% to 7% of pleomorphic adenomas.The risk of malignant degeneration is estimated at 1.5% in the first 5 years and 9.5% after 15 years.

• Histologic findings include those of benign pleomorphic adenoma with carcinomatous degeneration.

• A typical clinical history includes a longstanding salivary mass that begins to rapidly enlarge, often to substantial size, although many patients have no history of a prior


Low Grade Rare Subtypes

Polymorphous low-grade adenocarcinoma

Epithelial-myoepithelial carcinoma

Basal cell adenocarcinoma

Papillary cystadenocarcinoma

Myoepithelial carcinoma


High Grade Rare Subtypes

Squamous cell carcinoma

Small cell carcinoma

Sebaceous carcinoma

Mucinous adenocarcinoma

Oncocytic carcinoma

Adenocarcinoma

Salivary duct carcinoma


Diagnosis

• Malignant salivary neoplasms present as a painless mass in approximately 75% of patients. Rarely,patients are initially seen with pain or facial nerve palsy.

• A palpable mass arising in a salivary gland, associated with pain, and/or nerve paralysis is more likely to be malignant than benign.

• It is believed that episodic pain suggests continued obstruction, whereas constant pain is more suggestive of malignancy.

• Trismus, cervical adenopathy, fixation, numbness, loose dentition, or bleeding also suggest the presence of malignancy.


TNM

TX Primary tumor cannot be assessed

T0 No evidence of primary tumor

T1 Tumor 2 cm or less in greatest dimension without gross extraparenchymal extension

T2 Tumor more than 2 cm but not more than 4 cm in greatest dimension without gross extraparenchymal extension

T3 Tumor more than 4 cm and/or tumor having gross extraparenchymal extension

T4a Tumor invades skin, mandible, ear canal, and/or facial nerve

T4b Tumor invades skull base and/or pterygoid plates and/or encases carotid artery


TNM

NX Regional lymph nodes cannot be assessed

N0 No regional lymph node metastasis

N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension

N2a Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension

N2b Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension

N2c Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension

N3 Metastasis in a lymph node more than 6 cm in greatest dimension


Stage Grouping

Stage I T1 N0 M0

Stage II T2 N0 M0

Stage III T3 N0 M0

T1 N1 M0

T2 N1 M0

T3 N1 M0

Stage IVA T4a N0 M0

T4a N1 M0

T1 N2 M0

T2 N2 M0

T3 N2 M0

T4a N2 M0

Stage IVB T4b Any N M0

Any T N3 M0

Stage IVC Any T Any N M1


Diagnostic Studies

• CT (with contrast)

• Requires contrast and radiation

• Excellent detail of the tumor volume

• Useful in evaluating the parapharyngeal space

• Relation of tumor to vascular and bony structures helpful in surgical planning

• Lymphatic survey


Diagnostic Studies

• MRI

• Does not require iodination or radiation

• Excellent soft tissue detail

• Superior in defining the tumor boundaries

• Useful to determine if nerve involvement present

T1, low signal intensity

T2, high signal intensity


Diagnostic Studies

• PET Scan

• Useful in staging and follow-up

• Rule out distant and regional metastases

• Predicted the nature of the neoplasm in 69%

• Demonstrated 100% sensitivity for malignancy

• False-positive rate of 30%

• Role not yet well defined


PET

Increased FDG uptake

• Inflammatory lesions,

• warthin’s and

• pleomorphic adenomas


Fine-Needle Aspiration Biopsy

• Opponents argument:

• Doesn’t change management

• Often surgery regardless of reported diagnosis

• Obscuring final pathologic diagnosis

• Frequency of “inadequate” sampling, requires multiple biopsies,

prolongs course until definitive treatment, increases cost


Fine-Needle Aspiration Biopsy

• Proponent’s argument:

• Important to distinguish benign vs. malignant nature of

neoplasm

• Preoperative patient counseling

• Surgical planning

• Differentiate between neoplastic and non-neoplastic

processes

• Avoid surgery in a number of patients


Value of the cytological diagnosis inthe treatment of parotid tumors.

Jafari et. al.

• Concluded:

• In the majority of parotid tumors, there was a good correlation between the FNA cytological diagnosis and the histopathological results

• FNA provides an adjuvant tool in the strategic and surgical approach of a parotid tumor:

• wider resection of parotid gland

• cervical neck dissection


Treatment – The Primary

• What surgery should I perform on the primary tumor?

• Does this patient need postoperative radiation?


Surgeries for parotid

If no t f o r t h e f a c ia l n er v e paro t i d s u rg ery wou ld j u s t b e a l i p oma exc i s i on


Surgeries for parotid

• Superficial Parotidectomy

• Adequate Parotidectomy

• Total conservative Parotidectomy

• Total radical Parotidectomy

• Extended radical Parotidectomy



• Superficial parotidectomy has been touted as the minimal surgery of the parotid gland

• Use of lesser procedures• A higher risk of facial nerve injury and• The potential for intraoperative seeding of tumor resulting in

recurrence.

• The safety of parotidectomy has been well established, and the complication rate remains low.



• Total parotidectomy may be necessary for tumor extension into the

deep parotid lobe or when the tumor primarily arises in the deep

lobe. This can be performed with preservation of the facial nerve

• Occasionally, patients may require extended parotidectomy, which

includes resection of the masseter muscle or the ascending portion

of the mandible.



• Facial nerve sacrifice is not routinely advocated.

• Nerve preservation in primary salivary malignancy is recommended if

the nerve is functioning normally before surgery.

• Every attempt to dissect the tumor from the individual branches

should be undertaken.

• If tumor is completely encasing the nerve branches, neural sacrifice

is limited to the involved branches.


• Concluded:

• Selective sacrifice when nerve impaired or where tumor margins

compromised seems to improve local control and survival.

• QOL significantly affected.

• Pre-op FNA and CT extremely useful in counseling patients.

• Patients managed with XRT better local control.


Adequate parotidectomy

• Jesus Medina of Oklahoma University

• Procedure less than a classical superficial parotidectomy

• For low grade parotid tumours in tail of parotid or accessary parotid –

away from facialN

• Warthins tumour


Revision Parotid Surgeries

• Inadequate and incomplete primary surgery

• Difficult to perform when facial N in scar tissue

• Always perform a proper and complete surgery in the first chance

itself

• High incidence of nerve damage and neuro praxia



• Chen, in 2007, 207 patients who, over 5 decades, received surgery

without XRT as primary modality

• He identified patients who were at high risk of locoregional

recurrence with surgery alone

• Based on these observations, he recommended postoperative XRT

for patients with T3-T4 disease, positive surgical margins, high grade

tumor histology, or regional nodal metastasis


Concluded

• Recommended postop XRT for:

• High-grade histology

• Recurrent disease

• Inadequate surgical margins

• Perineural invasion

• Extension of disease beyond the gland

• Nodal disease



• In general, tumors of the submandibular gland require

complete excision of the gland.


Malignant lesions –SM gland

• Simple excision of the submandibular gland sufficient in cases where

the tumor is confined within the capsule of the gland

• Given the high incidence of adenoid cystic carcinoma at this site, a

more extensive regional resection is often required(adjacent muscles,

the lingual or hypoglossal nerves,part of mandible, or the floor of the

mouth)


Malignant Lesions: Minor Salivary Glands

• Surgical treatment will vary depending on the site of origin.

• In general, these lesions are resected in a manner similar to that

utilized for squamous carcinoma arising at the same primary site.


Management of nodal mets

• Incidence of regional metastases is relatively low for most types of

salivary cancer

• Appropriately treating the neck in salivary malignancy is important for

patient outcomes


Treatment – The Neck

• How should I treat the neck in my patient?

• Observation, elective neck dissection, or elective neck irradiation?


• Palpable nodal metastases - comprehensive neck dissection

indicated

• Elective neck dissection reserved for those with a high incidence of

nodal involvement (high grade mucoepidermoid carcinoma or

primary squamous carcinoma),locally advanced disease


Role of Chemotherapy

• Adjuvant chemotherapy is currently indicated only for palliation.

• Doxorubicin(induce apoptosis) and platinum-based agents(promote

cell arrest) are most commonly used.

• Platinum-based agents, in combination with mitoxantrone or

vinorelbine, are effective in controlling recurrent salivary gland

malignancy..


Conclusions

• Malignancies of the major salivary glands represent a rare and

diverse group of cancers

• Knowledge about tumor staging and histologic grading is necessary

for prognostic predictions, patient counseling, and treatment planning

• Surgical treatment should be the primary therapy with removal of all

gross disease as the surgical goal


Conclusions

• Patients should receive postoperative radiation to the primary site if

the tumor is stage III or IV, or if the pathology shows positive

margins or perineural invasion

• Careful consideration must be given to treatment of the neck, with

clinical disease as definite indication for neck dissection and/or neck

XRT

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