neck node management of unknown primary

MANAGEMENT OF THE NECK NODES WITH OCCULT PRIMARY

Dr rekha aryaModerator:-dr anurita

DEFINITION

Carcinomas with an unknown primary site Carcinomas with an unknown primary site (CUP) are tumors that present with lymph (CUP) are tumors that present with lymph

node or distant metastases when node or distant metastases when appropriate investigations fail toappropriate investigations fail to

localize a primary sitelocalize a primary site..

FNAC

Sqamous cell carcinoma,

Adenocarcinoma,

Undifferenciated

Poorly differenciated

Anaplastic carcinoma

FNACLymphoma

SCC suspecting

that primary is in head and neck

EPIDEMOLOGY AND ETIOLOGY Exact incidence is unknown.

POINTS TO CONSIDER WHEN LOOKING FOR A PRIMARY 1) Location of lymph nodes2) Lymphatic drainage of the region3) Possible location of the primary tumor

(hidden sites)4) Histology of nodes5) Past history (relevant)

1) LYMPHATICS

Profuse capillary lymphatic network present in

Nasopharynx & Pyriform sinus Paranasal sinuses, middle ear and true vocal

cords have sparse capillary lymphatics

2) RISK GROUPS BASED ON LOCATION AND SIZE OF PRIMARY TUMOR

Group

Estimated Risk of Subclinical Neck Disease % Stage Site

Low risk <20 T1 FOM, RMT, gingiva, hard palate, buccal mucosa

Intermediate risk

20-30 T1 Oral tongue, soft palate, pharyngeal wall, supraglottic larynx, tonsil

    T2 FOM, oral tongue, RMT, gingiva, hard palate, BM

High risk >30 T1-4 Nasopharynx, Pyriform sinus, BOT

    T2-4 Soft palate, pharyngeal wall, supraglottic larynx, tonsil

    T3-4 FOM, oral tongue, RMT, gingiva, hard palate, BM

3) HISTOLOGICAL DIFFERENTIATION

Proposed explanations for inability to detect the occult primary

The primary tumor may have involuted spontaneously and is no longer detectable, despite the presence of metastatic disease.

The malignant phenotype of the primary tumor favors metastatic biologic behavior over local tumor growth.

In evaluating metastatic SCC to cervical lymph nodes, the occult primary is eventually detected in about half of the cohort.

ROUTES OF SPREAD

Diagnostic work up

DIAGNOSTIC WORKUP History

Physical examination

Careful examination of the neck and supraclavicular regions with attention to skin

Examination of oral cavity, pharynx, and larynx

Mirror & fiberoptic examination to visualise nasopharynx,oropharynx,hypopharynx,larynx

Radiological Studies Chest imaging CT with contrast or MRI with Gd (skull base through thoracic

inlet) PET CT scan (If other tests do not reveal a primary)

Laboratory studies Complete blood cell count Blood chemistry profile

HPV testing (Suggestive of occult primary in BOT or Tonsil, helps in customize radiation targets)

EBV testing

EVIDENCE ON ROLE OF PET CT In a meta-analysis of 16 studies looking at the

role of PET in 302 patients with cervical node metastases where a primary has yet to be discovered through the work up, 25%25% of primaries are identified through PET. Previously unrecognized regional or distant metastases were identified in 27% of patients

Rusthoven, KE, Koshy, M, Paulino, AC, The role of fluorodeoxyglucose PET in cervical lymph node metastases from an unknown primary tumor. Cancer 2004; 101:2461

CHARACTERISTICS OF FDG-PET IMAGING

FNACFNAC

SCC

H & N exam ,radiological studies

Primary found Primary Primary

not foundnot found

MANAGMENT

IF ONLY CN1+ Selective or modified radical neck dissection

ADVANTAGE1) Directs pathology2) Post-op RT dose is lower

DISADVANTAGE1) Surgical morbidity

If no additional lymphadenopathy or extracapsular extension (ECE) - observe

If >2 LN or ECE: post-op RT or chemo-RT

IF > CN2+ Early N2 disease (N2A, early N2B): RT

Advanced N2-N3: chemo-RT

PET/CT 8 weeks after RT or chemo-RT

Risk of residual disease <5% : observe Risk of residual disease >5% 1. Nodes >15 mm, 2. Focal lucency,3. Enhancement or calcification in lymph node, 4. ECE or nodal rupture : neck dissection

NECESSITY FOR ADJUVANT NECK DISSECTION IN SETTING OF CONCURRENT CHEMORADIATION FOR ADVANCED HEAD-AND-NECK CANCER.BRIZEL DM1, PROSNITZ RG, HUNTER S, FISHER SR, CLOUGH RL, DOWNEY MA, SCHER RL.

A total of 154 patients received concurrent chemoradiation. Of these, 108 presented with nodal disease: N1, n = 30; and N2-N3, n = 78. MND was performed in 65 (60%) of 108 patients. The median follow-up was 4 years. The 4-year disease-free survival rate was 75% for N2-N3 patients who had a cCR and underwent MND vs. 53% for patients who had a cCR but did not undergo MND (p = 0.08). The 4-year overall survival rate was 77% vs. 50% for these two groups of patients (p = 0.04).

Int J Radiat Oncol Biol Phys. 2004 Apr 1;58(5):1418-

23.

STUDIES OF POSTRADIOTHERAPY NECK DISSECTION Narayan et al. (1999): Clayman et al. (2001): Brizel (IJROBP 2004): Liauw et al. (2006): Yao et al. (2007): Van der Putten et al. (2009):

NECK DISSECTIONS Radical Gold standard operation

Modified radical Preservation of non lymphatic

structures

Selective Preservation of lymph node

groups

Extended Removal of additional lymph

node groups or non lymphatic structures

Post surgery management depends upon:- 1)Stage 2) Level of LN 3)Presence of extracapsular extension

Typically irradiate nasopharynx, oropharynx, and both sides of neck

Hypopharynx and larynx were irradiated historically; eliminated more recently because they are rarely the primary site and including these sites greatly increases morbidity of treatment

Consider hypopharyngeal and laryngeal irradiation for adenopathy centered in level III/IV

Oral cavity is not irradiated unless submandibular lymphadenopathy is present

If submandibular lymphadenopathy: perform neck dissection and observe, or irradiate oral cavity and oropharynx but not nasopharynx

CONVENTIONAL RADIOTHERAPY PLANNING

Simulation and field designPatient set-up:

supine, hyperextend head, may need bolus, shoulders pulled down with straps, immobilization with thermoplastic mask or bite block.

Volumes:

Nasopharynx,oropharynx,bilateral retropharyngeal nodes and levels IB-IV, ipsilateral ± contralateral supraclavicular nodes

Include oral cavity only if submandibular adenopathy present,and may eliminate nasopharynx in that case

CONVENTIONAL BORDERSUpper Neck FieldsParallel -opposed lateral fields at 1.8–2 Gy/fraction

Superior = covers nasopharynx and level Ib and V to base of tongue

Posterior = behind spinous processes to C2 , cord shielded after 40–44 Gy, with posterior electron field matching to therequired target dose

Anterior = 2 cm margin on nasopharynx and the base of tongue; shield skin and subcutaneous tissue of submentum as much as possible

Inferior = thyroid notch

Lower Neck Fields

Superiorly - the field should match the upper fields with an isocentric or half-beam block technique, Inferior border - including the clavicular heads.

Laterally, the field should cover the medial or entire supraclavicular region, depending on the extent of nodal involvement.

A laryngeal block may be placed to spare the larynx and hypopharynx .

IMRT for HNCUP has survival rates comparable to those with conventional radiotherapy.

By using IMRT the degree of toxicity can be reduced compared with conventional methods.

High OS, DFS, and nodal control can be

achieved for patients with T0N1 or T0N2a disease without ECE spread.

Patients with extra capsular spread or bulky T0N2b–c or T0N3 disease have a worse prognosis and may benefit from the addition of more cytotoxic chemotherapy,molecular targeted therapy, and/or accelerated radiation regimens.

DOSES

COMPLICATIONS

SurgicalOperative mortality 2–3%Morbidity = infection, hematoma/seroma, lymphedema, wound dehiscence, chyle fistula, pharyngocutaneous fistula, cranial nerve VII, X, XI, XII injury, carotid exposure, or rupture

Incidence of complications is greater with RT doses >60 Gy Radiation therapyAcute and chronic mucositis, xerostomiaSkin reactionSubcutaneous fibrosis

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