Sentinel node biopsy in oral cancer

DR AJAY MANICKAM

FELLOW, HEAD NECK SURGICAL ONCOLOGY

TATA MEDICAL CENTRE, KOLKATA

SENTINEL NODE BIOPSY IN

ORAL CANCER

SENT TRIAL

INTRODUCTION

• 33% of stage I/II Oral cancer have

occult cervical disease, undetectable by

current imaging

• Cervical metastasis is associated with

50% reduction in cure

SO WHAT WE DO NOW?

• Elective neck Dissection

• 80% - UNNECESSARY?

SENTINEL NODE BIOPSY

• WHAT TO DO IN A N0 NECK?

• SENT – WITHOUT ELECTIVE

NECK DISSECTION

AIM & MATERIALS METHODS

• SNB - SAFE AND RELIABLE THERAPEUTIC

TEHNIQUE IN T1-T2 ORAL SCC

• STUDY PERIOD – OCT 2005- OCT 2010

• PATIENTS HAD – 0.5 – 4CM ORAL SCC + N0 NECK ON

CT AND/OR MRI < 1.1CM – 1.5CM IN LEVEL2 AND NO

ATYPICAL FEATURES + USG GUIDED FNAC.

• PATIENT MUST BE FIT FOR SURGERY IF SNB

PROVES DISEASE.

TOTAL CASES – EXCLUDED CASES

• 480 CASES SELECTED

• 66 cases - 14% EXCLUDED FROM FINAL ANALYSIS.

SENT – DUAL STUDY

• PRE OP – LYMPHOSCINTIGRAPHY – 24HRS PRIOR TO

SURGERY - Tc99m NANOCOLLOID WAS INJECTED – 4

POINTS AROUND THE TUMOUR – (57MBq – 60 MBq) -

POSITION MARKED BY GAMMA CAMERA

• BLUE DYE – PERITUMORAL INJECTION – RECORDED BY

COLOUR.

• LN – RADIATION COUNT MORE THAN 3 TIMES – SN .

• RADIATION HOT SPOT MORE THAN ONE NECK LEVEL –

PRIMARY SN – MAX RAD COUNT.

• SN – FIXED IN FORMALIN – H&E – ANTI PAN CYTOKERATIN

AB

• METASTASIS – VIABLE/ NON VIABLE.

UICC

• ISOLATED TUMOUR CELLS – ITC -

<200CELLS / <0.2 mm Deposits

• MICROMETASTASIS – 0.2 – 2mm

• MACROMETASTASIS - >2mm

RESULTS

LN DRAINAGE

• Avg size – SN – 3-30 mm - 11.8mm

• Lateral tumours drained – I/L – 87%

• Lateral Tumours drained – B/L – 10%

• Lateral tumours drained C/L – 2.4%

• 60% of midline lesions drained B/L

OCCULT CERVICAL DISEASE

• SNB – Detected METS – 23% (16% -ITC, 48% Micromets, 36%

Macromets)

• 15 patients with negative SNB – developed cervical mets – with

negative primary tumour site. - False negative rates.

• SENITIVITY – 86%

• NEGATIVE PREDICTIVE VALUE – 95%

• FALSE NEGATIVE RATE – 14%

RESULTS

• ALL PATIENTS WITH POSITIVE SNB – ND

• 85% NO FURTHER POSITIVE NODES WERE

FOUND IN COMPLETION SPECIMEN.

• DISEASE RECURRED IN 56 PATIENTS.

ADJUVANT THERAPY

• 12% RECEIVED CT/RT

• SNB POSITIVE PATIENT – 27% RECIEVED

ADJUVANT THERAPY ( ONE

POSITIVE/ECS)

• FALSE NEGATIVE GROUP

• BUT NO SINIFICANT SURVIVAL

DIFFERENCE BETWEEN THOSE

WITH/WITHOUT ADJUVANT RT

OUTCOME

• POSITIVE NODES & SN STATUS – SIGNIFICANT FACTORS.

MAIN OBJECTIVES

• SNB is a safe oncological procedure. This

has been confirmed with DFS of 92% at 3

years following treatment.

• The second objective was to determine, in

the context of oral and oropharyngeal cancer,

whether SNB was an effective diagnostic test

for microscopic deposits of metastatic cancer.

The study showed conclusively that the SNB

technique works effectively in the oral cancer.

NEGATIVE

• The SNB technique failed to detect occult metastasis in 14% (15 in 109) of patients, only half of whom (53.3%: 8 in 15) were amenable to salvage.

• counterbalanced through identification of unexpected contralateral lymphatic drainage by SNB. This occurred in 12% (49 in 369) of cases.

TUMOUR SPILLAGE

• The results of SENT when reported in an identical way show the neck recurrence rate for SNB- and SNB+ and the total group were 5%, 15% and 7.5%.The low rate of regional recurrence argues against tumour spillage .

ADVANTAGES

• 71% of patients spared neck dissection – PROTOCOL

• 47 patients with midline tumours must have received B/L ND – only 8

underwent.

• Second primary tumours – where ND already done – help in identification

of aberrant drainage patterns.

• Metastatic type – ITC/Micro/Macro – very important for future - because

they have a value for overall survival.

• BUT REGIONAL RECURRENCE RATE OF 18% HIGH – BUT WORTH

NOTICING THAT - OVER 1/3RD RECURRENCE OCCURRED IN C/L

NECK

REFERENCES