ROLE OF SENTINAL NODE BIOPSY

1. SLNB &Lymphadenectomy in
Gynae-oncology
Dr.KG Hewawitharana

2. Lymph Drainage of Pelvic Organs
• The lymphatic system embryologically develops from vascular plexuses that arise
from the venous system.
• Lymphatic channels follow the same course as venous drainage.
• Drainage route to third-spaced interstitial fluid, lymph.
• Pelvic organs generally drain to several main lymph node groups

3. organ Lymph nodes involve (FIGO 2018 data)
Fallopian tubes and
ovaries
External iliac, internal iliac, common iliac, lateral sacral, para-aortic, inguino-
femoral(Occasionally)
Uterus External iliac, internal iliac, common iliac-sacral, Para-aortic (direct spread
possible and found with SNB)
cervix Pelvic and para –aortic nodes
Para-aortic is the second most commonest site of recurrence
vagina Upper 1/3-Obturator,internal iliac, external iliac (pelvic)
Middle 1/3-Pelvic + inguino-femoral nodes
Lower1/3-Inguino-femoral (groin)
vulva Inguino-femoral & pelvic nodes
Central lesions-B/L groin nodes, clitoris may drain directly to iliac nodes
Lateral lesions-ipsilateral groin nodes

4. What is sentinel node
The sentinel lymph node (SLN) is defined as any lymph node
that receives a direct drainage from the tumor site and is the first
node to be involved with metastasis, and is therefore regarded
as the “gatekeeper of the nodal basin”
Detect by node mapping
1-blue dye
2-scintigraphy with radio labelled tracer
So detection rate is improved and minimize false negative rate

5. uses
• Identify metastatic nodal spread and offset need for systematic
lymphadenectomy
• Reduce morbidity associated to unnecessary lymphadenectomy
• Help to find unusual metastatic sites that can be missed to naked eye
• Detection of metastasis will upstage disease and warrant surgical or
adjuvant chemo-radiation interventions influencing
prognosis/survival
• SNB is superior to current imaging modalities including PET/MRI/CT in
sensitivity of node detection

6. Limitation
• Adverse effects-anaphylaxis to dye (<1%)
• False negative SLNB due to technical errors or larger tumor blocking
lymphatics
• Route of dye injection
• Skip nodes???

7. Technique
• Pre-op sctintigraphy-Tc99 isotope 1ml inject to 4 quadrants of tumor in
equal 4 parts then after 2-4 hrs CT- Lymph scintigraphy is done prior to
surgery
• During surgery Gamma probes used to see isotope accumulated hot spots
• After anesthesia- Iso sulfan blue dye & water 1:1 (Total dye max 4ml)
injected as above and naked eye visualization is done
• Combination of both improve detection rate
• A node is said to be hot, when it is 10 times more radioactive than tumor
bed
• Then send for fresh frozen section, if it negative micro-staging is done.(0.2-
2 mm deposits check)
• Depend on finding decide further intervention/s

8. Role of SLNB in Vulval carcinoma
• For Vulval cancer, presence or absence of groin node metastasis is
very critical
• About 25-35% by the time they present, already groin node
metastasis is there.
• SLNB prevents unnecessary groin dissection & associated morbidity
up to 75% of patients.
• Sensitivity is 98% with 2% false negative rate
• Small <4cm lesions, unifocal lesions, clinically absent groin nodes and
when no adjacent organ infiltration-SLNB is indicated.

9. Role of SLNB in Cervical CA
• In early stage cancers , SLNB is feasible and aimed to reduce
morbidity of systemic morbidity
• As tumor is visible on cervix ,easy to inject
• 1A2 & 11B 1 stages are eligible for SNB
• Nodes should harvest from each hemipelvis (laparoscopy is ok)
• If one side node is positive, complete lymph node dissection with
removal of all bulky nodes is essential

10. Influences to cervical cancer by SNB
• Help to identify unusual node + sites which may easily missed (10%
cases) with conventional approach.
• Allow tailoring of surgery in small volume cervical CA

11. SLNB in Endometrial carcinoma
• Corner stone of endometrial CA mx is TAH+BSO +/- LND
• There is a conflict on LND as full dissection has not shown overall
survival advantage
• But LN metastasis is important as a prognostic factor
• Some centers do not perform systematic LN dissection while some
perform only for Grade 3 endometrioid and other high risk histology
types In type 2 cancers
• SLNB shown to bring improved detection of LN metastasis than
conventional approach and impact on MX strategy

12. • Replacement of conventional systematic LND reduce acute & chronic
morbidity . Still evidence are lacking for this regard to endo CA
• LN involvement is low in grade 1 and 2 cancers
• But final grading is upgraded in about 15-30% pts. After surgery.
• Unfortunately positive node women miss with unattended LN
assessment
• Such women may benefit by SNB, while others anyhow undergo SNB.
• If SNB fails to identify positive node, then it is recommended for full
dissection on that side. Reason is problem with injection technique,
lymphatic blockage with larger tumors.

13. Site of Injection of dye/radiocolloid
• Cervical is preferred as it has detection rate 80-100%
• Better than hysteroscopic endometrial lesion injection (50-80%) as
potential dissemination of cancer cell to peritoneal cavity
• Injection to fundus is not much superior in detection of probable
missing nodes (false negative) with cervical route (Fundus to para-
aortic nodes may lead 1-6% nodes missing)
• This sub serosal fundal injection pre-operatively is uncomfortable for
patient and has 92% detection rate
• Only about 1-2% of women are having positive para-aortic nodes
while negative pelvic nodes

14. SENTI-ENDO study-France
• 125-early stage CA pts
• 75% pelvic SNB found
• 5% para-aortic SNB found
• 85-90% detection rate(sensitivity)-Hysteroscopy low detection rate
• 100% specificity
• False negative rate 0%
• NPV 100%

15. conclusion
• SNB is evolving and current evidence supports SNB and Systematic
LND rather conventional approach that has significant operative
morbidity and mortality with reduced QOL.

16. THANK YOU
References
1-FIGO cancer report 2018
2-RCOG SNB in endometrial CA SIP 2016
3-Kavitha S-Gynecology & obstetrics; challenges and
management options 1st edition 2016
4-Jamie N-Lymphadenectomy in the management of
gynecologic cancer ;2019