Supra notch vs infranotch in advanced Gb sulcus tumours , what is operable How to decide, is there a need of new classification and staging

1. MANAGEMENT OF
SUPRANOTCH DISEASE
Dr Ankit Vishwani

2. Staging

3. Anatomy of Masticator Space (MS)
The MS -
● masticator muscles
● posterior body ,ramus of the mandible
● mandibular nerve ,the internal maxillary
artery.
Fascia enclosed pyramidal-shaped space
Base toward the skull base and the apex at the
lower border of the mandible
The foramina ovale and spinosum lie in the roof of
this space.

4. Anatomy of muscles
medial pterygoid muscle which originates from the
medial surface of the lateral pterygoid plate insert at
the medial surface of the vertical mandibular ramus.
lateral pterygoid muscle from the greater wing of
sphenoid and lateral pterygoid plate,insert into the
condyle of mandible .
The temporalis origin from the temporal fossa and
from the deep part of temporal fascia, Insert into
the coronoid process of the mandible
The masseter origin from zygoma and inserts into
outer surface of the vertical ramus near the
mandibular angle and the coronoid process.

5. T 4 b masticator space
● Cancer of the oral cavity adjacent to the MS and/or PP can deeply invade
into.
● Unfortunately, these are deep anatomic sites
Hence there’s difficulty in
● Surgical approach
● Clear preoperative imaging because of tumor infiltration
● Adequate surgical margins.

6. NCCN

7. Fact check -T4b doesn’t mean unresectable
The concept of considering tumors with masticator
space involvement as noncurable was challenged by
Liao et al. In 2006
Supranotch and infranotch by Liao et al
by a trans-axial plane which crosses the mandibular
notch in the axial section of the MRI/CT image.

9. ● Lateral pterygoid muscle ,the tendon of temporalis, the upper 2/3 of the
pterygoid plates lie in the supranotch compartment.
● The bulk of the masseter, medial pterygoid muscle ,lower ⅓ of pterygoid plates
parts lie in the infranotch

10. SPREAD from MS
In the MS, there are at least 2 possible ways for tumor spreading to occur.
● an upward invasion along the neurovascular bundle,
● medial to the lateral wall of the maxilla.
achieving appropriate safety margins requires an experienced head and neck
surgeon and a well-trained head and neck cancer team.

11. ● mandibular notch to the skull base is at only 2 cm
● inferior part of the PP to the skull base is about 3 cm.
● Thus achieving appropriate negative margins may be a challenge.
● Bleeding from pterygoid venous plexus also makes surgery technically
difficult.
All these factors combined with fear of poor eventual outcome may
contribute to clinicians deciding against offering curative intent treatment.

12. January 1996 to December 2000 Retrospective
103 T4 patients (reclassified by AJCC 2002) without carotid
artery encasement and skull base extension
58 T4a disease and 45 T4b disease -upfront surgery.
No statistical difference 5-year local control, neck control,
DFS and OS rates between the T4a and T4b groups
# most of there T4 b were infra notch #

13. Demonstrated a flaw in the staging system
● Aggressive surgery combined with adjuvant therapy, in T4 b can offer a
reasonable survival rate.
● They should not be deemed ‘‘unresectable’’ according to this staging
system
● Would certainly have no survival rate, (if not treated at all or treated with
another modality.)

14. ● oral oncology in 2007
● 45 T4b OSCC patients were included.
● 7 were supra-notch T4b and 38 were infra-notch T4b tumors.
● Significantly higher 5-year loco-regional control and survivals were observed in
infra-notch

15. The supranotch tumors had
● higher percentages of posterior masticator space involvement (supra-notch vs
infra-notch 71.4% vs 42.1%),
● nerve invasion (supra-notch vs infra-notch 71.4% vs34.2%),
● tumor depth 15 mm (supra-notch vs infra-notch)83.3% vs 50%), and
● tumor size 40 mm (supra-notch vs infra-notch 71.4% vs 47.4%).
● higher incidence for advanced-stage nodal metastases and extracapsular
spread (pN2 status 50% vs 31.6%, and extracapsular spread 50% vs 21%).

16. Conclusion by Liao et al
A radical tumor excision of curative intent needs safety margin of at least 1 cm.
Floor of the mandibular notch is an ideal landmark for safety for surgery
● the supra-notch tumors involved more MS/PP components
● the supra-notch tumors were close to the skull base
● the tumor behaviors seemed to be more aggressive in supra- than in
infra-notch tumors
They give a generalised statement that, a radical surgery should not be
performed in T4b OSCC patient with a supra-notch extension.

17. ITF
The exact boundaries of the ITF are a subject of controversy. All
definitions agree that is an irregular nonfascial lined space lying
medial to the inner surface of the vertical ramus of the mandible
and the zygomatic arch
The boundaries defined by Cummings are as follows; anteriorly,
by the posterior surface of the maxilla and the inferior orbital
fissure; posteriorly, by the mastoid and tympanic portions of the
temporal bone; and superiorly by the inferior surfaces of the
greater wing of the sphenoid
and the squamous portion of the temporal bone. The ITF
communicates with the temporal fossa cranially. Laterally the ITF
is bounded by the zygomatic arch and ascending ramus of the
mandible.3
The ITF is a nonfascial lined space containing much of the MS
(except masseter), the retroantral buccal fat and the medial part
of prestyloid PPS.

19. Trivedi et al reinforced the concept proposed by Liao et al.
● T4 b buccal cancer is an Indian disease
● involvement of the masticator space is purely due to the anatomic proximity
It would be inappropriate to label these patients as non treatable and bad
biology and proper evaluation of tumor resectability should be considered.

20. ● N 45 patients (T4b),prospective
● medial-pterygoid in 12 and both pterygoids in 22 cases ,masseter-muscle in 32
cases.
● Average margin after compartment surgery was 2 cm and positive in 3 cases.
● The group with involvement of medial pterygoid muscle had safest margin
● It was also possible to achieve negative margins for group involving lateral pterygoid
muscle and plates.
● The involvement of pterygomaxillary fissure was area of concern (developing local
recurrence with intracranial extension. )
● At 2 year follow up, 38 patients were alive without disease while 2 developed local
recurrence at the skull base.

21. They proposed further subclassification based on
their pathology study(section of specimen at intervals to know
involvement of various structures ) categorizing them in 3
groups.
Class I: low masticator space = medial pterygoid
and masseter muscles, ascending ramus of
mandible (infranotch).
Class II: intermediate masticator space = class I +
lateral pterygoid and temporalis muscle and lower
half of pterygoid plates (low supra-notch).
Class III: high masticator space = involvement of
pterygomaxillary fissure and intracranial extension
(high supra-notch).

22. The attempt was aimed at identifying
1 group of patients that has a high chance of cure,
1 group of patients in which there is potential for cure,
1 group of patients that is beyond cure.

23. The concept of compartment resection
Proposed to remove the entire anatomic compartment
of the masticator space in order to achieve improved
marginal control at depth (skull base).

24. 1All previously untreated, consecutive patients with advanced buccal cancer (T4b) treated at Mazumdar Shaw
Cancer Center, Bangalore, India, from March 2009 to June 2010 were included in this prospective series.
2Imaging evidence of masticator space involvement was the main criterion to stage patient as T4b.
Exclusion criteria
Patients with involvement of internal or common carotid artery, intracranial extension and pre-vertebral fascia
involvement were excluded from this study.
30 patients with advanced buccal cancer involving masticator space (T4b) were included in this study
Assessment of surgical margins for all these structures showed positive margins in only 2 (7%) patients. Anterior
mandibular bone margin was positive in one case, and pterygomaxillary fissure margin in one case. Rest of soft
tissue margins were negative in all cases

25. Masticator space
● multidimensional anatomy
● peritumoral edema
● pterygoid venous plexus causes severe bleeding
Conventional surgical approach
● surgical dissection through structures of the masticator space
● removed in piecemeal fashion resulting in compromised
margin control.
Compartment approach remove the entire anatomic unit of the
masticator space.
● Dissection in an anatomic facial plane around normal
structures
● Easy, repetitive, minimal bleeding.

26. Surgical considerations (prevention of
complications)
● The internal maxillary artery enters the compartment
between the 2 heads of the lateral pterygoid muscles.
This can be clamped early in the procedure.
● The use of hypotensive anesthesia when working
near pterygoid plexus
● Keeping surgical resection planes close to the
sphenoid bone
● Bleeding from the foramen ovale persistent -bone
wax

27. The entire content of masticator space is removed en bloc irrespective of the
extent of tumour spread into this area (both pterygoid muscles and masseter
muscle are removed from origin to insertion)

28. Masseter muscle is detached from zygoma,
Part of temporalis muscle is transacted to reach greater wing of sphenoid bone
Internal maxillary artery is ligated between two heads of lateral pterygoid muscles.
Condyle is included in resection if involved
Lingual and inferior alveolar nerves are cut at the level of foramen ovale.
Soft tissue dissection ends when we reach the root of lateral pterygoid plates.
If partial maxillectomy is planned, bone cuts pass through pterygomaxillary fissure and root of
pterygoid plates.
The specimen is delivered with pterygoid plates and whole medial and lateral pterygoid muscles

30. ● Masseter muscle is detached from zygoma,
● Part of temporalis muscle is transacted to reach greater wing of sphenoid bone
● Internal maxillary artery is ligated between two heads of lateral pterygoid
muscles.
● Condyle is included in resection if involved
● Lingual and inferior alveolar nerves are cut at the level of foramen ovale.

31. ● Soft tissue dissection ends
when we reach the root of
lateral pterygoid plates.
● If partial maxillectomy is
planned, bone cuts pass
through pterygomaxillary
fissure and root of pterygoid
plates.
● The specimen is delivered with
pterygoid plates and whole
medial and lateral pterygoid
muscles

32. ● With proposed resection, probably additional 2 cm of muscles of mastication
in masticator space is taken
● Even after conventional surgery, the residual portion of these structures do
not maintain any function(involved by a massive fibrosis)

33. The data regarding patients with supra-notch tumor extension is very minimal and
further studies are essential before labeling them as nontreatable
Results of all study of Supranotch including trivedu

34. N 282 T4 a and T4b ( prospective study July 2009 to December 2016.)
The pT4b category was further subdivided into Class I, II, III pathologically
66.9% Class I,23.7% Class II and 9.3% Class III.
The most commonly involved muscles
● the medial pterygoid (n = 81,68.6%) masseter (n = 66, 55.9%),
● lateral pterygoid (n = 30, 25.4%)
● temporalis (n = 13, 11.0%).
● The pterygoid plates (n=11 9.3%).

35. ● 282 patients/182 T4b
● Class I/II -174
● Margin control 87 %(Class I/II)
● Local control 78 % (Class I/II)
● Overall survival 59 %(Class I/II)
Inference
● Class I/II has good outcome
● Compartment surgery can obtain consistent margin control in them.

39. Downstage the tumor by neoadjuvant therapies
Joshi et al 9
Fang et al 10

40. Down staging Supranotch

41. 1. 79 patients T4b OSCC treated with CRT from January 2009 to December
2014,prospective
2. (IMRT), radical dose (median 70 Gy) with concurrent cisplatin.
3. 65 cases -partial or complete response after CRT,
● 33 were treated further Sx
● 32 with Non Sx
The 3-year LRC, OS, and CFS rates were respectively 72.3, 75.1, and 72.6 % in
the SRR group compared with 32.8, 47.7, and 44.3 % in the non-SRR group (p
<0.05)

42. For T4b OSCC,
● Incorporating SRR in the therapy is safe and has survival benefit, with a
significant response after CRT .
● Supra-notch tumor invasion, was observed in 52 cases (66%).
● Of the 52 cases,41 (80 %) had CR or PR and 27 (52 %) were converted to
infra-notch status.
● All cases had a margin free resection (complete resection rate, 100 %),
● Including the 9 cases with radiographically residual tumor in the supra-notch
area after CRT.
● No further adjuvant therapy was administered to any patient after SRR.
● The results of flap failure (9.2 %) or neck wound necrosis (12.1 %) were
comparable with those reported for preoperative CRT.

43. ● Prospective study ,N 210 , cT4 buccal mucosa ( excluding supranotch)
● All patients underwent upfront radical surgery followed by adjuvant
● T4a 135 T4b
● Local recurrence rate was similar for T4a 19.3%) and T4b (22.7%) disease
suggesting the importance of radical surgery in infra-notch T4b buccal
cancers
● For Supranotch disease they recommended NACT

45. Our experience and the evidence from the literature suggest that complete surgical
excision followed by adjuvant treatment makes T4b equivalent in outcome to T4a disease.

46. ● Retrospective
● N -721 T 4b technical unresectable OSCC (hyoid ,vallecula , supranotch
,zygoma)
● 2# NACT - SX +CTRT/RT vs no Sx
● 43 % had sufficient deduct to undergo surgery
● Over all cohort had LRC 24 months - 20% (32 % Sx vs 15% in non Sx)
● OS 19.6 months vs 8.16 months (Sx vs non Sx)

47. LITERATURE SUMMARY
● Aggressive surgery is key to improved outcome
● Low ITF ( class I) good outcome - stage should be changed to T4a
● Intermediate ITF ( class II) - subset of patients with Supranotch has potential to
cure( upfront surgery / nact + surgery)
● High ITF (class III) - pterygomaxillary fissure , foramen ovale and intracranial
extension should not be touched ( difficult to clear)

48. LITERATURE SUMMARY
● Compartment surgery should be standard approach to achieve consistency in
margin control for ITF.
● Approach to downstage is an interesting concept but needs larger studies.
● All further studies should report their results in a standard format(
classification )for uniformity and ease of interpretation.

49. Thank you