Ch 89 Mandibulectomy and maxillectomy Flashcards
dogs tolerate extensive oral surgery extremely well and that cats, although less tolerant of major oral tumor resections than dogs, can experience excellent short- and long-term results if surgical candidates are chosen carefully and managed appropriately in the early postoperative period
mandible
- body, horizontal component containing the teeth
- ramus, which is the vertical component that articulates with the skull at the temporomandibular joint and does not contain teeth
- The mandibular nerve provides sensory innervation (branch of the trigeminal nerve)
- courses through the canal as the inferior alveolar nerve; and exits laterally through the mental foramina
- The mandibular and sublingual salivary ducts course medial to the body of the mandible (transection of the ducts without ligation does not usually lead to complications)
List the major muscles of mastication (and their origin and insertion)
MTPD
Masseter (Zygomatic arch to lateral body and ventral ramus)
Temporalis (Temporal region of skull to dorsal ramus)
Pterygoideus (Pterygoid, sphenoid and palatine skull to angular process of ramus)
Digastricus (Occipital region of skull to ventral body)
What is the major blood supply to the mandible?
And to the maxilla?
Mandible - Inferior alveolar artery (branch of the maxillary artery)
Maxilla - Major palatine artery and infraorbital artery (both branches of the maxillary artery)
maxilla
- major palatine artery courses through the caudal nasal cavity, passes through the caudal portion of the hard palate via the caudal palatine foramen (Ligation does not have adverse effects)
- The infraorbital artery courses through the caudal nasal cavity, passes through the maxillary foramen and infraorbital canal of the maxilla, exiting laterally through the infraorbital foramen (can be transected without adverse consequences)
- infraorbital nerve (can be transected without adverse consequences)
- parotid salivary gland and zygomatic salivary gland; the ducts can usually be transected during maxillectomy without adverse consequences
List the three bones of the maxillary region
Maxilla - Contains the molar, premolar and canine teeth
Incisive bone (Premaxilla) - Contains the incisors
Nasal Bone - Long, slender bone on dorsal midline
List the most common types of oral tumours in dogs in order of decreasing frequency
Give the metastatic rate of each
Malignant melanoma - 81%
SCC - 20 - 82%
Fibrosarcoma - 35%
Osteosarcoma - v. high
Acanthomatous ameloblastoma - 0%
Each has significant potential to invade surrounding tissues
tumor biology
- Each has significant potential to invade surrounding tissues
- however, they vary significantly in their metastatic potential
- Fibrosarcoma may occur in a histologically low-grade, biologically high-grade variant ( fibrous connective tissue microscopically but aggressively invades bone)
- OSA: survival times after surgical excision appear to be superior to appendicular OSA
- MM: tumor is often darkly pigmented but may be amelanotic
reasonably accurate guess regarding tumor type
- MM, SCC and FSA usually arise from the gingiva
- MM tends to affect older small-breed dogs
- SCC tends to affect older large-breed dogs, often has a flat, ulcerative appearance
- FSA usually affects middle-aged and older large-breed dogs (near the maxillary carnassial)
- OSA medium- and large-breed dogs and may arise in the maxilla or mandible
non malignant
- canine acanthomatous ameloblastoma (CAA) typically occurs in the rostral portion of the mouth
Define canine acanthomatous ameloblastoma (CAA), peripheral odontogenic fibroma (POF) and focal fibrous hyperplasia (FFH)
CAA - A nonmetastatic but locally invasive tumour arising from the adontogenic tissue. looks like SCC. Typically treated with mandibulectomy or maxillectomy
POH - A slow-growing, firm, pedunculated or broad based tumour originating from the gingiva, May be fibromatous or ossifying. Can have good success with local resection however removing the bone surrounding the involved tooth gives higher chance of cure
FFH - Benign reactive lesion resulting from irritation caused by plaque or calculus
List the most common forms of oral neoplasia in the cat
SCC - by far the most common and is very locally invasive making complete excision very challenging
Also can get FSA and OSA
Feline Oral Tumors
Biologic Behavior
- SSC may arise in either sublingual or gingival mucosa
- highly invasive
- Tumors involving the mandible often have intramedullary extension of the tumor well beyond the gross limits of the mass.
- often occur caudal to the canine teeth
- 20% to 30% regional lymph node metastases
FSA and OSA
- associated with low rates of distant metastases
- locally invasive; however, excellent long-term survival data in cats undergoing mandibulectomy
List the predisposing factors for oral SCC in cats
Flea collars
Eating canned food (esp tuna)
Environmental tobacco smoke
Preoperative staging > imaging
RADS
- Thoracic radiographs for pulmonary metastases > yield of this test is generally low but = contraindication to aggressive surgery
- plain radiographs tend to underestimate the extent of bone destruction and are an unreliable tool for surgical planning
- poor representation of the degree of involvement of normal soft tissues
CT/MRI
- superior modalities for assessing bony and soft tissue margins (especially when caudal, midline or dorsal explansion)
pre-op staging > biopsy + lymph nodes
biopsy
- beccause of similar potential for local invasiveness, the histologic type strongly influences the chances for survival but minimally impacts the surgical plan
- Alternatively, cytology from a deep aspirate or needle insertion
- consdier surgical margins when perforing biopsy
regional lymph nodes
- mandibular, parotid, and medial retropharyngeal
- size as determined by palpation is an unreliable indicator (MM study, low sens ad spec)
- Cytologic examination
- lymph node extirpation of 3 ideal, can be perfomed pre-op
- 35.5% evidence of metastases to one or more of the three lymph nodes; however, of these, only 54.5% had metastases to the mandibular node
What is the diagnostic accuracy of FNA for oral neoplasia?
95%
Surgery
Owner Preparation
thorough description of the cosmetic and functional results of surgery before making a decision.
Preoperative Patient Preparation
- considered clean-contaminated procedures
- Administration of prophylactic broad-spectrum antibiotics can be considered optional rather than essential
Local nerve blocks
- 0.5 to 1.0 mL of 0.5% bupivacaine
- rostral mandibulectomy: rostral to the mental foramen at the level PM2
- entire body: mandibular n. near the mandibular foramen, medial side angle of the mandible.
- The rostral maxilla: infraorbital n. at infraorbital foramen dorsal PM4
- entire maxilla: blocked by injecting the maxillary nerve
haemostasis
- inferior alveolar artery must be identified and ligated during mandibulectomy.
- major palatine artery or infraorbital artery may need to be transected and ligated during partial maxillectomy
- hemorrhage nasal cavity: electrocautery, gelatin sponges, and topical epinephrine
- Temporary or permanent occlusion of the carotid arteries
How can you use epinephrine to control diffuse haemorrhage from nasal turbinates during maxillectomy?
Dilute 1mg/ml epinephrine 1:10 in sterile saline. Several mls are then used to fill the nasal cavity defect and left in place for 30-60 seconds prior to being removed with suction
Mandibulectomy
- Bone should always be transected between tooth roots at least 1 cm from the margin of the tumor.
list types of mandibulectomy
- rostral: excision some or all of the lower incisors +/- canines
- central: segment of body, including premolars and/or molars
- caudal: removal of all or a portion of ramus
- hemimandibulectomy: entire one half of the mandible
Rostral and Central Mandibulectomy
- gingival margins should be 0.5 cm beyond the level of the planned bone transection
- the oral mucosa, labial mucosa, muscular attachments, and skin are transected and dissected away
- Transection of the mandibular body may be performed using an oscillating saw
- inferior alveolar artery ligated/cauterised
- small tumors confined to incisors, it may be possible to preserve symphysis by transecting the bone across canine tooth roots and then removing the remnants of the roots
- Preservation of the integrity of the symphysis and mandibular body likely reduce postoperative pain
- resection specimen and wound bed should be closely inspected to ensure that margins appear adequate.
- objective is to restore mucosal integrity over the transected bone ends without excessive tension
- synthetic monofilament or braided absorbable suture material
- Extensive rostral mandibulectomies are somewhat prone to dehiscence over the transected bone ends
Caudal Mandibulectomy and Hemimandibulectomy
- The cheek may be transected full thickness from the commissure of the lip to the level of the caudal border of the ramus to improve exposure
- zygomatic arch removal dramatically improves exposure of the dorsal ramus and the temporomandibular joint (can be replaced)
- soft tissue structures 1 cm from tumor: masseter, digastricus, temporalis, and pterygoid muscles and the capsule of TMJ
- inferior alveolar artery must be identified, ligated,
- Hemimandibulectomy: first completing the soft tissue dissection and transecting the symphysis > rotate out
- Cosmetics improved by advancing the commissure of the lip rostrally to prevent the tongue from lagging
Maxillectomy types
- rostral: all of the incisors and occasionally one or both canine teeth +/- nasal planum
- central: premolar teeth/canine/molar
- caudal: bone surrounding the molar teeth +/- ventral orbit +/- zygomatic arch.
Rostral and Central Maxillectomy
- sharp incision of the overlying soft tissues (labial mucosa, gingiva, and palate).
- Electrocautery can be used to control diffuse bleeding
- bone of the maxilla and hard palate is relatively thin > use osteotome (Major arteries or nerves are not encountered)
- central maxillectomy > transect and ligate the major palatine and infraorbital arteries
- Ligatures or metal clips > control major arterial bleeding.
- Diffuse hemorrhage nasal turbinates > electrocautery, direct pressure, and gelatin sponges.
Caudal Maxillectomy
- exposure can be improved by full-thickness incision of the cheek from the commissure of the lip
- caudal border of the resection is usually located in either the soft palate or the hard palate > major palatine artery must be ligated or cauterized
- Ligation of artery easiest after all osteotomies; the caudal osteotomy should be completed last
- Oral tumors ventral to the eye may require transection of the rostral zygomatic arch
- consdier: combining intraoral approach with a rostral-to-caudal skin incision situated over the dorsolateral aspect of the maxilla.
- closure: suturing the labial to the palatine mucosa +/- dorsally based flap of labial to reduce tension +/- preplaced holes in the bone of the hard palate
- extends beyond the midline of the palate, the superficial cervical axial pattern skin flap or the angularis oris axial pattern buccal flap may be used
How can you prevent ventral drooping of the nose after rostral maxillectomy?
Dorsal nasal cartilage can be sutured to pre-drilled holes in the nasal bone prior to closure
Post-op care
- analgesia
- Bilateral rostral mandibulectomy with complete removal of the symphysis tends to be the most painful (independent movement)
- An esophagostomy or gastrostomy tube can be considered
- soft food only 1-2 weeks
- substantial facial swelling in the early postoperative period that may take several days to resolve
- The skin overlying maxillectomy sites may rise and fall with respiration
complications (6)
- Haemorrhage (maxilla)
50% excessive bleeding, 24- 50% need transfusion
1.4% for mandible - intraoral dehiscences
some dehiscences will heal by second intention, less likely to if over bone ends > removing small amounts of additional bone to limit pressure on the incision, and resuturing - oronasal fistulas
many asymptomatic and can simply be monitored, those that result in food impaction and nasal discharge or halitosis > repeat surgery - inadvertent trauma to residual tooth roots
- mandibular drift
chronic TMJ pain, difficulty drinking or prehending, and pressure sores and ulcerations of the palate and lips from dental malocclusion - tongue may lag from the mouth, increased drooling
What can be used to close large or recurrent oronasal fistulas?
The angularis oris axial pattern flap
cosmetic/functional changes
- near-complete removal mandibular bodies bilaterally or bilateral rostral maxillectomy with nasal planum excision
- both mandibles: likely to require hand feeding for life and may need to be given water via bulb syringe
- may be difficult to for owners
Describe two option to improve mandibular drift post hemimandibulectomy
prevention?
Use or orthodontic rubber chains from canine tooth of intact mandible to ipsilateral 4th maxillary premolar. Needs to be changes weekly and requires good compliance
Removal or shortening of the mandibular canine tooth to prevent trauma of the hard palate
Prevention?
- mandibular reconstruction with locking reconstruction plates (Arzi 2019)
Mandibular Regeneration and Immediate Reconstruction
Implantation of a precontoured titanium locking plate with implantation of calcium-collagen, compression-resistant matrix impregnated with recombinant human bone morphogenic protein 2 (rhBMP-2)
rhBMP-2 is contraindicated in surgical sites with tumour cells. May have to stage procedure to confirm complete margins prior to implantation
What long-term follow-up is recommended after mandibulectomy or maxillectomy
During first 2 years, 3-4 monthly incision inspection to assess for local recurrence
What major difference is there for post-op care of cats compared to dogs after mandibulectomies?
Most cats will not eat for prolonged periods and an oesophagostomy tube should always be placed at the time of surgery.
A small proportion of cats never regain the willingness to eat, most of which have had >50% of the body removed
List some general prognosis conclusions based off of multiple studies
- Aggressive surgical management improves prognosis. 1yr survival of 70-90% is common with recurrence under 50%
- Tumour type strongly influences survival. Malignant melanoma and OSA assoc with poorer survival due to high met potential
- Tumour location strongly influence local recurrence. Caudal = poorer prognosis
- Incomplete excision is a negative prognostic indicator. Recurrence 15-22% for completely excised tumours vs 62-65% incomplete
- Rostral SCC and Acanthomatous ameloblastoma good chance of surgical cure
- FSA have a comparable high recurrence rate (often located caudal)
Interpretation complicated by incomplete follow-up and variablendpoints
What is the prognosis with surgical excision of oral tumours in cats?
Recurrence 43% (SCC is very locally invasive and is often not amenable to complete excision)
Progression free survival 56% 1yr, 49% 2yr
SCC associated with shorted survival time than FSA or OSA
What are the reported complete remission rates of gross melanoma after hypo-fractionated radiation therapy?
54-69%, median progression free survival 7.9m (vs 36m SCC and 26m FSA)
What is the reported effect of intralesional cisplatin on oral malignant melanoma?
70% of tumours decreased in volume by 50% or more (20 dogs)
What is the reported effect of systemic carboplatin in dogs with gross oral malignant melanoma?
28% of dogs had a reduction in tumour volume of more than 50%
What is the melanoma vaccine?
A xenogenic vaccine which targets tyrosinase, an enzyme which is overrepresented in malignant cells and is essential for the production of melanin
malignant melanoma is considered to be a relatively radiation-resistant tumor
unknown efficacy
chemo
recent multi-institutional study of 151 dogs with oral melanoma treated by excision with or without systemic adjuvant therapies was unable to demonstrate that adjuvant therapies conferred a survival benefit
Radiation
Much of the available information concerning the responsiveness of various oral malignancies to radiation therapy comes from retrospective studies of dogs that either did not have surgery or that had residual gross disease after surgery.
data suggest that because the common oral malignancies are frequently responsive to radiation and large tumors are less responsive than small tumors, postoperative irradiation has the potential to provide excellent long-term local control when used to treat microscopic volumes
The use of a sling suture for ventral orbital stabilization
after inferior orbitectomy in three dogs
Logothetou 2024
The nylon sling suture provided a quick, easy, safe and effective technique to stabilize the ventral orbit during a combined caudal maxillectomy and
orbitectomy in dogs.
Periorbital tumors are commonly malignant with
multilobular tumor of bone (MLO), osteosarcoma (OSA),
SCC and FSA being more frequent.
orbital instability can occur following partial
orbitectomies, leading to complications including strabismus, blindness, conjunctivitis, infection and neurological signs if a craniotomy is performed.
alternatives:
1. temporalis muscle flap
2. temporalis fascia transposition flap
3. masseter muscle flap
4. plate reconstruction
5. orthopedic wire covered/collagen sheet
6. three-dimensional (3D) printed tissue engineered constructs
Kinematic analysis of mandibular motion before and after mandibulectomy and mandibular reconstruction in dogs
Boaz Arzi 2019
AVJR
cadavers of 16 dogs
Both unilateral segmental and bilateral rostral mandibulectomy resulted in significantly greater mandibular motion and instability, compared with results for intact mandibles.
These alterations were corrected after mandibular reconstruction with locking reconstruction plates. Findings reinforced the clinical observations of the beneficial effect of reconstruction on mandibular function and the need for reconstructive surgery after mandibulectomy in dogs
Feline maxillary sarcoma:
clinicopathologic features
of spindle cell sarcomas
from the maxilla of 25 cats
Alexandra Harvey 2022
Feline maxillary sarcomas are aggressive spindle cell neoplasms that occur within the
maxilla, palate and upper lip of cats. This diagnosis includes fibrosarcoma and sarcomas with indeterminate
histomorphology, excluding melanocytic tumors and sarcomas that can be differentiated by histomorphology
In this study of feline maxillary sarcomas in 25 cats, the cats’ ages ranged from 4 to 16 years (median 12.5). These
sarcomas presented as smooth thickenings or mass lesions of the gingiva and palate,
may be difficult to
differentiate from a benign, reactive process or other types of spindle cell neoplasms
Cats were often euthanized because of local recurrence following incomplete tumor excision and local
tumor progression. Median survival time from the date of histologic diagnosis was 70 days (n = 12).
Inter- and intraobserver agreement for CT measurement of
mandibular andmedial retropharyngeal lymph nodes is
excellent in dogs with histologically confirmed oralmelanoma
Brad Cotter
VRU
While size alone is considered inadequate for
detecting nodal metastasis,
In conclusion, this study demonstrates that follow-up measurement
of the long and short axis of mandibular lymph nodes and the
short axis of medial retropharyngeal lymph nodes in the transverse
plane can be performed by different veterinary radiologists with minimal
impact on clinical decisionmaking.
CT features of malignant and benign oral tumors in 28 dogs
VRU
However, there was a considerable overlap
of CT findings among the different types of oral tumors and between benign and
malignant tumors. Histological evaluation therefore remains necessary for definitive
diagnosis.
Common CT features of malignant tumors included heterogeneous
enhancement, tumor invasion into the adjacent bone, tooth loss, and ipsilateral
mandibular lymphadenopathy. Malignant tumors were significantly larger than
benign tumors. Bone lysis was found in benign tumors (n = 4) such as acanthomatous
ameloblastoma, giant cell granuloma, and plasmacytoma.
ONCEPT
Dogs with caudal oral tumors, primary
tumors≥2 cm, higher clinical stage (stage 2 or 3),LNinvolvement,
higher MI, presence of bone lysis, and presence of gross disease had
higher risk of tumor progression and death in the univariable analyses.
prospective controlled study is needed to determine the clinical
benefit of ONCEPT
Clinicopathological features
of peripheral odontogenic fibromas
in dogs and risk factors for their
laboratory diagnosis
- They often displace teeth and can appear aggressive macroscopically, but do not invade bone or metastasise.
Piezosurgical bone-cutting technology reduces risk
of maxillectomy and mandibulectomy complications in dogs
Warshaw 2023
41 maxillectomies and 57 mandibulectomies met the inclusion criteria (98 in total). Only 1 (1.02%) case was associated with excessive surgical bleeding requiring administration of blood products.
CLINICAL RELEVANCE
intraoperative hemorrhage requiring the use of blood products during mandibulectomy or maxillectomy is rare when using a piezoelectric unit to perform osteotomies, and is substantially lower than oscillating saws or other bone-cutting devices
rapid identification of hemorrhage may be difficult or impossible in locations where vessels may retract into osseous recesses
Piezosurgery > Due to a better visibility and to the sparing-effect on soft tissues, blood vessel damage is reduced
Piezoelectric surgery utilizes ultrasonic micro-oscillations at a rate of 28 to 36 oscillations/s, which allows the instrument to cut mineralized tissues with precision while sparing the soft tissues
Histomorphological studies have demonstrated that piezoelectric surgery results in increased local expression of bone morphogenic proteins and transforming growth factor as well as decreased inflammatory cytokines such as interleukin 1β for better bone healing compared with conventional surgery
One cited disadvantage of piezoelectric surgery is relatively increased surgical time
temporary or permanent carotid ligation risks and complications:
- hemorrhage,
- prolonged surgical time,
- trauma to the vasosympathetic trunk, recurrent laryngeal nerve, and internal jugular vein.
- hematoma formation,
- retinal damage,
- cerebral ischemia
Zygomatic arch reconstruction with a patient-specific polycaprolactone/beta-tricalcium phosphate scaffold after parosteal osteosarcoma resection in a dog
Kang 2022
Comparison of unilateral rostral, middle and caudal segmental mandibulectomies as an alternative treatment for unilateral temporomandibular joint ankylosis in cats: an ex vivo study
Lenin A Villamizar-Martinez 2021
30 cadaver heads
The mean postoperative recovered range of mandibular motion for the rostral, middle and caudal segmental mandibulectomies was 50.4%, 81.9% and 90.4%, respectively.
removal of a minimum of 1.2 cm of the caudal mandibular body was required to achieve nearly full recovery of presurgical mouth opening in the specimens of this study. The caudal segmental mandibulectomy may eliminate the risk of iatrogenic periarticular neurovascular damage inherent to more invasive surgeries performed at the temporomandibular joint area.
alternative to:
Surgical procedures such as gap arthroplasty, condylectomy or wide extra-articular osteotomy have been recommended to treat this condition; these techniques are challenging, time-consuming and have been occasionally associated with postoperative recurrence, severe periarticular neurovascular iatrogenic trauma and death
Analysis of risk factors associated with complications following mandibulectomy and maxillectomy in dogs
Cray 2021
risk factors n=459 dogs
- complications: 171/459 (37.3%)
62.1% minor, 30.8% major
- risk factors:
increased surgical time
pre-op RT or chemo → increased odds of dehiscence or oral fistula
maxillectomy (esp caudal)→ increased odds of dehiscence or fistula vs mandibulectomy
- for tumour recurrence: malignant tumours, largest tumour dimension
- for blood transfusion: largest tumour dimension, maxillectomy, caudal resection
Survival time of juvenile dogs with oral squamous cell carcinoma treated with surgery alone: A Veterinary Society
of Surgical Oncology retrospective study
Surabhi Sharma 2021
Retrospective study.
Animals or sample population: Twenty-five dogs, <2 years of age (18 were <12 months)
none had mets. Histological margins were complete in 24 dogs and incomplete in one
No dogs had evidence of metastatic disease or tumor recurrence
median follow-up time was 1556 days
Median disease-specific survival time
was not reached.
Conclusion: The prognosis after wide surgical excision of OSCC in juvenile
dogs was excellent
Twenty dogs (80%) had a rostral tumor location,
risk factors and the potential relationship between canine papilloma virus and OSCC.
Results indicated histologic evaluation of only 1 MLN was insufficient to
definitively rule out lymph node metastasis in dogs with OMM or OSCC;
therefore, bilateral lymphadenectomy of the MLN and MRLN lymphocentra
is recommended for such dogs
grimes 2019
Bilateral caudal maxillectomy for resection of tumors crossing
palatal midline and use of the angularis oris axial pattern flap
for primary closure or dehiscence repair in two dogs
Tuohy 2019
Outcomes following surgical excision
or surgical excision combined with adjunctive,
hypofractionated radiotherapy in dogs
with oral squamous cell carcinoma or fibrosarcoma
Julia Riggs 2018
Dogs undergoing postoperative
radiotherapy after incomplete excision of oral SCCs had a significantly
longer MST (2,051 days) than did dogs with incompletely excised tumors
and no radiotherapy (MST, 181 days). Postoperative radiotherapy of dogs
with incompletely excised FSAs did not appear to offer protective value
Goldschmidt 2023 – contrast-enhanced and indirect CT lymphangiography for SLN in oral tumours
Plos 1
SLN identified in 38/39 (97%) → correct draining centre in 100% of metastatic nodes
- overall 33% metastatic nodes, most commonly ipsilateral mandibular LN
- confined to SLN in 85%
- contrast-enhanced CT: short axis length >10.5mm may predict metastasis
- ICTL features not accurate for prediction of metastasis
- tumour distribution: MM 67%, 28% met; SCC 10%, 50% met; MCT 5%, 100% met
APOT 5%, 0% met; AA 2.6%, 0% met; Carcis 2.6%, 0% met
FSA 2.6%, 100% met; HSA 2.6%, 0% met; e-LSA 2.6%, 100% met
de Mello Souza 2019 – ventral mandibulectomy
proposed advantages: easy identification of anatomic structures, zygomatic osteotomy not
required for caudal mandibulectomy, concurrent LN extirpation
Carroll 2020 – maxillary artery ligation prior to caudal maxillectomy via modified combined
dorsolateral-intraoral approach
exposure and ligation of maxillary artery at the rostral aspect of orbit
- modified DL-IO with pre-ligation → 1/16 (6%) intra-op transfusion, 19% hypotension
- traditional DL-IO → 4/6 (67%) intra-op transfusion
Goldschmidt 2022 – review, surgical margins for excision of AA
- 5-10mm margin may be most appropriate
- complete removal of periodontal ligament may not be required
Polton 2024 – consensus statement and guidelines
Surgical resection using wide margins is currently the mainstay of therapy for the local control of melanomas, regardless of primary location. CT imaging is the optimal strategy for surgical planning of jaw-invasive melanoma.
Surgical excision of tributary lymph nodes in oral, subungual, footpad and cutaneous melanoma is recommended. It adds important information regarding the clinical stage of the disease and it improves local tumor control.
When adequate local control cannot be achieved surgically, radiotherapy should be considered.
Immunotherapy appears to be the optimal method of treating microscopic disease, provided that macroscopic disease is effectively controlled.
The ONCEPT® Canine Melanoma Vaccine has an evidence base for treatment of stage 2 and 3 malignant melanoma with adequate local tumor control.
There is limited scientific literature to support the use of other medical therapies for melanoma.
Location is the major prognostic factor, although it is not completely predictive of local invasiveness and metastatic potential. The oral/mucosal subtype carries the worst prognosis, with a high degree of local invasiveness and high metastatic potential, and reported MST between 3 and 24 months,
More recent reports suggest dogs with stage 1 oral melanoma treated with standardized therapies, including surgery, radiotherapy, and/or chemotherapy, have an MST of approximately 12 to 14 months, with most dogs dying of distant metastatic disease, not local recurrence
Liptak 2021 – maxillectomy in 60 cats
- complications: post-op 56.7% - hyporexia 20.0%, dehiscence 20.0%
- hyporexia median duration 7 days- 68.3% malignant tumours → 18.3% local recurrence, 4.9% metastatic rate (SCC)
- mPFI, MST not reached
- survival: benign: 1y 100%, 2y 79%
malignant: 1y 89%, 2y 89% - FSA 94%, 94%; SCC 83%, 83%; OSA 80%, 80% - poor px for: PFI – mitotic index, adjuvant chemotherapy
survival – adjuvant chemotherapy, local recurrence
