Miscellaneous H/N Oncology Flashcards
(9 cards)
Free Flap Microvascular reconstruction of Medication Related Osteonecrosis of the Head and Neck
1) Osteonecrosis is associated with Bisphosphonate use
- This condition is rare
2) Conservative management of Osteonecrosis of the Maxilla or Mandible
- Debridement
- Antibiotics
- Maximizing oral hygiene
- Medications that improve blood flow
3) Treatment of Osteonecrosis of the jaws when conservative management fails:
- Free flap reconstruction
- Free flap reconstruction is highly successful in these patients: 96% success
4) Indicators of success or failure in FF reconstruction of MRONJ
- Preoperative antibiotic use improves success, but post op abx use does not improve success
- Edentulous patients more likely to have preop pathologic fractures
- Below normal serum Albumin were more likely to have a preop pathologic fracture compared to those with a normal serum Albumin level
- Preop Tobacco use associated with higher rates of external hardware exposure
- FF survival rate is lower in those with preoperative EtOH use
Resource: Microvascular Reconstruction of Medication Related Osteonecrosis of the Head and Neck. Sweeny L, Long SM, et al: Head Neck; 2024; 46 (August): 1902-1912
Squamous Cell Carcinoma of the Lungs: is it a second primary or a distant metastasis?
Squamous cell carcinoma of the lungs in a patient with SCCA of the head and neck:
1. In patients with distant mets not involving the lung, 30% of patients had no match between the primary tumor and the distant met
2. In patients where the lungs were the only organ involved, 36% had a match between their primary tumor and the distant met, while 64% did not match
Note: The comparison of the distant met to the primary tumor was made by comparing targeted sequencing of 22 genes as well as HPV genotype
Resource: Separating Distant Recurrences From Second Primaries in Head and Neck Squamous Cell Carcinomas - A DAHANCA Group Analysis on Paired Tumor Samples. Kjems J, Lilja-Fischer JK, et al: Head Neck; 2024; 46 (October): 2532-2539
What is the definition of Mandibular Osteoradionecrosis (MORN)?
Nonhealing irradiated bone exposure of greater than 3 months duration without evidence of neoplasia.
What are the proposed theories of the pathophysiologic mechanism of mandibular osteoradionecrosis?
I. Oldest explanation - sequence
1. Radiation
2. Hypoxic-hypocellular-hypo vascular tissue
3. Tissue breakdown
4. Chronic nonhealing wounds
II. Radiation Induced Fibro atrophic Process: ORN is a consequence of activation and dysregulation of fibroblastic activity, propagated by free radical production, endothelial dysfunction, microvascular thrombosis, and local inflammation which leads to fibro atrophic tissue prone to chronic wound formation
III. Bacterial inoculation and infection lead to ORN
What is the staging classification systems for mandibular osteoradionecrosis?
There are multiple staging systems, but the most widely used is the Notani system. The inferior alveolar nerve canal (IANC) is used as a critical landmark.
I. Stage I - confined to the alveolar bone
II. Stage II - Limited to alveolar bone and mandible above the level of the IANC
III. Stage III - Any involvement below level of the IANC, including pathologic fracture and orocutaneous fistula
What is the current treatment of mandibular osteoradionecrosis?
The treatment paradigms are based on the disease stage:
I. Early of moderate disease treatment options:
1. Close observation
2. Early surgical sequestrectomy or saucerization
3. Hyperbaric Oxygen Therapy (HBOT)
4. Targeted medical therapy
II. PENTO/PENTOCLO
1. Pentoxifylline - a vasodilator with antitumor necrosis factor, anti-inflammatory, and antiplatelet aggregation properties that increase erythrocyte flexibility and decrease blood viscosity.
2. Tocopherol - a potent antioxidant that prevents oxidative reactions driven by reactive oxidative species such as lipid peroxidation of cell membranes, including the endothelium, which may impact arterial blood flow. It is also a partial inhibitor of transforming growth factor Beta1 which also reduces inflammation and tissue fibrosis.
III. Surgical Therapy:
1. When the above fail, progression of the disease necessitates segmental resection and microvascular reconstruction with osteocutaneous free flaps. This is effective at controlling MORN and restoring mandibular continuity, but incurs significant morbidity.
- Segmental resection of the mandible with osteocutaneous free-flap reconstruction is the established gold-standard for advanced disease. Patient’s with MORN are at higher risk for flap complications (21%-60%) and flap loss (as high as 20%).
- Fascia-only variation of the Anterolateral Thigh Fascia Lata Rescue Flap: a transoral marginal mandibulectomy with debridement of nonviable necrotic bone sequestrectomy, dental extraction, or removal of dental hardware as needed, followed by imbricated coverage and obliterated of the defect with vascularized fascia lata. Iliac crest bone graft may also be utilized to promote bone formation. There is a 96% successful arrest of MORN with very little morbidity.
Note: There are no robust trials supporting any of these options as gold-standard therapy.
What is PENTO/PENTOCLO therapy for mandibular osteoradionecrosis?
I. Medications:
1. Pentoxyfylline is a vasodilator with antitumor necrosis factor, anti-inflammatory, and antiplatelet aggregation properties that increase erythrocyte flexibility and decrease blood viscosity.
2. Tocopherol is a potent antioxidant that prevents oxidative reactions driven by reactive oxidative species such as lipid peroxidation of cell membranes, including the endothelium, which may impact arterial blood flow. It is also a partial inhibitor of transforming growth factor Beta1 which also reduces inflammation and tissue fibrosis.
3. Clodronate is a first-generation oral alkylbisphosphonate that reduces osteoclast activity, inhibits fibroblast and macrophage proliferation, and promotes bone formation by osteoblasts. It has been suggested as an addition to PENTO in managing MORN.
- Biphosphonates (both oral and intravenous) are associated with medication-related osteonecrosis of the mandible. Biphosphonate-induced osteonecrosis of the mandible ranges from 2.5% to 27.3%
II. PENTO vs PENTOCLO - PENTO has been found to be superior to PENTOCLO.
Hyperbaric Oxygen Therapy for mandibular osteoradionecrosis - is it effective?
HBOT is not effective in the treatment of MORN. A meta-analysis of 4 randomized controlled trials and 7 cohort studies assert that HBOT is not a substitute for surgical and antibiotic treatment. HBOT is also not effective in preventing MORN after dentoalveolar surgery. There is no conclusive evidence to support HBOT combined with surgery or as single modality treatment.
