1.25.23 Mostafa Osteoporosis, antiresorptives, radiation

Question 1

Describe T-score and Z-score.

What value is osteopenia & osteoporosis?

Answer 1

T-score: Compares to healthy young adult 20-35 yrs old.

Z score: Compares to a person the same age & gender as yourself.

Osteopenia: -1.5 to 2.4
Osteoporosis: less than -2.5

Question 2

How is bone mineral density measured?

Answer 2

DXA/DEXA:
“Dual Energy x-ray absorptiometry”

Xrays of different energies are passed through the lower spine, hip, lower arm, wrist, fingers, heel.

Question 3

What are first-line and 2nd-line antiresorptive agents?

Answer 3

Chen & Sambrook 2012
First line: bisphosphonates, monoclonal antibodies (Denosumab)

2nd line: Estrogens, SERMs (selective estrogen receptor modulators), calcitonin

Question 4

Which bisphosphonate is more powerful, and by how much? : Nitrogen-containing vs. non- nitrogen containing

Answer 4

Non-nitrogen containing bisphosphonates are more powerful.
100 - 10,000x more potent

Question 5

What is denosumab?

Answer 5

Human monoclonal ab binding to RANKL

E.g.: Prolia, Xgeva

Question 6

What famous papers discuss MRONJ?

Answer 6

Ruggiero 2014 -AAOMS position paper

Ruggiero 2022 - AAOMS updated position paper
% risk of MRONJ:
Cancer patients:
Oral BP: N/A
IV BP (Zolendronate): 0-18% (<5% in most studies)
Denosumab: 0-6.9% (<5% in most studies)
Osteoporosis:
Oral BP: <0.05%
IV BP (Zolendronate): <0.02%
Denosumab: 0.3%

So, greatest risk of MRONJ is in cancer patients, and IV bisphosphonates. The Osteoporosis patients and oral BP patients are very low risk of MRONJ.

MRONJ definition:
1. History of antiresorptive tx
2. Exposed bone or probe-able bone present for >8 wks
3. No history of radiation or cancer of the jaw

Question 7

What are the stages of MRONJ?

Answer 7

Stage 0:no exposed bone. But, there are symptoms

Stage 1: exposed/necrotic bone or probe-able bone; no evidence of infection/inflammation

Stage 2:
exposed/necrotic bone or probe-able bone; patients are symptomatic and evidence of infection

Stage 3: exposed/necrotic bone or probe-able bone; patients are symptomatic and evidence of infection; lesion is extending beyond alveolar ridge, affecting the sinus, or causing widespread problems

Treatment: eliminate the infection & necrotic bone

Question 8

At what dose does radiotherapy have negative side effects?

Answer 8

≥50 Gy
Side effects:
* Persistent hyposalivation
* radiation caries
* periodontal disease progression
* soft tissue fibrosis
* trismus
* ORN (osteoradionecrosis of the jaws)

Anderson et al (Dr. Wang group) 2013
Decision guidelines: when is it safe to place implants?
* Don’t place during radiation, <14 days before radiation, <6 months after, and >24 months after.
* All other times are OK.
* Note: Dr. Wang placed implants >24 months after and it was ok. However, the bone may have fibrosis

Question 9

Is hyperbaric oxygen therapy useful in treatment of MRONJ?

Answer 9

Beth-Tasdogan 2017: Insufficient evidence regarding benefits

Question 10

What is osteoradionecrosis?

Answer 10

Unhealing bone lesion present for at least 6 months due to radiation damage

Question 11

What are the radiation dose risks?

Answer 11

≥120 Gy: Highest risk
75-120 Gy: high risk
65-74 Gy: relatively high risk
50-65 Gy: Moderate risk
≤50 Gy: Low risk. Can place implants with standard precautions

Question 12

What is implant survival in irradiated bone?

Answer 12

Non-irradiated residual bone: 95%
Irradiated residual bone: 72%
Grafted iliac: 54%

(so, placement into grafted bone decreases the survival even more)

Question 13

What is important to know before treating a chemotherapy patient?

Answer 13

Postpone procedure if:
* Platelet count ≤75,000 /mm3
* Neutrophil count ≤1000/mm3
*