This document discusses the importance of dental clearance for cancer patients prior to starting cancer therapy. Certain medications used in cancer treatment like bisphosphonates and monoclonal antibodies have been linked to osteonecrosis of the jaw (ONJ). Dental clearance, which involves treating any existing dental issues, can help prevent ONJ and other dental complications that can negatively impact a cancer patient's quality of life. The document emphasizes that all cancer patients should receive dental clearance before starting treatment given the risks to oral health posed by various cancer therapies and medications.

1. Dental clearance
of cancer patients
- A preventive
step in oncology
therapy.
Barrett R, Tasgaonkar N.

2. DENTAL CLEARANCE SHOULD BE AN ESSENTIAL STEP IN THE
PLANNING OF THERAPY FOR PATIENTS WITH HEAD AND NECK
CANCERS, AND FOR PATIENTS SUFFERING FROM ALL OTHER
TYPES OF CANCER.
CANCER PATIENTS DISPROPORTIONATELY SUFFER FROM
OSTEONECROSIS OF THE JAW (ONJ) WITH DIMINISHED
QUALITY OF LIFE. WE WILL HIGHLIGHT THE PROBLEMS WITH
RADIATION THERAPY AND SEVERAL MEDICATIONS THAT HAVE
POTENTIAL TO INDUCE ONJ.

3. Radiation and medicines
Radiation [1] and medicines are known to precipitate ONJ. Medicine such as
bisphosphonates [e.g. ibandronic acid (Bondronat®, Iasibon®, Bonviva®,
Quodixor®), pamidronate disodium, risedronate sodium (Actonel®), sodium
clodronate acid (Loron®, Bonefos®, Clasteon®), zoledronic acid
(Aclasta®,Zerlinda®, Zometa®)] and monoclonal antibody [e.g. human
denosumab (Prolia®, Xgeva®), bevacizumab (Avastin®)] amongst potentially
others [2,3] are known to cause medication-related ONJ (MRONJ) and they
should be reviewed prior to cancer therapy. These medicines are
administered orally, intravenously, intramuscularly and subcutaneously in a
variety of time intervals including weekly, monthly, six times a year, annually,
only for four doses, or for 4 years.

4. Barriers to healing
Through their mechanisms of action [4,5], these medicines reduce blood
circulation to the bone and pose barriers to healing over potentially a longer
time frame than previously assumed [6] due to potential underreporting of
adverse drug reactions.[7]
Cancer therapies, especially for hormone-dependent cancers (e.g.
blood, breast, testes and prostate organs), often use monoclonal
antibody that target sex steroids and inevitable sex organs via the
hypothalamic-gonadal feedback axis. This in turn causes
parathyroid and calcitonin imbalance and bone remodelling,
leading to bone demineralisation and potentially causing
osteoporosis and ONJ.

5. Bone
remineralisation
Secondary healing processes of bone remineralisation
can also lead to bisphosphonates being deposited
within the bone matrix. Soap bubble[8] type
appearances may appear in the bone matrix of
multiple myeloma patients resulting in cell production
that is suboptimal. Denosumab, an inhibitor of
receptor activator of nuclear factor κ-B ligand, is an
approved treatment of giant cell tumour of bone
(GCTB) in adults and “skeletally mature” adolescents.
Safety concerns include over suppression of bone
remodelling, with risk of ONJ and atypical femur
fractures during treatment in adults and rebound
hypercalcemia after treatment cessation in
children.[9]

6. Dental clearance
Not all patients who receive bisphosphonate and monoclonal
antibody therapy, receive dental clearance prior to cancer
therapy. Dental clearance constitutes extraction of decayed teeth,
or oral care to prevent potential damage prior to cancer therapy.
Practicing good oral hygiene such as brushing, flossing, use of
interdental brushes, WaterPik®, fluoride mouthwash or high
fluoride toothpaste, avoiding carbonated beverages, smoking
cessation, is advised in addition to any targeted remedial care.
Patients are particularly encouraged to present regularly for
routine dental care while in cancer therapy, as this could detect
early symptoms of dental complications.[10]Dental clearance and
ongoing care is important because bone healing is reduced and
delays to oral treatment can lead to irreversible, unwanted,
complications including resection of the jaw, with knock-on
impact on speech, swallowing, malnutrition and diminished
quality of life for cancer patients.

7. Patients & practitioners
In practice, this impacts community-based
dentists who may see cancer patients in the
community, oncology doctors who prescribe
medicines and primary care practitioners such as
general practitioners (GPs), pharmacists and
nurses. This particularly concerns all osteoporotic
patients, especially those suffering from
comorbidities such as cancer, those on
polypharmacy and those who have had sex organ
removals (e.g. hysterectomy).
All patients undergoing cancer therapy should
have dental clearance irrespective of their
medication therapy because aspects (e.g.
infection, pre-existing oral conditions) of dental
care might impact their cancer care.

8. References:
[1] Omolehinwa TT, Akintoye SO. Chemical and Radiation-Associated Jaw Lesions. Dent Clin North Am 2016;60:265–77. https://doi.org/10.1016/j.cden.2015.08.009.
[2] Kumar M, Vineetha R, Kudva A. Medication related osteonecrosis of jaw in a leukemia patient undergoing systemic arsenic trioxide therapy: A rare case report. Oral Oncol 2019;99:104343. https://doi.org/10.1016/j.oraloncology.2019.06.024.
[3] Owosho AA, Scordo M, Yom SK, Randazzo J, Chapman PB, Huryn JM, et al. Osteonecrosis of the jaw a new complication related to Ipilimumab. Oral Oncol 2015;51:e100–1. https://doi.org/10.1016/j.oraloncology.2015.08.014.
[4] Ellis LM. Mechanisms of Action of Bevacizumab as a Component of Therapy for Metastatic Colorectal Cancer. Semin Oncol 2006;33:S1–7. https://doi.org/10.1053/j.seminoncol.2006.08.002.
[5] Teixeira S, Branco L, Fernandes MH, Costa-Rodrigues J. Bisphosphonates and Cancer: A Relationship Beyond the Antiresorptive Effects. Mini Rev Med Chem 2019;19:988–98. https://doi.org/10.2174/1389557519666190424163044.
[6] Migliario M, Mergoni G, Vescovi P, Martino ID, Alessio M, Benzi L, et al. Osteonecrosis of the Jaw (ONJ) in Osteoporosis Patients: Report of Delayed Diagnosis of a Multisite Case and Commentary about Risks Coming from a Restricted ONJ Definition. Dent J
2017;5:13. https://doi.org/10.3390/dj5010013.
[7] Hazell L, Shakir SAW. Under-Reporting of Adverse Drug Reactions. Drug Saf 2006;29:385–96. https://doi.org/10.2165/00002018-200629050-00003.
[8] Zhang J, Wang H, He X, Niu Y, Li X. Radiographic examination of 41 cases of odontogenic myxomas on the basis of conventional radiographs. Dento Maxillo Facial Radiol 2007;36:160–7. https://doi.org/10.1259/dmfr/38484807.
[9] Uday S, Gaston CL, Rogers L, Parry M, Joffe J, Pearson J, et al. Osteonecrosis of the Jaw and Rebound Hypercalcemia in Young People Treated With Denosumab for Giant Cell Tumor of Bone. J Clin Endocrinol Metab 2018;103:596–603.
https://doi.org/10.1210/jc.2017-02025.
[10] Karna H, Gonzalez J, Radia HS, Sedghizadeh PP, Enciso R. Risk-reductive dental strategies for medication related osteonecrosis of the jaw among cancer patients: A systematic review with meta-analyses. Oral Oncol 2018;85:15–23.
https://doi.org/10.1016/j.oraloncology.2018.08.003.