Chemoprevention of oral cancer: A review and future perspectives

Abstract

Background: Oral cancer causes significant morbidity and mortality. Chemoprevention utilizes medication or natural compounds to reverse oral premalignant lesions and to prevent second primary tumors. Methods: A comprehensive PubMed database and Cochrane Library search from 1980 to 2021 was performed using the keywords "leukoplakia," "oral premalignant lesion," and "chemoprevention."Results: Chemopreventive agents included retinoids, carotenoids, cyclooxygenase inhibitor, herbal extracts, bleomycin, tyrosine kinase inhibitors, metformin, and immune checkpoint inhibitors. Although some agents demonstrated effect in reducing premalignant lesions and preventing second primary tumors, the results among different studies were highly variable. Conclusions:The results of different trials, albeit inconsistent, provided substantial information for future studies. In the era of personalized medicine, future studies will focus on identifying specific biomarkers and molecular profile to monitor and to prevent malignant transformation. Larger trials are warranted to validate the effect of chemopreventive agents.

Advances in Small Molecular Agents against Oral Cancer

“…Quercetin (19) can cause mitochondrial dys-function and inhibit the viability, migration, and invasion of OCC via the mitochondrial apoptosis pathway [53,54]. Baicalein (20) induces the apoptosis, causes the GO/G1 phase arrest, and reduces the NF-κB activity of OSCC cells. In addition, baicalein inhibits the proliferation of OSCC in vivo and in vitro by down-regulating the relative mRNA levels of the transcription factors Sp1, p65, and p50 [55].…”

“…Despite advances in diagnostic imaging, surgery, radiation, and chemotherapy, oral cancer is often diagnosed at a later stage of disease development, leading to poor prognosis and high mortality. Moreover, many patients with oral cancer are resistant to standard treatments owing to heterogeneity within the tumour or a genetic mutation which occurs during treatment, resulting in the high recurrence rate of this disease [19][20][21]. Oral cancer metastasises to various tissues or organs of the body through the lymphatic system or blood, and generally has no specific location, but it is more likely to metastasise to the head and neck area [20].…”

“…Moreover, many patients with oral cancer are resistant to standard treatments owing to heterogeneity within the tumour or a genetic mutation which occurs during treatment, resulting in the high recurrence rate of this disease [19][20][21]. Oral cancer metastasises to various tissues or organs of the body through the lymphatic system or blood, and generally has no specific location, but it is more likely to metastasise to the head and neck area [20]. Thus, the development of safe and reliable drugs is crucial for the effective treatment of oral cancer.…”

Chemoprevention in oral leukoplakia: challenges and current landscape

“…The emergence of chemoprevention for OSCC was based on the failure of conventional therapies for definitive control of OPMD. Chemoprevention denotes the application of either natural or synthetic chemical agents, applied topically or systemically, which are used to preclude the advancement or genesis of oral cancer ( 20 , 21 ).…”

Michelia compressa-Derived Santamarine Inhibits Oral Cancer Cell Proliferation via Oxidative Stress-Mediated Apoptosis and DNA Damage

“…The most common oral cancer cell type is oral squamous cell carcinoma (OSCC), at higher than 90% [ 3 ]. Although radio- or chemo-therapy [ 4 ] can improve oral cancer treatment, their benefits are halted by the accompanied adverse effects [ 5 , 6 ]. Hence, it is essential to identify additional drugs with fewer side effects in oral cancer therapy.…”