Oral Cancer
Oral cavity cancer is a major disease burden in South Asia, with a risk factor profile — including tobacco and areca nut use — that differs from that in many other regions. Potentially malignant disorders such as oral submucous fibrosis and leukoplakia sit upstream of it.
Disease categories
Major disease categories
- Oral squamous cell carcinoma
- Oral submucous fibrosis and other potentially malignant disorders
- Leukoplakia and erythroplakia
- Minor salivary gland tumours
Molecular
Molecular considerations
TP53, CDKN2A, NOTCH1, PIK3CA and FAT1 alterations are frequently described in oral squamous cell carcinoma.
Markers commonly discussed in oral cancer
- TP53
- CDKN2A
- PIK3CA
- NOTCH1
- PD-L1
- p16 (site-dependent)
Not exhaustive, and not every marker is assessed in every patient. Which of these is relevant depends on the individual case and should be discussed with the treating team.
Testing
Genomic testing considerations
Molecular profiling is discussed in recurrent and metastatic disease.
Germline
Germline considerations
Considered where the presentation is unusually young or the family history is suggestive.
Molecular monitoring
ctDNA and liquid biopsy considerations
Investigational in this setting.
Single-cell & computation
Single-cell and algorithmic approaches
Single-cell sequencing in head and neck cancer is used to characterise immune exclusion and the stromal compartment, both of which vary substantially between tumours that look similar histologically. Single-cell DNA analysis contributes to field-change questions — whether a second lesion is a recurrence or an independent primary, which clonal analysis can often settle. Algorithm work includes HPV integration site analysis, deconvolution of immune composition from bulk expression, and viral circulating-DNA trajectory modelling.
Decisions
Treatment decision questions
Questions worth raising with a treating team when a decision is being made:
- Is the precise subsite recorded?
- Have potentially malignant changes in the surrounding mucosa been documented?
- Are margins and their status clearly described?
Resistance
Resistance and recurrence questions
- Is a new lesion a recurrence or a second primary?
Trials
Clinical trial considerations
Trial options vary considerably by region and by prior treatment.
When a precision oncology review may help
A review is most useful where the standard pathway has been exhausted or where the picture is more complicated than a protocol accounts for — rare presentations, treatment resistance, complex or apparently contradictory molecular findings, or a decision between several defensible options.
The output is a structured analysis and a set of questions for the treating team. It is not treatment, and it does not replace the treating oncologist.