Introduction

When people hear the term ‘oral cancer’, they often imagine something serious but vague, perhaps a sore in the mouth that will not heal or something that only affects tobacco users. However, what many do not realise is that oral cancer is not a single disease; it is an umbrella term for a group of cancers that spread in different parts of the mouth, an integral part of head and neck cancer that have different manifestations. One of the most distinctive subtypes is lip cancer.^1,2,3 

At first glance, lip cancer might seem like just another form of oral cancer because, after all, lips are just a part of the mouth, right? Although lip cancer falls under the broader category of oral cancers, you will find key differences that affect everything from its detection, clinical presentation, prognosis and treatment paths. If caught early, lip cancer has a relatively good prognosis, while cancers in other parts of the mouth are more difficult to detect due to delayed symptoms, which may require more aggressive treatment.^1,3 

Recognising these differences is more than clinical detail, as this can be the difference between early intervention and late diagnosis, smooth recovery and a challenging journey. A clearer understanding of how lip cancer stands apart from other oral cancers can help people recognise early signs with confidence and seek appropriate care without delay, supporting timely diagnosis.⁴ 

Anatomical and clinical presentations

The World Health Organisation (WHO) and International Classification of Diseases (ICD-10) coding categorise lip cancer separately to aid in accurate staging and treatment plans. Oral cancers arise within the internal structures of the mouth, including the lips, teeth, gums, front two-thirds of the tongue, buccal mucosa, retromolar trigone, hard, and soft palate. Accounting for 25-30% of cases, lip cancer is the most common of all oral cancers.^3,4

Squamous cell carcinomas (SCCs) are the less aggressive type that constitute most lip cancers, primarily affecting the external region of the mouth, specifically the lower lip and the vermilion border, where the skin transitions to the red part of the lip. Lip cancer clinically originates from the inner lining that secretes mucus and is classified as a subtype of other oral cavity cancers due to the lip’s unique exposure to environmental factors such as ultraviolet radiation (UV) from the sun.^3,5 

More than 95% of SCCs present themselves as sore, non-healing ulcers or unusual lumps with white (leukoplakia) and red (erythroplakia) discoloured patches in the early stages, which often go undetected until later stages due to their location. When the cancer grows, it can spread to nearby areas, causing:

• Loose teeth
• Difficulty opening the mouth
• Numbness
• Ear pain
• Swelling in the neck

On the other hand, lip cancer has early visibility that shows up as a raised, crusty sore on the surface of the lips. In more advanced cases, it may grow deeper into the lip muscle, with the surrounding skin showing sun damage with changes in colour, thinning, or patches of rough and white areas. These are the visible signs that make lip cancer easier to spot early on compared to cancers deeper inside the mouth.^1,4 

Risk factors and causes

Lip cancer and other oral cancers have some common risk factors, but there are also notable differences. People who have outdoor occupations, such as farmers and construction workers, are more susceptible to lip cancer because of long-term exposure to solar radiation from the sun, especially in fair-skinned individuals.⁵ 

Tobacco use is the greatest well-established risk factor that significantly increases the chances of lip cancer, but this plays an even larger role in cancers in other regions of the mouth. Smoking exposes the individual to an array of carcinogens, making the risk of oral cancer three times higher than that of non-smokers, with chances made worse by alcohol consumption, as it damages the lining of the mouth.⁴

In recent years, infection with human papillomavirus (HPV), mainly strains 16 and 18, has also been linked to certain oral cancers, including oropharyngeal cancer that leads to the development of tumours in the tonsils and base of the tongue. Additionally, individuals who have undergone haematopoietic stem cell transplants, most frequently with cancer originating from the salivary glands and tongue, 5-9 years after their transplantation, have a 4-7 times higher risk than the general population of developing oral cancer.

Oral cancers are more commonly found in older adults, especially men over the age of 50, although patterns deviate in younger populations due to HPV transmission from oral sex.^3,4

Diagnosis and staging

Lip cancer and other oral cancers are typically diagnosed using a combination of:

• Physical exams
• Tissue biopsies
• Imaging techniques like computed tomography (CT) scans and magnetic resonance imaging (MRI) are used to determine how the cancer has progressed

These tools help doctors, oral surgeons, and oncologists gather the necessary information needed for staging the disease. Both cancer types are classified using the tumour-node-metastasis (TNM) system to categorise tumours, which evaluates the size of the tumour (T), whether cancer has spread to nearby lymph nodes (N), and if it has spread to nearby parts of the body (M).^4,5

Diagnosing and staging lip cancer focuses more on the depth and invasion of the tumour into the cortical bone, inferior alveolar nerve, floor of the mouth, and skin on the chin or nose. Other oral cancer staging considers tumour invasion into the deeper anatomical structures such as the muscles of the tongue, maxillary sinus and skin on the face, which may be overlooked during a routine examination.⁵

Lip cancer is usually diagnosed at a lower stage due to its more visible signs that make identification easier. Other cancers in the mouth, however, are likely to be found at a later stage when they have already grown and spread due to their hidden location and subtler early symptoms. Accurate staging is important because it directly guides and influences treatment decisions and allows doctors to provide a prognosis.^4,5 

Prognosis and outcomes

The lips are exposed, so changes are easily noticeable with less spread, which makes the outlook of most cases generally positive and curable. Treatment is usually effective and may involve radiotherapy or minor surgeries (Mohs technique) that leave some visible scarring. Follow-up care may involve skin and oral exams to monitor for tumours and sun damage. This means that lip cancer has high survival rates of above 90% for early-stage tumours compared to other oral cancers, with a prognosis that heavily varies depending on the stage of diagnosis.^1,3,6

The survival for oral cancers decreases from 85% at stage I compared to 40% for stage IV, remarkably, which makes the survival rate and prognosis of these cancers poorer, as they are often diagnosed at a later stage when they have already spread to nearby tissues or lymph nodes.¹

Treating other oral cancers is more intensive and complex, requiring multimodal therapy, a comprehensive approach that combines surgery with chemoradiotherapy, which comes with potential long-term consequences of affecting speech, swallowing, taste and dental health. That may require other treatments in addition to restoring form, function and aesthetics following tumour removal.

The outcome of both lip and oral cancers significantly depends on several factors, including:

• The stage of diagnosis
• The location of the tumour
• The patient’s overall health and lifestyle

Regular dental check-ups, awareness of early warning signs, and lifestyle changes like quitting smoking and reducing alcohol intake can improve the long-term outcomes and recurrence of diagnosed patients, whilst preventing incidence and serving as a vital public health message for oral cancer altogether.⁴ 

FAQs

Is there a way to prevent lip cancer and oral cancer?

The use of lip balms with SPF and protective measures for people who are in prolonged exposure to UV rays is a preventative strategy for lip cancer. HPV vaccination, tobacco, and alcohol reduction decrease the chances of all other oral cancers. 

Is there a chance of recurrence?

Lip cancer has a low chance of recurrence when detected early and completely removed. However, other oral cancers carry a higher risk of recurrence, especially if diagnosed at a later stage. 

Summary

Lip cancer and other oral cancers may seem similar at first glance, but they differ in their causes, presentation, treatment, and outcomes. Lip cancer is mainly linked to sun exposure and can be caught early because of its visibility, resulting in a high survival rate. In contrast, other oral cancers, such as those of the tongue and inner cheek, are strongly associated with heavy drinking and smoking, whilst a small but significant role for HPV is also recognised. Oral cancers are often diagnosed later with more serious repercussions. Whilst diagnosing methods for cancers are similar, treatment intensity, rehabilitation, and recurrence risk differ. Lip cancer requires less aggressive support and has minimal long-term consequences, whilst other cancers may impact basic oral functions like speech and swallowing, which are things that many of us take for granted every day.