Lip cancer is a malignancy that develops on the skin of the lips. Most cases are classified as squamous cell carcinoma (SCC), originating in the thin, flat cells found in the middle and outer layers of the skin. This malignancy is grouped with other cancers that occur within the mouth, collectively known as oral cavity cancer.
Overall Incidence and Prevalence
Lip cancer is relatively uncommon compared to major cancers like lung or breast cancer. Cancers of the lip and oral cavity combined are not among the most frequently diagnosed malignancies globally, ranking around the 16th most common cancer worldwide. Approximately 389,846 new cases of lip and oral cavity cancer were reported globally in 2022.
Within head and neck malignancies, lip cancer is the most common malignant lesion of the oral cavity, accounting for 25% to 30% of all oral cavity cancer cases. Incidence rates vary significantly by geography, reflecting environmental differences, particularly sun exposure. For example, the incidence rate in the United States is 1.8 cases per 100,000 population, but rises to 13.5 per 100,000 in areas like Australia.
Demographics and Primary Risk Factors
The populations most affected by lip cancer share common exposure and lifestyle factors. The disease is diagnosed more frequently in older adults, typically appearing in the sixth decade of life or later. Males are significantly more affected than females, often being up to three times more likely to develop the disease.
Chronic exposure to ultraviolet (UV) radiation from the sun is the single biggest cause of lip cancer. About 90% of lip cancers occur on the lower lip, which receives higher levels of sun exposure than the upper lip. Individuals with fair skin are also at increased risk due to lower natural protection against UV damage.
Lifestyle choices are another major causal factor, including tobacco use and heavy alcohol consumption. Tobacco use, whether smoked or smokeless, exposes the lips to cancer-causing chemicals. Alcohol acts as an irritant that enhances the absorption of these carcinogens, and the combined risk of using both tobacco and alcohol is substantially greater than their individual effects.
Prognosis and Survival Rates
The prognosis for lip cancer is generally favorable because its visible location allows for early detection. This early diagnosis significantly improves the outcome, giving lip cancer one of the highest survival rates among all oral cancers.
The five-year relative survival rate for lip cancer is approximately 90% overall. When the cancer is localized (confined to the lip and has not spread), the five-year survival rate is even higher, nearing 93% to 94%. This high figure reflects the effectiveness of modern treatments when the disease is caught early.
The survival rate decreases significantly if the cancer progresses. Once the disease has spread to distant parts of the body, the five-year survival rate drops to around 38%. This difference underscores the importance of timely diagnosis and intervention for the best possible long-term outlook.
Methods for Reducing Risk
Since UV exposure is a primary cause, protecting the lips from the sun is a direct way to lower risk. Individuals should apply a lip balm or sunscreen with an SPF of at least 30 anytime they are outdoors. Limiting sun exposure during peak hours, generally between 10 a.m. and 4 p.m., also helps minimize UV damage.
The complete cessation of tobacco use is a highly effective preventative measure. Reducing heavy alcohol intake is also advised, with moderation defined as no more than two drinks per day for males and one for females. Regular self-examinations can help identify any persistent sores, lumps, or whitish discolorations on the lips. Any lip sore that does not heal within two weeks should prompt a visit to a healthcare provider for assessment.