Introduction

Lip cancer, which can look like a mouth sore, is a type of oral cancer that begins in the cells of the lips, most commonly affecting the lower lip. It may initially resemble a persistent mouth sore before progressing to form a malignant tumour.^1,2 It is a dangerous but preventable disease that may lead to significant physical and emotional distress. One of the most important risk factors for lip cancer is tobacco use.²

Tobacco is consumed in various forms, including cigarettes, cigars, and smokeless tobacco products such as chewing tobacco and snuff.³ As all of these products come into direct contact with the lips, the lip tissue and surrounding oral structures are frequently exposed to harmful chemicals and carcinogens that can lead to the development of cancer. Understanding the connection between cancer and tobacco products can be key in preventing the increasing number of cancer patients.

Overview of tobacco products

Cigarettes

Cigarettes are the most common form of tobacco use.⁴ They are made via finely cut tobacco leaves wrapped in paper, which are then burned and inhaled.⁵ Cigarette smoke contains thousands of chemicals, including deadly carcinogens such as benzene, formaldehyde, and nitrosamines. As the lips are constantly exposed to both the heat of the burning tobacco and the toxic chemicals in the smoke, the risk of developing lip cancer is significantly increased.³

Cigars

Cigars differ from cigarettes in size, composition, and use.⁶ Cigar tobacco is often fermented and aged, a process that results in a higher concentration of carcinogenic compounds. Even though cigar smokers may not always inhale deeply, cigars are typically held in the mouth for prolonged periods. This allows smoke, heat, and tar to come into direct contact with the lips. This prolonged contact increases the risk of developing lip and other oral cancers, even without deep inhalation.

Smokeless tobacco (chewing tobacco, snuff, etc.)

Smokeless tobacco, such as chewing tobacco and snuff, is placed directly in the mouth between the lip and gum.⁷ While some may think chewing tobacco is safer than smoking it, this is a dangerous misconception. The tobacco remains in direct contact with the tissues of the lips and gums for extended periods, often several hours, exposing them to the carcinogenic chemicals. This continuous exposure greatly increases the risk of lip, gum, and cheek cancers.³

Mechanisms linking tobacco use to lip cancer

Tobacco contains a number of harmful chemicals that damage the DNA of cells and trigger the formation of cancer.⁸ The lips, skin, and mucosal cells, when in constant contact with tobacco smoke, experience chronic irritation and inflammation. Due to this irritation, cellular changes and genetic mutations may occur over time.^1,2 Two carcinogens present in tobacco, nitrosamines and polycyclic aromatic hydrocarbons, directly interfere with the normal growth and repair of cells, causing normal, healthy cells to become cancerous.⁸

Clinical features and diagnosis of lip cancer

Early signs of lip cancer can be easily overlooked, as they may resemble common mouth sores or ulcers. However, persistent sores or ulcers on the lip that fail to heal, the presence of lumps, ongoing pain, discolouration, or thickening of the lip tissue may indicate lip cancer. ^1,2 Some patients may also experience bleeding on the lips, numbness, or changes in lip texture.

Diagnosis for lip cancer typically begins with an evaluation by a general practitioner (GP) or dentist, followed by a biopsy if cancer is suspected. A biopsy involves taking a small tissue sample that is then examined under a microscope to confirm whether the cells are cancerous. If malignancy is confirmed, imaging tests such as MRI or CT scans may be conducted to determine whether the cancer has spread to surrounding tissues. These early detection methods are key to improving the chances of successful treatment and recovery.⁹

Treatment and prognosis

Treatment for lip cancer depends on the stage and extent of the disease. If lip cancer is detected early, it can often be treated successfully via surgical removal of the tumour.¹⁰ However, if the cancer has progressed to later stages, alternative treatments such as radiation therapy or chemotherapy may be required.^11,12

When recovering from successful treatment, it is important to make lifestyle changes, especially for those who smoked. Quitting tobacco use altogether is essential not only for improving one's health, but also to prevent future complications. Additionally, a person recovering from cancer should have frequent medical check-ups to ensure no traces of the cancer remain.

Summary

Regardless of the form in which it is used, whether cigarettes, cigars, or smokeless tobacco, tobacco is a major risk factor for the development of lip cancer. The harmful chemicals and carcinogens constantly exposed to the tissues of the lips can cause cellular changes and genetic mutations in normal, healthy cells, leading to cancer development in the form of a tumour. Lip cancer is diagnosed through a biopsy and, depending on the stage of cancer progression, the tumour may be surgically removed, or radiation therapy and chemotherapy may be carried out. Preventive measures, particularly avoiding tobacco use and adopting healthier lifestyle choices, can greatly lower the risk of lip cancer and improve long-term oral and overall health.