Precancer

Precancer, also called a precancerous lesion or precancerous condition, refers to tissue changes that are not yet cancerous but carry an increased risk of developing cancer over time. Precancers are usually non-invasive and remain confined to the epithelium or lining from which cancer could arise. They may exhibit cellular abnormalities such as dysplasia, metaplasia, or hyperplasia. Not all precancers progress to cancer; some stay stable for years, and others may regress, especially if the underlying risk factors are addressed.

Common examples include cervical intraepithelial neoplasia related to human papillomavirus infection; actinic keratosis on the skin; Barrett’s esophagus, which can predispose to esophageal adenocarcinoma; and adenomatous polyps of the colon, which can progress to colorectal cancer. Other precancerous conditions include certain laryngeal lesions, bronchial dysplasia, and various breast and oral mucosal changes. Detection relies on screening, cytology, biopsy, and imaging, with histopathology confirming the precancerous state.

Management focuses on preventing progression to cancer through surveillance, removal or destruction of the lesion, and addressing modifiable risk factors such as infection, smoking, or chronic inflammation. Treatments may involve surgical excision, endoscopic or topical therapies, or ablation, depending on the location and grade of the lesion. The prognosis varies by type and degree of abnormality, but early intervention generally reduces the risk of subsequent cancer.

In public health, the concept of precancer emphasizes early detection and prevention to lower cancer incidence and improve outcomes.