ABSTRACT
Genital squamous cell cancers have a pre-invasive stage of intra-epithelial neoplasia. The likelihood and timescale of progression is better understood for cervical disease than for vulval, vaginal, penile and anal intra-epithelial neoplasia. Pre-invasive lesions are often asymptomatic and even symptomatic external disease may have a non-specific appearance causing delayed diagnosis. Screening and treatment of preinvasive lesions may prevent progression to malignancy but do have associated physical and psychological morbidity and economic costs.
