Anal cancer and cervical cancer screening: Key differences

Abstract

Cervical cancer and anal cancer share many similarities including causation by oncogenic human papillomaviruses; however, significant differences exist in their epidemiology, risk factors, biologic behavior, management, and treatment. Although rare, the incidence of anal cancer is alarmingly high and continues to increase in high-risk populations, particularly men who have sex with men regardless of their human immunodeficiency virus (HIV) status. There are no national screening guidelines for anal cancer. Using the success of cervical cancer screening as a model, anal cancer screening approaches apply anal cytology, highresolution anoscopy, and directed biopsy to guide treatment and management strategies. Although much has been learned about the natural history and epidemiology of anal intraepithelial neoplasia (AIN), the rate of progression of high-grade anal intraepithelial neoplasia (HGAIN) to invasive squamous cell carcinomas is not known. The impact of screening and treatment of HGAIN on morbidity and mortality from anal cancer are also unknown. Because the incidence of HGAIN and anal squamous cell carcinoma continue to increase, it is imperative to find pathways for effective screening, early detection, and therapeutic intervention. This article provides an overview of anal cancer screening while highlighting its differences from cervi- Compared with cervical cancer, anal cancer is rare. The National Cancer Institute estimates that 5260 patients will be diagnosed with anal cancer in 2010 and that 720 men and women will die of the disease. 1 Compare this to cervical cancer statistics in the United States for 2010: 12,200 will be diagnosed with cervical cancer and 4210 women will die and this is with successful opportunistic Papanicolaou (Pap) testing to screen for this cancer in the United States. Yet, in patients with the highest risk of anal cancer, its incidence was more than double that of cervical cancer prior to the initiation of Pap screening and is increasing, while rates for cervical cancer continue to decrease. As the incidence of anal carcinoma increases in populations at risk, cytologic screening, combined with early detection and treatment, has been proposed as a method to reduce the morbidity and mortality from invasive anal squamous cell carcinoma (ASCC).

Anal Squamous Intraepithelial Lesions and HPV Among Young Black Men Who Have Sex with Men

“…However, anal cytology has been shown to have a much lower sensitivity for HGSIL (46%) than for LGSIL (77%) or ASCUS (87%) in an HIV-positive population. 7 It is possible that high-grade disease was present and went undetected due to the relatively low sensitivity of this screening tool. Some authors have reported higher percentages of HGSIL in their HIV-positive populations.…”

Psychosocial aspects of anal cancer screening: a review and recommendations

“…High rates of HPV infection and anal cancer in HIV-infected individuals and men who have sex with men (MSM) have led to a growing concern that screening, prevention and early intervention efforts need to be implemented, similar to other cancers 4 . Baseline and annual follow up anal cytological screening is recommended for HIV-infected individuals in the New York State Guidelines.…”

“…Progression and regression rates from HPV infection to anal cancer are unknown, but the screening process is similar to the highly effective cervical cancer model 4 . While there is no universally accepted anal cancer screening or treatment protocol, typically, the screening process involves two stages.…”

High-Risk HPV DNA Test for Screening Anal Lesions in HIV-Positive and Negative Patients

“…However, high-resolution anoscopy provides additional evaluation even for patients with negative Pap smears [22,23].…”