Study: Women with prior cervical cancer face higher long-term anal cancer risk, may warrant screening

A large U.S. study published Wednesday found that women who survive cervical cancer face an increased long-term risk of anal cancer, a rare but rising disease, and that risk is concentrated more than a decade after the initial diagnosis. The authors say their findings support considering age- and duration-based screening for women with a history of cervical cancer.

Researchers led by Dr. Haluk Damgacioglu of the Medical University of South Carolina analyzed cancer registry data on more than 85,500 women diagnosed with cervical cancer from 1975 through 2021. After excluding women who already had anal cancer or who developed it within two months of their cervical diagnosis, the investigators followed patients for a median of nine years and identified 64 subsequent anal cancer cases.

The study found that the risk of anal cancer increased markedly 10 to 15 years after cervical cancer treatment. Nearly 60% of anal cancer cases occurring in women aged 65 to 74 were diagnosed more than 15 years after their cervical cancer diagnosis. In that age group, the estimated anal cancer incidence reached about 17.6 cases per 100,000 people, a level the authors note is comparable to thresholds commonly used to justify organized screening programmes.

"These findings support the need for age-based and duration-based anal cancer screening recommendations for women with a cervical cancer history," Damgacioglu wrote in JAMA Network Open. He added that the study provides important data to inform screening recommendations and that further work is needed to weigh benefits and harms and to identify the most appropriate ages to introduce screening.

Human papillomavirus (HPV) infection is implicated in the vast majority of both cancers: the authors and other experts say high-risk HPV strains cause at least 90% of anal cancers and are found in nearly all cervical cancers. The shared viral etiology is a likely driver of the elevated anal cancer risk observed among cervical cancer survivors, the report said.

Anal cancer remains uncommon overall, but its incidence has been climbing, particularly among older women. The study and accompanying commentary cite data showing rates are rising fastest in women older than 65, at roughly a 4% annual increase for that group. Specialists at the U.S. National Cancer Institute have previously warned that, if current trends continue, the number of anal cancer cases could double in fewer than 20 years.

Current screening recommendations for anal cancer in many countries target people at markedly elevated risk, including individuals with HIV and some with a history of vulvar cancer. The new analysis argues that women with past cervical cancer represent a previously overlooked high-risk population because their absolute risk in certain age groups meets commonly accepted thresholds for screening.

Survival for anal cancer depends heavily on stage at diagnosis. When detected early, five-year survival can be approximately 95%, but it falls sharply—to about 15%—when the disease has metastasized, the study notes. Common symptoms include anal bleeding, pain, lumps near the anus, changes in bowel habits and abnormal mucus; those signs can also result from benign conditions such as hemorrhoids or fissures, and clinicians advise evaluation of persistent or unusual symptoms.

The analysis adds to a body of evidence connecting HPV-related diseases and underscores the public health importance of vaccination and screening. In the United Kingdom, authorities invite women aged 25 to 49 for cervical screening (smear tests) every three years, but uptake is incomplete; roughly 70% of eligible women attend scheduled tests. Public health officials have also urged people under 25 who missed routine HPV vaccination at school to seek catch-up doses, saying the immunization is highly effective at preventing HPV infections that can lead to cancer years later.

The report cites notable public cases to illustrate the disease's profile and social impact. Actress Farrah Fawcett disclosed an anal cancer diagnosis in 2006 and died in 2009 after the disease spread. Actress Marcia Cross announced an anal cancer diagnosis in 2017 and has publicly discussed the role of HPV in related cancers.

The authors call for additional research to determine whether organized screening in this population would reduce mortality and to define optimal screening modalities, intervals and age ranges. They emphasized that any screening policy should be informed by a careful assessment of potential benefits, harms and resource implications.

Clinicians and public health officials said the findings may prompt a reassessment of which patients are considered high risk for anal cancer. In the meantime, they encourage adherence to existing cervical screening programmes and HPV vaccination recommendations, and advise that individuals consult a clinician for persistent rectal bleeding, pain or other concerning symptoms.