Epidemiology of Anal HPV and Anal Cancer
Overview of the role of HPV in cancer.
Over 100 different types.
HPV 16 causes over half anal cancers. Other oncogenic types together cause about 80% of anal cancers.
Infection with many types is common.
Over 40% MSM have HPV infection at any one time. More common in HIV positive, and more common again if immunosuppressed which makes clearance less likely.
Anal cancer increases with age above 45 years.
The rates are much higher in HIV positive MSM compared with HIV positive men.
In the current HAART era 3% of HIV positive MSM develop anal cancer, rates that equal cancers like colorectal carcinoma.
Screening was offered and readily accepted.
In HIV positive individuals there was almost twice the number of abnormal PAPs compared to HIV negative.
Abnormal cytology had high sensitivity but low specificity.
Adding HPV 16 + increases specificity.
What should we be doing for our patients now?
The HPV vaccines are a game changer.
Should we screen for early HGAIN (high-grade anal intraepithelial neoplasia)?
Similarities with cervical carcinoma, and that has a screening program.
There are key differences - larger area to swab, harder to identify lesions, different natural history (more high grade lesions less likely to progress to cancer), 40-60% would need to go on to high-resolution anoscopies, we need better treatments for high grade lesions.
Currently, more than 50% of anal cancers are visible externally, with an average size of 2.9cm, making them at least stage II disease.
Are we ready to screen for early cancers?
Can we implement early detection with an annual digital rectal exam?
Most HIV physicians think it is very important to screen for anal cancer, yet hardly any do.
Annual DARE (digital anal rectal examination) is well tolerated and an acceptable screening test for patients.
An update of the Study for the Prevention of Anal Cancer (SPANC)
High grade lesions are 5 times less likely to progress to cancer than cervical cancer in HIV positive men and 50 times less likely to progress to cancer in HIV negative men.
Mean age was 50 years.
Mean duration of HIV infection 15 years.
90% on treatment.
Almost all had CD4 nadir < 200.
Almost all were virologically suppressed.
After 1 year of SPANC the following findings:
The rates of HPV 16 were very high.
Clearance of this type is less than half of the other types.
Lesions were not associated with age or length of time infected with HIV.
High grade lesions were related to immunosuppression and lifetime anal experience.
New infection is common.
There is a high rate of 9-valent types in infections.
Over 50% of lesions persisted for 12 months.
Anal cancer is a huge and increasing problem.
Educating the community about HPV and anal cancer
AFAO (Australian Federation of AIDS Organisations).
The Bottom Line - campaign developed by AFAO to increase awareness of HPV and anal cancer.
Increasing awareness of HPV infection, DARE, anoscopy and biopsy, and information for those diagnosed with anal cancer.
Campaign materials included a web-site (www.thebottomline.org.au), 2 printed booklets for clinicians to give to their patients, poster.
A community perspective on anal cancer and anal HPV
Postal survey of how much respondents knew about anal cancer.
People thought their risk of anal cancer was the same as the general population.
People did understand what the symptoms would be.
Most had never discussed HPV or anal cancer with their doctor.
Of those that did discuss this with their doctor, it was the patient that brought it up.
One third of people would be really uncomfortable discussing this with their doctor.
76% had never been screened for anal cancer.
Most common examination was DARE, followed by high-resolution anoscopy.
84% hadn’t been vaccinated.
Living through the diagnosis and treatment of anal cancer
I was diagnosed with anal cancer in 2014, aged 52.
Diagnosed with HIV 1999, started ARVs 2005.
Having annual DARE because of family history of prostatic carcinoma.
Had surgery, then went back to work the following week.
Looked after himself mainly, despite not coping well.
I needed to return early for a chemotherapy session, my liver was not functioning properly.
My skin was prickly, I was feeling nauseous, and it was recommended I admit myself to hospital.
Was told liver wasn’t working and I had to stop my HIV medication and pain relief.
I was released from hospital after 8 days, and prescribed bactrim, and had lost 20kg.
My CD4 count had dropped to 70.
I began my HIV medications again, and regained weight, but my kidneys shut down.
I had a problem with an overactive bladder throughout this (it was unclear what the cause was, my prostate or post-radiotherapy change). I was catheterised with a long-term catheter a few times, and developed a UTI.
My cancer has been cured.
My bladder has improved.
Is there a benefit vaccinating older people with early anal lesions?
There is evidence that early cervical lesions do have reduced recurrence following vaccination but no evidence yet for anal.
It is only funded for under 25 year olds, but if you can afford it, it is unlikely to do you any harm.
Should we be doing a DARE on HIV negative patients?
No, it is not cost effective, because it is not common enough.
If you’re going to do it, do it on a regular basis.