I actually just spoke to my doctor the other day about my risk for anal cancer. I was concerned because I had had a flare up of warts around and in my anus (small ones, hardly noticeable). I had used Aldara cream on them and they cleared up nicely. I asked him for an anal pap and he said that I couldn't get one. I live in NZ where procedures have to be approved by the health board before they are subsidized by the government. There just isn't enough empirical evidence to suggest that getting anal paps reduce cancer risk. Part of the reason for this, as my doctor explained, is that a pap can come back as 'abnormal' when the HPV virus is detected, even though there's no pre-cancerous growth. The current practice is to then burn off warts, which is very damaging to the anus, even though they may not be cancerous. He said that a digital rectal exam is sufficient to test for lumps and bumps inside the anus that may need to be biopsied.
I called the American Cancer Society's free hotline to get a second opinion and the specialist there concurred with my doctor, that there really isn't enough evidence to show that a pap is useful except to show that you have HPV or warts and may be susceptible to anal cancer.
The advice I received mirrors my own experience with HPV. I've had two outbreaks of warts since I tested HIV+ in 2006. During my first outbreak I had an anal pap that came back abnormal and a proctologist suggested I get them burned off. He gave me the option to wait and see, and that's what I did. An anal pap I had a few years later came back normal. So, it seems that HPV is a condition that can come and go, just as my doctor here in NZ explained to me, and its presence doesn't necessarily mean cancer. It's important to be cognizant of what's going on around your anus and get any abnormalities checked out. Even if it makes you uncomfortable.
In the United States medical care is for profit, so the more procedures they can do to you, the more they can bill your insurance. Sometimes that motive comes into conflict with doing what's really best or most effective for the patient.
As far as other STD's are concerned, just get checked up regularly, every 3 months if you're barebacking a lot. A lot of the reasons why STIs turn into horror stories is because people are too embarrassed to get checked up regularly, especially when testing positive for an STI usually comes with a healthy dose of slut shaming and condom preaching. That's why it's also important to find a doctor who understands gay men's health issues.
It's also important to look at your overall health. Eat properly, exercise, stay away from drugs and tobacco. And for God's sake stop consuming so much added sugar!