Is it true that circumcision protects against penile cancer and HPV?
Circumcision early in life is associated with a clearly lower risk of invasive penile cancer and a reduced likelihood of carrying HPV, but part of that protection operates through the prevention of phimosis. HPV vaccination is a better-supported prevention step for most people.
Almost half of all penile tumours contain HPV DNA, and type 16 is the most commonly found type. A history of genital warts increased the risk of penile cancer by almost six times. Yet HPV is far from the whole story: phimosis (a narrowed foreskin), smoking and chronic inflammation are independent risk factors that have nothing to do with HPV.
Circumcision early in life is associated with a considerably lower risk of invasive penile cancer, roughly 67% lower compared with uncircumcised men. A population-based study in the United States confirmed this picture: men who had never been circumcised or who were circumcised only after the newborn period developed penile cancer more than three times as often. An important caveat: when researchers accounted for phimosis, the protective effect of circumcision disappeared in two out of three studies. This suggests that circumcision works partly by preventing phimosis, rather than necessarily acting as a direct protection in its own right. For precursor lesions of penile cancer (non-invasive forms), no protective effect has been found, regardless of when circumcision took place.
Circumcision in adulthood shows a different picture. Three studies found a possible increase in the risk of invasive penile cancer, but the result was not statistically significant. It is possible that men who are circumcised later in life already had pre-existing penile complaints. This is therefore not a proven risk, but neither is it a reassurance.
For HPV infection, the protective effect of circumcision is most clearly demonstrated for the likelihood that a man carries HPV at any given moment: circumcised men have a 30 to 43% lower chance of an active genital HPV infection, with the strongest effect at the glans and coronal sulcus. Whether circumcision also protects against acquiring a new HPV infection is unclear: two large analyses contradicted each other. And for the spontaneous clearance of an infection, no difference has been demonstrated. Against genital warts, circumcision demonstrably offers no protection.
Medical reviews mention circumcision as one possible prevention option alongside HPV vaccination, smoking cessation and treatment of phimosis. However, the quality of the evidence is insufficient for firm policy recommendations; cost-benefit analyses are largely absent. HPV vaccination has the advantage of also protecting female partners, which circumcision does not.
This answer draws on three independent meta-analyses (each combining multiple studies), supplemented by a population-based case-control study and several medical reviews. The meta-analyses on HPV infection prevalence encompass up to thirty individual studies, which gives the findings on prevalence a relatively solid foundation. For penile cancer, only three case-control studies per meta-analysis are involved, and the results for circumcision in adulthood and for HPV incidence are not statistically compelling. The researchers themselves emphasise that the quality of the evidence is insufficient for firm guidelines and that cost-benefit analyses are needed.
What exactly does the HPV vaccine do for your protection against cervical cancer?
The HPV vaccine provides strong protection against cervical cancer, but works best when received before first sexual contact; after that point, the benefit diminishes rapidly.
Does fasting or intermittent fasting help prevent cancer?
There is no evidence that fasting prevents cancer in humans; the animal results are promising but contradictory. If you want to address excess weight as a way of reducing risk, intermittent fasting can be a tool for that, but do not expect a direct cancer-preventive effect.
Do lycopene and tomatoes protect against prostate cancer?
The association between tomatoes, lycopene, and lower prostate cancer risk is plausible, but not yet proven firmly enough to justify specific supplement recommendations. Tomatoes as part of a varied diet is a sensible choice; taking lycopene in isolation has no proven added value at this time.
Does using the contraceptive pill increase my risk of cancer?
The pill demonstrably lowers the risk of ovarian and uterine cancer, but slightly raises the risk of breast cancer with long-term use or use before a first pregnancy. Discuss your personal situation with your GP or gynaecologist if you have any doubts.
Does working with pesticides increase your risk of cancer?
Working with pesticides is associated in multiple studies with an increased risk of several types of cancer, including bladder, bowel, and blood cancers. Avoiding unprotected contact is sensible, especially if you are pregnant or planning to become pregnant.
Should I, as a man, get tested for prostate cancer with the PSA test?
Whether the PSA test is worthwhile depends on your personal risk. Men aged 55 to 69 with an elevated risk, such as a family history or Black ethnicity, have the greatest reason to discuss this with their GP.