Exploring cancer risk in men on International Men’s day

Worldwide, cancer rates are rising in both men and women, but compared to women, men are more likely to develop cancer and sadly to die from the disease. One in five men will be diagnosed with some form of the disease, compared with one is six women. But what could be the reasons behind this? Dr Úna Mc Menamin, Editorial Board Member of BMC Cancer, investigates.


Lifestyle and healthcare interaction

We know that modifiable lifestyle factors such as smoking, being overweight or obese and drinking alcohol are related to 4 out of 10 cancers and men are more likely to have at least one or more of these risk factors. Taking tobacco as an example, smoking in men has had a significant impact on the rates of certain cancer types, particularly lung, head and neck, bowel, bladder, pancreatic – cancers that can have particularly poor outcomes. Fortunately, smoking rates in men are now steadily falling and we’re starting to see a subsequent decline in the incidence of some of these cancers.

Another potential reason is that men are less likely to have as many opportunities for contact with health professionals across their lifetime in order to obtain health information or to report possible cancer-related symptoms. Women are more likely to have frequent contact on matters relating to contraception, pregnancy, child rearing or menopause and they have also had exposure to healthcare professional through participating in breast (and cervical) cancer screening for the past three decades.

In contrast, men have only recently had the opportunity to participate in such programs in the form of bowel cancer screening, but the test is conducted at home, which further limits opportunities for healthcare professional contact.

Sex differences

But what about inherent differences between the sexes, could they be responsible for some of these differences in cancer rates? Sex hormones, including oestrogens (the primary female sex hormone) and testosterone (the primary male sex hormone), are related to sex-specific cancers such as breast in women and prostate in men but surprisingly, little research has been conducted to see if they are involved in the development of cancers that affect both sexes.

It’s unclear whether these observations represent a potentially protective effect for oestrogen or a detrimental effect for testosterone – or both.

Cancers of the oesophagus (or food pipe) and stomach are particularly more common in men than in women and are cancers which are linked to poor outcomes. The difference in rates between the sexes is especially pronounced for adenocarcinomas, the type that most commonly occurs in developed countries, with reports estimating up to a 7-fold difference in men compared to women.

The variation by sex is not fully explained by known risk factors such as smoking, obesity and gastroesophageal reflux and the male-to-female ratio is highest during female reproductive years, when oestrogen concentrations are highest. But it’s unclear whether these observations represent a potentially protective effect for oestrogen or a detrimental effect for testosterone – or both.

In the first study of reproductive and hormonal factors in men, we recently found that male pattern balding (used as a proxy for higher testosterone levels) was associated with a small increase in risk of stomach cancer and was more marked for adenocarcinomas among men enrolled in the UK Biobank, a large UK cohort study. To investigate this further, we are conducting studies to examine the use of common hormone-modulating medications, in addition to circulating blood levels of sex hormones, in both men and women to see how these may impact subsequent risk of these cancers.

This research, along with the work of others, will provide insights into the possible biological reasons for the difference in oesophageal and stomach cancer rates between men and women and in the future, could lead to the identification of potentially exploitable prevention strategies. It’s important to point out though that this work is still very much in the early stages and additional research is required before any firm conclusions can be drawn.

What can men do to reduce cancer risk?

Unfortunately, it is unlikely that there is one single cause as to why men develop cancer more frequently compared to women. In addition to the investigation of potential biological factors, it’s clear that we need a focus on cancer prevention and early diagnosis and campaigns such as Be Clear on Cancer in the UK are trying to address this – but increased and sustained efforts are needed.

So on this International Men’s Day, what can men do to reduce their overall risk of developing cancer in the future? The World Cancer Research Fund’s evidence-based recommendations for healthy lifestyle choices include:

  • Be a healthy weight
  • Be physically active
  • Eat wholegrains, vegetables, fruits and beans
  • Limit the consumption of “fast-foods”
  • Limit consumption of red and processed meats
  • Limit alcohol intake

In addition to healthy lifestyle choices, it’s important to know yourself, your family history, and to tell your doctor if you notice a change which isn’t normal for you, such as a persistent cough, change in bowel movements or difficulty swallowing.

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