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How obesity causes cancer, and may make screening and treatment harder

This rising obesity burden is the outcome of a host of factors

Alessandro R Demaio Anna Beale | The Conversation 

Photo: Shutterstock
Photo: Shutterstock

Today, almost two in every three Australian adults are overweight or obese, as is one in four children. Obesity is a disease itself and a risk factor linked to ischaemic heart disease (the leading cause of premature deaths today in Australia), stroke (the third leading cause), and musculoskeletal conditions (the second major cause of disability), among others.

This rising burden is the outcome of a host of factors, many of which are beyond the control of the individual. It is having a devastating impact on the of the nation. What’s often overlooked though, is the link between and

is a disease of altered gene expression that originates from changes to the DNA caused by a range of factors. These include inherited mutations, DNA damage, inflammation, hormones, and external factors including tobacco use, infections (for example viruses such as HPV), radiation, chemicals, and carcinogenic agents in

Strong evidence also links to a number of cancers. These include oesophageal adenocarcinoma; bowel (the third leading cause of preventable death in Australia); of the liver, gall bladder and bile ducts; pancreatic cancer; postmenopausal breast cancer; endometrial cancer; kidney cancer; and multiple myeloma (in the plasma in the blood).

This is just the tip of the iceberg, as highly suggestive evidence exists for a further eight cancers.

How does increase the risk of

There are many complex ways is thought to cause or increase the risk of

Increased body fat is associated with increased inflammation in the body, increased release of oestrogens (in part from the fat cells themselves), and decreased insulin sensitivity associated with raised insulin production.

Insulin, “insulin-like growth factor-1” (IGF1) and leptin are all elevated in obese people, and can promote the growth of cells.

Secretion of the hormone insulin is usually tightly controlled and a healthy part of our body’s sugar regulation processes. But it can be significantly elevated in people with obesity-related pre-diabetes or diabetes due to insulin resistance.

This state of elevated insulin levels in the blood can act as a growth signal for tumour cells, and increases the risk of cancers of the colon and endometrium (the lining of the uterus), and likely of the pancreas and kidney.

Insulin-like growth factors (IGFs) regulate cell growth, differentiation and death, and IGF-1 has been associated with prostate, breast and bowel cancers.

Leptin, a hormone implicated in hunger and satiety, can stimulate proliferation of many pre-and cells. Increased leptin levels in obese people are associated with bowel and prostate cancers.

Sex steroid hormones including oestrogens, testosterone, and progesterone are crucial to healthy body development and sexual function, but are also likely to play a role in and Increased levels of sex steroids are strongly associated with risk of developing endometrial and postmenopausal breast cancers, and may contribute to other cancers such as bowel

Fat tissue is the main site of oestrogen production in the body for men and postmenopausal women (while in premenopausal women the ovaries are the major producer). can predispose premenopausal women to polycystic ovarian syndrome, which causes elevated testosterone and therefore could contribute to risk.

also causes inflammation in the body, meaning the body’s immune system is consistently more active than is normal in healthy weight people.

Evidence for a role of sex hormones and chronic inflammation in affecting the relationship between and is strong, and the evidence for a role of insulin and IGF is moderate. There are a range of other mechanisms still under investigation.

Where does lie on cancer-risk scale?

Overall, obesity-associated cancers represent up to 8.2% of all cancers in the UK, compared to smoking which is responsible for approximately 19%.

Of all deaths from in the USA, excess body weight is close behind smoking as the attributable cause, at 20% versus 30% respectively.

Does affect the and detection of

Focusing on just two types of cancer, breast in women and prostate in men, some evidence suggests that can delay the identification of through - but does not reduce the importance or accuracy of tools or programs.

For breast cancer, the most common form of in women in Australia, the good news is that accuracy is similar across weight status. The Swiss national survey found the accuracy of mammography is maintained in obese women - with similar ability of the tests to detect cancers, but reduced ability to ensure the positive result definitely means This meant obese women had a 20% higher false positive rate than normal weight individuals, but does not suggest any cancers were missed.

The troubling news though is, studies suggest obese women with breast cancer detected through mammogram tend to present to their doctors later, and when the cancer is more serious, than their healthy weight counterparts. The exact reasons for this are not clear but may include possible difficulties in breast self-examination and delayed health-seeking. Such findings reinforce the crucial importance of strategies to encourage appropriate and timely medical follow-up among overweight and obese women.

For prostate cancer, the most common form of in Australia, large studies suggest a link between and decreased risk of low-grade or early prostate cancer, but increased risk of advanced disease.

The reasons for this are again thought to be numerous, but one potential reason may be linked to greater difficulty in diagnosing prostate in overweight men. While this is thought to possibly delay diagnosis and treatment, it is unlikely entirely to explain the links between and prostate risk.

What risks does pose in the treatments of

can impact treatments and their success. Obese patients have a significantly higher risk of heart attack following surgery, as well as risk of wound infection, nerve injury, and urinary infection. alone increases the risk of poorer outcomes following surgery, and morbid increases the risk of death.

In treatments, one study has shown significantly increased surgical complications and prolonged hospital stay with morbid obesity in bowel cancer. Another suggests may reduce chemotherapy efficacy in breast cancer, with lower disease-free survival rates.

Is this risk reversible?

By 2025 it’s estimated that more Australians will be obese than normal weight. At the same time, cancer is a leading contributor to early deaths and disability in Australia and the major cause of years lost from people’s lifespans.

The question is not whether can cause cancer; it is how we can better prevent or mitigate this important risk factor. Reassuringly, there is suggestive evidence that weight loss may reduce or reverse many of the above processes and their associated risks.

While is just one of the drivers of the burden in Australia, it is one that is preventable and in doing so, would bring other enormous benefits.


Alessandro R Demaio, Medical Doctor, Associate Researcher, University of Copenhagen and Anna Beale, Medical doctor; PhD candidate in cardiology, Monash University

This article was originally published on The Conversation. Read the original article.

The Conversation

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How obesity causes cancer, and may make screening and treatment harder

This rising obesity burden is the outcome of a host of factors

This rising obesity burden is the outcome of a host of factors

Today, almost two in every three Australian adults are overweight or obese, as is one in four children. Obesity is a disease itself and a risk factor linked to ischaemic heart disease (the leading cause of premature deaths today in Australia), stroke (the third leading cause), and musculoskeletal conditions (the second major cause of disability), among others.

This rising burden is the outcome of a host of factors, many of which are beyond the control of the individual. It is having a devastating impact on the of the nation. What’s often overlooked though, is the link between and

is a disease of altered gene expression that originates from changes to the DNA caused by a range of factors. These include inherited mutations, DNA damage, inflammation, hormones, and external factors including tobacco use, infections (for example viruses such as HPV), radiation, chemicals, and carcinogenic agents in

Strong evidence also links to a number of cancers. These include oesophageal adenocarcinoma; bowel (the third leading cause of preventable death in Australia); of the liver, gall bladder and bile ducts; pancreatic cancer; postmenopausal breast cancer; endometrial cancer; kidney cancer; and multiple myeloma (in the plasma in the blood).

This is just the tip of the iceberg, as highly suggestive evidence exists for a further eight cancers.

How does increase the risk of

There are many complex ways is thought to cause or increase the risk of

Increased body fat is associated with increased inflammation in the body, increased release of oestrogens (in part from the fat cells themselves), and decreased insulin sensitivity associated with raised insulin production.

Insulin, “insulin-like growth factor-1” (IGF1) and leptin are all elevated in obese people, and can promote the growth of cells.

Secretion of the hormone insulin is usually tightly controlled and a healthy part of our body’s sugar regulation processes. But it can be significantly elevated in people with obesity-related pre-diabetes or diabetes due to insulin resistance.

This state of elevated insulin levels in the blood can act as a growth signal for tumour cells, and increases the risk of cancers of the colon and endometrium (the lining of the uterus), and likely of the pancreas and kidney.

Insulin-like growth factors (IGFs) regulate cell growth, differentiation and death, and IGF-1 has been associated with prostate, breast and bowel cancers.

Leptin, a hormone implicated in hunger and satiety, can stimulate proliferation of many pre-and cells. Increased leptin levels in obese people are associated with bowel and prostate cancers.

Sex steroid hormones including oestrogens, testosterone, and progesterone are crucial to healthy body development and sexual function, but are also likely to play a role in and Increased levels of sex steroids are strongly associated with risk of developing endometrial and postmenopausal breast cancers, and may contribute to other cancers such as bowel

Fat tissue is the main site of oestrogen production in the body for men and postmenopausal women (while in premenopausal women the ovaries are the major producer). can predispose premenopausal women to polycystic ovarian syndrome, which causes elevated testosterone and therefore could contribute to risk.

also causes inflammation in the body, meaning the body’s immune system is consistently more active than is normal in healthy weight people.

Evidence for a role of sex hormones and chronic inflammation in affecting the relationship between and is strong, and the evidence for a role of insulin and IGF is moderate. There are a range of other mechanisms still under investigation.

Where does lie on cancer-risk scale?

Overall, obesity-associated cancers represent up to 8.2% of all cancers in the UK, compared to smoking which is responsible for approximately 19%.

Of all deaths from in the USA, excess body weight is close behind smoking as the attributable cause, at 20% versus 30% respectively.

Does affect the and detection of

Focusing on just two types of cancer, breast in women and prostate in men, some evidence suggests that can delay the identification of through - but does not reduce the importance or accuracy of tools or programs.

For breast cancer, the most common form of in women in Australia, the good news is that accuracy is similar across weight status. The Swiss national survey found the accuracy of mammography is maintained in obese women - with similar ability of the tests to detect cancers, but reduced ability to ensure the positive result definitely means This meant obese women had a 20% higher false positive rate than normal weight individuals, but does not suggest any cancers were missed.

The troubling news though is, studies suggest obese women with breast cancer detected through mammogram tend to present to their doctors later, and when the cancer is more serious, than their healthy weight counterparts. The exact reasons for this are not clear but may include possible difficulties in breast self-examination and delayed health-seeking. Such findings reinforce the crucial importance of strategies to encourage appropriate and timely medical follow-up among overweight and obese women.

For prostate cancer, the most common form of in Australia, large studies suggest a link between and decreased risk of low-grade or early prostate cancer, but increased risk of advanced disease.

The reasons for this are again thought to be numerous, but one potential reason may be linked to greater difficulty in diagnosing prostate in overweight men. While this is thought to possibly delay diagnosis and treatment, it is unlikely entirely to explain the links between and prostate risk.

What risks does pose in the treatments of

can impact treatments and their success. Obese patients have a significantly higher risk of heart attack following surgery, as well as risk of wound infection, nerve injury, and urinary infection. alone increases the risk of poorer outcomes following surgery, and morbid increases the risk of death.

In treatments, one study has shown significantly increased surgical complications and prolonged hospital stay with morbid obesity in bowel cancer. Another suggests may reduce chemotherapy efficacy in breast cancer, with lower disease-free survival rates.

Is this risk reversible?

By 2025 it’s estimated that more Australians will be obese than normal weight. At the same time, cancer is a leading contributor to early deaths and disability in Australia and the major cause of years lost from people’s lifespans.

The question is not whether can cause cancer; it is how we can better prevent or mitigate this important risk factor. Reassuringly, there is suggestive evidence that weight loss may reduce or reverse many of the above processes and their associated risks.

While is just one of the drivers of the burden in Australia, it is one that is preventable and in doing so, would bring other enormous benefits.


Alessandro R Demaio, Medical Doctor, Associate Researcher, University of Copenhagen and Anna Beale, Medical doctor; PhD candidate in cardiology, Monash University

This article was originally published on The Conversation. Read the original article.

The Conversation
image
Business Standard
177 22

How obesity causes cancer, and may make screening and treatment harder

This rising obesity burden is the outcome of a host of factors

Today, almost two in every three Australian adults are overweight or obese, as is one in four children. Obesity is a disease itself and a risk factor linked to ischaemic heart disease (the leading cause of premature deaths today in Australia), stroke (the third leading cause), and musculoskeletal conditions (the second major cause of disability), among others.

This rising burden is the outcome of a host of factors, many of which are beyond the control of the individual. It is having a devastating impact on the of the nation. What’s often overlooked though, is the link between and

is a disease of altered gene expression that originates from changes to the DNA caused by a range of factors. These include inherited mutations, DNA damage, inflammation, hormones, and external factors including tobacco use, infections (for example viruses such as HPV), radiation, chemicals, and carcinogenic agents in

Strong evidence also links to a number of cancers. These include oesophageal adenocarcinoma; bowel (the third leading cause of preventable death in Australia); of the liver, gall bladder and bile ducts; pancreatic cancer; postmenopausal breast cancer; endometrial cancer; kidney cancer; and multiple myeloma (in the plasma in the blood).

This is just the tip of the iceberg, as highly suggestive evidence exists for a further eight cancers.

How does increase the risk of

There are many complex ways is thought to cause or increase the risk of

Increased body fat is associated with increased inflammation in the body, increased release of oestrogens (in part from the fat cells themselves), and decreased insulin sensitivity associated with raised insulin production.

Insulin, “insulin-like growth factor-1” (IGF1) and leptin are all elevated in obese people, and can promote the growth of cells.

Secretion of the hormone insulin is usually tightly controlled and a healthy part of our body’s sugar regulation processes. But it can be significantly elevated in people with obesity-related pre-diabetes or diabetes due to insulin resistance.

This state of elevated insulin levels in the blood can act as a growth signal for tumour cells, and increases the risk of cancers of the colon and endometrium (the lining of the uterus), and likely of the pancreas and kidney.

Insulin-like growth factors (IGFs) regulate cell growth, differentiation and death, and IGF-1 has been associated with prostate, breast and bowel cancers.

Leptin, a hormone implicated in hunger and satiety, can stimulate proliferation of many pre-and cells. Increased leptin levels in obese people are associated with bowel and prostate cancers.

Sex steroid hormones including oestrogens, testosterone, and progesterone are crucial to healthy body development and sexual function, but are also likely to play a role in and Increased levels of sex steroids are strongly associated with risk of developing endometrial and postmenopausal breast cancers, and may contribute to other cancers such as bowel

Fat tissue is the main site of oestrogen production in the body for men and postmenopausal women (while in premenopausal women the ovaries are the major producer). can predispose premenopausal women to polycystic ovarian syndrome, which causes elevated testosterone and therefore could contribute to risk.

also causes inflammation in the body, meaning the body’s immune system is consistently more active than is normal in healthy weight people.

Evidence for a role of sex hormones and chronic inflammation in affecting the relationship between and is strong, and the evidence for a role of insulin and IGF is moderate. There are a range of other mechanisms still under investigation.

Where does lie on cancer-risk scale?

Overall, obesity-associated cancers represent up to 8.2% of all cancers in the UK, compared to smoking which is responsible for approximately 19%.

Of all deaths from in the USA, excess body weight is close behind smoking as the attributable cause, at 20% versus 30% respectively.

Does affect the and detection of

Focusing on just two types of cancer, breast in women and prostate in men, some evidence suggests that can delay the identification of through - but does not reduce the importance or accuracy of tools or programs.

For breast cancer, the most common form of in women in Australia, the good news is that accuracy is similar across weight status. The Swiss national survey found the accuracy of mammography is maintained in obese women - with similar ability of the tests to detect cancers, but reduced ability to ensure the positive result definitely means This meant obese women had a 20% higher false positive rate than normal weight individuals, but does not suggest any cancers were missed.

The troubling news though is, studies suggest obese women with breast cancer detected through mammogram tend to present to their doctors later, and when the cancer is more serious, than their healthy weight counterparts. The exact reasons for this are not clear but may include possible difficulties in breast self-examination and delayed health-seeking. Such findings reinforce the crucial importance of strategies to encourage appropriate and timely medical follow-up among overweight and obese women.

For prostate cancer, the most common form of in Australia, large studies suggest a link between and decreased risk of low-grade or early prostate cancer, but increased risk of advanced disease.

The reasons for this are again thought to be numerous, but one potential reason may be linked to greater difficulty in diagnosing prostate in overweight men. While this is thought to possibly delay diagnosis and treatment, it is unlikely entirely to explain the links between and prostate risk.

What risks does pose in the treatments of

can impact treatments and their success. Obese patients have a significantly higher risk of heart attack following surgery, as well as risk of wound infection, nerve injury, and urinary infection. alone increases the risk of poorer outcomes following surgery, and morbid increases the risk of death.

In treatments, one study has shown significantly increased surgical complications and prolonged hospital stay with morbid obesity in bowel cancer. Another suggests may reduce chemotherapy efficacy in breast cancer, with lower disease-free survival rates.

Is this risk reversible?

By 2025 it’s estimated that more Australians will be obese than normal weight. At the same time, cancer is a leading contributor to early deaths and disability in Australia and the major cause of years lost from people’s lifespans.

The question is not whether can cause cancer; it is how we can better prevent or mitigate this important risk factor. Reassuringly, there is suggestive evidence that weight loss may reduce or reverse many of the above processes and their associated risks.

While is just one of the drivers of the burden in Australia, it is one that is preventable and in doing so, would bring other enormous benefits.


Alessandro R Demaio, Medical Doctor, Associate Researcher, University of Copenhagen and Anna Beale, Medical doctor; PhD candidate in cardiology, Monash University

This article was originally published on The Conversation. Read the original article.

The Conversation

image
Business Standard
177 22