This article emphasizes various risk factors – modifiable and non-modifiable.
Question: Now Dr Shah, what leads to breast cancer, what are the risk factors ?
Answer: There is a large body of literature on this subject with many very large scale studies. This has been summarized well on the website nccn.org for the interested readers. We don’t know the reason in all cases.
Que: What are the known risk factors ?
Ans: We like to divide them as non-modifiable and potentially modifiable.
Non-modifiable risk factors are:
Family history: breast cancer in a first degree relative is a significant risk factor. More the number of relatives and Younger the age at diagnosis, higher the risk.
Genetics: many of the patients with strong family history have an underlying identifiable genetic mutation such as BRCA1 or 2 mutation, that can be tested for to identify family members at risk. Not all family members obtain this mutation from their forefathers.
Female gender: a very small proportion of breast cancer is seen in men.
Age: increasing age is associated with increasing risk, especially after age 50, and it continues to increase with advancing age.
Early Menarche (before 11) and Late Menopause (after 55) – both increase risk, as they likely increase exposure to estrogen. This risk factor is potentially a result of lifestyle changes, but not clearly proven.
Que: What are the potentially modifiable risk factors ? I think our readers are more interested in knowing about them.
Ans: Yes, and that is where biggest impact is possible in preventive efforts. Following numbers give an idea of what we can achieve as a country if we control these risk factors. Incidence in USA is over 200,000 new breast cancers per year, with a population of about 240 million, whereas in India it is still only about 80,000 per year with a population of about 1000 million. This is due mainly to the difference in lifestyle. In other words, if we adopt all the risk factors similar to USA population, our incidence of breast cancer could potentially become 800,000 i.e.10 times the number what we have today. Unfortunately however, we are changing fast in the wrong direction.
Obesity – high weight especially significant weight gain at a young age, or after menopause is an important risk factor
Alcohol consumption – one to two drinks per day significantly increase risk.
Nulliparity – not having children, or having less number of children.
Older age at first live birth.
Current or prior estrogen and progesterone hormone replacement therapy – especially if long term i.e. many years.
Personal history of benign proliferative disease of breast – having a normal breast biopsy in past without atypical hyperplasia does not seem to increase risk.
The so called Western lifestyle seems to increase risk. Study of Japanese women have shown that after they moved to USA, their risk increased, which is likely lifestyle related. This is especially important since obesity and sedentary lifestyle are fast increasing in India, and more so in Gujarat.
Answer: There is a large body of literature on this subject with many very large scale studies. This has been summarized well on the website nccn.org for the interested readers. We don’t know the reason in all cases.
Que: What are the known risk factors ?
Ans: We like to divide them as non-modifiable and potentially modifiable.
Non-modifiable risk factors are:
Family history: breast cancer in a first degree relative is a significant risk factor. More the number of relatives and Younger the age at diagnosis, higher the risk.
Genetics: many of the patients with strong family history have an underlying identifiable genetic mutation such as BRCA1 or 2 mutation, that can be tested for to identify family members at risk. Not all family members obtain this mutation from their forefathers.
Female gender: a very small proportion of breast cancer is seen in men.
Age: increasing age is associated with increasing risk, especially after age 50, and it continues to increase with advancing age.
Early Menarche (before 11) and Late Menopause (after 55) – both increase risk, as they likely increase exposure to estrogen. This risk factor is potentially a result of lifestyle changes, but not clearly proven.
Que: What are the potentially modifiable risk factors ? I think our readers are more interested in knowing about them.
Ans: Yes, and that is where biggest impact is possible in preventive efforts. Following numbers give an idea of what we can achieve as a country if we control these risk factors. Incidence in USA is over 200,000 new breast cancers per year, with a population of about 240 million, whereas in India it is still only about 80,000 per year with a population of about 1000 million. This is due mainly to the difference in lifestyle. In other words, if we adopt all the risk factors similar to USA population, our incidence of breast cancer could potentially become 800,000 i.e.10 times the number what we have today. Unfortunately however, we are changing fast in the wrong direction.
Obesity – high weight especially significant weight gain at a young age, or after menopause is an important risk factor
Alcohol consumption – one to two drinks per day significantly increase risk.
Nulliparity – not having children, or having less number of children.
Older age at first live birth.
Current or prior estrogen and progesterone hormone replacement therapy – especially if long term i.e. many years.
Personal history of benign proliferative disease of breast – having a normal breast biopsy in past without atypical hyperplasia does not seem to increase risk.
The so called Western lifestyle seems to increase risk. Study of Japanese women have shown that after they moved to USA, their risk increased, which is likely lifestyle related. This is especially important since obesity and sedentary lifestyle are fast increasing in India, and more so in Gujarat.
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