Obesity has a negative impact on outcomes in women with breast cancer
4 September 2014
Sorry to throw so much medical jargon at you - but this article does have an interesting message... We know that obesity affects every organ system in some way, however the relationship between obesity and cancer risk is a relatively new concept. There appears to be increasing evidence that obesity affects not only your risk of getting cancer but it also affects how well you will do following cancer treatment ie your prognosis. This is scary, especially for people who struggle with losing weight and keeping it off and those who have a family history of certain types of cancer. However, the good news is that decreasing your weight over the longterm is able to reverse this risk and keep you cancer free or improve your outcome if you have had cancer. Yay, I'm glad there is some good news in all of this! Anyway, if you want to have further discussions around this or any other aspects of Bariatric surgery ie Gastric Banding, Sleeve Gastrectomy or Gastric Bypass, then you know who to call.
Obesity and diabetes have adverse effects on outcomes in breast cancer patients who receive chemotherapy as primary treatment before surgery (neoadjuvant chemotherapy), according to research presented at the 9th European Breast Cancer Conference (EBCC-9). Although a high BMI is known to have a negative impact on cancer development and prognosis, until now there has been uncertainty as to whether having a high BMI had an equal effect on patients with different types of breast tumours.
Dr Caterina Fontanella, a trainee in medical oncology from the University of Udine (Italy) and a research fellow with the German Breast Group, based in Neu-Isenburg, near Frankfurt am Main, Germany, presented an analysis based on nearly 11,000 patients with early breast cancer treated with neoadjuvant chemotherapy. She showed that a high BMI adversely affects the chances of surviving without the breast cancer recurring or spreading to other parts of the body, although this detriment was not seen in those women had been diagnosed with HER2-positive disease.
"We think that hyperinsulinemia may encourage the growth of tumour cells by providing them with large amounts of glucose"
"Although the overall survival of patients with metastatic breast cancer has increased over the past few decades, it remains an incurable disease," said Fontanella. "So preventing disease relapse after primary treatment of early breast cancer is fundamentally important in oncology daily practice. Considering that about one-third of the worldwide population has a BMI>25, investigating the possible higher risk of relapse that affects overweight and obese patients compared with normal weight patients should be a priority."
The researchers studied data from 8,872 early breast cancer patients from the German Breast Group, and 1,855 from a joint EORTC/BIG trial. All had received a modern treatment consisting of an anthracycline/taxane-based neoadjuvant chemotherapy, anti-HER-2 drugs, or hormone therapy according to tumour type and national guidelines.
The vast majority of the patients in this study received chemotherapy doses capped at a body surface area (BSA) of 2.0m², which is often the limit when calculating doses.
"Obese patients may have a BSA of more 2.0m², but the chemotherapy dose they receive will not reflect this. It is a very common practice in these patients for fear of overdosing, but of course it means that they will often receive a relatively lower quantity of chemotherapy," she said. "In my opinion, a deeper understanding of chemotherapy metabolism and distribution in patients with high BMI and with increased adipose tissue is needed."
"We already know that obese hormone receptor-positive tumour patients respond less well to aromatase inhibitors as adjuvant treatment, and this underlines a key role of higher aromatase activity in patients with increased adipose tissue."
Aromatase is an enzyme that synthesises oestrogen, and blocking it is important in cancers where oestrogen encourages tumours to grow.
Final analysis of outcomes from the two groups in the joint study showed a significant decrease in survival without the cancer spreading (metastasising) – distant disease-free survival (DDFS) – or the cancer recurring – distant relapse-free survival (DRFS) – in patients with increased BMI in all tumour types, apart from those with HER2-positive tumours.
"The exception in this group can probably be explained by the impressive impact of anti-HER2 treatment," said Fontanella. "Given the significant proportion of the world's population with a BMI higher than recommended for good health, it is vitally important that we find a way to treat overweight and obese cancer patients that combines maximum efficacy with the avoidance of unnecessary side-effects."
In a second study, Fontanella and colleagues investigated the incidence of Type 2 (adult onset) diabetes in patients with early breast cancer at the time of diagnosis, as well as its effect on the outcome after neoadjuvant chemotherapy. Diabetes has been reported in 15%-20% of elderly breast cancer patients, although in the group of just over 4,000 patients studied it was considerably lower.
"This was probably because these patients were enrolled in clinical trials and were therefore selected to be in good physical condition without other illnesses that could complicate procedures and outcomes," she explained. "However, we did find that patients with diabetes were more likely to have their cancer diagnosed at a more advanced stage, and this suggests that diabetes may affect the size of the tumour. We also found that patients with diabetes had worse distant disease free survival rates."
Diabetes is currently believed to be associated with a 49% increased risk of death from all causes in breast cancer patients, as well as being an independent prognostic factor for the risk of recurrence and metastasis. Increased insulin levels seem to be related to a high risk of recurrence after primary treatment, and an increase in C-peptide  levels has been associated with an increased risk of cancer-related deaths, particularly in hormone receptor-positive tumours.
"We think that hyperinsulinemia may encourage the growth of tumour cells by providing them with large amounts of glucose. We therefore believe that strict control of blood sugar levels is essential to the successful treatment of breast cancer," she concluded.
"The growing epidemic of obesity needs to be given greater attention as a risk factor for developing breast cancer, and in how we treat patients in routine practice,” said Professor David Cameron, from the University of Edinburgh, UK, who is a member of the EBCC-9 executive scientific committee. “The data presented by Dr Fontanella are important as they challenge not only the concept of 'chemotherapy dose capping' but also highlight how much we need to learn about the interaction between obesity and the biology of breast cancer."
Fat shaming needs to stop!
27 August 2014
This is an opinion piece by Dave Shaw a Dietitian on the way society treats obese individuals. I think he is right in suggesting that with the spotlight being put firmly on Obesity in our community, there have been insidious changes in the attitude of society towards obesity. There is some need for attitudes to change so that a healthy BMI looks 'normal' to the average person, but there is the risk that the changes swings too far to the negative and obese people bear the brunt of unhelpful opinion. There is often a lot of detrimental self talk and image issues that go hand in hand with morbid obesity and adding baggage to this is not helpful. And inversely, there are a lot of positive steps that can be taken to improving issues around obesity and generational obesity and these are the tactics as a society, that we should be focussing on. Hope you are all keeping warm - not too much more winter to go! Regards,
Shame is no friend to health promotion. Yet, the way obese people are seen by the public is becoming increasingly similar to how we view smokers - almost shameful. And although aiming to achieve a healthy body weight is important, stigmatising and ostracising our bigger community are not effective motivators for change.
And for these reasons, a recent video has sparked a great deal of controversy as it crudely depicts the lifestyle of an obese individual.
No doubt, we all have our opinions about health and how we should look. In some way, we are all biased. Which is why I write this to ask you, with no intention of being suggestive, have we lost sight of what a healthy body weight actually is?
Admittedly, many of us do need to change our perception about what a healthy weight looks like. Our obesogenic society has a tendency to consider being overweight as normal. I know, just as well as you do, it's not.
On the contrary, one could argue that many healthy people believe they are overweight when, in fact, they are not. But if statistics are anything to go by, then one argument heavily outweighs the other.
This may seem provocative, but are we simply too sensitive as a population to call a spade a spade and say, "you're too fat" or "you're too thin", and leaving it at that? No stereotyping. No stigmatising. No ostracising.
Therefore, no shaming. If this were the case, would those who did need to lose a few kilos be able to break through societal stigma to rectify the situation they have found themselves in?
Evidence shows shaming and blaming does not grow motivation. Obese women are a group constantly in the firing line of stigmatising messages and as a result, there could be devastating consequences on their mental wellbeing. Evidence also suggests that despite people believing controversial messages raise public awareness, individuals who feel ashamed of their weight engage in behaviours that reinforce weight gain or prevent weight loss.
Einstein once said, "we can't fix our problems with the same thinking we used that created them". A lack of public awareness, action and support has led to the demise of our health. To fix this, we have to change the way we think.
So, how do we help New Zealand children make healthy choices, when many adults are struggling themselves. How do we make the healthier choice the easier choice, when food manufacturers prioritise money over wellbeing?
Wagging a finger at the parents of obese kids isn't a step in the right direction. The increase in childhood obesity doesn't necessarily mean parental or medical neglect. But it does question whether enough action is taking place.
Wendell Berry, an American novelist, said "people are fed by the food industry, which pays no attention to health, and are treated by the health industry, which pays no attention to food". What do you think?
How many doctors actually ask their patients whether they need healthy eating advice and refer them to dietitians?
I believe most of us have the power to change and with great power comes great responsibility. However, being empowered requires knowledge, and at this stage, what the government and food manufacturers are doing to improve our education is not enough. Even with their earnest attempts to do so.
For me, diet is numero-uno, but I'll admit I'm biased. On some level, there is shame in feeding our loved ones with soft drink and chips everyday, when we know the destruction they cause. Knowledge underlies responsibility and it is our responsibility to care for those around us the best way we know how.
We don't all come from the same sperm and egg. So, we can't all eat the same and expect to look the same. There is no shame in asking for help. Obesity is not one-dimensional and we can't sit here waiting on the world to change. Small steps are crucial. The first step is changing the way we think about obesity.
Obesity raises risk of 10 common cancers
19 August 2014
I think you would all agree that this is fairly shocking reading! Hot off the press from the NZ Herald this morning, this is a landmark study that has been published in a landmark Journal (The Lancet). Population type studies are very costly and not frequently performed (because of this). This one includes data from 5 million patients in the UK ie more than the population of New Zealand. They also, if performed well, produce very powerful data that is generally quoted for years to come. This is shocking and just provides more evidence for why the obesity epidemic should be treated very seriously. Steph Ulmer
More than 12,000 new cases of cancer every year can be attributed to the patient being overweight or obese, the biggest ever study of the links between body mass index and cancer has revealed.
Overweight and obesity was closely linked to 10 common cancers, researchers said. Every five-point increase in BMI - equivalent to an increase in weight of around 17.5kg - was associated with a 62 per cent higher risk of cancer of the uterus, a 31 per cent increased risk of gallbladder cancer and a 25 per cent increased risk of cancer of the kidney.
Having a higher BMI was also linked with a greater overall risk of liver, colon, ovarian and breast cancer, the study by experts at the London School of Hygiene & Tropical Medicine (LSHTM) and the Farr Institute found.
While it has been known for some time that higher weight increases the chances of contracting certain cancers, risk levels have never been determined in such detail before.
The study, which is published in The Lancet medical journal, analysed the GP records of more than five million patients in the UK.
The researchers estimated that, if current trends in overweight and obesity rates continue, then by the mid 2020s there could be more than 3,500 additional cases of cancer every year.
"The number of people who are overweight or obese is rapidly increasing both in the UK and worldwide," said study leader Dr Krishnan Bhaskaran, of LSHTM. "It is well recognised that this is likely to cause more diabetes and cardiovascular disease. Our results show that if these trends continue, we can also expect to see substantially more cancers as a result."
Excess weight may account for as many as 41 per cent of uterine cancer cases, and 10 per cent of cancers of the gallbladder, kidney, liver and colon.
The study also found some evidence that, for prostate cancer and for breast cancer in young women, a higher BMI actually reduced the risk.
Precisely how fat could impact upon cancer risk is not fully understood. Dr Bhaskaran said that the variation in its impact across different forms of cancer said it must be affecting risk "through a number of different processes, depending on the cancer type".
Tom Stansfeld, health information officer at Cancer Research UK, said: "This study of over five million people has found new and stronger links between obesity and several different cancer types, highlighting the number of cancers that obesity causes in the UK.
"Although the relationship between cancer and obesity is complex, it's clear that carrying excess weight increases your risk of developing cancer. Keeping a healthy weight reduces cancer risk, and the best way to do this is through eating a healthy, balanced diet and exercising regularly."
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