Weight – the NET Effect


Firstly, let me say that I have no intention of advising you how to lose or gain weight!  Rather, I’d like to discuss what factors might be involved and why people with NETs might lose or gain weight either at diagnosis or after treatment.  Clearly, I can talk freely about my own experience and associated weight issues. If nothing else, it might help some in thinking about what is causing their own weight issues.

I once wrote a patient story for an organisation and the headline was “Did you mean to lose weight”.  Those were actually the words a nurse said to me after I nonchalantly told her I thought I’d lost some weight (….about half a stone).  I answered the question with “no” and this response triggered a sequence of events that led to all the stories in all the posts in this blog (i.e. my diagnosis).

I annoyingly can’t remember at which point I started to lose the weight, but I was initially reported to have Iron Deficiency Anemia due to a low hemoglobin result and my subsequent iron test (Serum Ferritin) was also low and out of normal range.  This, combined with the weight loss, the GP was spot on by referring me to a clinic.  The sequence of events during the referral led to a diagnosis of metastatic NETs (Small Intestine Primary). If I had been a betting man, I would have put money on my GP thinking “Colorectal Cancer”.  So, my adage If your doctors don’t suspect something, they won’t detect anything applies.

Why did I lose weight?

The drop from 12st to 11st was clearly something to do with the anemia symptoms (the NETs). But after my diagnosis, I had major surgery about 10 weeks later.  When I left the hospital after my 19 days stay, I was a whole stone lighter (14 lbs or 6.3 kg).  I guess 3 feet of intestine, the cecum, an ascending colon, a bit of a transverse colon together with an army of lymph nodes and other abdominal ‘gubbins’ actually weighs a few pounds.

However, add the gradual introduction of foods to alleviate pressure on the ‘new plumbing’, and this is also going to have an effect on weight.  I remember my Oncologist after the surgery saying to use full fat milk – the context is lost in memory, but I guess he was trying to help me put weight back on.  I also vividly remember many of my clothes not fitting me after this surgery. In fact, since 2010, I’ve actually dropped 2 trouser sizes and one shirt/jumper size.  I did spend a lot of time in the toilet over the coming months, so I guess that also had an impact!  However, what I wasn’t aware of was the side effect of my surgery.  I started to put on some weight in time for my next big surgery – a liver resection.  The average adult liver weighs 1.5 kg so I lost another 1 kg in one day based on a 66% liver resection.  I didn’t really lose much weight after the liver resection, probably because my dietary regime had stabilised following the big operation in late 2010.

Eating is good for you – but only if being absorbed

What was also going on in the first couple of years after surgery was something that took me a while to figure out – malabsorption and vitamin/mineral deficiency. My new ‘plumbing’ wasn’t really as efficient as my old one, so the malabsorption. issues caused by a lack of terminal ileum was slowly starting to have an effect. The commencement of Lanreotide in Dec 2010 added to this complication. That knowledge led me to understand some of the more esoteric nutritional issues that can have a big effect on NET patients and actually lead to a host of side effects that might be confused with one of the several NET syndromes.  What it also confirmed to me was that I could still eat foods I enjoy without worrying too much about the effect on my remnant tumours or the threat of a recurrence of my carcinoid syndrome, something I was experiencing prior to and after diagnosis.

Armed with the ‘consequences of NETs’ knowledge, I did eventually adjust my diet and my weight has now ‘flat-lined’ at around 10 st 7 lbs (give or take 1 or 2 lbs fluctuation).  Amazingly, the same weight I was when I left hospital after major surgery, looking thin and gaunt and not very well at all!  The difference today is that I have adapted to my new weight and look fit and healthy.

There are other reasons for weight loss

I actually lost another half a stone (7 lbs or 3.5 kg) in 2014 whilst training for an 84 mile charity walk in 2014 – many commented that I looked thin and gaunt despite feeling extremely fit from all the training. Perspectives!  It took several months to put the weight back on but at least I knew what had caused the loss and then subsequent gain.

What I’ve discovered over the years is that 2 or 3 pounds is nothing to worry about, I found you could put on or lose that amount in a day, depending on time of weighing and food intake. I’m looking for downwards or upwards trends of 7lbs or more (3kg). I try to weigh myself at the same time of day, wearing the same clothes and using the same scales.

I don’t have any appetite issues although I try to avoid big meals due to a shorter gut, so I snack more.  With the exception of the 4 months of intense training for the 84-mile hike and a bad chest infection in 2018, I cannot seem to lose or gain weight.  As my current weight is bang in the middle of the BMI green zone (healthy), I’m content.

Summary of my Weight Challenges

I guess that weight loss or weight gain can be a worry. I also suspect that people might be happy to lose or gain weight if they were under/overweight before diagnosis (every cloud etc).  However, if you are suddenly losing or gaining weight, I encourage you to seek advice soonest or ask to see a dietician (preferably one who understands NETs).

Edit:  I changed my blood thinner in May 2017 and lost 2kg (4 pounds) after 6 months.

Edit: I started Creon at the beginning of 2018 (read about this here) and almost immediately put on 2kg (4 pounds) to offset the 2kg loss from 6 months prior.  However, no real change after 3 months of Creon (March 2018).

Edit: In March 2018, I was formally diagnosed with Hypothyroidism, one of the symptoms can be weight gain.  Clearly that has not applied to me.

Edit: Due to a bad chest infection in June 2018 and the effects of that illness, I dropped three quarters of a stone (~10lbs).  My lightest weight for over 30 years (I have my medical documents from the military covering 1972-2001).   To me that is a significant loss of weight in such a short space of time. This was a worry because I need the weight!

Edit: 4 Sep 2018. After the 10lbs (~4.5kg) loss following the chest infection, people who see me regularly have noticed the visible difference. My trousers feel loose. I’m still struggling to get back beyond 10st after 2 months. Monitoring this really closely.

Edit: 28 Nov 2018. I’m back at 10st after increasing my dosage of Creon.

Edit: 10 Jan 2019.  I’m back at 10st 3lbs, my approximate weight before the chest infection.  It’s taken 7 months and the recent acceleration coincides with Creon dose increase.

Edit 7th Feb 2019.  Changed from Creon to Nutrizym on a trial basis.

Edit: 17 Mar 2019.  It appears my trouser waist size is back to 32″.  Is the use of Pancreatic Enzymes making me eat more, or getting more nutrients through, or making me eat food which makes me put on weight? Perhaps I’ve got the dosing better?  Still monitoring.

Edit: 29 Nov 2019.  Back to 10st 7lbs – which was my ‘flatline’ weight for several years before and the “you look really ill” weight after my surgery in November 2010, i.e. I’m the same weight I was 9 years ago but looking much healthier!

Edit: 13 Jan 2020.  I’m now running at 10st 9lbs but the holidays might have something to do with that.  However, I suspect I need more exercise and the pancreatic enzymes are having some kind of weight gain effect.

Edit:  11 Feb 2021.  I’m now running at 10st 11lbs, only a kilo over 12 months but the trend over 2 years is still up.

For those wishing to see the output from an online discussion with Tara Whyand on the subject of ‘Weight’ issues for NET patients – please see this link inside my closed Facebook group.

weight online chat
Click the Link to see the online event output

The NETs Jigsaw

Like anything in NETs, things can get complex.  So, it is entirely possible that weight loss or weight gain is directly caused by NETs, can be caused by side effects/secondary effects of treatment, and it’s also possible that it could be something unrelated to NETs (Dr Liu “Even NET patients get regular illnesses“).  I guess some people might have a good idea of the reason for theirs – my initial weight loss was without doubt caused by cancer and the post-diagnostic issues caused by the consequences of the cancer.

Why do NET patients lose weight?

That’s a tricky one but any authoritative resource will confirm fairly obvious things such as (but not limited to) loss of appetite and side effects of cancer treatments.  NETs can be complex so I resorted to researching the ISI Book on NETs, a favourite resource of mine.  I wanted to check out any specific mentions of weight and NETs whether at diagnosis or beyond. Here’s some of the things I found out:

Carcinoid Syndrome.  Weight loss is listed but not as high a percentage as I thought – although it tends to be tied into those affected most with diarrhea.

Gastrinoma/Zollinger-Ellison Syndrome.  Up to half of these patients will have weight loss at diagnosis.

Glucagonoma.  90% will have weight loss.

Pheochromocytoma.   Weight loss is usual.

Somatostatinoma.  Weight loss in one-third of pancreatic cases and one-fifth in intestinal cases.

VIPoma.  Weight loss is usual.

MEN Syndromes.  One of the presentational symptoms can be weight loss.

Secondary Effects of NETs.

Many NETs can result in diabetes (particularly certain pNETs) and as somatostatin analogues can inhibit insulin, it could push those at borderline levels into formal diabetic levels (including any type of NET using long term somatostatin analogues).  In people with diabetes, insufficient insulin prevents the body from getting glucose from the blood into the body’s cells to use as energy. When this occurs, the body starts burning fat and muscle for energy, causing a reduction in overall body weight. 

Hypothyroidism is another potential issue. 

It must be emphasised that there will always be exceptions and the above will not apply to every single patient with one of the above.

What about weight gain?

You always associate weight loss with cancer patients but there are some types of NETs and associated syndromes which might actually cause weight gain.  And of course some people will gain weight naturally, women are more prone to this than men, i.e. The hormonal changes of menopause might make you more likely to gain weight around your abdomen than around your hips and thighs. But, hormonal changes alone don’t necessarily cause menopause weight gain. Instead, the weight gain is usually related to aging, as well as lifestyle and genetic factors. One of the most common comorbidities in those aged 50 plus is Hypothyroidism which has a listed side effect of weight gain.

In terms of direct links to NETs, here’s what I found from ISI and other sources (as mentioned):

Cushing’s Syndrome.  Centripetal weight gain is mentioned.  (Centripetal – tends to the centre of the body).  I also noted that Cushing’s Syndrome tends to be much more prevalent in females. Cushing’s syndrome comprises the signs and symptoms caused by excessive amounts of the hormone cortisol (hypercortisolism) or by an overdosage of drugs known as glucocorticoids.

Insulinoma. Weight gain occurs in around 40% of cases, because patients may eat frequently to avoid symptoms and sugar containing foods seem to work.  However, according to an Insulinoma support group site, I did note that after treatment (some stability), things can improve and the need for sugary foods decreases.

Again, it must be emphasised that there will always be exceptions and the above will not apply to every single patient with one of the above.  As in weight loss scenarios, the Secondary Effects of NETs can have an effect.  Hypothyroidism is another potential issue and weight gain is a listed symptom.  I was diagnosed with mild hypothyroidism in 2017 but I was not gaining weight!

Causes of weight gain during cancer treatment

American Society of Clinical Oncology ® Cancer.Net, Doctor-Approved Patient Information

This great article from ASCO is worth a read.  This is general for all cancers and applicable for some cases of NETs. 

The following cancer treatments may lead to weight gain:

Chemotherapy. Chemotherapy can lead to weight gain in several ways, including by:

  • Causing the body to hold on to excess fluid, called edema.
  • Causing people to reduce physical activity, usually because of fatigue.
  • Causing nausea that is improved by eating.
  • Triggering intense food cravings.
  • Decreasing a person’s metabolism, which is the rate that the body uses energy.
  • Causing menopause in some women, which decreases metabolism.

Steroid medication. Doctors prescribe steroids during cancer treatment for several reasons, including:

  • To reduce symptoms of inflammation, such as swelling and pain.
  • To treat nausea.
  • As part of the treatment for cancer itself.

However, steroids can cause certain side effects, including:

  • An increase in appetite.
  • An increase in fatty tissue (with long-term use), which can increase the size of a person’s abdomen and cause fullness in the neck or face.
  • Weight and muscle mass loss, called wasting.
  • A noticeable increase in weight (with continuous, long-term use).

Hormonal therapy. Hormonal therapy may be used to treat breast, uterine, prostate, and testicular cancers. It involves medicines that decrease the amount of estrogen or progesterone in women and testosterone in men. Decreases in these hormone levels can increase fat, decrease muscle, and lower metabolism.

Read the rest of the article here. and

Suggested reading for putting weight back after surgery

An excellent reference document produced by Royal Free Hospital, authored by Tara Whyand and distributed via the NET Patient Foundation – hints and tips for different types of NET by anatomy:  click here.

See also the excellent video series from Tara Whyand which includes a section on gaining weight.  Click here.


I am not a doctor or any form of medical professional, practitioner or counsellor. None of the information on my website, or linked to my website(s), or conveyed by me on any social media or presentation, should be interpreted as medical advice given or advised by me. 

Neither should any post or comment made by a follower or member of my private group be assumed to be medical advice, even if that person is a healthcare professional.   

Please also note that mention of a clinical service, trial/study or therapy does not constitute an endorsement of that service, trial/study or therapy by Ronny Allan, the information is provided for education and awareness purposes and/or related to Ronny Allan’s own patient experience. This element of the disclaimer includes any complementary medicine, non-prescription over the counter drugs and supplements such as vitamins and minerals.

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5 thoughts on “Weight – the NET Effect

  • Great article Ronny. I am on 10 Créons with meals. Cannot gain weight. My extensive whipple causes malabsorption. My blood panels are fairly normal even on affinitor / lanreotide.

  • Jean Rodda

    Thanks for this post, Ronny. I started Lanreotide in January 2017, then somewhere around May or June, I began to lose weight. I’ve had to adjust my eating, ie. remove added sugars and most dairy, to prevent pain in the gall bladder area or pancreas area, but certainly not enough change to warrant the 15 pounds that I’ve lost. I’m thinking, based on your post, that it may be the cumulative effect of the Lanreotide over the first few months. And on my next doctor’s appointment, I will try to get an appointment with a dietician to see if there is something that I can to do to mitigate the weight loss. I don’t mind the weight loss, but I do not want to be malnourished.


  • Neil Colville

    Good to hear you are still in light training. I purposely lost almost a stone before Xmas as I suddenly found that some of my 34″ trousers had shrunk. Cut out chocolate biscuits and the Mars bars and Snickers that we consumed after the first 9 holes, 3 or 4 times a week. Dipped below 12st last month but risen slightly since. Fingers crossed it was the lack of calories in sweet bars.

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