It seems you are discussing two different things
what do you mean by "getting it again"--ie getting another new breast cancer vs recurrence of your original breast cancer?
As far as I know there are no figures for how the risk of recurrence of the original her2+ breast cancer is influenced by weight gain/loss.
Most studies looked at ALL breast cancers, which by nature are about 10-15% ER-PR-HER2-, 20-25%her2+ (which seem to be spread about 45% ER+ and 55% ER-) and 55-60% ER+PR+her2-. The exact figures are hard to get to as her2 testing is not done everywhere and not done equally well everywhere.
I estimated these figures based on the fact that ER+ tumors are about 67% of tumors, her2 about 20-25% of tumors, and triple negatives make up the rest.
Studies that lumped everyone together showed exercise decreased recurrence of tumors in ER+ patients even when it was not associated with weight loss.
Weight loss helps the body with its use of insulin and there is a role (very complicated and still being discovered) of insulin growth factor receptor as alternate signalling/complicating factor for her2+ breast cancers. I don't
think it is well worked out yet but I have heard implied that it may be involved in someway with deciding whether or not lapatinib may be effective (more reading needed on my part!)
In any case, if you have extra "upholstery" it will make recurrences harder for the doctor to detect (it has hard to feel a pea in a dumpling!), may make breathing harder for you if you get metastases to your lung (expecially lying down you have to "lift" up that heavy chest with your breathing), makes harder work for your heart to transport the body the around by walking, makes harder work for your bones should you get metastases, and if associated with high blood pressure may increase your risk of stroke.
That said, many on this site believe having a few extra pounds on you is like a squirrel burying away some nuts for the future. If they tend to be thin, they hope it will tide them over if they need to take future courses of chemo which might "ruin their appetite"
The study that came out last year showed recurrences decreased in ER- tumors as a group (her2 + and- and not differentiated as I recall) with a low fat diet. I would have to go back and look for it (I am sure you can find it with the search feature of this site) but one of the authors was Chlebowski, I believe.
Again, as far as I know nooone has shown particularly that weight loss perse keep her2+ breast cancer from recurring (that doesn't mean it doesn't. just that they haven't done the study just looking at her2+ patients). The studies we have been discussing recently have to do with BMI (weight) status and risk of breast cancer in general, ie, getting it in the first place or getting a second one!
Hope this helps!
|