I she does have to opt for surgery,I just hope there's a way to keep the reduction to a minimum while stopping the growth.That way she can retain her goddessey proportions and not worry about back problems.
I'm no where near as big as Himiwako, and at my age, I know I never will be. Still, I have some experience with this. There is no "cure" for macromastia. The breast tissues become hyper-sensitive to the body's hormones. In some cases, hormone levels are completely normal... it's just how the breast responds to what's there. In other cases, hormones are thrown off by some triggering event.
In my case, the growth was slow enough that medication or hormonal therapy could control or even stop it. Someone like Himiwako is likely well past that point since her growth was very fast, more similar to someone like Pilma. There have even been cases where women go for reductions and then gain everything back! This makes sense... if the tissue is hyper-responsive, it will continue to grow. In these cases, mastectomy is the only way to completely stop the growth.
But Himiwako seems to enjoy her size. This will surely have an impact on her decisions, whatever they may be.