I have been feeling the heaviest in my life round my belly. Thought it was all due to bloating from The tamoxifen but turns out it’s a menopause thing! https://aaptiv.com/magazine/menopause-belly
As with many things, it all depends on your genes. I have two older sisters and two older brothers. My sisters and I are thin. My brothers struggle with their weight. I have my mum's legs, my sisters have my dad's legs. Not much you can do about other illnesses combined with cancer.