I'm a 4-year breast cancer survivor. My friend had breast cancer recently; she's had a lumpectomy, and had several lymph nodes in the armpit removed. Her onc told her that, due to the risk of getting lymphedema, she could never put her arm in warm water again. No hot tubs, no tub baths, no swimming. I'm an avid swimmer, and I've had no problems whatsoever using hot tubs at the gym. Is this a new precaution?