phaedrus

Hi there. Well, I for one believe you have some reason to doubt her story, but this doesn't mean that she is not sick, but it could be something else (I will go into that later). Mainly because as I understand it, her parents would have to legally consent to any treatment she undergoes, as she is under the age of 18. Even if the age of consent in medical treatment is 16, she still falls below. I also doubt tremendously that she could have chemo and maintain daily routines. If you look under the general board for cancer, you can read some stories about people who have had chemo. It has many side effects, the main one being nausea and vomitting, unless she is also on anti nausea meds. However, in the late stages of cancer, the tumour would likely hurt, and may have many other symptoms, including skin texture and colour change, nipple discharge and a visible mass. My grandmother died of breast cancer, and my mother cared for her at our home till she passed. She was bedridden for the last few months, and was clearly wasting away. This is not something that is easily hidden, though it is true that there are often few visible side effects till the last part.
Here is what I suggest: Show an interest in her illness. Find out what stage she is (and it is so much more complicated than 1, 2, 3 or 4) and what her tumour is called, and what type of cell growth there is, which drug she is on. Here is some language you can use:

Names of Tumours
Ductal Carcinoma in situ (DCIS)
Lobular Carcinoma in situ (LCIS)
Invasive Ductal Carcinoma (IDC)
Invasive Lobular Carcinoma (ILC)

Types of Cell Growth:
Solid
Cribiform
Papillary
Comedo

Chemo Drugs:
Cyclophosphamide
Epirubicin
5-Fluorouracil or 5 FU
Methotrexate
Mitomycin
Mitozantrone (mitoxantrone)
Doxorubicin (Adriamycin)

A cancer patient knows their condition, especially if they are dealing with it without parental supervision. This way, you can look up side effects like hairloss when she tells you which drug it is.
This is a guess, but I also do not see how a breast tumour can press on your heart. There is a whole rib cage between the breast and the heart.
If this is bogus, this may be a cry for help...maybe she feels that she doesn't get enough attention at home (how often do her parents leave like this?). Is there anything else going on in her life that would leave her needing to know people care about her? Is annorexia a possiblity. A story like chemo treatments would cover weight loss, hairloss, altered periods, fatigue, an overall lack of wellness. Annorexia isn't just about eating, it is about deception and feeling empowered. I had a friend who became alcoholic as a result of annorexia (she needed alcohol for regular energy boosts and carried a bottle of vodka around with her at school, so her friends wouldn't notice any difference in her energy levels).
Lastly, there is a condition called Munchausen's syndrome. This is a mental illnes. The patient compulsively creates illnesses for themselves in order to get attention over and over again. They are often very well read on medical issues, and sometimes aspire to be a medical professional. They are in and out of hospitals and medical facilities with various illnesses regularly. Very often, they will go to the extreme of harming themselves physically (like injecting toxic substances) in order to make themselves ill and require treatment. I do think this is unlikely, but clearly, if this is untrue, your friend has a problem that needs figuring out. I think it may be a very good idea to contact her parents, or at least tell yours. You are a good friend to care so much. Good luck, I hope your friend is not suffering from this terrible disease. Let us know what you find out...