How dangerous is breast cancer?

Variable. Although never trivial, mammographically detected breast cancer, if small and estrogen receptor positive has a very good prognosis with relatively minor surgery and radiation. Conversely, inflammatory breast cancer with positive nodes has an extremely poor prognosis without very aggressive treatment. Most bc's are in the middle with a relatively favorable prognosis.
It Varies. Breast cancer is really many different diseases which vary based upon its unique molecular "fingerprint". Survival is dependent upon our ability to eradicate breast cancer cells that may have spread from the breast to vital organs (lungs, liver, bone etc). While chemotherapy isn't always effective, we have made tremendous advances over the past decade and expect more to follow.
Depends on stage. Breast cancer can be a very serious disease. Survival is dependent on the stage of the cancer.

Related Questions

How serious or dangerous is breast cancer?

It depends! It depends on the type of breast cancer, the "stage" (ie how big or small, whether it has spread to lymph nodes), and other factors. Most breast cancer is detected early and cured. Left untreated, breast cancer can definitely lead to death. Overall, compared to other cancers, breast cancer has a very good prognosis. More than 85% of women are alive 5 years after diagnosis!
Can be serious. It depends on the type and stage of the breast cancer. Breast cancer can be very serious and dangerous.

How dangerous can stage 4 breast cancer that has mets to lungs and adrenal gland be if it goes untreated without chemo?

Hard to Predict. Among all patients with breast cancer who present with distant disease, one fourth will survive beyond 5 years. It would be good to know the patient's age and receptor status (er, pr, her2) to answer this question, because we are finding much better results now with certain treatments (like Herceptin (trastuzumab) for her2+ pts) than in the past. Ask your oncologist for info.
Fatal? Cancer that is so aggressive and wide spread is not likely to regress or give up on it's own. Without any chemo it may spread rapidly through the lung and to more organs. Even with chemo rx there may not be much help with such an advanced cancer.
Wide spread. Cancer is likely to lead to death regardless of treatment. Ask about benefit of chemo vs. Toxicity, and appropriateness of hospice.

What are metastatic and recurrent breast cancer? Are they more dangerous?

Yes. "recurrent" breast cancer may imply cancer coming back in the same breast following a lumpectomy, a new cancer developing in the opposite breast, or the presence of breast cancer cells that spread to another organ in the body ("metastases"). Each of these types of recurrences are managed differently; metastatic disease is the most serious.
Yes. Metastatic breast cancer refers to breast cancer cells that have traveled from the breast to distant sites of the body.

Is subaerola abscess something dangerous or causes breast cancer? My abscess is not going since a month.

Breast Abscess. Seek immediate in person medical care and possible I&D... No relationship to breast cancer!
Breast abscess. Breast abscess is not going to cause breast cancer, but has to make sure breast cancer is not presenting like an abscess. Abscess need to be treated with drainage and proper wound care.

I am 17 years old and a dark spot appeared on my breast and I wanna know if it may be something dangerous or a breast cancer?

Reassured. I think it is a very low likelihood to be breast cancer. Breast cancer would present itself to you as a lump deeper in your breast, not as a dark spot. What you describe sounds more like a mole. If the dark spot is growing or otherwise changing, see a doctor about finding out if it needs to be romoved.
Unlikely. Breast cancer is very unusual in a 17 year old young lady it is more likely that you have a benign skin nevus or freckle if you are worried please see you doctor.
See your derm. Any new skin lesions should be brought to the attention of your friendly dermatologist.

Prostate cancer vs breast cancer, which one is more dangerous?

Very similar. Breast and prostate cancers are among the most treatable cancers. The risk of ever dying of cancer with either diagnosis is about one in four.

Transmission of breast cancer to bone is it dangerous if stage 0?

Not anywhere. Stage 0 breast cancer is non-invasive and by definition does not spread to the bone or anywhere else.
Highly unlikely. Stage 0, or cis (carcinoma in situ) will not metastasize by the definition as it is confined to the original structure it started in (duct or lobule). Continue or start your monthly self breast exams and get your annual mammograms.
Stage 0 is called. Dcis, ductal carcinoma in situ, and if the cancer cannot burst through the duct, it cannot access the blood stream, or set up colonies elsewhere. The risk of dcis is that it may progress to invasive cancer, which is why dcis is treated...To prevent progression.