Prognosis of outlook of any cancer depends on several factors. Notable among these is how early the cancer is detected and treated. The stage of the cancer thus at the beginning of therapy determines the outlook of a breast cancer patient.

Overall, in the UK, more than 85% diagnosed with breast cancer live for at least 5 years after diagnosis. More than 75% live for at least 10 years.

Over years, with the development of medicines and surgical procedures for breast cancer treatment the outlook for breast cancer has continued to improve. The number of women dying from breast cancer has gone down significantly in the last 20 years in the UK mainly because of efficient and early screening and detection of the cancer.

Some of the most important factors that determine survival of a breast cancer patient include:

• Location of the tumor and how far it has spread
• Grade of the tumor
• Stage of the tumor
• Hormone receptor positive or negative status
• Presence of tumor markers
• General condition and age of the patient

Remission and relapse

Once a cancer recedes and is undetectable after initial therapy, the patient is said to be in remission. If breast cancer comes back, it is usually within the first 2 years. Breast cancer can come back 10 or 20 years after initially remission. This is, however, rare and the more time that passes since diagnosis, the less likely it is that the cancer will come back.

Outlook of breast cancer based on grade of cancer

Just like outlook of breast cancer depends on staging of the cancer, it is also dependent on grade of the cancer. A ''well-differentiated'' tumor for example is low grade and resembles normal tissue. A ''poorly differentiated'' tumor is composed of disorganized cells and, therefore, does not look like normal tissue and is termed high grade. Some are ''moderately differentiated'' or intermediate grade.

This is important because high grade cancers may be faster growing and more likely to spread. The Nottingham Prognostic Index (NPI) that determines outcome or prognosis of breast cancer is based on grade of the cancer. 

Outlook of breast cancer depending on stage

The earlier a breast cancer is diagnosed, the smaller it is likely to be and the lower the chance that it has spread.

The numbers below come from the National Cancer Data Base, and are based on people who were diagnosed with breast cancer in 2001 and 2002.

*These numbers are correct as written (stage IIIB shows worse survival than stage IIIC).

Outlook of Ductal carcinoma in situ (DCIS)

In DCIS the cancer cells are present within the ducts of the breast. So there is very little risk of the cancer cells spreading. Treatment for DCIS usually means a certain cure.

Outlook of hormone receptor positive or negative status

About 75% of breast cancers are estrogen receptor-positive (ER-positive, or ER+). About 65% of ER-positive breast cancers are also progesterone receptor-positive (PR-positive, or PR+). Cells that have receptors for one of these hormones, or both of them, are considered hormone receptor-positive.

These cancers are sensitive and responsive to hormone therapy. Hormone therapy includes tamoxifen or aromatase inhibitors. Hormone receptor-negative tumors are referred to as hormone resistant.

A better outlook is seen in women who have hormone receptor-positive tumors because these cells grow more slowly than receptor-negative cells. In addition, women with hormone receptor-positive cancer have more treatment options.

Outlook of tumours positive for tumor markers

Tumor markers are proteins found in blood or urine when cancer is present. Tumor markers relevant for breast cancer prognosis includeHER2, CA 15-3, CA 27.29, CEA, ER, PgR, uPA, and PAI-1. HER2-positive cancer usually occurs in younger women and is more quickly-growing and aggressive than other types of breast cancer. The HER2 marker is present in about 20% of cases of invasive breast cancer. Those with HER2 positive tumors respond to trastuzumab (Herceptin) or lapatinib (Tykerb).

Outlook based on general condition and age of the patient

Frail and elderly patient with poor helth often have poorer outcome and lowered capacity to withstand therapy for breast cancer and respond adequately to therapy.