One of the main factors that affect breast cancer prognosis is the stage at which it is diagnosed. In most cases, the prognosis is best for a person whose breast cancer is diagnosed in stage zero or one, which are the earliest stages of breast cancer. In contrast, a person who has reached stage four typically has the worst chance of surviving for five years. Other factors that may influence a person’s prognosis include the patient’s overall health, her age, the type of breast cancer she has, and the treatments that are used.
As with many diseases, the prognosis for breast cancer is best when the cancer is diagnosed or treated in an early stage. When a person has stage zero or stage one breast cancer, the tumor is usually equal to or smaller than 0.79 inches (about 2 centimeters). At this point, the breast cancer has not spread to any other parts of the body or affected the patient’s lymph nodes. The five-year survival rate for this type of cancer is well over 90 percent.
The prognosis for someone with stage two breast cancer isn’t as good for someone who is diagnosed in the earliest stages, but it is still above 80 percent. A person with this type of cancer has a tumor that is smaller than 2 inches (about 5 centimeters), but it has affected her lymph nodes. This stage also applies for a person with a tumor that is above 2 inches (about 5 centimeters), but it has not spread at all. In many cases, larger tumors translate into a less desirable prognosis.
Once a person reaches stage three, her breast cancer prognosis declines even more. In this stage, a person has a breast cancer that is any size but has spread to either the lymph nodes or begun to grow into nearby body tissues. For example, a tumor may grow into the patient’s chest wall. The size of the cancer factors heavily in this stage, and a person still has above a 50-percent chance of surviving for five years.
If a person is diagnosed with stage four cancer, her breast cancer prognosis is generally poor. Once a person has reached this stage, the cancer has spread far across the body and survival rates plummet down to an average of about 20 percent over five years. Often, doctors know they will not be able to cure patients who have reached this stage and focus their efforts on using treatments to prolong the patient’s life and keep her more comfortable.
In addition to the cancer stages, there are other factors that can influence breast cancer prognosis. They include the presence of other health problems and the patient's ability to withstand treatment. The type of breast cancer a person has may play a role as well, as some are more aggressive or harder to treat than others. Additionally, such factors as a patient’s age and race can influence the chances of survival.
