Some types of cancer can form and grow undetected for 10 years or more, as one study found, making diagnosis and treatment much more difficult. Many women who are diagnosed with breast cancer never have any signs or symptoms, and their cancer is detected during a mammogram. If this were true, a cancer with a doubling time of 200 days would take 20 years to develop into a detectable tumor. A doubling time of 100 days would take 10 years to be discovered in the exam.
In contrast, a breast tumor with a doubling time of 20 days would take only 2 years to develop. When you can feel it, the breast tumor is usually just over half an inch in size (about one-third the size of a golf ball). The actual time it takes for breast cancer to grow from a single cancer cell to a cancerous tumor is unknown. Metastasis, the spread of breast cancer to other parts of the body, is responsible for most deaths from breast cancer.
A number of factors, such as age or a history of hormone replacement therapy, can influence the growth rate of breast cancer cells. All other stages of breast cancer (stage I to stage IV) are considered invasive and have the potential to spread. However, other types of cancer can form and grow undetected for 10 years or more, as one study found, making diagnosis and treatment much more difficult. The results suggest that growth varied significantly depending on the subtype of breast cancer and the role of estrogen receptors in those subtypes.
Breast cancer can also cause a rash similar to mastitis, an infection of the breast tissue that most commonly affects women who are breastfeeding. Depending on symptoms, these changes may be attributed to rarer cancers, such as Paget's disease of the breast or an unusual but aggressive form of breast cancer known as inflammatory breast cancer. Some types of cancer that are not often found are slow-growing conditions, giving doctors a better chance of getting successful treatment. This also applies to new symptoms if you've already been diagnosed with secondary breast cancer, as it may be a sign that the cancer is progressing.
Among women with warning signs, the most common warning sign is a lump in the breast or armpit. Breast cancers are sometimes detected when they are very small because of microcalcifications in the breast. That said, it's a good idea to familiarize yourself with the way your breasts normally feel, so you can alert your healthcare provider to any changes and have them evaluate the changes if they don't resolve within a few weeks. Tumor growth rate of invasive breast cancers during waiting times for surgery as evaluated by ultrasound.