The words tumor or mass refer to any kind of lump. A lesion is a very general term used to describe any type of abnormality (not necessarily a cancer). If we say something is neoplastic (or a neoplasm) that means it is growing. Any of the words already defined can refer to a benign or a malignant process.
A benign tumor is not cancer. It does not have the ability to spread to other areas of the body, and is not life threatening. Usually, a benign tumor can be surgically removed and it will not come back. A malignant tumor is cancer. It has the ability to spread to other areas of the body, and may come back after removal.
Cancer is a malignant growth. The place that a cancer starts is called the primary site. Carcinoma refers to a particular category of cancers, for example carcinoma of the breast. A cancer that comes from gland cells is called an adenocarcinoma. A cancer of the lymph glands is called a lymphoma. A cancer of the bones, muscles or fat is called a sarcoma.
With any type of cancer, there are certain terms used to describe the different ways that a cancer can come back or spread. If a cancer comes back in the same area, it is called a local recurrence. If it has spread to the lymph glands it is called a nodal or regional metastasis.If the cancer spreads beyond the original organ or lymph glands it is called a distant metastasis. If a new cancer develops in another organ it is called a second primary breast cancer.
The word "cancer" refers to an abnormal mass which is growing at an unusually fast rate. Its growth is faster than normal tissues, and its growth is not prevented by contact with other tissues. In other words, it is tissue growing out of control. A cancer starts as a single abnormal microscopic cell. This cell divides into two cells in a certain period of time. Every time the cell (or cells) divide we call that doubling. The time it takes to double is the doubling time. A reasonable doubling time for a breast cancer cell is three months. In other words, every three months the cancer cells double in number, and the cancer doubles in size. In order for a cancer to form a lump that is one centimeter (3/8") in diameter it must contain about 100 billion cells. A cancer doubling at a rate of once every three months takes eight to ten years to get to this size.
This means that whenever a cancer is detected it probably began growing many years ago, and may have spread by the time it was diagnosed. However, each cancer has its own behavior pattern; and although it theoretically had the ability to spread, it may not have been its nature to spread at three years, or ten years, or at all. Although this idea may not be comforting, it does mean that any slight delay in treatment of a cancer is probably not what will determine the ultimate chance of cure. Also, it means that a person can take the time needed to decide how to proceed with the treatment of their cancer. There is no data to suggest that a delay of a week or two in deciding treatment is detrimental.