Cancer is a devastating and potentially fatal disease that develops when healthy cells undergo a genetic change and begin to proliferate rapidly and uncontrollably. The genetic mutations accumulated by cancer cells allow the cells to proliferate indefinitely, evade cell death and eventually invade other tissues. Although there are several types of cancer, each staged according to specific diagnostic criteria, many cancers have similar steps of disease progression.
Initial Tumor Growth
The first stage of cancer development is the uncontrolled proliferation of cells, which usually forms a tumor. In the earliest stages of cancer, tumor growth remains localized within one part of the tissue. As more as more cancer cells are formed, the tumor cells begin to attack and actively kill healthy cells around the tumor, facilitating the growth of a larger tumor. Depending on the location of the tumor, cancer patients at this stage may notice a range of symptoms, from a palpable mass in tumors near the skin to unexplained pain in the region of tumor growth. If detected at the early stages, many cancers can be effectively treated with radiation therapy, surgery, chemotherapy or other targeted therapies.
Growth Towards Other Tissues
As cancer progresses, tumor cells begin to grow towards neighboring tissues and structures. Many forms of cancer spread to surrounding lymph nodes, organs that help make up a part of the immune system and allow for lymph fluid circulation through lymph vessels. As cancer cells invade lymph nodes, patients may notice symptoms associated with swollen lymph nodes. Enlarged lymph nodes are most easily detected in the armpit, the groin or the sides of the neck, reports the University of Maryland Medical Center. Enlarged lymph nodes deeper within the body may cause pain as the lymph node presses against surrounding nerves and tissues. In some cases, cancers that can spread to the lymph nodes may still be treated with surgery.
Metastasis
In advanced stages of cancer, the cancer cells metastasize, or begin to colonize in distant organs throughout the body. Cancer cells may enter the bloodstream or the lymph vessels to circulate throughout the body, or they may migrate to organs around the initial tumor. The site of metastasis depends on the characteristics of the cancer cell, and how it is able to interact with the microenvironment in the distant tissue to allow for new tumor growth. Tumors formed as a result of metastasis are called secondary tumors, and they may develop within multiple organs at the same time. Since metastastic typically cancer affects multiple organs, it cannot be effectively treated with surgery, though some patients may undergo surgery to relieve pain associated with cancer progression. The American Cancer Society states that most patients who die from cancer develop secondary tumors, and that metastasis is the cause of death in most cancer cases.
