Cancer is a progressive disease which starts as a malignant cell which is not visible even on scans. As the cells multiply, it takes form of a tumor or malignancy on an organ and continues to grow. This nature of cancer has made staging a very vital part of diagnosis. For a layman the term stage 0, I, II, III, or IV is just another number, but these numbers are very important and play a huge part in planning and treatment and prediction of prognosis for the patient.
Cancer staging is divided into clinical and pathologic stages which are denoted in medical reports with letter ‘c’ or ‘p’. The TNM is a very common staging system worldwide, where T stands for primary tumor, N for involvement of regional lymph nodes and M denotes metastasis. TX means the primary tumor cannot be evaluated, T0 shows no evidence of primary tumor and Tis denotes Carcinoma in situ. T1, T2, T3, and T4 show to what extent the primary tumor has grown. Similarly NX means the regional lymph nodes cannot be evaluated, N0 shows no regional lymph node involvement and N1, N2, N3 denote to what degree is the involvement of regional lymph nodes. MX means that the distant metastasis cannot be evaluated, M0 indicates no distant metastasis and M1 denotes the presence of distant metastasis.
Another equally important aspect of cancer diagnosis is identifying recurrence where cancer has reappeared after being in remission. Here is brief information which will help in understanding the 5 stages of cancer more clearly.
5. Stage 0
Not many are aware of the Stage 0 in cancer, as cancer is not diagnosed that early, moreover, it is not applicable to all types of cancer. Obliviously, it is easy to understand that stage 0, also known as carcinoma in SITU, is the earliest stage of cancer which is easily treatable. Though cancer cells are present, it is contained in the tissue where it has developed without breaking the membrane and spreading to the tissues nearby. It is non-invasive cancer at this stage.
4. Stage I
Though at this stage the cancer cells begin to clump together and start penetrating the top layer of cells in the affected organ, it is still contained within the organ it started in. As cancers in stage I are localized in one part of the body, it can be surgically removed to stop it from spreading any further. Doctors do not opt for radiation or chemotherapy at this stage, as with the surgery there is high rate of survival in many cancer patients diagnosed at stage I.
Further Reading: Top 10 Warning Signs Of Cancer
3. Stage II
If cancer has been left undetected at stage I, it develops into stage II where the clumps of cancerous cells begin to grow into a tumor. Though the cancer has advanced locally, it has not yet spread to the surrounding tissues, but is contained within the organ of origin. Even when the cancer cells have spread into nearby lymph nodes, it can still be a stage II cancer. Treatment in stage II may involve chemotherapy and radiation along with surgery.
4. Stage III
Stage III does not differ much from stage II other than the cancer tumor is larger and has started to spread to the surrounding tissues, further, cancer is also seen the lymph nodes near the affected area. The treatment is also quite similar to that of stage II cancer, which usually involves surgery, radiation and chemotherapy. For further accuracy the stage III cancer is classified as stage IIIA, IIIB and IIIC to identify how much the cancer has spread.
5. Stage IV
Cancer is said to be in stage IV when it has spread from point of its origin to other distant tissues and organs of the body. Stage IV cancer is the most advanced form of cancer which is also referred to as metastatic or secondary cancer. When the cancer reaches this stage, it is difficult to treat, though it can be contained with intensive treatment. It is important to know that the treatment is aimed at slowing the progress of cancer and relieving symptoms rather than curing it.