As we discussed in a previous article, the lethal nature of cancer is because of its propensity to invade (grow into adjacent tissues and organs) and metastasize (spread to distant organs).
Cancers occur as a result of normal cells becoming abnormal (mutation). Once the cells become cancerous, cancer progresses in stages. The stage when individual cells have transformed into cancer, but have not yet invaded adjacent tissues or spread to distant organs is called Stage 0 Cancer. Stage 0 cancer is also called in-situ (in place) cancer, or pre-invasive (before invasion) cancer.
Most Stage 0 cancers can be completely cured. While some stage 0 cancers can even be observed closely, most require treatment. This is because some stage 0 cancers can progress to a higher stage if not treated. However, the treatment required is usually much simpler than that for higher stages. Treatment is directed at the site of disease alone(local treatment) – usually surgical removal of the affected portion. Even the surgery required is often limited, for example, either no sampling or limited sampling of the regional lymph nodes. While most stage 0 cancers require no further treatment after surgery, some may require adjuvant treatments (for example Stage 0 breast cancer may require adjuvant radiation if the breast is preserved). Chemotherapy is almost never required – since the chance of distant spread is virtually non-existent.
People with Stage 0 cancers may still require regular follow-up after treatment, and some may require an assessment to see if there is a genetic predisposition to developing cancer.