In biostatistics, survival rate is a part of survival analysis, indicating the percentage of people in a study or treatment group who are alive for a given period of time after diagnosis. Survival rates are important for prognosis; for example, whether a type of cancer has a good or bad prognosis can be determined from its survival rate.
One-third of patients with early stages of non-small cell lung cancer could be cured with surgery alone. This percentage is much smaller in patients with early stage small cell cancers — less than five percent. In the majority of patients in whom cure is not possible survival may vary from months to years, depending on the extent of the cancer, the overall condition of the patient, as well as his/her response to treatment and the duration of that response. If the lung cancer is detected before it has had a chance to spread to other organs, and if it is treated appropriately, at least 49% of patients can survive five years or longer after the initial diagnosis. Only 15% of lung cancers, however, are found at this early stage. When the precise cause of death is not specified, this is called the overall survival rate or observed survival rate. Doctors often use mean overall survival rates to estimate the patient’s prognosis.
This is often expressed over standard time periods, like one, five, and ten years. Although non – small cell lung cancers can be removed surgically, removal does not always result in a cure. Supplemental (adjuvant) chemotherapy after surgery can help increase the survival rate. In non – small cell lung cancer, chemotherapy also prolongs survival and treats symptoms. In people with non–small cell lung cancer that has spread to other parts of the body, the median survival increases to 9 months with treatment. The prognosis depends on the type of lung cancer, its stage, and the overall health of the patient. About 10 per cent of patients can expect to be ‘cured’ – that is alive five years after diagnosis with no evidence of the cancer having returned. Because many people die from lung cancer, terminal care is usually necessary.