First line treatment is a type of medical treatment that is recommended first for a particular condition. It is usually the most effective and least expensive option available. It is usually the first choice of treatment that a doctor will recommend when treating a patient. It is also the treatment that is tried first before any other treatments are considered.
Second line treatment is a type of medical treatment that is recommended when first line treatment does not work or is not the best option. It may involve more expensive medications, more invasive procedures, or different forms of therapy. It is usually recommended when the first line treatment does not work or does not provide the desired results.