There are structures on the surface of many types of cancer cells, known as epidermal growth factor receptors (EGFRs). The receptors allow epidermal growth factor (a particular protein present in the body) to attach to them. When epidermal growth factor (EGF) attaches to the receptor, it causes chemical processes to occur inside the cell that make it grow and divide more quickly.

Drugs known as EGFR antagonists attach themselves to the EGF receptor inside the cell, and prevent the receptor from being activated. This can help to stop the cancer cells from growing so quickly.

Erlotinib (Tarceva®), is an EGFR (epidermal growth factor receptor) antagonist. It is sometimes used to treat people with non-small cell lung cancer whose cancer has come back after initial treatment, or has not responded to at least one course of chemotherapy. Erlotinib is given as a tablet. Side effects are generally mild and can include diarrhoea, a rash, nausea and tiredness.

The National Institute for Health and Clinical Excellence (NICE) is an independent body that was set up by the government. NICE assesses medicines and treatments and gives guidance to doctors on how they should be used in the NHS in England and Wales. The equivalent body in Scotland is the Scottish Medicines Consortium (SMC) .

In November 2008 NICE assessed the use of erlotinib in the NHS. It recommends that erlotinib can only be used as an alternative to docetaxel, in people with non-small cell lung cancer who have already tried one chemotherapy course that has not worked. It can only be used if the drug company supplies it at the same cost as that of docetaxel. However, people who were already having erlotinib before the guidance from NICE came out, can continue to have it.

In Scotland, erlotinib can be given to people with advanced non-small cell lung cancer who have had at least one course of chemotherapy.