A study to followup patients that have previously been treated for pituitary tumours with either photodynamic therapy or placebo in a previous trial. The study aims to determine whether photodynamic therapy has any long term effect on tumour size, visual fields or endocrinological function.

No patients will receive any medical or procedural treatments in this study, since these have been administered in a previous trial. The previous trial participants will be contacted and asked to attend a clinic or to have a telephone interview, where they will answer a questionnaire. They will be assessed clinically for visual fields, as well as undergoing an MRI scan of their head to assess tumour size (unless they have had a scan anyway in the previous 12 months), these tests would ordinarily form part of the routine outpatient workup for patients with pituitary tumours. There is no significant risk to the physical well-being of the patients with any of the methods to be used.

Inclusion Criteria:

• Patients who were previously included in the initial pituitary PDT trial, in addition to those who were randomised as part of the RCT arm of the study. These patients have already participated in phase I/II trials. Of note, these patients all have pituitary tumours.

Exclusion Criteria:

• Patients who were not included in the above mentioned trials. Patients included in the original trials who have subsequently died (of any cause).

Details of previous research participants will be extracted from the study files by the researchers, who are all members of the direct care team.