Introduction: In recent years, there has been an increase in the use of oral chemotherapy, for its comfort and for allowing a higher quality of life. However, one of the main drawbacks is the lack of adherence to treatment with important clinical, social and economic consequences. In this scenario, the investigators did not have a questionnaire designed and validated to measure adherence in onco-hematological patients, a population that was erroneously considered very adherent.

The objective of the investigators is to build and validate a questionnaire to measure adherence to treatment in oncohematological patients in treatment with oral anti-cancer drugs.

Methods and analysis: An observational study to validate questionnaires will be carried out combining qualitative and quantitative research techniques. With the results of a systematic review of the literature and a qualitative study based on focus groups, a questionnaire will be designed to measure adherence in oncohematological patients in treatment with with oral anti-cancer drugs. The investigators will include patiens from two hospitals in the Valencian Community.

Discussion: It is essential to have a simple, reliable and validated instrument for measuring adherence in cancer patients undergoing treatment with oral antineoplastic agents. With this, lack of therapeutic compliance and its causes can be detected in order to establish interventions that improve it.

Inclusion Criteria:

• Patients over the age of 18 in treatment with oral anti-cancer drugs (groups L01 and L02 according to the ATC drug classification), that come to the San Juan Hospital or Elda General Hospital to collect their medication, will be included.

Exclusion Criteria:

• Those patients with communication difficulties, and/or do not agree to take part in the study, will be excluded

Patients over the age of 18 in treatment with oral anti-cancer drugs (groups L01 and L02 according to the ATC drug classification) who come to hospital to collect their medication,