Diagnosis delay and follow-up strategies in colorectal cancer. Prognosis implications: a study protocol

Background: Controversy exists with regard to the impact that the different components of diagnosis delay may have on the degree of invasion and prognosis in patients with colorectal cancer. The follow-up strategies after treatment also vary considerably. The aims of this study are: a) to determine if the symptoms-to-diagnosis interval and the treatment delay modify the survival of patients with colorectal cancer, and b) to determine if different follow-up strategies are associated with a higher survival rate. Methods/Design: Multi-centre study with prospective follow-up in five regions in Spain (Galicia, Balearic Islands, Catalonia, Aragon and Valencia) during the period 2010-2012. Incident cases are included with anatomopathological confirmation of colorectal cancer (International Classification of Diseases 9th revision codes 153-154) that formed a part of a previous study (n = 953). At the time of diagnosis, each patient was given a structured interview. Their clinical records will be reviewed during the follow-up period in order to obtain information on the explorations and tests carried out after treatment, and the progress of these patients. Symptoms-to-diagnosis interval is defined as the time calculated from the diagnosis of cancer and the first symptoms attributed to cancer. Treatment delay is defined as the time elapsed between diagnosis and treatment. In non-metastatic patients treated with curative intention, information will be obtained during the follow-up period on consultations performed in the digestive, surgery and oncology departments, as well as the endoscopies, tumour markers and imaging procedures carried out. Local recurrence, development of metastases in the follow-up, appearance of a new tumour and mortality will be included as outcome variables. Actuarial survival analysis with Kaplan-Meier curves, Cox regression and competitive risk survival analysis will be performed.
This study has received a grant for each participating group from the Ministry of Science and Innovation, Carlos III Institute, Healthcare Research Fund; PS09/00663, PI09/01800, PS09/00954, PS09/01614 and PS09/01375. In addition, the study has received the support of the Health Promotion and Preventive Activities - Primary Healthcare Network, which is supported by other grants from the Ministry of Health ISCIII-RETCI G03/170 and RD06/0018.; The study is also partially supported by a XUGA grant (08CSA073916PR) and the Galician Network for Colorectal Cancer Research.