Aspirin for Dukes C and High Risk Dukes B Colorectal Cancers

An International, Multi-centre, Double Blind, Randomised Placebo Controlled Phase III Trial

Colorectal cancer is the third most common cancer worldwide. There are almost 1 million new colorectal cancer cases diagnosed each year with more than half of these patients dying from the disease (WHO Globocan database 2000). To date the current treatment of patients with (Dukes C and high risk Dukes B stage) colorectal cancer is surgery followed by a course of chemotherapy and/or radiotherapy, which has been shown to decrease the risk of patients relapsing by approximately 30%. However, numerous studies have been found to show that Aspirin use can also reduce colorectal tumour growth by some 40 to 50% in some patients.
To date, there have been no prospective studies evaluating the use and benefit of Aspirin as an additional therapy in a colorectal cancer setting. Therefore, the ASCOLT study will be the first prospective study to look at and evaluate the long term benefit of Aspirin in patients with Dukes C /high risk Dukes B colorectal cancer.

This study will recruit eligible patients with Dukes C and high risk Dukes B stage colorectal cancer. Patients must have previously undergone surgery and completed their standard course of 3 months chemotherapy (and radiotherapy). Patients will then be randomised (randomly allocated) to one of two treatment options; the first, 200 mg Aspirin tablet once a day for 3 years, the second, 200 mg placebo tablet once a day for 3 years.

In order to accurately assess whether a patient’s response is truly due to the use of the Aspirin in this disease group and is not due to any other variation, such as, type of disease, or previous treatment given, it is important to be able to measure their response against an identical set of patients (with the same disease characteristics and treatment history), who have had no exposure to Aspirin. Therefore, for half the patients recruited into this study a placebo (a dummy tablet) is used. Neither will the patient nor the treating doctor know which treatment the patient is receiving (known as double blinding) to prevent any bias from either doctors or patients in both the allocation of study treatment to the patient and the results of the final data.

Once recruited, patients are followed-up at 3 monthly intervals either by attending an assessment visit or by telephone for 3 years, followed by 6 monthly assessments for an additional 2 years. Patients will be followed-up for 5 years in total.

Over a 5 year period this study is looking to recruit a total of 2660 patients, with patients currently being recruited from Singapore, China, India, and Indonesia (with the possibility of extending recruitment to other countries).

The overall purpose of this study is to evaluate the long term effects of Aspirin on the length of time patients remain disease free as well as the effect on patients overall survival.

This is just a brief summary of the above study.  If you would like further information on this or any other study being run by INDOX please contact the INDOX Coordinating Centre in Oxford.