Study Of PRoliferation and Apoptosis in rectal caNcer as predictive and prognostic biOmarkers: a histopathology and imaging analysis (SOPRANO)

Treatment for rectal cancer involves a course of chemo and radiotherapy (CRT) followed by major abdominal surgery to remove the tumour. After MRI scans performed after CRT have shown that up to 40% of patients will have an extremely good response to treatment with no visible residual tumour. Clinicians question the value of major surgery and its associated complications for a cancer that has effectively ‘disappeared’. However, by not operating on patients, are we leaving viable cancer cells behind and putting patients at risk of recurrence? What is needed is a marker that will predict and measure a patient’s response to CRT at a cellular level, in order to confirm and validate the MRI findings.

The DNA in a cancer cell is damaged. A healthy cell would ‘self-destruct’, a process known as apoptosis. However, cancer cells evade apoptosis and replicate in an uncontrolled manner leading to growth of the tumour. CRT works by causing cancer cells to undergo apoptosis. We believe we can use apoptosis as a marker for the cell ‘death’ seen after CRT. The SOPRANO trial will use a special stain for ‘dead cells’ and count the number of cells with DNA damage. This will give an apoptotic index and should directly equate to a patients response to CRT. This together with the MRI findings would enable us to give patients a more accurate picture of how their tumour is likely to behave in the future and whether or not they would require an operation or further drug treatment. SOPRANO will also measure proliferation, which is a marker of continued cancer growth and will add to the biological basis for our treatment decisions.

The SOPRANO trial is now closed to recruitment.
