 - 2nd Sample: e.g. before cycle 3, if undergoing a 4 cycle regimen or before cycle 4 in a 6 cycle regimen. If the chemotherapy regimen changes following the commencement of chemotherapy or after surgery, then blood samples will be taken at the time points determined by the original plan i.e. if a patient was to have 6 cycles of chemotherapy and this was then changed to 4 cycles samples will be taken before cycle 4 