Tumour depositis- a novel approach to improve colorectal cancer survival

Colorectal cancer is the third most common malignancy. Despite improvements in recent decades the 5-year survival is 65%. Tumour recurrence is common.

Our proposal is focused on developing a novel prediction marker with therapeutic potential, to improve survival of colorectal cancer patients. Our project challenges the current TNM classification and has high clinical relevance.

Tumour deposits (TDs) are aggregates of cancer nodules discontinuous with the primary tumour, not associated with lymph nodes.

We have shown that histopathological TDs after colorectal cancer resection are associated with advanced tumours, metachronous distant metastasis and decreased survival. In the current TNM classification TDs are accounted as N1c. If lymph node metastasis is present, TDs are not further considered.

We hypothesize that TDs are an important prognostic marker and TDs should be identified preoperatively to tailor neoadjuvant treatment.

We will determine how TDs impact patient survival by 1) investigating TD count in relation to lymph node status, 2) testing if TDs can be identified radiologically at diagnosis, and 3) examining if specific genetic alterations correlate to TD histopathology. We will use the Swedish colorectal cancer registry data to identify TD positive patients and controls.

Radiological imaging will be reviewed and DNA extracted from pathological resection specimens and blood for genetic analysis. Our project will close the knowledge gap on TDs in colorectal cancer.