Raising the alarm: early signals of colorectal cancer indicate opportunities for more timely diagnosis

Medical data from over 7500 people has recently been analysed in an observational study to map out when cancer features might first appear in patients with colorectal cancer.

CanTest affiliate member Dr Yin Zhou (GP and clinical research fellow at the University of Cambridge) talks with Euan Lawson from the British Journal of General Practice about the team’s novel findings in a new podcast available here:

In it she summarises the findings from the study and what they mean for improving timely diagnosis of cancer. The diagnosis journey can be complex and prolonged, and this research has identified when alarm signals might occure, so that both patients and doctors can be vigilant for the possibility of colon and rectal cancers.

The research showed that in the data examined, certain symptoms were in fact present in some patients 8 – 10 months before diagnosis.

Rectal bleeding was identified up to 10 months earlier than the average diagnosis for colon cancer, followed by a change in bowel habits (8 months) and abdominal pain (8 months). Rectal bleeding was identified up to 8 months prior to diagnosis for rectal cancer, followed by abdominal pain (7 months).

Blood tests also factored into the early warning signs, with levels of the following first becoming abnormal at at varying times before diagnoses:

• Low haemoglobin (protein in red blood cells that carries oxygen through the body) – rates increased from 9 months pre-diagnoses for both colon and rectal cancer.
• High platelet count (pieces of cells in bone marrow that help form clots) – this increased as early as 9 months from pre-diagnoses for rectal cancer, and 8 months for colon cancer.
• High inflammatory markers (tests than detect inflammation that could be caused by cancers or other diseases/conditions) – this increased as early as 9 months from pre-diagnoses for rectal cancer, and 8 months for colon cancer.

In terms of using these findings to improve cancer diagnoses, the research has indicated that patients with alarm symptoms could benefit from more timely referrals and the earlier use of tests such as FIT (Faecal Immunochemical Test i.e., stool tests) which could be used for patients who are experiencing less specific symptoms/signs. Additional monitoring or safety netting (advising on future actions regarding symptoms) could also be utilised for patients who do not fit the criteria for further tests/referrals.

Overall, the research has helped to establish how long rectal and colon cancers can take to develop, and identify windows of opportunity for doctors to take action earlier when investigating abnormalities.

See Yin’s brief summary of findings here, and read the full published research paper in BJGP here.