OCTOPUS: Obesity and Cancer TOgether imPact Upon Survival

From left to right: Emma Kennedy, Matt Sperrin, Andrew Renehan, Hannah Lennon

Obesity and Cancer

Being overweight or obese is the second biggest preventable cause of cancer in the UK after smoking, and contributes to around 18,100 cases of cancer every year. With over 60% of the UK population falling into that category, that number is set to increase.

Heightened BMI (body mass index) is an established risk factor for 13 cancers including pancreatic, oesophagus, colorectal and endometrial. For information on that study, please click here.

Thanks to public awareness campaigns, the link between excess body weight and a cancer diagnosis is slowly reaching the masses. Some studies have also indicated that an obese cancer patient may expect a poorer prognosis than one with a healthy BMI.

The OCTOPUS Project

From the World Cancer Research Fund (WCRF) Continuous Update Project (CUP), we know that elevated BMIs are associated with increased risk of several cancers. The OCTOPUS project will research the impact of obesity on survival after cancer treatment for colorectal (bowel) and endometrial (womb) cancers, as both are high on the list of obesity related cancers.

Data from the cancer post-diagnosis setting can be susceptible to biases due to stage misclassification, reverse causality treatment allocation (where two illnesses are associated but behave and impact on each other differently to how you would expect) and dose-capping chemotherapy in obese patients. Therefore, we will secondary analyse trial data, where stage, treatment and cancer endpoints are governed by protocol.

In summary, we will collect and analyse patient data from many studies – being careful to take into account the differences in particular studies – to test how bowel or womb cancer patients with significantly higher BMI measurements compare with patients who have a lower BMI. This method is called an Individual Patient Data (IPD) meta-analysis.

IPD meta-analysis can improve the quality of data and the type of analyses that can be done, producing more reliable results (Stewart and Tierney 2002). For this reason they are considered to be a ‘gold standard’ of systematic review. In fact, IPD meta-analyses have produced definitive answers to clinical questions, which might not have been obtained from summary data. Find out more information about this here.

Cancer e-lab

OCTOPUS will establish a cancer e-Lab (a secure electronic platform for data sharing) to address this complex question. This facility will enable our research team to analyse many different clinical trials, gaining a clear understanding of the effect of an elevated BMI on survival prognosis.

The OCTOPUS project is funded by the World Cancer Research Fund.

This review is registered with PROSPERO International prospective register of systematic reviews.

For further information on the OCTOPUS Project please contact:

Emma Kennedy
Project Manager
07741 297 624


Researchers involved: