Obesity does not influence outcomes in patients treated for appendix and colon cancer that has spread to the abdominal cavity

This study evaluated whether obesity has any influence on survival in patients with peritoneal surface disease from colon or appendix cancers undergoing hyperthermic intraperitoneal chemotherapy after cytoreductive surgery.

Peritoneal surface disease (PSD) is a condition where cancer has spread to many spots on the surface of the peritoneum (a sheath lining the abdominal cavity and covering the abdominal organs). PSD is usually caused by cancers of abdominal organs covered by the peritoneum, such as the appendix and colon or ovaries. When a cancer spreads this way, complete surgical removal is difficult. Therefore, the surgeon usually tries to remove as much of the cancer as safely possible. This is called a cytoreductive surgery (CRS), also known as “debulking”. In order to improve efficacy of CRS, the abdominal cavity is washed with a warm solution of chemotherapy. This treatment is called hyperthermic intraperitoneal chemotherapy (HIPEC). 

Obesity is defined as a Body Mass Index or BMI (weight divided by the square of height) of 30kg/m2 and above. Obesity has been shown to have negative effects on a person's overall health. Severe obesity is defined as having a BMI of above 35 kg/m2. The aim of this study was to evaluate outcomes for obese versus non-obese patients with PSD treated with CRS and HIPEC.

The medical records of 246 appendix and colon cancer patients with a BMI of 30kg/m2 or higher who underwent CRS/HIPEC for PSD between 1991 and 2012 were reviewed. 38.6% of these patients were severely obese. Outcomes for obese patients were compared to a similar group of non-obese patients. The average follow up period for these patients was 52 months. Results showed that surgery outcomes (length of the surgery and complication rates) were similar for obese and non-obese patients. Also, median hospital stay for both groups was 9 days, with an average of 1 day in the intensive care unit. The average overall survival or OS (defined as the percentage of patients surviving a certain time after treatment) for non-obese patients with low grade cancer of the appendix and PSD was 107 months, whereas for obese patients OS was 73 months. However, in severely obese patients the average OS was 52 months. OS was similar in obese and non-obese patients with PDS from colon or high grade appendix cancer.  

In summary, the authors of this study found similar outcomes for obese and non-obese patients with PDS undergoing CRS/HIPEC. This research shows that obesity should not be considered a reason for denying a patient access to these therapies.

Ask your doctor whether CRS/HIPEC is a good treatment option in your situation.