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Link Between Diabetes, High Blood Pressure, and Colon Cancer Recurrence
In a retrospective analysis of more than 36,000 patients with colon cancer, researchers at the Temple University School of Medicine and at Fox Chase Cancer Center in Philadelphia, Pa., have shown that patients with early-stage disease and diabetes or high blood pressure — two components of metabolic syndrome — have a greater risk of the cancer returning after treatment and of dying compared with patients with colon cancer who do not have either condition.
“Although metabolic syndrome has been linked to colon cancer — the third leading cause of cancer death in the U.S. — previous work looking at its effect on mortality has not adequately accounted for cancer stage or treatment,” said senior author Nestor Esnaola, MD, MPH, MBA. “Our results suggest that patients with early-stage colon cancer who also have diabetes or hypertension may need to be followed more closely for recurrence and could potentially benefit from broader use of adjuvant chemotherapy.”
The new findings were reported online in the journal Cancer.
Metabolic syndrome is a cluster of conditions that affects one in five American adults and that can include diabetes, obesity, high blood pressure, low levels of “good” cholesterol, and high amounts of lipids in the blood.
To better understand the effect of metabolic syndrome on colon cancer outcomes, Esnaola and his colleagues linked data from the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) program — a large population-based database — to Medicare data from 1998 to 2006 on 36,079 patients with colon cancer, including 7,024 patients (19.5%) who were identified as having metabolic syndrome. They analyzed the effect of metabolic syndrome and its components on colon cancer recurrence and overall survival, controlling for various sociodemographic factors, tumor factors, other medical conditions, and cancer treatments.
The researchers found that, among patients with early-stage colon cancer, those with diabetes or high blood pressure had a significantly greater risk of cancer recurrence and death after treatment. For example, 48% of patients who did not have diabetes were still alive 5 years after diagnosis compared with 41% of patients with diabetes. The researchers also found that cancer recurrence rates at 5 years were approximately 8% higher in patients with diabetes or hypertension.
In contrast, the analysis showed that patients with abnormally high levels of lipids in the blood had a lower risk of recurrence and death from colon cancer. Overall, 39% of patients with normal lipid levels were still alive after 5 years, compared with 53% of patients with abnormal levels. Cancer recurrence rates were approximately 11% lower in patients with abnormal lipid levels.
The researchers suspected that the higher survival and lower recurrence rates observed in patients with high lipid levels were likely due to the protective effects of statins, which are widely used to lower cholesterol and lipid levels and which have been shown to lower the risk of developing colon cancer.
Esnaola currently is investigating the effect of metabolic syndrome and its components on other cancer types. “In the interim, our results underscore the need for clinical trials to define the true benefits of [the diabetes drug] metformin and statins in patients with early-stage colon cancer,” he said.
Source: Temple University; December 19, 2012.