Researchers have discovered that patients with type 2 diabetes who develop cancer are more likely to be diagnosed with advanced disease if they do not undergo routine screenings, according to a new study published by Jansana et al in the European Journal of Cancer. The new findings were also presented at the 13th European Breast Cancer Conference (Abstract 25).

Study Background

Unlike breast cancer and colorectal cancer—for which routine population screening is available in many countries—cancers such as lung, ovarian, and prostate do not have national screening programs and were shown to have a greater likelihood of being diagnosed in patients with type 2 diabetes only once the cancer started to metastasize.

“Our results underline the importance of paying particular attention to patients with pre-existing diseases of the heart, blood vessels, or metabolism, such as type 2 diabetes, so that signs of cancer can be identified at an earlier stage when it is more likely to be treated successfully,” said Anna Jansana, PhD, a postdoctoral scientist at the Nutrition and Cancer Multimorbidity group at the International Agency for Research on Cancer.

Until now, it has not been known whether patients are at a greater risk of having a cancer diagnosed at an advanced stage when they have a pre-existing cardiometabolic disease, such as diabetes, heart disease, or stroke.

Research Methods and Results

Dr. Jansana and her colleagues identified 11,945 cases of cancer diagnosed between 1992 and 2012 among 400,577 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. They looked at cases where patients had already been diagnosed with cardiovascular diseases, type 2 diabetes, both, or none, and conducted analyses based on cancers that could be screened for (breast cancer and colorectal cancer) and cancers for which there were no population-based screening programs in the six European countries included in the study.

During a median 15 years of follow-up, among the 11,945 patients diagnosed with cancer, 87% of them had no pre-existing cardiometabolic diseases at the time of diagnosis. Five percent of cancers occurred in patients with a pre-existing diagnosis of cardiovascular disease, 7% in patients with a pre-existing diagnosis of type 2 diabetes, and 1% in patients with a pre-existing diagnosis of both cardiovascular disease and type 2 diabetes.

A total of 2,623 patients had breast cancer and 1,722 had colorectal cancer. For these two cancers, no statistically significant association was found between a later stage of diagnosis and pre-existing cardiovascular diseases and type 2 diabetes. However, for the 7,400 cases of nonscreened cancers, the researchers found that patients who had pre-existing type 2 diabetes had a statistically significant 26% increased risk of being diagnosed once their cancers had already metastasized, compared with people who did not have pre-existing cardiometabolic conditions. Twenty-six cases were detected before the cancer had started to spread and 41 cases were detected after it had metastasized.

“The good news is that for patients with breast [cancer] or colorectal cancer, the national screening programs seem to be detecting cancer often before it has started to spread, both for those with and without pre-existing diagnoses of cardiovascular disease and type 2 diabetes. Our findings underline the importance of participating in screening when invited,” emphasized Dr. Jansana. “However, for cancers for which there are no national screening programs, our results may prompt policymakers to broaden the scope of public health recommendations to encompass patients affected by cardiometabolic diseases and cancer. At present, cancer screening guidelines do not include recommendations on cancer screening among [patients] with cardiometabolic diseases. It may be necessary for those involved in health care and policymaking to consider whether the recommendations need any adjustment in terms of cancer screening,” she added, noting that “In addition, health-care professionals should pay special attention to people with pre-existing cardiometabolic conditions. Our findings suggest it might be worth developing interventions and treatments to target the common pathways involved in these noncommunicable diseases.”

Conclusion

“These findings, which come from the long-running EPIC study, provide additional valuable evidence for the usefulness of national screening programs for breast [cancer] and [colorectal] cancer. The presentation by Dr. Jansana shows that screening is successful in detecting these particular cancers at an earlier stage independently from pre-existing cardiometabolic conditions. Unfortunately, this is not the case for other cancers, for which there are no national screening programs, and which are more frequently detected in advanced stages in patients who present with cardiometabolic disease,” underscored Laura Biganzoli, MD, Director of the Breast Center in the Department of Oncology at the Hospital of Prato and Co-Chair of the European Breast Cancer Conference, who was not involved in the study, concluding that, “This is important information to be shared with the medical community but unfortunately, at this stage, no recommendations can be provided on specific monitoring procedures to be implemented in this population, apart from recommending participation in already existing screening programs.”

Disclosure: For full disclosures of the study authors, visit ejcancer.com.