Assessing the Effect of Cancer Diagnosis on Beliefs about Comorbid Diabetes

Increasingly, patients diagnosed with cancer also live with chronic comorbidities, and it is important to understand the impact of a new cancer diagnosis on perceptions about preexisting conditions. This study assessed the effect of cancer diagnosis on beliefs about comorbid diabetes mellitus and assessed changes in beliefs about cancer and diabetes over time.

We recruited 75 patients with type 2 diabetes who were newly diagnosed with early-stage breast, prostate, lung, or colorectal cancer and 104 age-, sex-, and hemoglobin A1c-matched controls. Participants completed the Brief Illness Perception Questionnaire four times over 12 months. The authors examined within-patient and between-group differences in cancer and diabetes beliefs at baseline and over time.

Overall, diabetes beliefs did not differ between cancer patients and controls at baseline. Cancer patients' beliefs about diabetes varied significantly over time; they reported less concern about cancer, less emotional effect, and greater cancer knowledge over time. Participants without cancer were significantly more likely to report that diabetes affected their life across all time points, though this effect did not persist after adjustment for sociodemographic variables.

While all patients' diabetes beliefs were similar at baseline and 12 months, cancer patients' beliefs about both illnesses fluctuated during the months following cancer diagnosis.

Oncology nurses can play a key role in recognizing the effects of cancer diagnosis on beliefs about comorbid conditions and fluctuations in these beliefs during treatment. Assessing and communicating patient beliefs between oncology and other practitioners could produce more effective care plans based on patients' current outlook on their health.