People with diabetes mellitus have a significantly increased risk of developing head and neck cancer (HNC) compared with those without the condition, show results of a large study conducted in Taiwan.
Yung-Song Lin (Taipei Medical University) and colleagues showed that the incidence of HNC was 1.47 times higher in a cohort of more than 89,000 patients with diabetes than it was in an equal-sized control group matched for age, gender, geographic location, income and comorbidities including obesity, coronary artery disease, hyperlipidaemia, hypertension, chronic kidney disease and chronic obstructive pulmonary disease (used as a surrogate for smoking).
These findings “highlight the importance of monitoring patients with [diabetes mellitus] for HNC”, the researchers remark.
This may be particularly true for men and patients aged 40–65 years, as the incidence was highest in these groups.
Of the specific HNCs assessed, cancer of the oral cavity had the highest incidence in both groups but was significantly more common among the patients with diabetes (0.41%) than the controls (0.24%) during the follow-up period, which began in 2002 and continued until the death of the participant or the end of 2011, whichever came first.
Oropharyngeal cancer and nasopharyngeal carcinoma were also significantly more common in the diabetes group.
After adjustment for age, gender and comorbidity, the patients with diabetes had a 1.48-fold increased risk of HNC compared with controls. The risk was 1.74 times higher for oral cavity cancer, 1.53 times higher for oropharyngeal cancer and 1.40 times higher for nasopharyngeal carcinoma. No increased risks were observed for hypopharyngeal, rhinosinusitis or laryngeal cancers.
Of note, the researchers observed no significant difference in overall survival between the diabetes and control groups that developed HNC, but they suggest this may be because the follow-up periods were limited by the reduced overall survival observed in the participants who developed HNC.
Writing in JAMA Otolaryngology–Head and Neck Surgery, Lin and team say that the mechanisms underlying the association between diabetes and the development of HNC remain unclear.
They suggest that long-term exposure to insulin may be a factor as “[i]nsulin is a potent growth factor that promotes proliferation and carcinogenesis in various ways, directly and through [insulin-like growth factors].”
They add: “Another reasonable explanation is hyperglycemia, which may directly promote tumors: cancer cells rely on increased glucose consumption.”
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