Medical Emergencies · patient case question
An elevated BMI is most strongly associated with an increased incidence of which malignancies?
Patient case: Type 2 diabetes in a patient with a BMI of 30
Patient: Male, 47 years old
Chief Complaint: “My gums bleed and my mouth is always dry.”
Background: Type 2 diabetes mellitus diagnosed three years ago, on metformin. Sedentary desk work. No tobacco.
Vital Signs: BP 138/86 mmHg · HR 78 bpm · BMI 30.4 kg/m² · HbA1c 8.1%
Findings: Generalized moderate periodontitis with bleeding on probing. Reduced salivary flow. No caries.
Show answer and explanation
Correct answer: A. Colorectal and renal carcinoma
- A. CORRECT. Obesity is an established risk factor for at least thirteen cancers, and COLORECTAL and RENAL (kidney) carcinoma are among the best characterised. The mechanisms are chronic hyperinsulinaemia and raised IGF-1 signalling, which promote cell proliferation and inhibit apoptosis; adipose-derived oestrogen; and low-grade systemic inflammation. Others in the group include endometrial, postmenopausal breast, oesophageal adenocarcinoma, gastric cardia, liver, gallbladder, pancreatic, ovarian, thyroid, meningioma and multiple myeloma.
- B. Retinoblastoma is a childhood tumour driven by biallelic RB1 loss, and optic nerve glioma is associated with neurofibromatosis type 1. Neither has a metabolic risk association.
- C. Acute lymphoblastic leukaemia is a childhood malignancy with genetic and environmental associations unrelated to adult adiposity.
- D. Basal cell carcinoma is driven overwhelmingly by cumulative ultraviolet exposure and by fair skin phototype, not by body mass.
Note: The dental relevance runs the other way as well: obesity and type 2 diabetes are independently associated with more severe periodontitis, and the relationship is bidirectional — treating periodontitis produces a small but measurable fall in HbA1c.
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