Obesity and High Risk Pathological Features of Papillary Thyroid Carcinoma: A Retrospective Analysis of a University Hospital in Pakistan.

BACKGROUND: Incidence of papillary thyroid carcinoma (PTC) and the frequency of obesity is increasing globally. In literature, relationship between excessive body weight and bad prognostic features of PTC is still debatable. In this study, we aimed to explore the association of obesity with high risk pathological features of PTC in a population treated by total thyroidectomy +/- neck dissection.

MATERIALS AND METHODS: Retrospective analysis of patients at Aga Khan University Hospital from January 2013 to December 2014, who underwent total thyroidectomy +/- neck dissection due to PTC. Patients were grouped according to World Health Organization (WHO) classification of BMI. They were categorized into two groups, i.e. normal (BMI= 18.5 - 24.9 kg/m2) and obese (BMI = 30 kg/m2) as none of our patients lie in underweight and overweight category. Pathological features i.e. T-stage, multifocality, bilaterality, extrathyroidal extension, vascular invasion and N-stage were assessed. All tumors were staged according to TNM staging system proposed by 2010 American Joint Committee on Cancer (AJCC). Odds ratio (OR) with 95% confidence interval was used to examine the association between BMI ∧ pathological characteristics of PTC.

RESULTS: A total of 53 patients were treated for PTC in two-years period. There were 38 female and 15 male patients. Twenty-eight patients had BMI in normal while twenty-five in obese category. Patients who were in obese category had a significantly greater risk of having a multifocal tumor (OR=5.55, p-value=0.02) and bilaterality (OR=6.54, p-value=0.01) compared to normal weight patients. No positive associations were identified between BMI and extrathyroidal extension, high T-stage, vascular invasion and N-stage.

CONCLUSION: Obesity is not associated with high risk pathological features such as extrathyroidal extention, high T-stage, vascular invasion and N-stage in PTC. Although it has been correlated with multifocal and bilateral tumors in this retrospective study, the presence of these factors alone is not adequate to support the association conclusively.