Impact of body mass index on survival outcome in patients with differentiated thyroid cancer.
BACKGROUND
Increased body mass index is known to be associated with the high prevalence of differentiated thyroid cancers; however data on its impact on survival outcome after thyroidectomy and adjuvant therapy is scanty.


OBJECTIVE
We aimed to evaluate the impact of body mass index on overall survival and disease free survival rates in patients with differentiated thyroid cancers.


METHODS
Between 2000 and 2011, 209 patients with differentiated thyroid cancers (papillary, follicular, hurthle cell) were treated with thyroidectomy followed by adjuvant radioactive iodine-131 therapy and thyroid-stimulating hormone suppression. Based on body mass index, patients were divided into five groups; (a) <18.5kg/m2(underweight); (b) 18.5-25kg/m2(normal weight); (c) 26-30kg/m2(overweight); (d) 31-40kg/m2(obese) and (e) >40kg/m2(morbid obese). Various demographic, clinical and treatment characteristics and related toxicity and outcomes (overall survival, and disease free survival) were analyzed and compared.


RESULTS
Median follow up period was 5.2years (0.6-10). Mean body mass index was 31.3kg/m2(17-72); body mass index 31-40kg/m2was predominant (89 patients, 42.6%) followed by 26-30kg/m2seen in 58 patients (27.8%). A total of 18 locoregional recurrences (8.6%) and 12 distant metastasis (5.7%) were seen. The 10 year disease free survival and overall survival rates were 83.1% and 58.0% respectively. No significant impact of body mass index on overall survival or disease free survival rates was found (p=0.081). Similarly, multivariate analysis showed that body mass index was not an independent prognostic factor for overall survival and disease free survival.


CONCLUSIONS
Although body mass index can increase the risk of thyroid cancer, it has no impact on treatment outcome; however, further trials are warranted.
King Saud University, College of Medicine, Department of Otolaryngology-Head & Neck Surgery, Riyadh, Saudi Arabia.
Yousif
Y
Al-Ammar
King Saud University, College of Medicine, Department of Otolaryngology-Head & Neck Surgery, Riyadh, Saudi Arabia.
Bader
B
Al-Mansour
King Saud University, College of Medicine, Department of Otolaryngology-Head & Neck Surgery, Riyadh, Saudi Arabia.
Omar
O
Al-Rashood
King Fahad Medical City, Radiation Oncology, Riyadh, Saudi Arabia.
Mutahir A
MA
Tunio
King Saud University, College of Medicine and Research Center, Riyadh, Saudi Arabia.
Tahera
T
Islam
King Fahad Medical City, Radiation Oncology Comprehensive Cancer Center, Riyadh, Saudi Arabia.
Mushabbab
M
Al-Asiri
King Saud University, College of Medicine, Department of Otolaryngology-Head & Neck Surgery, Riyadh, Saudi Arabia. Electronic address: kqresearch@hotmail.com.
Khalid Hussain
KH
Al-Qahtani
D018263:Adenocarcinoma, Follicular / Q000401:mortality* / Q000473:pathology / Q000556:secondary / Q000628:therapy; D015992:Body Mass Index; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D013964:Thyroid Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy*; D013965:Thyroidectomy
D007457:Iodine Radioisotopes; C000614965:Iodine-131
Body mass index; Câncer diferenciado de tireoide; Differentiated thyroid cancers; Disease free survival; Overall survival; Sobrevida global; Sobrevida livre de doença; Índice de massa corporal