ABSTRACT
Background: Radiation-induced hypothyroidism (RIH) is common after neck irradiation, and biochemical evaluation of thyroid function is recommended periodically for early diagnosis and treatment. This study aimed to evaluate the predictors of RIH after completion of adjuvant radiotherapy (RT) for primary oral squamous cell carcinoma (OSCC). Methods: This is a retrospective study involving 195 patients who received RT after surgery for OSCC between August 2011 and December 2016. Thyroid function tests were obtained every 6 months and patients were considered to be hypothyroid if thyroid-stimulating hormone level was >5 mIU/mL. Results: The study cohort comprised 130 men with a median age of 52 years (range 21–77 years). About 107 (54.87%) patients developed hypothyroidism, with a median of 21 months (range 2–67 months) for the development of RIH. Women [41 (63.1%) versus 66 (50.8%), p=0.035], addition of chemotherapy [36 (63.2%) versus 71 (51.4%), p= 0.019], and higher cumulative dose to the thyroid gland (median dose 4690 cGy versus 2981 cGy, P < 0.001) resulted in higher incidence of RIH on univariate analysis. On multivariate Cox regression analysis, female sex (P = 0.042), bilateral irradiation (P = 0.046), and cumulative dose to the thyroid (P = 0.001) were factors associated with increased risk of developing RIH. Conclusion: The addition of chemotherapy, high dose of radiation to the thyroid gland, bilateral irradiation, and female sex were at higher risk of developing RIH. However, more studies are required to identify the dose-volume constraints of the thyroid gland
ABSTRACT
From Jan. 1982 to Dec. 1990, 77 patients with rectal cancer were treated with curative surgical resection followed by postoperative adjuvant irradiation alone or combined with chemotherapy at the Department of Radiation Oncology, Korea University Hospital (KUH). Fifty-four(54/77, 70.1%) patients underwent abdominoperineal resection, 20(20/77, 26%) patients underwent low anterior resection, and 3(3/77, 3.9%) patients had wide excision only. Thirty-nine(39/77, 50.5%) received sequential chemotherapy (2 cycles to 12 cycles). The 5-year survival rate for the entire group was 43%: 78.2% in B2+B3, 39.4% in stage C1+C2+C3. Survival rates decreased with increasing penetration of the bowel wall by tumor and the presence of regional lymph node metastasis. Those patients survival who underwent an abdominoperineal resection also experienced a significant decrease in compared to low anterior resection(23.1% vs. 63.8% in 5-year survival, p<0.05). Local failure occurred in 15 (19.5%) out of the 77 patients overall, 1 (5.3%) of 19 in stage B2+B3, and 14(24.1%) of 58 in Stage C1+C2+C3. Presacral area was most common site of local failure (8/17, 47.1%). Distant failure occurred in 13(16.9%) of 77 patients. The most frequent site of distant failure was the lung followed by the liver, the bone, and the brain. Combined locoregional and distant failure occurred in 2 (2.6%) of 77 patients. Pathological confirmation of perirectal fat and/or regional lymph node involvement resulted in a significant decrease in survival and local control.