Background: This study aimed to analyze the temporal changes of the clinicopathologic characteristics, and the long-term outcomes, of various types of anaplastic and poorly differentiated thyroid cancer. Methods: A retrospective analysis was conducted on patients with anaplastic and poorly differentiated thyroid cancer who were treated from the period 1985 to 2013. The outcome measures included the clinical response to treatment and the survival rates of three separate thyroid cancer groups: anaplastic thyroid cancer (ATC), poorly differentiated thyroid cancer (PDTC), and differentiated thyroid cancer (DTC) with anaplastic foci. Results: The 5 years disease specific survival rate was significantly higher, both in DTC with anaplastic foci and in PTDC (81.3% and 65.8%, respectively), than in ATC (14.3%; p<0.001). The proportion of cases of DTC with anaplastic foci has been increasing over time, while that of ATC has decreased. Survival rate was found to be significantly higher in resectable tumors (71.4% and 26.5%, respectively) (p<0.001). In ATC, external beam radiation therapy showed longer survival rates than surgery-based treatment in unresectable tumors (19.2 vs 7.7 months, p=0.006). Adjuvant treatment with external beam radiation or radioactive iodine increased survival duration in PDTC and in DTC with anaplastic foci. Lymphatic invasion was the most significant postoperative prognosticator in ATC (p=0.013). Conclusions: The choice of treatment of ATC and PDTC could be modified according to resectability and lymphatic invasion of the cancer.

To investigate predictors affecting the development of hypothyroidism after radiotherapy for head and neck cancer, focusing on radiation dose-volumetric parameters, and to determine the appropriate radiation dose-volumetric threshold of radiation-induced hypothyroidism. A total of 114 patients with head and neck cancer whose radiotherapy fields included the thyroid gland were analysed. The purpose of the radiotherapy was either definitive (n = 81) or post-operative (n = 33). Thyroid function was monitored before starting radiotherapy and after completion of radiotherapy at 1 month, 6 months, 1 year and 2 years. A diagnosis of hypothyroidism was based on a thyroid stimulating hormone value greater than the maximum value of laboratory range, regardless of symptoms. In all patients, dose volumetric parameters were analysed. Median follow-up duration was 25 months (range; 6–38). Forty-six percent of the patients were diagnosed as hypothyroidism after a median time of 8 months (range; 1–24). There were no significant differences in the distribution of age, gender, surgery, radiotherapy technique and chemotherapy between the euthyroid group and the hypothyroid group. In univariate analysis, the mean dose and V35–V50 results were significantly associated with hypothyroidism. The V45 is the only variable that independently contributes to the prediction of hypothyroidism in multivariate analysis and V45 of 50% was a threshold value. If V45 was <50%, the cumulative incidence of hypothyroidism at 1 year was 22.8%, whereas the incidence was 56.1% if V45 was ≥50% (P = 0.034). The V45 may predict risk of developing hypothyroidism after radiotherapy for head and neck cancer, and a V45 of 50% can be a useful dose-volumetric threshold of radiation-induced hypothyroidism.

To determine a new metric utilizing multileaf collimator (MLC) speeds and accelerations to predict plan delivery accuracy of volumetric modulated arc therapy (VMAT). To verify VMAT delivery accuracy, gamma evaluations, analysis of mechanical parameter difference between plans and log files, and analysis of changes in dose-volumetric parameters between plans and plans reconstructed with log files were performed with 40 VMAT plans. The average proportion of leaf speeds ranging from l to h cm s(-1) (Sl-h and l-h = 0-0.4, 0.4-0.8, 0.8-1.2, 1.2-1.6 and 1.6-2.0), mean and standard deviation of MLC speeds were calculated for each VMAT plan. The same was carried out for accelerations in centimetre per second squared (Al-h and l-h = 0-4, 4-8, 8-12, 12-16 and 16-20). The correlations of those indicators to plan delivery accuracy were analysed with Spearman's correlation coefficient (rs). The S1.2-1.6 and mean acceleration of MLCs showed generally higher correlations to plan delivery accuracy than did others. The highest rs values were observed between S1.2-1.6 and global 1%/2 mm (rs = -0.698 with p < 0.001) as well as mean acceleration and global 1%/2 mm (rs = -0.650 with p < 0.001). As the proportion of MLC speeds and accelerations >0.4 and 4 cm s(-2) increased, the plan delivery accuracy of VMAT decreased. The variations in MLC speeds and accelerations showed considerable correlations to VMAT delivery accuracy. As the MLC speeds and accelerations increased, VMAT delivery accuracy reduced.

To compare the acute gastrointestinal (GI) and genitourinary (GU) toxicity profiles between intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT) in rectal cancer patients treated with neoadjuvant chemoradiation (NCRT) using meta-analysis and pooled-analysis from published articles. Literature search was performed in PubMed and EMBASE from inception to March 2017. The odd ratios (ORs) were calculated and random effects model was used for meta-analysis. Chi-square or Fisher’s exact test was performed for the pooled-analysis. Six studies including a total of 859 patients met the inclusion criteria. Most patients (98.7%) received NCRT. In the meta-analysis, IMRT reduced grade ≥ 2 acute overall GI toxicity, diarrhea and proctitis with ORs of 0.38, 0.32 and 0.60, respectively (all P < 0.05), compared to 3DCRT. IMRT also reduced acute grade ≥ 3 proctitis compared to 3D-CRT (OR, 0.24; P = 0.03). No significant heterogeneity or publication bias was detected. In the pooled-analysis, IMRT reduced the incidence of grade ≥ 2 acute overall GI toxicity, diarrhea, proctitis and GU toxicity (all P < 0.05). Moreover, lower incidence of grade ≥ 3 acute overall GI toxicity, diarrhea and proctitis were observed in the patients treated with IMRT (all P < 0.05). IMRT significantly reduced acute toxicity in locally advanced rectal cancer patients treated with NCRT compared to 3DCRT.