Recurrence-free survival and prognosis after adjuvant therapy with radioactive iodine-131 in patients with differentiated thyroid carcinoma.

This study aimed to assess recurrence-free survival (RFS) rates and recurrence-related factors of patients who received adjuvant therapy (AT) with radioactive iodine (RAI) for differentiated thyroid cancer (DTC) following thyroidectomy. We evaluated 284 patients who underwent AT between January 2011 and July 2020 at our hospital. Recurrence was defined as visible recurrent lesions on image analysis or need for repeat surgery with pathologically confirmed recurrent lesions. RFS rate and prognostic factors were statistically evaluated. The median observation period was 30.2 months (range, 5.7-294 months). Overall, 192 patients were female and 92 were male, and the median age was 54 years (range, 9-85 years). Initial assessment revealed 39 recurrence cases. The 3-year RFS rate was 85.8% (95% confidence interval: 81.1-90.9%). Univariate analysis revealed that histology (except for papillary carcinoma), Tg level > 4 ng/dL before AT, and AT result significantly exacerbated the RFS rate. In multivariate analysis, histology and AT result were also important contributors to the worsening RFS rate. Results of AT can be determined relatively early and are important in predicting future recurrence in patients with DTC. Increasing the success rate of AT may lead to an improved prognosis.

Highly hypofractionated intensity-modulated radiation therapy for nonmetastatic prostate cancer with a simultaneous integrated boost to intraprostatic lesions: a planning study.

PURPOSE: The purpose of this planning study was to develop an acceptable technique for highly hypofractionated intensity-modulated radiation therapy using simultaneous integrated boost technique (SIB-hHF-RT) for nonmetastatic National Comprehensive Cancer Network high-risk prostate cancer. MATERIALS AND METHODS: We created SIB-hHF-RT plans for 14 nonmetastatic prostate cancer patients with MRI-detectable intraprostatic lesions (IPLs) and without intestines locating close to the seminal vesicle and prostate. We prescribed 57 Gy for IPLs and 54 Gy for the remainder of planning target volume (PTV) in 15 fractions. The IPLs were contoured based on magnetic resonance imaging, and PTV was generated by adding 6-8-mm margins to the clinical target volume. For the dose-volume constraints of organs at risk (OARs), the same constraints as 54 Gy plans were used so as not to increase the toxicity. RESULTS: All created plans fulfilled the dose-volume constraints of all targets and OARs. The median estimated beam-on time was 108.5 s. For patient-specific quality assurance, the global gamma passing rates (3%/2 mm) with 10% dose threshold criteria were greater than 93% in all cases and greater than 95% in 11 cases. CONCLUSION: SIB-hHF-RT plans were developed that fulfill the acceptable dose-volume constraints and pass patient-specific quality assurance. We believe these plans can be applied to selected patients with nonmetastatic prostate cancer.

Increased risk of disease progression in younger men: Analysis of factors predicting biochemical failure and castration-resistant prostate cancer after high-dose intensity-modulated radiation therapy for nonmetastatic prostate cancer.

BACKGROUND: The aim of this study was to investigate the clinical significance of the effect of age on disease control in men who received high-dose intensity-modulated radiation therapy (IMRT) for nonmetastatic prostate cancer (NMPCa). METHODS: NMPCa patients with favorable intermediate to very high-risk features (National Comprehensive Cancer Network risk classification) treated with IMRT at our institution between September 2000 and May 2011 were analyzed retrospectively. Treatment consisted of high-dose IMRT (74-78 Gy/37-39 fractions) combined with 6 months of neoadjuvant hormonal therapy. Multivariable analysis using Fine and Gray's regression model was performed to evaluate whether age at initiation of IMRT was associated with biochemical failure (BF) and castration-resistant prostate cancer (CRPC) progression. RESULTS: A total of 367 patients were analyzed. The median follow-up period was 8.8 years after IMRT. The 5- and 10-year BF rates were 22.1 and 31.7%, and those of CRPC rates were 4.5 and 12.6%, respectively. Multivariable analysis revealed that a younger age (cut-off: 70 years old) at the initiation of IMRT was significantly correlated with both a higher BF rate (hazard ratio: 1.691, P= 0.0064) and higher CRPC rate (hazard ratio: 2.579, P = 0.0079). CONCLUSIONS: Younger men with NMPCa had increased risks of BF and CRPC after high-dose IMRT, and may benefit from more intensive treatments. Our findings should be further tested in prospective studies.

Comparison of thyroid hormone withdrawal and recombinant human thyroid-stimulating hormone administration for adjuvant therapy in patients with intermediate- to high-risk differentiated thyroid cancer.

OBJECTIVE: To compare the clinical outcome in patients who received adjuvant therapy with radioactive iodine (RAI) using different preparation methods, namely, thyroid hormone withdrawal (THW) and recombinant human thyroid-stimulating hormone (rhTSH), after undergoing thyroidectomy for intermediate- to high-risk differentiated thyroid carcinoma (DTC) according to the American Thyroid Association criteria. METHODS: Between May 2012 and October 2018, 136 patients who underwent adjuvant therapy with high-dose (3700 MBq) RAI for DTC without any metastatic lesions or macroscopic residual lesions after surgical resection were retrospectively selected. Patients were excluded if distant metastasis was confirmed during adjuvant therapy or if the outcome could not be confirmed; thus, 112 patients were finally evaluated. Patients underwent either a 3-week I restriction with thyroxine withdrawal or a 2-week I restriction with rhTSH administration. The serum thyroglobulin (Tg) concentration was measured, and 131I scintigraphy (370 MBq) was performed 6-12 months after adjuvant therapy. The definition of the initial achievement of adjuvant therapy was the disappearance of the uptake of 131I at the thyroid bed and serum Tg concentration < 2.0 ng/mL. The results of the adjuvant therapy between the groups were compared using the Fisher's exact test, and the TSH levels and estimated glomerular filtration rate (eGFR) were compared using the Welch's t test. RESULTS: The THW and rhTSH groups included 47 and 65 patients, respectively, and the intermediate- and high-risk groups included 63 and 49 patients, respectively. No patient was assigned to the low-risk group. In the THW and rhTSH groups, the initial RAI adjuvant therapy goal was achieved in 30/47 (63.8%) and 46/65 patients (70.8%), respectively (p = 0.54); mean ± standard deviation of the TSH levels was 123.8 ± 46.4 µIU/mL and 274.5 ± 97.7 µIU/mL, respectively (p < 0.01), and eGFR (treatment/pre-treatment) was 0.81 and 0.99, respectively (p < 0.01). In the intermediate- and high-risk groups, the initial RAI adjuvant therapy goal was achieved in 43/63 patients (68.3%) and 33/49 (67.3%), respectively (p = 1.0). CONCLUSION: No significant differences were observed between the preparation methods in the initial achievement of RAI adjuvant therapy. However, patients in the rhTSH group demonstrated higher TSH levels and retained eGFR.

A pilot study of highly hypofractionated intensity-modulated radiation therapy over 3 weeks for localized prostate cancer.

The purpose of this pilot study was to evaluate the feasibility of highly hypofractionated intensity-modulated radiation therapy (IMRT) in 15 fractions over 3 weeks for treating localized prostate cancer based on prostate position-based image-guided radiation therapy. Twenty-five patients with National Comprehensive Cancer Network (NCCN) very low- to unfavorable intermediate-risk prostate cancer were enrolled in this study from April 2014 to September 2015 to receive highly hypofractionated IMRT (without intraprostatic fiducial markers) delivering 54 Gy in 15 fractions over 3 weeks. Patients with intermediate-risk disease underwent neoadjuvant androgen suppression for 4-8 months. Twenty-four patients were treated with highly hypofractionated IMRT, and one was treated with conventionally fractionated IMRT because the dose constraint of the small bowel seemed difficult to achieve during the simulation. Seventeen percent had very low- or low-risk, 42% had favorable intermediate-risk, and 42% had unfavorable intermediate-risk disease according to NCCN guidelines. The median follow-up period was 31 months (range, 24-42 months). No Grade ≥3 acute toxicity was observed, and the incidence rates of Grade 2 acute genitourinary and gastrointestinal toxicities were 21% and 4%, respectively. No Grade ≥2 late toxicity was observed. Biochemical relapse was observed in one patient at 15 months, and the biochemical relapse-free survival rate was 95.8% at 2 years. A prostate-specific antigen bounce of ≥0.4 ng/ml was observed in 11 patients (46%). The highly hypofractionated IMRT regimen is feasible in patients with localized prostate cancer and is more convenient than conventionally fractionated schedules for patients and health-care providers.