• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2279-2285
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• 2014

Background: To evaluate treatment outcomes of patients with stage I-III endometrial cancer treated with postoperative radiation. Materials and Methods: A retrospective review of 166 endometrial cancer patients, undergoing surgery and postoperative radiotherapy at Siriraj Hospital from 2005-2008 was performed. Pathology was reviewed. Results of treatment were reported with 5-year loco-regional recurrence free survival (LRRFS), 5-year overall survival (OS), patterns of failure and toxicity, and according to stage and risk groups. Results: Median follow up time was 62.8 months. Pathological changes were found in 36.3% of the patients after central reviews, leading to 19% changes in risk groups. Most of the patients (83.7%) received pelvic radiation (PRT) and vaginal brachytherapy (VBT). Five-year LRRFS and OS of all patients were 94.9% and 85.5%, respectively. There was no recurrence or death in low and low-intermediate risk groups. For the high-intermediate risk group, 5-year LRRFS and OS were 96.2% and 90.8%, respectively, and for the high risk group 90.5% and 71%. Late grade 3 and 5 gastrointestinal toxicity was found in 3% and 1.2% of patients, respectively. All of them received PRT 5,000 cGy in 25 fractions. Conclusions: Low and intermediate risk patients had good results with surgery and adjuvant radiation therapy. For high risk patients, postoperative radiation therapy alone appeared to be inadequate as the most common pattern of failure was distant metastasis.

• Radiation Oncology Journal
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• v.31 no.4
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• pp.206-215
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• 2013

Purpose: Re-irradiation (re-RT) is considered a treatment option for inoperable locoregionally recurrent head and neck cancer (HNC) after prior radiotherapy. We evaluated the efficacy and safety of re-RT using Helical Tomotherapy as image-guided intensity-modulated radiotherapy in recurrent HNC. Materials and Methods: Patients diagnosed with recurrent HNC and received re-RT were retrospectively reviewed. Primary endpoint was overall survival (OS) and secondary endpoints were locoregional control and toxicities. Results: The median follow-up period of total 9 patients was 18.7 months (range, 4.1 to 76 months) and that of 3 alive patients was 49 months (range, 47 to 76 months). Median dose of first radiotherapy and re-RT was 64.8 and 47.5 $Gy_{10}$. Median cumulative dose of the two courses of radiotherapy was 116.3 $Gy_{10}$ (range, 91.8 to 128.9 $Gy_{10}$) while the median interval between the two courses of radiation was 25 months (range, 4 to 137 months). The response rate after re-RT of the evaluated 8 patients was 75% (complete response, 4; partial response, 2). Median locoregional relapse-free survival after re-RT was 11.9 months (range, 3.4 to 75.1 months) and 5 patients eventually presented with treatment failure (in-field failure, 2; in- and out-field failure, 2; out-field failure, 1). Median OS of the 8 patients was 20.3 months (range, 4.1 to 75.1 months). One- and two-year OS rates were 62.5% and 50%, respectively. Grade 3 leucopenia developed in one patient as acute toxicity, and grade 2 osteonecrosis and trismus as chronic toxicity in another patient. Conclusion: Re-RT using Helical Tomotherapy for previously irradiated patients with unresectable locoregionally recurrent HNC may be a feasible treatment option with long-term survival and acceptable toxicities.

• Radiation Oncology Journal
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• v.29 no.4
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• pp.236-242
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• 2011

Purpose: To compare photon thunderbird with deep match (technique 1) with 3-field technique with electron inguinal boost (technique 2) in acute skin toxicity, toxicity-related treatment breaks and patterns of failure in elective inguinal radiation therapy (RT) for curative chemoradiation in anal cancer. Materials and Methods: Seventeen patients treated between January 2008 and September 2010 without evidence of inguinal and distant metastasis were retrospectively reviewed. In 9 patients with technique 1, dose to inguinal and whole pelvis area was 41.4 to 45 Gy and total dose was 59.4 Gy. In 8 patients with technique 2, doses to inguinal, whole pelvis, gross tumor were 36 to 41.4 Gy, 36 to 41.4 Gy, and 45 to 54 Gy, respectively. The median follow-up period was 27.6 and 14.8 months in group technique 1 and 2, respectively. Results: The incidences of grade 3 radiation dermatitis were 56% (5 patients) and 50% (4 patients), dose ranges grade 3 dermatitis appeared were 41.4 to 50.4 Gy and 45 to 54 Gy in group technique 1 and 2, respectively (p = 0.819). The areas affected by grade 3 dermatitis in 2 groups were as follow: perianal and perineal areas in 40% and 25%, perianal and inguinal areas in 0% and 50%, and perianal area only in 60% and 25%, respectively (p = 0.196). No inguinal failure has been observed. Conclusion: Photon thunderbird with deep match technique and 3-field technique with electron inguinal boost showed similar incidence of radiation dermatitis. However, photon thunderbird with deep match seems to increase the possibility of severe perineal dermatitis.

• Radiation Oncology Journal
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• v.29 no.4
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• pp.219-227
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• 2011

Purpose: This study evaluated the treatment effectiveness and proper radiation dose of helical tomotherapy (HT) in spine oligometastases from gastrointestinal cancers. Materials and Methods: From 2006 to 2010, 20 gastrointestinal cancer patients were treated with HT for spine oligometastases (31 spine lesions). The gross tumor volume (GTV) was the tumor evident from magnetic resonance imaging images fused with simulation computed tomography images. Clinical target volume (CTV) encompassed involved vertebral bodies or dorsal elements. We assumed that the planning target volume was equal to the CTV. We assessed local control rate after HT for 31 spine metastases. Pain response was scored by using a numeric pain intensity scale (NPIS, from 0 to 10). Results: Spine metastatic lesions were treated with median dose of 40 Gy (range, 24 to 51 Gy) and median 5 Gy per fraction (range, 2.5 to 8 Gy) to GTV with median 8 fractions (range, 3 to 20 fraction). Median biologically equivalent dose (BED, ${\alpha}/{\beta}$ = 10 Gy) was 52 $Gy_{10}$ (range, 37.5 to 76.8 $Gy_{10}$) to GTV. Six month local control rate for spine metastasis was 90.3%. Overall infield failure rate was 15% and outfield failure rate was 75%. Most patients showed pain relief after HT (93.8%). Median local recurrence free survival was 3 months. BED over 57 $Gy_{10}$ and oligometastases were identified as prognostic factors associated with improved local progression free survival (p = 0.012, P = 0.041). Conclusion: HT was capable of delivering higher BED to metastatic lesions in close proximity of the spinal cord. Spine metastases from gastrointestinal tumors were sensitive to high dose radiation, and BED (${\alpha}/{\beta}$ = 10 Gy) higher than 57 $Gy_{10}$ could improve local control.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.640-644
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• 1998

AT cells exhibit defective cell cycle regulation following DNA damage. Previous studies have shown that induction of p53 and p2i proteins are delayed in response to ionizing rad iation, resulting in the failure of G1/S checkpoint in AT cells. In this study, further investigation of the molecular mechanisms underlying G1/S phase progression in AT cells was conducted. Exponentially growing normal and AT cells were exposed to 2 Gly of ionizing radiation and the expression levels and functional activities of Rb and E2F-1 proteins were determined. We observed overexpression of hyperphosphorylated Rb and E2F-1 proteins in AT cells, which was unaffected post-irradiation. Furthermore, gel shift assays showed that E2F-1-DNA binding was constitutive in AT cells, whereas it was inhibited in control cells following exposure to ionizing radiation. The data suggests that abnormalities in the function of Rb and E2F-1 proteins may also be responsible for the failure of AT cells to arrest in the G1/S checkpoint in response to DNA damage.

• Geomechanics and Engineering
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• v.23 no.6
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• pp.503-512
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• 2020

Mining activities focus on the production of mineral resources for energy generation and raw material requirements worldwide and it is a known fact that shallow reserves become scarce. For this reason, exploration of new resources proceeds consistently to meet the increasing energy and raw material demand of industrial activities. Rock mechanics has a vital role in underground mining and surface mining. Devices and instruments used in laboratory testing to determine rock mechanics related parameters might have limited sensing capability of the failure behavior. However, methodologies such as, thermal cameras, digital speckle correlation method and acoustic emission might enable to investigate the initial crack formation in detail. Regarding this, in this study, thermographic analysis was performed to analyze the failure behaviors of different types of rock specimens during uniaxial compressive strength experiments. The energy dissipation profiles of different types of rocks were characterized by the temperature difference recorded with an infrared thermal camera during experiments. The temperature increase at the failure moment was detected as 4.45℃ and 9.58℃ for andesite and gneiss-schist specimens, respectively. Higher temperature increase was observed with respect to higher UCS value. Besides, a temperature decreases of about 0.5-0.6℃ was recorded during the experiments of the marble specimens. The temperature change on the specimen is related to release of radiation energy. As a result of the porosity tests, it was observed that increase in the porosity rate from 5.65% to 20.97% can be associated to higher radiation energy released, from 12.68 kJ to 297.18 kJ.

• Radiation Oncology Journal
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• v.18 no.3
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• pp.187-193
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• 2000

Purpose : DNA ploidy pattern was shown to correlate with several clinicohistologic findings in several tumors. Aim of this study was to evaluate the correlation of the clinicohistologic findings in colorectal cancer and the failure pattern in rectosigmoid cancer with DNA ploidy. Materials and Methods DNA flow cytometry using the Hedley methods on paraffin embedded specimen from 117 patients with colorectal cancers after curative resection was peformed. We tried to find the correlation between DNA ploidy and various clinicohistologic findings. And then the correlation DNA ploidy and the failure pattern in 75 patients of rectosigmoid cancer was analized. Results : Forty samples (34.2%) from tumors gave aneuploidy histogram. There was no significant difference in the frequency of DNA aneuploidy in terms of age, sex, depth of invasion, location and Dukes stage. But there was a significant correlation between DNA ploidy and the failure rates in Dukes stage B rectosigmoid cancer (P=0.048). Conclusions : These findings suggest that DNA ploidy pattern shows the correlation with the treatment failure rates in Dukes stage B rectosigmoid, but not with many other clinicohistologic findings. However,more patients will be needed to disclose these findings.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.515-521
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• 2013

Purpose: To evaluate the efficacy and toxicity of induction chemotherapy followed by concurrent chemoradiotherapy (the treatment group) versus concurrent chemoradiotherapy with or without adjuvant chemotherapy (the control group) for locoregionally advanced nasopharyngeal carcinoma. Methods: The search strategy included Pubmed, Embase, the Cochrane Library, China National Knowledge Internet Web, Chinese Biomedical Database and Wanfang Database. We also searched reference lists of articles and the volumes of abstracts of scientific meetings. All randomized controlled trials were included for a meta-analysis performed with RevMan 5.1.0. The Grading of Recommendations Assessment, Development, and Evaluation system (GRADE) was used to rate the level of evidence. Results: Eleven studies were included. Risk ratios of 0.99 (95%CI 0.72-1.36), 0.37 (95%CI 0.20-0.69), 1.08 (95%CI 0.84-1.38), 0.98 (95%CI 0.75-1.27) were observed for 3 years overall survival, 3 years progression-free survival, 2 years loco-regional failure-free survival and 2 years distant metastasis failure-free survival. There were no treatment-related deaths in either group in the 11 studies. Risk ratios of 1.90 (95%CI 1.24-2.92), 2.67 (95%CI 0.64-11.1), 1.04 (95%CI 0.79-1.37), 0.98 (95%CI 0.27-3.52) were found for grade 3-4 leukopenia, grade 3-4 thrombocytopenia, grade 3-4 mucous membrane, and grade 3-4 hepatic hematologic and gastrointestinal toxicity, the most significant toxicities for patients. Conclusion: Compared with the control group, induction chemotherapy followed by concurrent chemoradiotherapy was well tolerated but could not significantly improve prognosis in terms of overall survival, loco-regional failure-free survival or distant metastasis failure-free survival.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.844-853
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• 2019

Objective: To evaluate the learning curve for C-arm cone-beam computed tomography (CBCT) virtual navigation-guided percutaneous transthoracic needle biopsy (PTNB) and to determine the amount of experience needed to develop appropriate skills for this procedure using cumulative summation (CUSUM). Materials and Methods: We retrospectively reviewed 2042 CBCT virtual navigation-guided PTNBs performed by 7 novice operators between March 2011 and December 2014. Learning curves for CBCT virtual navigation-guided PTNB with respect to its diagnostic performance and the occurrence of biopsy-related pneumothorax were analyzed using standard and risk-adjusted CUSUM (RA-CUSUM). Acceptable failure rates were determined as 0.06 for diagnostic failure and 0.25 for PTNB-related pneumothorax. Results: Standard CUSUM indicated that 6 of the 7 operators achieved an acceptable diagnostic failure rate after a median of 105 PTNB procedures (95% confidence interval [CI], 14-240), and 6 of the operators achieved acceptable pneumothorax occurrence rate after a median of 79 PTNB procedures (95% CI, 27-155). RA-CUSUM showed that 93 (95% CI, 39-142) and 80 (95% CI, 38-127) PTNB procedures were required to achieve acceptable diagnostic performance and pneumothorax occurrence, respectively. Conclusion: The novice operators' skills in performing CBCT virtual navigation-guided PTNBs improved with increasing experience over a wide range of learning periods.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.205-213
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• 2014

The outcomes of first-generation EGFR-TKIs (Gefitnib and Erlotinib) have shown great advantages over traditional treatment strategies in patients with non-small cell lung cancer (NSCLC), but unfortunately we have to face the situation that most patients still fail to respond in the long term despite initially good control. Up to now, the mechanism of acquired resistance to EGFR-TKIs has not been fully clarified. Herein, we sought to compile the available clinical reports in the hope to better understanding the subsequent treatment choices, particularly on whether restoring after a drug holiday or switching to another EGFR-TKI is the better option after failure of one kind of EGFR-TKI.