• Radiation Oncology Journal
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• v.37 no.1
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• pp.30-36
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• 2019

Purpose: This study aimed to identify the feasibility of the maximum standardized uptake value (SUVmax) on baseline 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) as a predictive factor for prognosis in early stage primary lung cancer treated with stereotactic body radiotherapy (SBRT). Materials and Methods: Twenty-seven T1-3N0M0 primary lung cancer patients treated with curative SBRT between 2010 and 2018 were retrospectively evaluated. Four patients (14.8%) treated with SBRT to address residual tumor after wedge resection and one patient (3.7%) with local recurrence after resection were included. The SUVmax at baseline PET/CT was assessed to determine its relationship with prognosis after SBRT. Patients were divided into two groups based on maximum SUVmax on pre-treatment FDG PET/CT, estimated by receiver operating characteristic curve. Results: The median follow-up period was 17.7 months (range, 2.3 to 60.0 months). The actuarial 2-year local control, progression-free survival (PFS), and overall survival were 80.4%, 66.0%, and 78.2%, respectively. With regard to failure patterns, 5 patients exhibited local failure (in-field failure, 18.5%), 1 (3.7%) experienced regional nodal relapse, and other 2 (7.4%) developed distant failure. SUVmax was significantly correlated with progression (p = 0.08, optimal cut-off point SUVmax > 5.1). PFS was significantly influenced by pretreatment SUVmax (SUVmax > 5.1 vs. SUVmax ≤ 5.1; p = 0.012) and T stage (T1 vs. T2-3; p = 0.012). Conclusion: SUVmax at pre-treatment FDG PET/CT demonstrated a predictive value for PFS after SBRT for lung cancer.

• Journal of Gastric Cancer
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• v.19 no.4
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• pp.393-407
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• 2019

Purpose: To identify the potential therapeutic role of postoperative radiotherapy (RT) in patients with locally advanced (stage II and stage III) gastric signet ring cell carcinoma (SRC). Materials and methods: Patients with locally advanced gastric SRC from the Surveillance, Epidemiology, and End Results program database between 2004 and 2012 were included in our study. Univariate and multivariate Cox proportional models were performed, and survival curves were generated to evaluate the prognostic effect of postoperative RT and surgery alone on SRC patients. Propensity score matching (PSM) was used to avoid selection bias among the study cohorts. Results: We found that patients with postoperative RT had better probability of survival compared with those who did not receive RT (overall survival [OS], P<0.001; cancer-specific survival [CSS], P<0.001). After PSM, analysis of both overall and CSS showed that patients who underwent postoperative RT had better prognosis than those receiving surgery alone in the matched cohort (OS, P=0.00079; CSS, P=0.0036). Multivariate Cox proportional model indicated that postoperative RT had better effect on prognosis compared with surgery alone with respect to both overall (hazard ratio [HR], 0.716; 95% confidence interval [95% CI], 0.590-0.87; P=0.001) and CSS (HR, 0.713; 95% CI, 0.570-0.890; P=0.003). Conclusions: Postoperative RT had better prognosis compared with surgery alone for both overall and CSS for patients with locally advanced gastric SRC.

• Radiation Oncology Journal
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• v.20 no.1
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• pp.41-52
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• 2002

Purpose : 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. Materials and Methods : The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were peformed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. Results : The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probabiliy. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values $(4\~5\%\;increased)$ for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased $(50\~70\%\;increased)$ for upon extending PTV margins by 2.0 cm. Conclusion : Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.

• Radiation Oncology Journal
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• v.36 no.1
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• pp.79-84
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• 2018

Deep inspiration breathing hold (DIBH) compared to free-breathing (FB) during radiotherapy (RT) has significantly decreased radiation dose to heart and has been one of the techniques adopted for patients with breast cancer. However, patients who are unable to make suitable deep inspiration breath may not be eligible for DIBH, yet still need to spare the heart and lung during breast cancer RT (left-sided RT in particular). Continuous positive airway pressure (CPAP) is a positive airway pressure ventilator, which keeps the airways continuously open and subsequently inflates the thorax resembling thoracic changes from DIBH. In this report, authors applied CPAP instead of FB during left-sided breast cancer RT including internal mammary node in a patient who was unable to tolerate DIBH, and substantially decreased radiation dose the heart and lung with CPAP compared to FB.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5401-5406
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• 2015

Background: Brain metastases are the most common intra-cranial neoplasms. The incidence is on a rise due to advanced imaging techniques. Aims: The objective of the study was to analyse the clinical and demographic profile of patients with brain metastases from primary solid tumors. Materials and Methods: This is a retrospective single institutional study covering 130 consecutive patients with brain metastases from January 2007 to August 2014. Results: Some 64.6% of the patients were females. The majority were in the sixth decade of life. The site of the primary tumor was the lungs in 50.8% of the cases. The overall median time from the diagnosis of the primary malignancy to detection of brain metastases was 21.4 months. Survival was found to be significantly improved in patients with solitary brain lesions when compared to patients with multiple brain metastases, and in patients undergoing surgical excision with or without cranial irradiation when compared to whole brain irradiation alone. The majority of the cases belonged to the recursive partitioning analysis class II group. Whole brain radiation therapy was delivered to 79% of the patients. Conclusions: Most of the patients with brain metastases in the study belonged to recursive partitioning analysis classes II or III, and hence had poor prognosis. Most of the patients in the Indian context either do not satisfy the indications for surgical excision or are incapable of bearing the high cost associated with stereotactic radiosurgery. Treatment should be tailored on an individual basis to all these patients.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.263-267
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• 1994

In clinical radiotherapy, the use of wide and irregular field techniques frequently results in considerable tumor dose inhomogeneity because of, the variation in physical characteristics of irradiated volumes. This report describes an analysis of the dosimetry of the irregular fields such as radiation fields for Hodgkin's disease(mantle field), esophageal cancer, and lung cancer when a 6 MV and a 15 MV linear accelerators are utilized. Doses were measured in a Rando phantom using methods of thermoluminescence dosimetry(TLD), and were calculated by radiotherapy planning computer system with the Clarkson's method for calculation of a irregular field. A dose variation of $5-22\%,\;6-9\%,\;6-14\%$ were found in the mantle field, esophageal cancer field, lung cancer field respectively. Higher doses occurred in the superior portion of the irregular field. The sites of maximum dose variation were the supraclavicular and the upper spinal cord region. To adjust for these substantial differences, a compensator or a shrinking field technique should be adopted.

• The Journal of Korean Medicine
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• v.39 no.4
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• pp.171-176
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• 2018

Background: Small cell lung cancer (SCLC) tends to grow more rapidly and spread much faster than non-small cell lung cancer (NSCLC). A concurrent combination of chemotherapy and thoracic radiotherapy is suggested as the standard conventional treatment, but it is more challenging for elderly patients having pulmonary and cardiovascular comorbidities. Case presentation: Here we present a case of an 80-year-old male, current smoker diagnosed with SCLC in limited stage T3N0M0 (36mm right upper lobe, satellite nodule) in Dec, 2015. The standard concurrent chemoradiotherapy was not available for his comorbidities, which included chronic obstructive pulmonary disease (COPD) and angina pectoris. Furthermore, he and his family refused the recommended chemotherapy or radiotherapy exclusively. Alternatively, he received various non-conventional treatments including local radiofrequency hyperthermia, mistletoe, and Traditional Korean medicine including acupuncture, moxibustion and herbs since Jan. 2016. Despite the progression in primary tumor size, there have been no other distant relapse so far, and the patient has been in stable condition ever since. Conclusion: We suggest that a combination of various alternative treatments could be a candidate for elderly patients intolerable to conventional cytotoxic treatments.

• Progress in Medical Physics
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• v.18 no.3
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• pp.167-171
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• 2007

In the case of radiotherapy following breast conservation therapy for breast cancer patients, the characteristic of skin dose was investigated in the treatment of intensity modulated radiation therapy (IMRT) for breast cancer patients by comparing and analysing entrance skin dose irradiated during radiotherapy using tangential technique radiotherpy, and IMRT. The calculation dose irradiated to breast skin was compared with TLD measurement dose in treatment planning by performing the two methods of radiotherapy using tangential technique, and IMRT in treatment planning equipment. The skin absorbed dose was measured to pass a nipple by spacing of 1 cm distance from center to edge of body. In the radiotherapy of tangential technique, for the irradiation of 180 cGy to PTV, the calculation dose was ranged from 103.5 cGy to 155.2 cGy, measurement dose was ranged from 107.5 cGy to 156.2 cGy, and skin dose in the center was maximum 1.45 times more irradiated than that in the edge. In the IMRT, for the irradiation of 180 cGy to PTV, the calculation dose was ranged 9.8 cGy at 80.2 cGy, measurement dose was ranged 8.9 cGy at 77.2 cGy, and skin dose in the center was maximum 0.23 times less irradiated than that in the edge. IMRT was more effective for skin radiation risks because radiation dose irradiated to skin in IMRT was much less than that in radiotherapy of tangential field technique.

• Radiation Oncology Journal
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• v.28 no.1
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• pp.39-49
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• 2010

Purpose: This aim of this study is to analyze the dosimetric difference between intensity-modulated radiation therapy (IMRT) using 3 or 5 beams and MSF in the radiotherapy of the left breast. Materials and Methods: We performed a comparative analysis of two radiotherapy modalities that can achieve improved dose homogeneity. First is the multistatic fields technique that simultaneously uses both major and minor irradiation fields. The other is IMRT, which employs 3 or 5 beams using a fixed multileaf collimator. We designed treatment plans for 16 early left breast cancer patients who had taken breast conservation surgery and radiotherapy, and analyzed them from a dosimetric standpoint. Results: For the mean values of $V_{95}$ and dose homogeneity index, no statistically significant difference was observed among the three therapies. Extreme hot spots receiving over 110% of the prescribed dose were not found in any of the three methods. A Tukey test performed on IMRT showed a significantly larger increase in exposure dose to the ipsilateral lung and heart than multistatic fields technique (MSF) in the low-dose area, but in the high-dose area, MSF showed a slight increase. Conclusion: In order to improve dose homogeneity, the application of MSF, which can be easily planned and applied more widely, is considered an optimal alternative to IMRT for radiotherapy of early left breast cancer.

• 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.