• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.4
• /
• pp.2243-2248
• /
• 2013

Background: To compare the dosimetric coverage of target volumes and organs at risk in the radical treatment of nasopharyngeal carcinoma (NPC) between intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT). Materials and Methods: Data from 10 consecutive patients treated with IMRT from June-October 2011 in Penang General Hospital were collected retrospectively for analysis. For each patient, dose volume histograms were generated for both the IMRT and 3DCRT plans using a total dose of 70Gy. Comparison of the plans was accomplished by comparing the target volume coverage (5 measures) and sparing of organs at risk (17 organs) for each patient using both IMRT and 3DCRT. The means of each comparison target volume coverage measures and organs at risk measures were obtained and tested for statistical significance using the paired Student t-test. Results: All 5 measures for target volume coverage showed marked dosimetric superiority of IMRT over 3DCRT. V70 and V66.5 for PTV70 showed an absolute improvement of 39.3% and 24.1% respectively. V59.4 and V56.4 for PTV59.4 showed advantages of 18.4% and 16.4%. Moreover, the mean PTV70 dose revealed a 5.1 Gy higher dose with IMRT. Only 4 out of 17 organs at risk showed statistically significant difference in their means which were clinically meaningful between the IMRT and 3DCRT techniques. IMRT was superior in sparing the spinal cord (less 5.8Gy), V30 of right parotid (less 14.3%) and V30 of the left parotid (less 13.1%). The V55 of the left cochlea was lower with 3DCRT (less 44.3%). Conclusions: IMRT is superior to 3DCRT due to its dosimetric advantage in target volume coverage while delivering acceptable doses to organs at risk. A total dose of 70Gy with IMRT should be considered as a standard of care for radical treatment of NPC.

• Journal of radiological science and technology
• /
• v.20 no.2
• /
• pp.79-82
• /
• 1997

Image-based three dimensional radiation treatment planning(3D RTP) has a potential of generating superior treatment plans. Advances in computer technology and software developments quickly make 3D RTP a feasible choice for routine clinical use. However, it has become clear that an evaluation of a 3D plan is more difficult than a 2D plan. A number of tools have been developed to facilitate the evaluation of 3D RTP both qualitatively and quantitatively. For example, beam's eye view(BEV) is one of the most powerful and time-saving method as a qualitative tools. Dose-volume histogram(DVH) has been proven to be one of the most valuable methods for a quantitative tools. But it has a limitation to evaluate several different plans for biological effects of the tissue and critical organ. Therefore, there is a strong interest in developing quantitative models which would predict the likely biological response of irradiated organs and tissues, such as tumor control probability(TCP) and normal tissue complication probability(NTCP). DVH and NTCP of hepatoma were evaluated for three dimensional conformal radiotherapy(3D CRT). Also, 3D RTP was analysed as a dose optimization based on beam arrangement and beam modulation.

• Radiation Oncology Journal
• /
• v.37 no.4
• /
• pp.271-278
• /
• 2019

Purpose: To investigate the differences in treatment outcomes between two radiation techniques, intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT). Materials and Methods: We retrospectively analyzed 160 (IMRT = 23, 3DCRT = 137) patients with stage I glottic cancer treated from January 2005 through December 2016. The IMRT was performed with TomoTherapy (16 patients), volumetric-modulated arc therapy (6 patients), and step-and-shoot technique (1 patient), respectively. The 3DCRT was performed with bilateral parallel opposing fields. The median follow-up duration was 30 months (range, 31 to 42 months) in the IMRT group and 65 months (range, 20 to 143 months) in the 3DCRT group. Results: The 5-year overall survival and 3-year local control rates of the 160 patients were 95.7% and 91.4%, respectively. There was no significant difference in 3-year local control rates between the IMRT and 3DCRT groups (94.4% vs. 91.0%; p = 0.587). Thirteen of 137 patients in the 3DCRT group had recurrences. In the IMRT group, one patient had a recurrence at the true vocal cord. Patients treated with IMRT had less grade 2 skin reaction than the 3DCRT group, but this had no statistical significance (4.3% vs. 21.2%; p = 0.080). Conclusion: IMRT had comparable outcomes with 3DCRT, and a trend of less acute skin reaction in stage I glottic cancer patients.

• Radiation Oncology Journal
• /
• v.32 no.3
• /
• pp.125-131
• /
• 2014

Purpose: We reviewed treatment outcomes and prognostic factors for patients with salivary ductal carcinoma (SDC) treated with surgery and postoperative radiotherapy from 2005 to 2012. Materials and Methods: A total of 16 patients were identified and 15 eligible patients were included in analysis. Median age was 61 years (range, 40 to 71 years) and 12 patients (80%) were men. Twelve patients (80%) had a tumor in the parotid gland, 9 (60%) had T3 or T4 disease, and 9 (60%) had positive nodal disease. All patients underwent surgery and postoperative radiotherapy. Postoperative radiotherapy was delivered using 3-dimensional conformal radiotherapy or intensity-modulated radiotherapy. Locoregional failure-free survival (LRFFS), distant failure-free survival (DFFS), progression-free survival (PFS), and overall survival (OS) were calculated using the Kaplan-Meier method. Differences in survival based on risk factors were tested using a log-rank test. Results: Median total radiotherapy dose was 60 Gy (range, 52.5 to 63.6 Gy). Four patients received concurrent weekly chemotherapy with cisplatin. Among 10 patients who underwent surgery with neck dissection, 7 received modified radical neck dissection. With a median follow-up time of 38 months (range, 24 to 105 months), 4-year rates were 86% for LRFFS, 51% for DFFS, 46% for PFS, and 93% for OS. Local failure was observed in 2 patients (13%), and distant failure was observed in 7 (47%). The lung was the most common involved site of distant metastasis. Conclusion: Surgery and postoperative radiotherapy in SDC patients resulted in good local control, but high distant metastasis remained a major challenge.

• Radiation Oncology Journal
• /
• v.37 no.2
• /
• pp.82-90
• /
• 2019

Purpose: To evaluate the results of hypofractionated radiotherapy (HFX) for early glottic cancer. Materials and Methods: Eighty-five patients with cT1-2N0M0 squamous cell carcinoma of the glottis who had undergone HFX, performed using intensity-modulated radiotherapy (IMRT, n = 66) and three-dimensional conformal radiotherapy (3D CRT, n = 19) were analyzed. For all patients, radiotherapy was administered at 60.75 Gy in 27 fractions. Forty-three patients received a simultaneous integrated boost (SIB) of 2.3-2.5 Gy per tumor fraction. Results: The median follow-up duration was 29.9 months (range, 5.5 to 76.5 months). All patients achieved complete remission at a median of 50 days after the end of radiotherapy (range, 14 to 206 days). The 5-year rates for locoregional recurrence-free survival was 88.1%, and the 5-year overall survival rate was 86.2%. T2 stage was a prognostic factor for locoregional recurrence-free survival after radiotherapy (p = 0.002). SIB for the tumor did not affect disease control and survival (p = 0.191 and p = 0.387, respectively). No patients experienced acute or chronic toxicities of ≥grade 3. IMRT significantly decreased the dose administered to the carotid artery as opposed to 3D CRT (V₃₅, p < 0.001; V₅₀, p < 0.001). Conclusions: Patients treated with HFX achieved acceptable locoregional disease control rates and overall survival rates compared with previous HFX studies. A fraction size of 2.25 Gy provided good disease control regardless of SIB administration.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.1
• /
• pp.75-79
• /
• 2012

Purpose: the study aimed to compare the quality of life (QOL) and radiotherapy complications among Chinese nasopharyngeal carcinoma (NPC) patients at different 3-dimensional conformal radiotherapy (3DCRT) stages adjusting for other variables. Methods: 511 NPC patients at different 3DCRT stages were enrolled. They were interviewed regarding SF-36, complications and socio-demographic variables and cancer- or treatment-related variables. Analysis of covariance (ANCOVA) based on SF-36, complications scores as dependent variables, 3DCRT stages as independent variables, and other variables as covariate were established. Results: The influencing factors of PCS included 3DCRT stages and age group. The influencing factors of MCS included 3DCRT stages and income. Most QOL scores of NPC patients were significantly associated with 3DCRT stage, after accounting for other variables. QOL scores of the patients receiving 3DCRT were the lowest, QOL scores of people after 3DCRT gradually increased. PCS scores of people greater than 5 years after 3DCRT was improved to or even better than the level before 3DCRT. The complications with significantly different scores of patients at different 3DCRT status included xerostomia, throat ache, hypogeusia, caries, hearing loss, snuffles. Conclusions: Clinicians should pay more attention to older NPC patients and patients with lower income. When patients receive 3DCRT, measures should be taken to reduce radiation injury to improve the patients' QOL.

• Radiation Oncology Journal
• /
• v.35 no.1
• /
• pp.71-77
• /
• 2017

Purpose: Although the technical developments of radiotherapy have been remarkable, there are currently few reports on the treatment results of radiotherapy for local recurrence of rectal cancer treated with surgery alone as initial treatment in this three-dimensional conformal radiotherapy era. Thus, we retrospectively evaluated the treatment results of radiotherapy for local recurrence of rectal cancer treated with surgery alone as the initial treatment. Materials and Methods: Thirty-two patients who underwent radiotherapy were enrolled in this study. The dose per fraction was 2.0-3.5 Gy. Because the treatment schedule was variable, the biological effective dose (BED) was calculated. Results: Local control (LC) and overall survival (OS) rates from the completion of radiotherapy were calculated. The 1-, 2-, 3-, 4-, and 5-year LC rates were 51.5%, 24.5%, 19.6%, 19.6%, and 13.1%, respectively. LC rates were significantly higher for the high BED group (${\geq}75Gy_{10}$) than for the lower BED group (<$75Gy_{10}$). All patients who reported pain achieved pain relief. The duration of pain relief was significantly higher for the high BED group than for the lower BED group. The 1-, 2-, 3-, 4-, and 5-year OS rates were 82.6%, 56.5%, 45.2%, 38.7%, and 23.2%, respectively. There was a trend toward higher OS rates in with higher BED group compared to lower BED group. Conclusion: For patients with unresectable locally recurrent rectal cancer treated with surgery alone, radiotherapy is effective treatment. The prescribed BED should be more than $75Gy_{10}$, if the dose to the organ at risk is within acceptable levels.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.8
• /
• pp.4163-4167
• /
• 2012

Aims: To prospectively assess the efficacy and safety of moderately hypofractionated conformal radiotherapy in patients with thoracic esophageal cancer. Methods and Materials: From Sept. 2002 to Oct, 2005, 150 eligible patients with T2-4N0-1M0 stage thoracic esophageal squamous cell cancers were enrolled to receive either conventional fractionated radiation (CFR) or moderately hypofractionated radiation (MHR) with a three-dimensional conformal radiation technique. Of the total, 74 received moderately hypofractionated radiation with total dose of 54-60Gy/18-20fractions for 3.5-4 weeks in the MHR arm, and 76 received conventional radiation with total dose of 60Gy/30 fractions for 6 weeks in the CFR arm. Concurrent chemotherapy comprised of paclitaxel and cisplatin. Safety was evaluated, and local control and overall survival rates were calculated. Results: Statistically significant differences between the CFR versus MHR arms were observed in local/regional failure rate (47.3% v 27.0%, P=0.034) and the percentage of patients with persistent local disease (26.3% v 10.8%, P=0.012). But 3 and 5-year overall survival rates (43.2%, 38.8% v 38.2%, 28.0%, respectively) were not different between the two arms (P=0.268). There were no significant differences in the incidences of grade 3 or higher acute toxicities (66.3% v 50.0%) and late complications rates (27.0% v 22.4%) between the MHR and CFR arms. Conclusions: Moderately hypofractionated, three-dimensional radiation treatment could improve the local control rate of esophageal cancer and potentially increase patients' survival.

• Radiation Oncology Journal
• /
• v.25 no.3
• /
• pp.170-176
• /
• 2007

Purpose: To determine the role of radiotherapy for the treatment of portal vein thrombosis (PVT) from hepatocellular carcinoma (HCC). Material and Methods: A retrospective analysis was performed on 70 patients that had been diagnosed with HCC and were treated with three-dimensional conformal radiotherapy (3D-CRT) for the PVT. The radiation dose ranged from 40 Gy to 60 Gy (median dose: 48 Gy) and the biological effective dose (BED) ranged from 31.3 Gy to 78.0 $Gy_{10}$ (median dose: 61.6 $Gy_{10}$). Response was determined by measuring the extent of the PVT on a CT image at 0, 1 and 3 months after completion of the radiotherapy. The median follow-up period was 9 months. Results: The response rate was 47.1% (33 patients), with two patients (2.9%) showing a complete response, 31 patients (44.3%) showing a partial response, and 35 patients (50%) showing stable disease or no response. The 1-year progression-free survival rate was 60%, and the median progression-free survival time was 17 months. The median overall survival time was 11 months, the median survival time in the responders was 15 months and in the nonresponders was 8 months (p=0.032). Four patients (5.7%) had transient liver function impairment during treatment. Radiation induced liver disease (RILD) was observed in only one patient (1.4%). Conclusion: Three-dimensional conformal radiotherapy for the treatment of PVT from advanced HCC was a relatively effective and safe method.

• Progress in Medical Physics
• /
• v.33 no.3
• /
• pp.25-35
• /
• 2022

Purpose: Planning for radiotherapy relies on implicit estimation of the probability of tumor control and the probability of complications in adjacent normal tissues for a given dose distribution. Methods: The aim of this pilot study was to reconstruct dose-volume histograms (DVHs) from text files generated by the Eclipse treatment planning system developed by Varian Medical Systems and to verify the integrity and accuracy of the dose statistics. Results: We further compared dose statistics for intensity-modulated radiotherapy of the head and neck between the Eclipse software and software developed in-house. The dose statistics data obtained from the Python software were consistent, with deviations from the Eclipse treatment planning system found to be within acceptable limits. Conclusions: The in-house software was able to provide indices of hotness and coldness for treatment planning and store statistical data generated by the software in Oracle databases. We believe the findings of this pilot study may lead to more accurate evaluations in planning for radiotherapy.