The Efficacy of CT-Based Conformal Electron Beam Radiation Therapy After Keloid Excision.

BACKGROUND: Adjuvant computed tomography-based conformal electron beam radiation therapy (RT) for patients with keloids enables radiation oncologists to customize the target volume with precision and deliver the maximal prescription dose while sparing normal surrounding tissues. OBJECTIVE: To report treatment and cosmetic outcomes by the patient's self-assessment survey. METHODS: Medical records of patients with keloids, who were treated with postoperative electron beam RT between January 2015 and December 2020, were reviewed. A total of 85 consecutive patients with 136 keloids were included in this study. Subjective cosmetic outcomes were scored by each patient using a 5-point Likert scale survey. RESULTS: The median follow-up time was 29.0 months (range, 12.1-77.9 months), and local recurrence was observed in 10 lesions (7.4%). The recurrence rate of keloids occurring in the ear was 5.4%, whereas the recurrence rate of keloids occurring at other body sites was 11.4%. Among the patients who responded to the questionnaire about the cosmetic outcome, 70.2% of patients declared being either very satisfied (44.7%) or satisfied (25.5%). CONCLUSION: Surgical excision, followed by CT-based conformal electron beam RT, for patients with keloids ensures a high degree of local control resulting in good cosmetic outcomes.

Comparison of Heart and Lung Doses According to Tumor Bed Boost Techniques in Early-Stage Left-Sided Breast Cancer: Simultaneous Integrated Boost versus Sequential Boost.

Background and Objectives: The boost dose to the tumor bed after whole breast irradiation (WBI) can be divided into sequential boost (SEQ) and simultaneous integrated boost (SIB). SIB using modern radiation therapy (RT) techniques, such as volumetric modulated arc therapy, allow the delivery of a highly conformal dose to the target volume and has a salient ability to spare at-risk organs. This study aimed to compare the radiation dose delivered to the heart and lungs according to boost technique and tumor bed location. Materials and Methods: RT planning data of 20 patients with early-stage left-sided breast cancer were used in this study. All patients were treated with volumetric modulated arc therapy after breast-conserving surgery with a sentinel lymph node biopsy. For each patient, two different plans, whole breast irradiation with simultaneous integrated boost (WBI-SIB) and sequential boost after WBI (WBI-SEQ), were generated. To compare the dose received by each organ at risk (OAR), dose-volume histogram data were analyzed. The mean dose (Dmean) and volume of each organ that received x Gy (Vx) were calculated and compared. Results: For the heart, the V10 was lower for the WBI-SIB plan than for the WBI-SEQ plan (5.223 ± 1.947% vs. 6.409 ± 2.545%, p = 0.008). For the left lung, the V5 was lower in the WBI-SIB plan than for the WBI-SEQ plan (27.385 ± 3.871% vs. 32.092 ± 3.545%, p < 0.001). The Dmean for the heart and left lung was lower for the WBI-SIB plan than for the WBI-SEQ plan (heart: 339.745 ± 46.889 cGy vs. 413.030 ± 52.456 cGy, p < 0.001; left lung: 550.445 ± 65.094 cGy vs. 602.270 ± 55.775 cGy, p < 0.001). Conclusions: The WBI-SIB plan delivered lower radiation doses to the heart and left lung than the WBI-SEQ plan in terms of Dmean and low-dose volume in hypofractionated RT of early-stage left-sided breast cancer patients. Furthermore, a large radiation dose per day may be advantageous, considering the radiobiologic aspects of breast cancer. Long-term follow-up data are needed to determine whether the dosimetric advantages of the WBI-SIB plan can lead to clinically improved patient outcomes and reduced late side effects.

Dosimetric comparison of VitalBeam® and HalcyonTM 2.0 for hypofractionated VMAT with simultaneous integrated boost treatment of early-stage left-sided breast cancer.

PURPOSE: This study compared the quality of treatment plans for early-stage, left-sided breast cancer, as planned for and delivered by the HalcyonTM and VitalBeam® . MATERIALS AND METHODS: Fifteen patients diagnosed with early-stage left-sided breast cancer, who had received VMAT with hypofractionated SIB, were recruited. All cases were planned using HalcyonTM comprising a dual-layer MLC (DL-MLC) and VitalBeam® with a Millennium 120 MLC (VB-MLC). For the PTVs, the quality of coverage (QC), conformity index (CI), and homogeneity index (HI) were calculated for each plan. The dosimetric differences between the two treatment plans were statistically compared using the Wilcoxon signed-rank test (p < 0.05). To evaluate delivery efficiency, the average delivery time for each patient's treatment plan was recorded and compared. RESULTS: For the PTVs, the two plans (DL-MLC and VB-MLC) were comparable in terms of the QC, CI, and HI. However, V30Gy and Dmean for the heart in the DL-MLC plan were significantly reduced by 0.49% and 14.6%, respectively, compared with those in the VB-MLC plan (p < 0.05). The Dmean value for the ipsilateral lung in the DL-MLC plan significantly decreased by 5.5%, compared with that in the VB-MLC plan (p < 0.05). In addition, the delivery times for the DL-MLC and VB-MLC plans were 79 ± 10 and 101 ± 11 s, respectively. CONCLUSIONS: DL-MLC plans were found to improve OAR sparing. In particular, when treating left-sided breast cancer via DL-MLC plans, the risk of heart toxicity is expected to be reduced.

Factors predicting intolerance to definitive conventional radiotherapy in geriatric patients.

PURPOSE: Although radiotherapy can be administered with a relatively low therapeutic burden, many elderly patients do not complete radiotherapy. In order to predict intolerance during radiotherapy, this study retrospectively analyzed the frequency of and risk factors for radiotherapy interruption among geriatric patients. METHODS: From September 2009 to December 2016, 353 patients aged ≥70 years received definitive radiotherapy with a conventionally fractionated schedule. "Total interruption" included completion of ≤90% of a planned radiotherapy, temporary discontinuation, and treatment-related mortality within 2 months. "Early-phase incompletion" and "mid-phase incompletion" represented completion of ≤50 and ≤80% of a planned radiotherapy, respectively. RESULTS: The median age of patients was 74 years. Early- and mid-phase incompletions and total interruption occurred in 4.2, 9.3, and 19.3% of patients, respectively. Total interruption occurred frequently in cancers involving the thorax (27.4%), head and neck (23.1%), abdomen (20.0%), pelvis (17.4%), and breast/extremity (8.1%). The Eastern Cooperative Oncology Group (ECOG) performance score (P = 0.004 and 0.002), serum albumin level (P = 0.016 and 0.002), and the expected 5­year survival (P = 0.033 and 0.034) were significant factors for mid-phase incompletion and total interruption. Age ≥ 75 years (P = 0.008), concurrent chemotherapy (P = 0.017), and the extent of radiation field (P = 0.027) were factors associated with total interruption. CONCLUSION: Overall, 19.3% of the elderly patients showed treatment intolerance during conventional radiotherapy. Serum albumin level and ECOG performance score should be considered as surrogate markers for radiotherapy interruption prior to the decision regarding definite conventional radiotherapy.

The Role of Adjuvant Radiation Therapy for Locoregionally Advanced Papillary Thyroid Carcinoma.

OBJECTIVES: To investigate the role of adjuvant radiation therapy in locoregional control in patients with locoregionally advanced papillary thyroid carcinoma (pT4 or pN1b) based on a comparison of a group that received radiation therapy and a group that did not receive radiation therapy. METHODS: A retrospective analysis was performed on 165 patients with locoregionally advanced papillary thyroid carcinoma who underwent treatment between 2002 and 2011. Of these, 32 patients received adjuvant radiation therapy, and 133 patients did not receive radiation therapy. RESULTS: The median follow-up period was 7.2 years (range, 3.4-13.6) for the overall study population. The 10-year locoregional recurrence-free survival rates for patients in the radiation therapy and no radiation therapy groups were 83.9 and 60.8%, respectively (p = 0.037). The overall survival rate and distant recurrence-free survival rate were not different between the two groups (p = 0.076 and p = 0.813, respectively). Multivariate analysis showed that adjuvant radiation therapy was an independent prognostic factor for locoregional recurrence-free survival (p = 0.040). CONCLUSIONS: Adjuvant radiation therapy for patients with either pT4 or pN1b disease improved locoregional recurrence-free survival and might be of benefit for patients with these high-risk features by reducing the need for additional salvage treatment after locoregional recurrence.

Quantitative analysis of tumor volume reduction after three-dimensional conformal radiation therapy for intracranial meningiomas.

To provide radiobiological information on the inherent response of intracranial meningiomas after three-dimensional conformal radiation therapy. Quantitative tumor volume measurements were generated from 120 magnetic resonance images of a total of 24 patients. Gross tumor volumes were delineated on a series of contrast-enhanced T1-weighted magnetic resonance images by using commercial software. The percentage of tumor volume reduction at each follow-up was determined and compared to the baseline tumor volume. The median follow-up time was 103.5 months (range 30-137 months). The mean pre-radiation therapy tumor volume was 30.0 cm(3) (range 1.3-167.4 cm(3)). Tumor volume reduction was observed in 96 % of the study population. The mean absolute and relative tumor volume reduction were 14.0 cm(3) (range -0.6-84.5 cm(3)) and 40.8 % (range -6.8-82.9 %), respectively. The mean relative tumor volume reduction was 15.9, 28.9, 40.5, 50.3, and 52.6 % at 2, 4, 6, 8, and 10 years after irradiation. The quantitative volumetric analysis of the pattern of tumor volume reduction in response to irradiation gives an insight into the radiobiological nature of intracranial meningiomas after conventionally fractionated radiation therapy.

Intraoperative Radiation Therapy for Gallbladder Cancer: Experience at a Single Institution.

BACKGROUND/AIMS: To investigate the survival outcome of intraoperative radiation therapy for patients with gallbladder cancer on the basis of experience at a single institution. METHODOLOGY: The medical records of 8 patients with gallbladder cancer who were treated with intraoperative radiation therapy during surgical resection or palliative surgery were retrospectively analyzed. The primary endpoint was overall survival. The median follow-up time was 20.8 months. RESULTS: The median survival time was 15.0 months. Overall survival for all patients was 75.0% at 1 year, 37.5% at 3 years, and 25.0% at 5 years. Three patients underwent complete resection, and 5 patients had residual tumor after resection or palliative surgery. The 3-year OS rate for 3 patients with no residual tumor after curative resection was 66.7%, with a mean survival time of 122.6 months, whereas the 3-year OS rate for 5 patients with macroscopic residual diseasewas 0% with a mean survival time of 13.5 months (P = 0.014). CONCLUSIONS: The results of the present study suggest that intraoperative radiation therapy with or without external beam radiation therapy was safe and beneficial for patients who underwent curative resection with negative margins and allows the possibility of long-term survival.

Radiation Therapy Dose for Limited-Stage Extranodal Marginal Zone Lymphomas of the Mucosa-Associated Lymphoid Tissues of the Stomach: A Meta-Analysis: RT Dose for Gastric EMZL.

PURPOSE: To compare the outcomes of two standard radiation therapy (RT) doses for limited-stage gastric extranodal marginal zone lymphoma (EMZL) of the mucosa-associated lymphoid tissues. METHODS AND MATERIALS: A database search was performed to identify articles published from database inception to August 31, 2023. Based on the current standard dose of 24.0-30.0 Gy, doses of approximately 30.0 Gy were classified as standard dose (SD), while those of approximately 24.0 Gy were classified as low dose (LD). Pooled estimates of the complete remission (CR) and local recurrence (LR) rates were calculated and compared. RESULTS: Data from 1,072 patients across 30 included studies were analyzed. SD was used in 28 studies (n = 987), while LD was used in six studies (n = 85), and both regimens were used in four studies. In all included studies, the CR rate was 0.96 (95% confidence interval [CI], 0.94-0.97), and the LR rate was 0.05 (95% CI, 0.04-0.06), showing no significant between-study heterogeneity (τ2 = 0 and I2 = 0% for both; P = 0.8447 and 0.9998, respectively). SD and LD resulted in no significant differences in the CR rates (0.96 [95% CI, 0.94-0.97] vs. 0.96 [95% CI, 0.89-0.99]; P = 0.9174) or LR rates (0.05 [95% CI, 0.04-0.06] vs. 0.03 [95% CI, 0.01-0.10]; P = 0.5495). CONCLUSION: Both the SD and LD groups achieved excellent CR and LR rates. These results indicate that the RT dose for limited-stage gastric EMZL may be safely de-escalated without compromising local tumor control.

Prophylactic supraclavicular radiotherapy after surgery in high-risk n1 breast cancer.

OBJECTIVES: To evaluate the role of prophylactic supraclavicular radiotherapy (RT) by comparing the clinical outcomes of locoregional recurrence (LRR) in high-risk N1 breast cancer. METHODS: We performed a retrospective comparison study of 250 high-risk N1 breast cancer patients treated at two institutions. Patients were considered to be high-risk when they had more than two of the following risk factors: lymphovascular invasion, extracapsular extension, metastasis to more than two axillary lymph nodes (ALNs), or level II or higher ALN metastasis. We compared two groups treated with different adjuvant RT fields for the purpose of prophylactic supraclavicular RT (SCRT). RESULTS: Among the 250 patients, 97 patients received SCRT while 153 did not. During follow-up, 32 patients (7 in the SCRT and 25 in the no-SCRT group) had recurrence, and LRR developed in 19 patients, 18 of whom had not received SCRT. In multivariate analysis, SCRT [hazard ratio (HR) 0.072; p = 0.011] and chemotherapy regimen (cyclophosphamide, Adriamycin, and taxane; TAC) were the significant prognostic factors in LRR-free survival (HR 0.385; p = 0.046), and chemotherapy regimen also showed significance for distant metastasis-free survival (HR 0.399; p = 0.037). CONCLUSIONS: Use of prophylactic SCRT may reduce the risk of LRR in patients with high-risk N1 breast cancer.

Combined primary tumor and extracranial metastasis status as constituent factor of prognostic indices for predicting the overall survival in patients with brain metastases.

We retrospectively analyzed the prognostic factors on overall survival (OS) in patients with brain metastasis (BM) and evaluated the role of combined primary tumor and extracranial metastasis (ECM) status as a constituent factor for prognostic index. This study involved 897 patients with BMs who underwent radiotherapy between April 2003 and December 2009. Among the clinical parameters, multivariate analysis showed that age, Karnofsky performance status (KPS), combined primary tumor and ECM status, number of BMs, and treatment group were significant prognostic factors for OS (P < 0.05). To compare the discriminatory ability of 5 prognostic indices, i.e., recursive partitioning analysis (RPA), basic score for BMs (BSBM), score index for radiosurgery (SIR), graded prognostic assessment (GPA), and modified GPA including the combined primary tumor and ECM status (mGPA), the Akaike information criteria (AIC) were calculated. The mGPA showed the lowest AIC value, followed by RPA, GPA, SIR, and BSBM, in that order. It is implicated that modified score of pre-existing factors (i.e., age and KPS) and addition of the combined primary tumor and ECM status to the prognostic index can improve its discriminatory ability and the combined primary tumor and ECM status may be useful as one of constituent factors for prognostic index.

Therapy-related myeloid neoplasm in early breast cancer patients treated with adjuvant chemotherapy.

BACKGROUND: Long-term complications are becoming more important as the survival rate of breast cancer improves. Treatment-related myeloid neoplasm is an important long-term complication in breast cancer survivors as it has a poor prognosis. OBJECTIVE: We evaluated the incidence and risk factors for the development of treatment-related acute myeloid leukaemia (AML)/myelodysplastic syndrome (MDS) in patients treated with early breast cancer. METHODS: We accessed the national Korean database to identify 153,565 patients diagnosed with breast cancer between January 2007 and October 2016 who underwent surgery for breast cancer. We estimated the cumulative incidence of AML/MDS and analysed the risk factors for developing AML/MDS. RESULTS: Of 153,575 patients, 79,321 received anthracycline-based adjuvant therapy, 14,317 received adjuvant therapy without anthracyclines and 46,657 did not receive adjuvant chemotherapy. Overall, 120 developed AML (105 in the anthracycline group, 9 in the non-anthracycline group and 6 in the control group), and 128 developed MDS (96, 9 and 23 in each group). The 10-year cumulative incidence of AML/MDS was the highest in the anthracycline group (0.221% and 0.199%), followed by the non-anthracycline group (0.122% and 0.163%) and the control group (0.024% and 0.089%). The risk of developing AML/MDS was significantly higher in patients treated with anthracyclines (hazard ratio [HR] 9.531; p < 0.0001 for AML and HR 2.559; p < 0.0001 for MDS) compared to patients in the control group. CONCLUSION: This study found that anthracycline-based adjuvant therapy significantly increased the risk of AML/MDS in Korean breast cancer patients, with the risk persisting for at least 10 years. While the cumulative incidence was low, the long-term risks of AML/MDS should be taken into account considering the poor outcomes associated with these neoplasms.

Feasibility of fast, four-dimensional computed tomography-based O-ring LINAC plans for lung stereotactic body radiotherapy in patients with poor performance status.

Purpose: We aimed to retrospectively analyzed the feasibility of fast four-dimensional computed tomography (4DCT)-based O-ring LINAC treatment for patients with an average respiratory amplitude was< 0.5 cm and who cannot endure long treatment times due to poor performance status in lung 4D-stereotactic body radiotherapy (SBRT). Methods: This study included data of 38 patients who received lung 4D-SBRT and had average respiratory amplitude< 0.5 cm in the full phase. C-arm LINAC plans were based on 4DCT data obtained at phase values ranging from 20-70% using a C-arm LINAC. O-ring LINAC plans were retrospectively established based on 4DCT data obtained at phase values of 0-90% using an O-ring LINAC. The conformity index (CI), homogeneity index (HI), and gradient measurement of the planning target volumes (PTV) were analyzed to compare dosimetric data between C-arm LINAC and O-ring LINAC plans. Organs at risk were analyzed in accordance with the Radiation Therapy Oncology Group 0915 protocol. Treatment delivery time and total monitor units were analyzed to compare the efficiency of treatment delivery. Statistical comparisons were performed using the Wilcoxon signed-rank test (P< 0.05). Results: For the PTV, there was no significant difference in the CI or HI between C-arm LINAC and O-ring LINAC plans. For organs-at-risk, all plans met the criteria for dose constraint. There was a significant difference between C-arm LINAC and O-ring LINAC plans except in the spinal cord. Treatment delivery time was 92% longer for C-arm LINAC plans than for O-ring LINAC plans. The total MU value for C-arm LINAC plans was 9.6% higher than that for O-ring LINAC plans. Conclusion: We verified the feasibility of fast 4DCT-based O-ring LINAC treatment for patients with average respiratory amplitude< 0.5 cm and who cannot endure long treatment times due to poor performance status in lung 4D-SBRT.

PIK3CA Mutation is Associated with Poor Response to HER2-Targeted Therapy in Breast Cancer Patients.

PURPOSE: Mutations in the PIK3CA gene occur frequently in breast cancer patients. Activating PIK3CA mutations confer resistance to human epidermal growth factor receptor 2 (HER2)-targeted treatments. In this study, we investigated whether PIK3CA mutations were correlated with treatment response or duration in patients with HER2-positive (HER2+) breast cancer. Materials and Methods: We retrospectively reviewed the clinical information of patients with HER2+ breast cancer who received HER2-targeted therapy for early-stage or metastatic cancers. The pathologic complete response (pCR), progression-free survival (PFS), and overall survival were compared between patients with wild-type PIK3CA (PIK3CAw) and those with mutated PIK3CA (PIK3CAm). Next-generation sequencing was combined with examination of PFS associated with anti-HER2 monoclonal antibody (mAb) treatment. RESULTS: Data from 90 patients with HER2+ breast cancer were analyzed. Overall, 34 (37.8%) patients had pathogenic PIK3CA mutations. The pCR rate of the PIK3CAm group was lower than that of the PIK3CAw group among patients who received neoadjuvant chemotherapy for early-stage cancer. In the metastatic setting, the PIK3CAm group showed a significantly shorter mean PFS (mPFS) with first-line anti-HER2 mAb. The mPFS of second-line T-DM1 was lower in the PIK3CAm group than that in the PIK3CAw group. Sequencing revealed differences in the mutational landscape between PIK3CAm and PIK3CAw tumors. CONCLUSION: Patients with HER2+ breast cancer with activating PIK3CA mutations had lower pCR rates and shorter PFS with palliative HER2-targeted therapy than those with wild-type PIK3CA. Precise targeted-therapy is needed to improve survival of patients with HER2+/PIK3CAm breast cancer.

Stage-to-stage comparison of neoadjuvant chemotherapy versus adjuvant chemotherapy in pathological lymph node positive breast cancer patients.

OBJECTIVE: The purpose of this study was to investigate the prognostic implications of post-neoadjuvant chemotherapy on the survival outcomes of breast cancer patients with persistent positive axillary lymph nodes by performing a stage-to-stage comparison between neoadjuvant chemotherapy and initial surgery. METHODS: Retrospective analysis was performed on 813 breast cancer patients with positive axillary lymph node after surgery, who were treated between 2001 and 2006. Of these, 269 patients received neoadjuvant chemotherapy, and 544 patients were treated with surgery followed by adjuvant chemotherapy. The median follow-up time was 5.9 years. RESULTS: The 5-year disease-free survival rates for patients in the neoadjuvant chemotherapy and adjuvant chemotherapy groups were 73 and 88%, respectively (P<0.001). The 5- and 9-year disease-free survival rates for ypStage II (82 and 76%) were significantly worse than those for pStage II (93 and 80%, P=0.002), and the rates for ypStage III (64 and 50%) were worse than those for pStage III (74 and 66%, P=0.04). The disease-free survival of ypStage II was similar to that of pStage III (P=0.16). Similar results were seen when comparing distant metastasis-free survival rates. Using multivariate analyses, grade, age, hormonal receptor status, final pathological stage and neoadjuvant chemotherapy itself were found to be independent negative prognostic factors for disease-free survival. CONCLUSIONS: Stage-to-stage comparison of pathologically node-positive patients revealed that the survival outcome at each ypStage after neoadjuvant chemotherapy was worse than that for the comparable pStage. These data may help to formulate more accurate prognoses for patients with residual positive nodes after neoadjuvant chemotherapy.

Effect of the biologically effective dose of electron beam radiation therapy on recurrence rate after keloid excision: A meta-analysis.

BACKGROUND AND PURPOSE: Adjuvant electron beam radiation therapy after keloid excision has been proven as highly effective in reducing local recurrence. We performed a meta-analysis of studies on hypofractionated electron beam radiation therapy after keloid excision based on accurate radiation dose information to provide a more precise estimate of the effect of the biologically effective dose (BED) on recurrence rate. MATERIALS AND METHODS: A literature search was performed in PubMed, Embase, and the Cochrane Library for the period from 1990 to December 2021. Studies that provided information on the recurrence rate for the exact prescription dose were selected for analysis. The recurrence rate with respect to the BED was evaluated using forest plots and the best-fit lines on scatter plots. RESULTS: From the 28 studies that were included for analysis, a total of 37 radiation dose datasets were extracted and 3128 excised keloids were identified. The recurrence rate for all sites and for the ear was 0.16 (95% confidence interval, 0.12-0.21; P < 0.01) and 0.11 (95% confidence interval, 0.06-0.20; P < 0.01), respectively. The estimated recurrence rate for all sites and the ear was calculated as "-1.992 + 1018.226/BED2" or "2.982 + 330.51/BED10" and "-16.8 + 1597.84/BED2" or "-14.65 + 656.58/BED10," respectively. CONCLUSIONS: Postoperative radiation therapy with higher BED resulted in lower recurrence rates. As expected, ear keloids had lower estimated recurrence rates than all keloids at all sites. We derived a model for estimating the recurrence rate using the dose fractionation scheme.

The role of adjuvant radiation therapy for locoregionally recurrent papillary thyroid carcinoma.

OBJECTIVES: To evaluate the role of adjuvant radiation therapy in patients with locoregionally recurrent (rpT4/N1b) papillary thyroid carcinoma (PTC). METHODS: The medical records of patients with rpT4/N1b PTC who were treated between January 2001 and December 2016 were reviewed. A total of 57 patients were analyzed, of which 24 patients were treated with adjuvant radiation therapy, and 33 patients did not receive adjuvant radiation therapy. Survival outcomes were compared between the 2 treatment groups. The primary endpoint was locoregional recurrence-free survival rate. RESULTS: The median follow-up period for all patients was 10.3 years (range, 2.8-19.2 years). The 15-year locoregional recurrence-free survival rate was 80.5% for those who received adjuvant radiation therapy and 28.1% for those who did not (p<0.001). The 15-year distant metastasis-free survival rate was 48.8% for those who received adjuvant radiation therapy and 33.4% for those who did not (p=0.906). The 15-year overall survival rate was 69.7% for those who received adjuvant radiation therapy and 53.1% for those who did not (p=0.921). CONCLUSIONS: Adjuvant radiation therapy ensured favorable locoregional recurrence-free survival in patients with rT4/N1b PTC and might contribute to improving patients' quality of life by reducing the need for additional salvage surgery and the economic burden of other salvage treatments, such as surgery or radioactive iodine therapy.

Quantitative analysis of extraocular muscle volume and exophthalmos reduction after radiation therapy to treat Graves' ophthalmopathy: A pilot study.

PURPOSE: The aim of this study was to provide radiological information on the inherent response of Graves' ophthalmopathy after radiation therapy. METHODS: Quantitative analysis of extraocular muscle volume was performed on 96 involved extraocular muscles in a total of 16 patients. A total of 48 computed tomography images were analyzed. Exophthalmos was also measured. The percentage reductions in extraocular muscle volume and exophthalmos length were determined and compared to the pre-radiation therapy values at 6-, 12-, and 24-month follow-up. RESULTS: The median follow-up time was 21.5 months (range: 7.2-29.4 months). The mean reduction in relative tumor volume compared to the pre-radiation therapy extraocular muscle volume was 46.1% (range: 33.3%-58.8%). The mean relative extraocular muscle volumes were 71.5% at 6 months, 59.2% at 12 months, and 54.3% at 24 months after radiation therapy. The volume of the involved extraocular muscles decreased rapidly within the first 12 months of follow-up. The mean pre-radiation therapy length of exophthalmos was 21.7 mm (range: 17.6-26.1 mm). The mean percentages of exophthalmos length by comparison with the pre-radiation therapy length were 96.7% at 6 months, 92.3% at 12 months, and 88.5% at 24 months after radiation therapy. Exophthalmos decreased slowly and steadily during the follow-up period. CONCLUSION: Quantitative volumetric analysis of the pattern of extraocular muscle volume reduction and exophthalmos length reduction in response to radiation therapy will allow clinicians to better understand the effect of radiotherapy on Graves' ophthalmopathy.

Sequential simulation computed tomography allows assessment of internal rectal movements during preoperative chemoradiotherapy in rectal cancer.

PURPOSES: The purpose of this study was to assess the internal rectal movement and to determine the factors related to extensive internal rectal movement using sequential simulation computed tomography (CT) images. MATERIALS AND METHODS: From 2010 to 2015, 96 patients receiving long-course preoperative chemoradiotherapy were included in our retrospective study. The initial simulation CT (Isim-CT) and follow-up simulation CT (Fsim-CT) for a boost were registered according to the isocenters and bony structure. The rectums on Isim-CT and Fsim-CT were compared on four different axial planes as follows: (1) lower pubis symphysis (AXVERYLOW), (2) upper pubis symphysis (AXLOW), (3) superior rectum (AXHIGH), and (4) middle of AXLOW and AXHIGH (AXMID). The involved rectum in the planning target volume was evaluated. The maximal radial distances (MRD), the necessary radius from the end of Isim-CT rectum to cover entire Fsim-CT rectum, and the common area rate (CAR) of the rectum (CAR, (Isim-CT∩Fsim-CT)/(Isim-CT)) were measured. Linear regression tests for the MRDs and logistic regression tests for the CARs were conducted. RESULTS: The mean ± standard deviation (mm) of MRDs and CAR <80% for AXVERYLOW, AXLOW, AXMID, and AXHIGH were 2.3 ± 2.5 and 8.9%, 3.0 ± 3.7 and 17.4%, 4.0 ± 5.2 and 27.1%, and 4.1 ± 5.2 and 25%, respectively. For MRDs and CARs, a higher axial level (AXVERYLOW/AXMID-HIGH, P = 0.018 and P = 0.034, respectively), larger bladder volume (P = 0.054 and P = 0.017, respectively), smaller bowel gas extent (small/marked, P = 0.014 and P = 0.001, respectively), and increased bowel gas change (decrease/increase, both P < 0.001) in rectum were associated with extensive internal rectal movement in multivariate analyses. CONCLUSIONS: As a result of following internal rectal movement through sequential simulation CT, the rectum above the pubis symphysis needs a larger margin, and bladder volume and bowel gas should be closely observed.

Is tumor bed boost necessary in patients who achieved ypCR following neoadjuvant chemotherapy and breast conserving therapy? (KROG 12-05 and 16-16).

PURPOSE: This multi-institutional study intended to investigate the effect of tumor bed boost in patients who achieved pathologic complete response (ypCR) following neoadjuvant chemotherapy (NAC) and breast-conserving therapy (BCT). MATERIALS AND METHODS: We identified 180 patients who initially had lymph node (LN) metastasis and achieved ypCR (ypT0/isN0) following NAC and BCT from the 13 institutions of the Korean Radiation Oncology Group (KROG) 16-16 and KROG 12-05. The effect of tumor bed boost on loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates was analyzed. RESULTS: In all patients, five-year LRC, DFS and OS rates were 97.5%, 95.4%, and 99.4%, respectively. Tumor bed boost was performed in 158 (87.8%) patients. Advanced N-stage (cN2-3, p = 0.036), close resection margin (p < 0.001), and sentinel lymph node biopsy (p = 0.040) were unfavorable factors for DFS. Tumor bed boost was not a significant factor for LRC, DFS, and OS. CONCLUSIONS: This study suggests the benefit of tumor bed boost might be minimal in ypCR patients following NAC and BCT. Larger prospective studies are needed to address this issue.

Treatment interruption during radiation therapy: Experience at a single institution in the Republic of Korea.

AIM: Our study analyzed the frequency and causes of treatment interruption among patients undergoing radiation therapy (RT). METHODS: A total of 1637 RT courses in 1500 patients were reviewed from September 2009 to October 2013. A continuous break over 7 days or a discontinuous break over 14 days was regarded as a temporary break and RT under 80% of planned treatment was regarded as incomplete. RESULTS: Two-hundred and twenty courses (13.4%) with treatment interruption were identified. Half of the patients received RT with a definitive aim, and the other half for palliative care. Completion after temporary break, near completion and incompletion were noticed in 12.3%, 21.3%, and 66.4% of cases, respectively. Among patients with a definite aim, thorax (19.2%) and abdomen (16.3%) had a higher interruption rate. For brain and bone with a palliative aim, the frequency of interruption was about 16%. Old age and worse performance negatively affected interruption. The most common cause of treatment interruption was cancer progression including death (30%) and the next was treatment-related side effects (23.1%). CONCLUSION: About 13% of RT cases were interrupted. Two third of patients received less than 80% of the planned RT. To improve RT completion rate, multidirectional efforts are needed.