Recent trends in radiotherapy use for major cancers in Korea.

BACKGROUND: Although the trend in radiotherapy in all cancer patients has been studied, changes in radiotherapy modalities for specific cancer types have not been reported. This study aimed to analyze radiotherapy patterns for major cancers in Korea in recent years. MATERIALS AND METHODS: We collected data from claims and reimbursement records of the Health and Insurance Review and Assessment Service from 2017 to 2020, according to initial diagnostic codes. The radiotherapy modalities for major cancers, such as lung, stomach, colorectal, breast and liver cancer, were analyzed. The radiotherapy modalities consisted of two-dimensional radiotherapy, three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, proton radiotherapy and stereotactic body radiotherapy. RESULTS: Overall, from 2017 to 2020, the use of two-dimensional radiotherapy and three-dimensional conformal radiotherapy decreased, and intensity-modulated radiotherapy increased. In 2017, three-dimensional conformal radiotherapy accounted for approximately half of the radiotherapy in patients for lung and colorectal cancer, which was replaced by intensity-modulated radiotherapy in 2020. In 2020, stereotactic body radiotherapy also accounted for a large proportion of radiotherapy used in liver cancer cases. Intensity-modulated radiotherapy was most used, followed by three-dimensional conformal radiotherapy and two-dimensional radiotherapy for breast cancer in 2020. Among major cancers, radiotherapy utilization for breast cancer is the highest. Compared with other cancers, the number of patients receiving radiotherapy for stomach cancer was low. CONCLUSION: The number of patients receiving radiotherapy for major cancers has increased. The use of advanced forms of radiotherapy, such as intensity-modulated radiotherapy, is rapidly increasing for major cancers. The rate of radiotherapy utilization was higher in major cancer patients than in all cancer patients.

Impact of diffusing lung capacity before and after neoadjuvant concurrent chemoradiation on postoperative pulmonary complications among patients with stage IIIA/N2 non-small-cell lung cancer.

BACKGROUND AND OBJECTIVE: This study aims to evaluate the impact of diffusing capacity of the lung for carbon monoxide (DLco) before and after neoadjuvant concurrent chemoradiotherapy (CCRT) on postoperative pulmonary complication (PPC) among stage IIIA/N2 non-small-cell lung cancer (NSCLC) patients. METHODS: We retrospectively studied 324 patients with stage IIIA/N2 NSCLC between 2009 and 2016. Patients were classified into 4 groups according to DLco before and after neoadjuvant CCRT; normal-to-normal (NN), normal-to-low (NL), low-to-low (LL), and low-to-very low (LVL). Low DLco and very low DLco were defined as DLco < 80% predicted and DLco < 60% predicted, respectively. RESULTS: On average, DLco was decreased by 12.3% (±10.5) after CCRT. In multivariable-adjusted analyses, the incidence rate ratio (IRR) for any PPC comparing patients with low DLco to those with normal DLco before CCRT was 2.14 (95% confidence interval (CI) = 1.36-3.36). Moreover, the IRR for any PPC was 3.78 (95% CI = 1.68-8.49) in LVL group compared to NN group. The significant change of DLco after neoadjuvant CCRT had an additional impact on PPC, particularly after bilobectomy or pneumonectomy with low baseline DLco. CONCLUSIONS: The DLco before CCRT was significantly associated with risk of PPC, and repeated test of DLco after CCRT would be helpful for risk assessment, particularly in patients with low DLco before neoadjuvant CCRT.

Early clinical outcomes of helical tomotherapy/intensity-modulated proton therapy combination in nasopharynx cancer.

This study aimed to evaluate the feasibility of combining helical tomotherapy (HT) and intensity-modulated proton therapy (IMPT) in treating patients with nasopharynx cancer (NPC). From January 2016 to March 2018, 98 patients received definitive radiation therapy (RT) with concurrent chemotherapy (CCRT). Using simultaneous integrated boost and adaptive re-plan, 3 different dose levels were prescribed: 68.4 Gy in 30 parts to gross tumor volume (GTV), 60 Gy in 30 parts to high-risk clinical target volume (CTV), and 36 Gy in 18 parts to low-risk CTV. In all patients, the initial 18 fractions were delivered by HT, and, after rival plan evaluation on the adaptive re-plan, the later 12 fractions were delivered either by HT in 63 patients (64.3%, HT only) or IMPT in 35 patients (35.7%, HT/IMPT combination), respectively. Propensity-score matching was conducted to control differences in patient characteristics. In all patients, grade ≥ 2 mucositis (69.8% vs 45.7%, P = .019) and grade ≥ 2 analgesic usage (54% vs 37.1%, P = .110) were found to be less frequent in HT/IMPT group. In matched patients, grade ≥ 2 mucositis were still less frequent numerically in HT/IMPT group (62.9% vs 45.7%, P = .150). In univariate analysis, stage IV disease and larger GTV volume were associated with increased grade ≥ 2 mucositis. There was no significant factor in multivariate analysis. With the median 14 month follow-up, locoregional and distant failures occurred in 9 (9.2%) and 12 (12.2%) patients without difference by RT modality. In conclusion, comparable early oncologic outcomes with more favorable acute toxicity profiles were achievable by HT/IMPT combination in treating NPC patients.

Diagnostic value of surveillance 18F-fluorodeoxyglucose PET/CT for detecting recurrent esophageal carcinoma after curative treatment.

PURPOSE: Esophageal carcinoma recurs within two years in approximately half of patients who receive curative treatment and is associated with poor survival. While 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is a reliable method of detecting recurrent esophageal carcinoma, in most previous studies FDG PET/CT scans were performed when recurrence was suspected. The aim of this study was to evaluate FDG PET/CT as a surveillance modality to detect recurrence of esophageal carcinoma after curative treatment where clinical indications of recurrent disease are absent. METHODS: A total of 782 consecutive FDG PET/CT studies from 375 patients with esophageal carcinoma after definitive treatment were reviewed. Abnormal lesions suggestive of recurrence on PET/CT scans were then evaluated. Recurrence was determined by pathologic confirmation or other clinical evidence within two months of the scan. If no clinical evidence for recurrence was found at least 6 months after the scan, the case was considered a true negative for recurrence. RESULTS: The diagnostic sensitivity and specificity of PET/CT for detecting recurrent esophageal carcinomas were 100% (64/64) and 94.0% (675/718), respectively. There were no significant differences in the diagnostic performance of PET/CT for detecting recurrence according to initial stage or time between PET/CT and curative treatments. Unexpected second primary cancers were detected by FDG PET/CT in seven patients. CONCLUSIONS: Surveillance FDG PET/CT is a useful imaging tool for detection of early recurrence or clinically unsuspected early second primary cancer in patients with curatively treated esophageal carcinoma but without clinical suspicion of recurrence.

Chemoradiotherapy versus surgery followed by postoperative radiotherapy in tonsil cancer: Korean Radiation Oncology Group (KROG) study.

BACKGROUND: Treatment of tonsil cancer, a subset of oropahryngeal cancer, varies between surgery and radiotherapy. Well-designed studies in tonsil cancer have been rare and it is still controversial which treatment is optimal. This study aimed to assess the outcome and failure patterns in tonsil cancer patients treated with either approaches. METHODS: We retrospectively reviewed medical records of 586 patients with tonsil cancer, treated between 1998 and 2010 at 16 hospitals in Korea. Two hundred and one patients received radiotherapy and chemotherapy (CRT), while 385 patients received surgery followed by radiotherapy and/or chemotherapy (SRT). Compared with the SRT group, patients receiving CRT were older, with more advanced T stage and received higher radiotherapy dose given by intensity modulation techniques. Overall survival (OS), disease-free survival (DFS), locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS), and clinicopathologic factors were analyzed. RESULTS: At follow-up, the 5-year OS, DFS, LRRFS and DMFS rates in the CRT group were 82, 78, 89, and 94%, respectively, and in the SRT group were 81, 73, 87, and 89%, respectively. Old age, current smoking, poor performance status, advanced T stage, nodal involvement, and induction chemotherapy were associated with poor OS. Induction chemotherapy had a negative prognostic impact on OS in both treatment groups (p = 0.001 and p = 0.033 in the CRT and SRT groups, respectively). CONCLUSIONS: In our multicenter, retrospective study of tonsil cancer patients, the combined use of radiotherapy and chemotherapy resulted in comparable oncologic outcome to surgery followed by postoperative radiotherapy, despite higher-risk patients having been treated with the definitive radiotherapy. Induction chemotherapy approaches combined with either surgery or definitive radiotherapy were associated with unfavorable outcomes.

Whole brain radiation dose reduction for primary central nervous system lymphoma patients who achieved partial response after high-dose methotrexate based chemotherapy.

Background: The whole brain radiotherapy (WBRT) dose for primary central nervous system lymphoma (PCNSL) patients who achieved complete response after induction chemotherapy was recently reduced to 23.4 Gy, but the optimal radiation dose for patients who achieved partial response (PR) is controversial. The aim of this study was to investigate the feasibility of reduced-dose WBRT for patients who achieved PR. Method: We retrospectively reviewed the medical records of PCNSL patients who were treated with high-dose methotrexate based chemotherapy. We compared treatment outcomes between the patients who received WBRT at either 36 Gy or 45 Gy. Results: The overall survival (OS) and intracranial progression-free survival (IC-PFS) was 66.3% and 42.6% at 5 years, respectively. There was no significant difference in treatment outcomes between the patients who received 36 Gy and 45 Gy, especially among patients who achieved PR. Three-year OS was 100% and 83.3% for 36 Gy and 45 Gy group, respectively (P = 0.313). Three-year IC-PFS was 60.0% and 66.7% for 36 Gy and 45 Gy group, respectively (P = 0.916). Conclusion: Findings of our study might provide a possibility for dose-reduction in patients achieving PR to induction chemotherapy, which may in turn reduce delayed neurologic sequelae. However, the number of patients included in this study was too small to lead to a concrete conclusion, thus further study is needed.

Comparison of Oncological and Functional Outcomes between Initial Surgical versus Non-Surgical Treatments for Hypopharyngeal Cancer.

BACKGROUND: Whether to administer surgical or non-surgical treatments (radiation or chemoradiation therapies) for the initial management of hypopharyngeal cancer (HPC) remains a topic of debate. Herein, we explored the differences between the two approaches in terms of oncological and functional outcomes in 332 HPC patients. METHODS: The primary endpoint was survival probability; secondary outcomes included post-treatment speech and swallowing functions and necessity of additional surgical procedures for salvage or complication management. Cox proportional hazard models using clinical variables were constructed to identify significant factors. RESULTS: The 2- and 5-year overall survival (OS) rates in all patients were 64.9 and 40.9 %, respectively. In early-stage HPC patients (N = 52), initial surgery ± radiation therapy (RT) or RT alone yielded similar oncological (60 % 5-year OS rate) and functional outcomes. As for resectable advanced-stage cancers (N = 177), initial surgery ± RT/chemoradiation therapy (SRC) and initial concurrent chemoradiation therapy (iCRT) resulted in similar 45-50 % 5-year OS rates. After sacrificing the larynx, 60 % of SRC patients recovered their speaking ability through voice prosthesis, which was less than the rate for iCRT patients (76.6 %; p = 0.008). Additional surgical interventions were required in 28.0-28.6 % of patients in both groups; however, 60 % of patients undergoing additional surgery in the iCRT group received multiple (two or more) surgical interventions (p = 0.029). CONCLUSIONS: Our data revealed similar oncological outcomes, but different functional outcomes, between initial surgical and non-surgical treatments for HPC. In resectable advanced-stage HPC, iCRT resulted in better verbal communication outcomes than SRC; however, more iCRT patients required multiple surgical interventions during clinical courses.

Low-Grade Salivary Gland Cancers: Treatment Outcomes, Extent of Surgery and Indications for Postoperative Adjuvant Radiation Therapy.

BACKGROUND: Histologic grade of tumor is one of the major prognostic predictors for patients with salivary gland cancer. Because of disease rarity, little is known about the optimal treatment modalities and outcomes in low-grade salivary gland cancers (LGSGC). We tried to identify prognostic factors, and the adequate treatment modalities and outcomes in pathologically confirmed LGSGC patients. METHODS: We retrospectively extracted the clinical and pathology data from 179 LGSGC cases from 1995 to 2013. Pathological features, such as extraparenchymal extension, perineural/nerve invasion, lymphovascular invasion/tumor emboli, and resection margin status were redefined for each case. Risk factors for recurrence, extent of surgery, and the role of postoperative radiation therapy were analyzed. RESULTS: Recurrence-free survival and overall survival were 89.6 and 96.6 % at 10 years, respectively. The presence of regional nodal metastasis and positive cancer cells at resection margin were significant unfavorable prognostic factors. Postoperative adjuvant radiation treatment significantly reduced recurrences, particularly in cases with pathology risk factors (perineural invasion, lymphovascular invasion, extraparenchymal extension, or cancer cells at the resection margin), node metastasis, and advanced T-stage tumors. Close surgical margin <5 mm was not a significant risk factor for recurrence, and less-than-total resection of the affected gland did not increase recurrence, if surgery could achieve a cancer cell-free surgical margin. CONCLUSION: Postoperative radiation clearly benefitted patients with pathology risk factors, node metastasis, and advanced T stage in LGSGC. Meanwhile, the oncological outcomes are very good with surgery alone in cases of pT1-2N0 LGSGC without pathology risk factors.

IMRT vs. 2D-radiotherapy or 3D-conformal radiotherapy of nasopharyngeal carcinoma : Survival outcome in a Korean multi-institutional retrospective study (KROG 11-06).

OBJECTIVE: We compared treatment outcomes of two-dimensional radiotherapy (2D-RT), three-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS: In total, 1237 patients with cT1-4N0-3M0 NPC were retrospectively analyzed. Of these, 350, 390, and 497 were treated with 2D-RT, 3D-CRT, and IMRT, respectively. RESULTS: 3D-CRT and IMRT showed better 5-year overall survival (OS) rates (73.6 and 76.7 %, respectively) than did 2D-RT (5-year OS of 59.7 %, all p < 0.001). In T3-4 subgroup, IMRT was associated with a significantly better 5-year OS than was 2D-RT (70.7 vs. 50.4 %, respectively; p ≤ 0.001) and 3D-CRT (70.7 vs. 57.8 %, respectively; p = 0.011); however, the difference between the 2D-RT and 3D-CRT groups did not reach statistical significance (p = 0.063). In multivariate analyses of all patients, IMRT was a predictive factor for OS when compared with 2D-RT or 3D-CRT, as was 3D-CRT when compared with 2D-RT. CONCLUSION: Our study showed that 3D-CRT and IMRT were associated with a better local progression-free survival and OS than was 2D-RT in NPC. IMRT was significantly superior in terms of OS for advanced primary tumors (T3-4).

Extra-nodal natural killer/T cell lymphoma in elderly patients: the impact of aging on clinical outcomes and treatment tolerability.

Extra-nodal natural killer/T cell lymphoma (ENKTL) is rare in elderly patients, and its clinical course is unclear. The efficacy and tolerability of non-anthracycline-based treatments as a standard regimen in elderly patients have not been fully investigated. This study assessed the impact of aging on clinical outcomes and treatment tolerability. We retrospectively analyzed 51 patients aged ≥60 years who were diagnosed with ENKTL from January 1998 to December 2012. We defined new treatments as non-anthracycline regimens (etoposide, ifosfamide, mesna, cisplatin, and dexamethasone (VIPD); etoposide, ifosfamide, mesna, dexamethasone, and L-asparaginase (VIDL); methotrexate, leucovorin, etoposide, ifosfamide, mesna, dexamethasone, and L-asparaginase (MIDLE); ifosfamide, methotrexate, etoposide, and prednisolone (IMVP16/PD); or methotrexate, leucovorin, etoposide, ifosfamide, mesna, dexamethasone, and L-asparaginase (SMILE), with or without radiation therapy). The median age was 66 years (60-83 years). Twenty patients were diagnosed at advanced stage, and 18 had poor performance status. The overall survival and progression-free survival were 6.7 and 5.2 months, respectively. Clinical outcomes of patients with early disease were superior to those of patients with advanced disease. Among patients who received new treatments, concurrent chemoradiation therapy (CCRT) for localized disease was tolerable, although 37.5 % of patients with advanced disease who received SMILE discontinued chemotherapy due to intolerability. Elderly patients with ENKTL have poor prognostic factors compared to younger patients. In particular, patients with advanced disease have extremely poor prognosis due to inability to tolerate treatment and rapid progression of disease.

Volume-Based Assessment With 18F-FDG PET/CT Improves Outcome Prediction for Patients With Stage IIIA-N2 Non-Small Cell Lung Cancer.

OBJECTIVE: We evaluated the prognostic impact of volume-based assessment by pretreatment (18)F-FDG PET/CT in patients who had clinical stage IIIA-N2 non-small cell lung cancer (NSCLC) treated with neoadjuvant concurrent chemoradiotherapy (CCRT) followed by surgical resection. MATERIALS AND METHODS: We reviewed 161 consecutive patients who had stage IIIA-N2 NSCLC treated with neoadjuvant CCRT followed by surgery. In all cases, N2 disease was pathologically confirmed by mediastinoscopic biopsy, endobronchial ultrasound-guided transbronchial needle aspiration, or video-assisted thoracoscopic surgery. We measured the total metabolic tumor volume (total MTV) and the maximum standardized uptake value (SUVmax), including a primary tumor and metastatic nodes on the pretreatment scan. Overall survival (OS) and disease-free survival (DFS) were assessed using the Kaplan-Meier method. The association of PET parameters with OS and DFS was determined by univariable and multivariable analyses performed using the Cox regression model. RESULTS: A higher total MTV was significantly associated with poor DFS (hazard ratio [HR], 1.82; p = 0.036) and OS (HR = 2.97; p = 0.012) in the multivariable analysis. In contrast, a higher SUVmax was not significantly associated with poor DFS and OS. Patients with a high total MTV (> 22 cm(3)) had a median survival time that was significantly shorter than that of patients with a low total MTV (median DFS, 11.3 vs 42.0 months, respectively [p < 0.001]; median OS, 38.3 months vs not reached [p < 0.001]). Kaplan-Meier curves showed significant differences on the basis of total MTV in patients with or without mediastinal downstaging after CCRT. Patients with a high total MTV had significantly worse DFS when they had post-neoadjuvant pathologic (yp) stage 0-II disease (p = 0.020) or yp stage III disease (p = 0.036). Higher total MTV was also associated with worse OS in patients with yp stage 0-II disease (p = 0.013) or yp stage III disease (p = 0.007). CONCLUSION: A higher pretreatment total MTV is associated with worse outcome, independent of yp stage, in patients with stage IIIA-N2 NSCLC treated with neoadjuvant CCRT followed by surgery.

Pretreatment clinical mediastinal nodal bulk and extent do not influence survival in N2-positive stage IIIA non-small cell lung cancer patients treated with trimodality therapy.

BACKGROUND: Treatment for patients with N2-positive stage IIIA non-small cell lung cancer has been a controversial issue. The current study evaluated the outcomes in patients treated with trimodality therapy, which consisted of neoadjuvant radiation therapy concurrent with chemotherapy followed by surgical resection, with emphasis on clinical and pathologic nodal status. METHODS: We reviewed the records of 355 patients who were treated with trimodality therapy between 1997 and 2011. RESULTS: After completion of neoadjuvant chemoradiation, overall down-staging and complete response rates were 50.4 % (179 patients), and 13.2 % (47 patients), respectively. With median follow-up of 35.3 months, median times of progression-free survival (PFS) and overall survival (OS) were 16.3 months and 45.5 months, respectively. Seventeen patients (4.8 %) died of postoperative complications, and the remaining 338 patients were analyzed on prognostic factors. Old age (p = 0.032), pneumonectomy (p < 0.001), and ypN+ (p < 0.001) were found to be the significant prognosticators for worse PFS, and old age (p = 0.013), pneumonectomy (p < 0.001), and ypN+ (p < 0.001) were related to worse OS. Clinical N2 status did not influence either OS or PFS: the number of involved stations (single station vs. multi-station; p = 0.187 for PFS; p = 0.492 for OS), and bulk (clinically evident vs. microscopic; p = 0.902 for PFS; p = 0.915 for OS). CONCLUSION: ypN stage was the most important prognosticator for both PFS and OS; however, neither initial bulk nor extent of cN2 disease influenced prognosis. Surgery following neoadjuvant chemoradiation should have contributed to improved clinical outcomes regardless of clinical nodal bulk and extent.

Volume-based assessment by (18)F-FDG PET/CT predicts survival in patients with stage III non-small-cell lung cancer.

PURPOSE: We evaluated the prognostic impact of volume-based assessment by (18)F-FDG PET/CT in patients with stage III non-small-cell lung cancer (NSCLC). METHODS: We reviewed 194 consecutive patients with stage IIIA NSCLC treated with surgical resection (surgical group) and 115 patients treated with nonsurgical therapy (nonsurgical group: 50 stage IIIA, 65 stage IIIB). Metabolic tumour volume (MTV), total lesion glycolysis (TLG), and maximum standardized uptake value (SUVmax) of primary tumours were measured using pretreatment (18)F-FDG PET/CT. Overall survival was assessed using the Kaplan-Meier method. The prognostic significance of PET parameters and other clinical variables was assessed using Cox proportional hazards regression analyses. To evaluate and compare the predictive performance of PET parameters, time-dependent receiver operating characteristic (ROC) curve analysis was used. RESULTS: In the Cox proportional hazards models, MTV (HR=1.27 for a doubling of MTV, P=0.008) and TLG (HR=1.22 for a doubling of TLG, P=0.035) were significantly associated with an increased risk of death after adjusting for age, gender, histological cell type, T stage, N stage, and treatment variables in the surgical group. SUVmax was not a significant prognostic factor in either the surgical or nonsurgical group. In the time-dependent ROC curve analysis, volume-based PET parameters predicted survival better than SUVmax. CONCLUSION: The volume-based PET parameters (MTV and TLG) are significant prognostic factors for survival independent of tumour stage and better prognostic imaging biomarkers than SUVmax in patients with stage IIIA NSCLC after surgical resection.

Concurrent chemoradiotherapy followed by L-asparaginase-containing chemotherapy, VIDL, for localized nasal extranodal NK/T cell lymphoma: CISL08-01 phase II study.

We conducted a phase II trial of concurrent chemoradiotherapy (CCRT) followed by 2 cycles of L-asparaginase-containing chemotherapy for patients who were newly diagnosed with stages IE and IIE nasal extranodal NK/T cell lymphoma (ENKTL). CCRT consisted of 40-44 Gy of radiotherapy with weekly administration of 30 mg/m(2) of cisplatin for 4 weeks. Two cycles of VIDL (etoposide (100 mg/m(2)), ifosfamide (1,200 mg/m(2)), and dexamethasone (40 mg) from days 1 to 3, and L-asparaginase (4,000 IU/m(2)) every other day from days 8 to 20) were administered sequentially. CCRT yielded a 90 % overall response rate without significant side effects in 30 patients, including 20 patients with complete response (CR); however, two patients showed distant disease progression. After CCRT, VIDL chemotherapy showed an 87 % final CR rate (26/30). Although grade III or IV hematologic toxicity was frequent during VIDL chemotherapy, no treatment-related mortality was observed, and L-asparaginase-associated toxicity was manageable. With a median follow-up of 44 months, 11 patients showed local (n = 4) and distant (n = 7) relapse or progression. The estimated 5-year progression-free and overall survival rates were 73 and 60 %, respectively. In conclusion, CCRT followed by L-asparaginase-containing chemotherapy is a feasible treatment for newly diagnosed stages IE/IIE nasal ENKTL.

Outcomes following hypofractionated radiation therapy alone for surgically unfit early esophageal squamous cell carcinoma patients; a retrospective single center analysis.

BACKGROUND AND PURPOSE: To report the feasibility of hypofractionated radiation therapy (RT) alone for early stage esophageal squamous cell carcinoma (ESCC) patients. MATERIALS AND METHODS: The oncologic outcomes of 60 cT1-2 N0 ESCC patients who received hypofractionated RT (54 âˆ¼ 60 Gy by 3.0 Gy per fraction) from 2004 to 2018 were retrospectively evaluated. RESULTS: The 5-year rates of local control (LC), progression-free survival, cancer-specific survival, and overall survival were 81.1 %, 44.2 %, 73.7 %, and 54.5 %, respectively. In Cox regression analysis, tumor length < 3 cm was correlated with favorable LC (HR 0.167, p = 0.090), and the 5-year LC rates were 95.7 % and 72.0 % in < 3 cm and ≥ 3 cm subgroups, respectively (p = 0.053). Grade ≥ 2 esophagitis was observed in 44 patients (73.3 %) and grade ≥ 2 esophageal strictures developed in five (8.3 %), respectively. The patients with ≥ 3 cm tumor more frequently suffered from grade ≥ 2 esophagitis (13/24 vs. 31/36, p = 0.006) and grade ≥ 2 esophageal stricture (0/24 vs. 5/36, p = 0.056), respectively. The patients with cT2 tumor suffered from grade ≥ 2 esophagitis more frequently than those with T1 tumor (29/44 vs. 15/16, p = 0.03). CONCLUSIONS: Hypofractionated RT alone, with the merit of short treatment course, could be used as feasible option in treating the early stage ESCC patients who are unfit for surgical resection or chemoradiation. Especially, tumor length < 3 cm seems a good indication of this treatment scheme based on favorable LC rate with low incidence of esophageal toxicities.

Comparison of radiotherapy techniques in patients with thymic epithelial tumor who underwent postoperative radiotherapy.

PURPOSE: This retrospective study aimed to compare clinical outcomes and dosimetric parameters between radiation therapy (RT) techniques in patients with thymic epithelial tumor (TET). MATERIALS AND METHODS: From January 2016 to December 2020, 101 patients with TET received adjuvant RT (median, 52.8 Gy; range, 48.4 to 66.0). Three different RT techniques were compared: three-dimensional conformal RT (3D-CRT; n = 59, 58.4%), intensity-modulated RT (IMRT; n = 23, 22.8%), and proton beam therapy (PBT; n = 19, 18.8%). RESULTS: The median age of the patients and the follow-up period were 55 years (range, 28 to 79) and 43.4 months (range, 7.7 to 77.2). Patients in the PBT group were of the youngest age (mean age, 45.4 years), while those in IMRT group had the largest clinical target volume (mean volume, 149.6 mL). Patients in the PBT group had a lower mean lung dose (4.4 Gy vs. 7.6 Gy vs. 10.9 Gy, respectively; p < 0.001), lower mean heart dose (5.4 Gy vs. 10.0 Gy vs. 13.1 Gy, respectively; p = 0.003), and lower mean esophageal dose than patients in the 3D-CRT and IMRT groups (6.3 Gy vs. 9.8 Gy vs. 13.5 Gy, respectively; p = 0.011). Twenty patients (19.8%) showed disease recurrence, and seven patients (6.9%) died. The differences in the survival rates between RT groups were not statistically significant. CONCLUSION: In patients with TET who underwent adjuvant RT, PBT resulted in a lower dose of exposure to adjacent organs at risk. Survival outcomes for patients in PBT group were not significantly different from those in other groups.

Radiation Oncologists' Perspectives on Oligometastatic Prostate Cancer: A Survey from Korean Oligometastasis Working Group.

BACKGROUND: Interest in the oligometastatic prostate cancer (OMPC) is increasing, and various clinical studies have reported the benefits of metastasis-directed radiation therapy (MDRT) in OMPC. However, the recognition regarding the adopted definitions, methodologies of assessment, and therapeutic approaches is diverse among radiation oncologists. This study aims to evaluate the level of agreement for issues in OMPC among radiation oncologists. METHODS: We generated 15 key questions (KQs) for OMPC relevant to definition, diagnosis, local therapies, and endpoints. Additionally, three clinical scenarios representing synchronous metastatic prostate cancer (mPC) (case 1), metachronous mPC with visceral metastasis (case 2), and metachronous mPC with castration-resistance and history of polymetastasis (case 3) were developed. The 15 KQs were adapted according to each scenario and transformed into 23 questions with 6-9 per scenario. The survey was distributed to 80 radiation oncologists throughout the Republic of Korea. Answer options with 0.0-29.9%, 30-49.9%, 50-69.9%, 70-79.9%, 80-89.9%, and 90-100% agreements were considered as no, minimal, weak, moderate, strong, and near perfect agreement, respectively. RESULTS: Forty-five candidates voluntarily participated in this study. Among 23 questions, near perfect (n = 4), strong (n = 3), or moderate (n = 2) agreements were shown in nine. For the case recognized as OMPC with agreements of 93% (case 1), near perfect agreements on the application of definitive radiation therapy (RT) for whole metastatic lesions were achieved. While ≥70% agreements regarding optimal dose-fractionation for metastasis-directed RT (MDRT) has not been achieved, stereotactic body RT (SBRT) is favored by clinicians with higher clinical volume. CONCLUSION: For the case recognized as OMPC, near perfect agreement for the application of definitive RT for whole metastatic lesions was reached. SBRT was more favored as a MDRT by clinicians with a higher clinical volume.

Clinical Outcomes in Adenoid Cystic Carcinoma of the Nasal Cavity and Paranasal Sinus: A Comparative Analysis of Treatment Modalities.

This study aimed to present the treatment patterns and outcomes for adenoid cystic carcinoma (ACC) arising in the nasal cavity and paranasal sinus. Sixty-one sinonasal ACC patients were retrospectively reviewed: 31 (50.8%) underwent surgery followed by postoperative radiation therapy (S+PORT), and 30 (49.2%) received definitive radiation therapy (D(C)RT). T4 disease was significantly more frequent in the D(C)RT group (25.8% vs. 80.0%, p < 0.001), where all T4b disease patients underwent D(C)RT. The 5-year local failure-free survival (LFFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival were 61.8% versus 37.8% (p = 0.003), 64.8% versus 38.1% (p = 0.036), 52.6% versus 19.3% (p = 0.010), and 93.2% versus 73.4% (p = 0.001) in the S+PORT and D(C)RT groups, respectively. The absolute differences in 5-year rates of LFFS, DMFS, and PFS between the two groups were smaller in the T3-4 subgroup. The univariate analysis showed that T4b disease, neurologic symptoms, longest diameter of tumor, radiological evidence of nerve involvement, and undergoing D(C)RT were associated with worse clinical outcomes, but the significance disappeared in the multivariate analysis, except for in the case of radiological evidence of nerve involvement. In conclusion, most patients with extensive disease underwent upfront D(C)RT and generally exhibited inferior clinical outcomes when compared to those with less extensive disease and who underwent S+PORT.

Radiation Oncologists' Perspectives on Oligometastatic Disease: A Korean Survey Study.

PURPOSE: Perspectives of radiation oncologists on oligometastatic disease was investigated using multi-layered survey. MATERIALS AND METHODS: Online survey on the oligometastatic disease was distributed to the board-certified regular members of the Korean Society for Radiation Oncology. The questionnaire consisted of four domains: five questions on demographics; five on the definition of oligometastatic disease; four on the role of local therapy; and three on the oligometastatic disease classification, respectively. RESULTS: A total of 135 radiation oncologists participated in the survey. The median length of practice after board certification was 22.5 years (range, 1 to 44 years), and the vast majority (94.1%) answered affirmatively to the clinical experience in oligometastatic disease management. Nearly two-thirds of the respondents considered the number of involved organs as an independent factor in defining oligometastasis. Most frequently perceived upper limit on the numerical definition of oligometastasis was 5 (64.2%), followed by 3 (26.0%), respectively. Peritoneal and brain metastasis were nominated as the sites to be excluded from oligometastastic disease by 56.3% and 12.6% of the participants, respectively. Vast majority (82.1%) agreed on the role of local treatment in the management of oligometastatic disease. Majority (72%) of the participants acknowledged the European Society for Radiotherapy and Oncology (ESTRO)-European Organisation for Research and Treatment of Cancer (EORTC) classification of oligometastatic disease, however, only 43.3% answered that they applied this classification in their clinical practice. Underlying reasons against the clinical use were 'too complicated' (66.0%), followed by 'insufficient supporting evidence' (30.0%), respectively. CONCLUSION: While most radiation oncologists supported the role of local therapy in oligometastatic disease, there were several inconsistencies in defining and categorizing oligometastatic disease. Continued education and training on oligometastatic disease would be also required to build consensus among participating caregivers.

Prognostic Value of Radiomic Analysis Using Pre- and Post-Treatment 18F-FDG-PET/CT in Patients with Laryngeal Cancer and Hypopharyngeal Cancer.

BACKGROUND: The prognostic value of conducting 18F-FDG PET/CT imaging has yielded different results in patients with laryngeal cancer and hypopharyngeal cancer, but these results are controversial, and there is a lack of dedicated studies on each type of cancer. This study aimed to evaluate whether combining radiomic analysis of pre- and post-treatment 18F-FDG PET/CT imaging features and clinical parameters has additional prognostic value in patients with laryngeal cancer and hypopharyngeal cancer. METHODS: From 2008 to 2016, data on patients diagnosed with cancer of the larynx and hypopharynx were retrospectively collected. The patients underwent pre- and post-treatment 18F-FDG PET/CT imaging. The values of ΔPre-Post PET were measured from the texture features. Least absolute shrinkage and selection operator (LASSO) Cox regression was used to select the most predictive features to formulate a Rad-score for both progression-free survival (PFS) and overall survival (OS). Kaplan-Meier curve analysis and Cox regression were employed to assess PFS and OS. Then, the concordance index (C-index) and calibration plot were used to evaluate the performance of the radiomics nomogram. RESULTS: Study data were collected for a total of 91 patients. The mean follow-up period was 71.5 mo. (8.4-147.3). The Rad-score was formulated based on the texture parameters and was significantly associated with both PFS (p = 0.024) and OS (p = 0.009). When predicting PFS, only the Rad-score demonstrated a significant association (HR 2.1509, 95% CI [1.100-4.207], p = 0.025). On the other hand, age (HR 1.116, 95% CI [1.041-1.197], p = 0.002) and Rad-score (HR 33.885, 95% CI [2.891-397.175], p = 0.005) exhibited associations with OS. The Rad-score value showed good discrimination when it was combined with clinical parameters in both PFS (C-index 0.802-0.889) and OS (C-index 0.860-0.958). The calibration plots also showed a good agreement between the observed and predicted survival probabilities. CONCLUSIONS: Combining clinical parameters with radiomics analysis of pre- and post-treatment 18F-FDG PET/CT parameters in patients with laryngeal cancer and hypopharyngeal cancer might have additional prognostic value.