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.

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.

A meta-analysis comparing efficacy and safety between proton beam therapy versus carbon ion radiotherapy.

BACKGROUND: This study aimed to compare the outcomes of proton beam therapy (PBT) and carbon ion radiotherapy (CIRT) by a systematic review and meta-analysis of the existing clinical evidence. METHODS: A systematic literature search was performed to identify studies comparing the clinical outcomes of PBT and CIRT. The included studies were required to report oncological outcomes (local control [LC], progression-free survival [PFS], or overall survival [OS]) or adverse events. RESULTS: Eighteen articles comprising 1857 patients (947 treated with PBT and 910 treated with CIRT) were included in the analysis. The pooled analysis conducted for the overall population yielded average hazard ratios of 0.690 (95% confidence interval (CI), 0.493-0.967, p = 0.031) for LC, 0.952 (95% CI, 0.604-1.500, p = 0.590) for PFS, and 1.183 (0.872-1.607, p = 0.281) for OS with reference to CIRT. The subgroup analyses included patients treated in the head and neck, areas other than the head and neck, and patients with chordomas and chondrosarcomas. These analyses revealed no significant differences in most outcomes, except for LC in the subgroup of patients treated in areas other than the head and neck. Adverse event rates were comparable in both groups, with an odds ratio (OR) of 1.097 (95% CI, 0.744-1.616, p = 0.641). Meta-regression analysis for possible heterogeneity did not demonstrate a significant association between treatment outcomes and the ratio of biologically effective doses between modalities. CONCLUSION: This study highlighted the comparability of PBT and CIRT in terms of oncological outcomes and adverse events.

Impact and optimal timing of local therapy addition in borderline resectable or locally advanced pancreatic cancer after FOLFIRINOX chemotherapy.

Background: To evaluate the efficacy and optimal timing of local treatment in patients with borderline resectable (BR) or locally advanced pancreatic cancer (LAPC) treated with upfront FOLFIRINOX. Method: Between 2015 and 2020, 258 patients with pancreatic ductal adenocarcinoma (PDAC) were analysed. Treatment outcomes were compared between systemic treatment group (ST) and multimodality treatment groups (MT) using Kaplan-Meier curves and log-rank test. The MT were stratified as follows: FOLFIRINOX + radiation therapy (RT) (MT1), FOLFIRINOX + surgical resection (MT2), and FOLFIRINOX + RT + surgical resection (MT3). Results: With median follow-up period of 18 months, the 2-year overall survival (OS) for the ST was 22.0%, and it was significantly worse than MT (MT1, 46.3%; MT2, 65.7% and MT3; 90.2%; P < .001). The 2-year locoregional progression free survival (LRPFS) and overall PFS in ST were 10.7% and 7.0%, which were also significantly lower than those of MT (2-year LRPFS: MT1, 31.8%; MT2, 45.3%; MT3, 81.0%; 2-year overall PFS: MT1, 23.3%; MT2, 35.0%; MT3, 66.3%; P < .001). In time-varying multivariate Cox proportional hazard model, local treatment contributed to better treatment outcomes, with adjusted hazard ratios of 0.568 (95% confidence interval [CI], 0.398-0.811), 0.490 (95% CI, 0.331-0.726), and 0.656 (95% CI, 0.458-0.940) for OS, LRPFS, and overall PFS, respectively. The time window of 11-17 months after FOLFIRINOX appeared to demonstrate the maximal efficacy of local treatments in OS. Conclusions: Adding local treatment in BR/LAPC patients treated with upfront FOLFIRINOX seemed to contribute in improved treatment outcomes, and it showed maximal efficacy in OS when applied 11-17 months after the initiation of FOLFIRINOX. We suggest that administration of sufficient period of upfront FOLFIRINOX may intensify the efficacy of local treatments, and well controlled prospective trials are expected.

Can Definitive Radiation Therapy Substitute Surgical Resection in Locally Advanced T3 or T4 Sinonasal Squamous Cell Carcinoma?

PURPOSE: This study aimed to compare oncologic outcomes between definitive radiation therapy (RT) and upfront surgical resection in patients with sinonasal squamous cell carcinoma (SCC). METHODS AND MATERIALS: Between 2008 and 2021, 155 patients with T1-4b, N0-3 sinonasal SCC were analyzed. The 3-year overall survival (OS), local progression-free survival (LPFS), and overall progression-free survival (PFS) were evaluated using the Kaplan Meier method and compared using a log-rank test. A pattern of regional neck lymph node (LN) failure and treatment-related toxicity profiles were investigated. RESULTS: A total of 63 and 92 patients underwent upfront RT (RT group) and surgical resection (Surgery group), respectively. The RT group included significantly more patients with T3-4 disease than the Surgery group (90.5% vs 39.1%, P < .001). The rates of 3-year OS, LPFS, and PFS in the RT and Surgery groups were 68.6% versus 81.7% (P = .073), 62.3% versus 73.8% (P = .187), and 47.4% versus 66.1% (P = .005), respectively. However, the corresponding rates in patients with T3-4 disease were 65.1% versus 64.8% (P = .794), 57.4% versus 56.8% (P = .351), and 43.2% versus 46.5% (P = .638), respectively, demonstrating no statistically significant differences between the 2 treatment modalities. Among the 133 N0 patients, regional neck LN progression was observed in 17 patients, and the most common sites of regional neck LN failure were ipsilateral levels Ib (9 patients) and II (7 patients). The 3-year neck node recurrence-free rate in cT1-3N0 patients was 93.5%, while that in cT4N0 patients was 81.1% (P = .025). CONCLUSIONS: Upfront RT may be considered in selected patients with locally advanced sinonasal SCC, as we have demonstrated similar oncologic outcomes to those of surgery. Prophylactic neck treatment in T4 disease requires further investigation to evaluate its efficacy.

Machine learning­based radiomics models for prediction of locoregional recurrence in patients with breast cancer.

Locoregional recurrence (LRR) is the predominant pattern of relapse after definitive breast cancer treatment. The present study aimed to develop machine learning (ML)-based radiomics models to predict LRR in patients with breast cancer by using preoperative magnetic resonance imaging (MRI) data. Data from patients with localized breast cancer that underwent preoperative MRI between January 2013 and December 2017 were collected. Propensity score matching (PSM) was performed to adjust for clinical factors between patients with and without LRR. Radiomics features were obtained from T2-weighted with and without fat-suppressed MRI and contrast-enhanced T1-weighted with fat-suppressed MRI. In the present study five ML models were designed, three base models (support vector machine, random forest, and logistic regression) and two ensemble models (voting model and stacking model) composed of the three base models, and the performance of each base model was compared with the stacking model. After PSM, 28 patients with LRR and 86 patients without LRR were included. Of these 114 patients, 80 patients were randomly selected to train the models, and the remaining 34 patients were used to evaluate the performance of the trained models. In total, 5,064 features were obtained from each patient, and 47-51 features were selected by applying variance threshold and least absolute shrinkage and selection operator. The stacking model demonstrated superior performance in area under the receiver operating characteristic curve (AUC), with an AUC of 0.78 compared to a range of 0.61 to 0.70 for the other models. An external validation study to investigate the efficacy of the stacking model of the present study was initiated and is still ongoing (Korean Radiation Oncology Group 2206).

The Role of Post-Mastectomy Radiotherapy in T1-2N1 Breast Cancer Patients: Propensity Score Matched Analysis.

This study aimed to evaluate the role of post-mastectomy radiotherapy (PMRT) in T1-2N1 breast cancer. Between 2006 and 2014, a total of 504 patients with T1-2N1 breast cancer were analyzed. PMRT was administered to 71 patients, and 1:2 propensity score matching (PSM) was performed between the PMRT and non-PMRT groups. Loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates were compared according to PMRT status. Thirteen and one loco-regional recurrences were observed in the PMRT and non-PMRT groups, respectively. Before PSM, the 8-year LRC, DFS, and OS rates in the non-PMRT and PMRT groups were 98.5% and 96.5% (p = 0.426), 89.7% and 91.2% (p = 0.700), and 91.5% and 92.1% (p = 0.679), respectively. Corresponding rates were 95.6% and 96.5% (p = 0.365), 84.1% and 91.2% (p = 0.185), and 88.4% and 92.1% (p = 0.276), respectively, after PSM. Multivariate analysis showed that three lymph node metastases were prognostic for LRC and DFS rates and LVI for OS rate. Arm lymphedema developed in 32.4% of patients who received PMRT, which was significantly higher than the non-PMRT group (p < 0.001). Contributions of PMRT for improvement of treatments outcomes in T1-2N1 breast cancer patients were not evident, while the incidence of arm lymphedema significantly increased after PMRT. Further prospective trials are required to re-evaluate the role of PMRT.

Skull Base Metastasis from Hepatocellular Carcinoma: Clinical Presentation and Efficacy of Radiotherapy.

Purpose: Skull base metastasis (SBM) from hepatocellular carcinoma (HCC) presents detrimental survival outcomes with cranial nerve symptoms; however, they have received little attention. This study aimed to investigate the clinical presentation and efficacy of radiation therapy (RT) in patients with SBM from HCC. Patients and Methods: We identified patients with SBM from HCC in Yonsei Cancer Center from 2005 to 2019. Image evaluations and SBM-related symptoms were reviewed. Overall survival was calculated using the Kaplan-Meier method and compared through the Log rank test. The oligometastasis group included patients with less than five foci of tumors, while the extensive metastasis group presented five or more sites. Results: The incidence of SBM from HCC was 1.5% (58/3793 patients), commonly found in the middle cranial fossa. SBM associated symptoms presented in 51 patients, and the most common were head and neck area pain, and orbital symptoms, The palliation rate after RT was 65% (24/39 patients) for overall symptoms and 83.3% (20/24 patients) for cranial nerve symptoms. In whole cohort, overall survival was analyzed, and the median overall survival of patients with oligometastasis was better than extensive metastasis (23.7 months vs 1.8 months, p < 0.001). In subgroup who received RT (39 patients), the median overall survival was 23.7 and 2.7 months for patients with oligo and extensive metastasis, respectively (p < 0.001). Conclusion: This study confirmed clinical features of SBM from HCC. Overall survival was generally poor, but patients presenting oligometastasis seemed to have possibility of relative long-term survival. Although radiation was effective in SBM-induced symptom relief, dose-response relationship in local control rate and overall survival needs further studies with larger number of patients.

Radiation Therapy for Recurrent or Residual Pituitary Macroadenoma Invading Extrasellar Structures.

PURPOSE: This study aimed to evaluate the efficacy of radiation therapy (RT) for recurrent or residual pituitary macroadenoma (PMA) invading extrasellar regions. MATERIALS AND METHODS: Patients from 2000 to 2020 who received RT with conventional fractionation for recurrent or residual PMA were included. The patients were divided according to the type of tumor [functioning (fx) or non-fx] and the aim of RT (salvage RT alone, immediate postoperative RT, delayed postoperative RT). Local and biochemical failure-free rates (FFR) were calculated using the Kaplan-Meier method. RESULTS: With a median follow up of 82 months (IQR; 42-132 months), 36 patients treated with conventional RT (total 45-54 Gy in 1.8 or 2 Gy per fraction) for recurrent or residual PMA were analyzed. The 10-year local FFRs after RT for non-fx and fx tumor were 100% and 74.4%, respectively (p=0.047). In the immediate postoperative RT group, the 10-year local FFR was 100%, which was higher than the 90% FFR for salvage RT alone or 80% FFR for the delayed postoperative RT group (overall p=0.043, immediate vs. salvage; p=0.312, immediate vs. delayed; p=0.072). The local FFR was compared according to size of tumor with a cut-off value of 4 cm, and there was no significant difference (10-year local FFR 100% vs. 84.7% for >4 cm vs. <4 cm, p=0.320). The extents of extrasellar region invasion were not predictive of local failure after RT. We found no grade ≥3 acute toxicities or newly developed visual impairments as a late toxicity of RT. CONCLUSION: Conventional RT is safe and effective for the local control of recurrent or residual PMA. Our data suggest that immediate postoperative RT can be beneficial in recurrent or residual PMA, although further studies to evaluate risk factors of treatment failure in terms of treatment and disease characteristics are required.

A phase II trial of hypofractionated high-dose proton beam therapy for unresectable liver metastases.

BACKGROUND AND PURPOSE: Proton beam therapy (PBT) is an effective treatment option for primary malignant liver disease. However, evidence regarding liver metastasis is insufficient. We aimed to investigate the efficacy and safety of hypofractionated high-dose PBT in the treatment of metastatic liver disease. MATERIALS AND METHODS: From January 2019 to January 2021, patients with unresectable liver metastases were enrolled. For PBT, the dose schemes of 60 Gy relative biological effectiveness (GyRBE) in 5 fractions (fx) (biologically effective dose [BED] 132 GyE) or 70 GyRBE in 10 fx (BED 119 GyE) were used. Either a passive scattered beam or pencil beam scanning (PBS)-based intensity-modulated proton therapy (IMPT) was performed with proper respiratory management. The primary endpoint of the study was 6-month freedom from local progression (FFLP) rate; and the Kaplan-Meier method was used to calculate the FFLP and survival rates. RESULTS: Of the 49 liver metastases in 46 patients, the colorectum accounted for 60% of the primary cancer sites, followed by the gastrointestinal organs and pancreas/biliary tract. Forty patients presented only 1 liver metastasis, while the other 6 patients had 2 to 4 metastases. The Six-month FFLP rate was 95.2%. The 1-year FFLP rate in patients with <3 cm liver metastasis was 87.4%, while that was 74.1% in patients with > 3 cm group (p = 0.087). With regard to systemic treatment, the 1-year FFLP rate after PBT was better (94.1%) than that without systemic treatment (75.8%; p = 0.051). Regarding PBT-related toxicity, one patient developed a grade 2 gastric ulcer, while none of the patients developed grade ≥3 toxicities. CONCLUSIONS: Hypofractionated PBT with a BED > 100 GyRBE for liver metastasis is safe and effective, given the high rate of 6-month FFLP without grade ≥3 treatment-related toxicities. However, further improvements are required for larger tumors and/or those without prior systemic therapy.

Automated coronary artery calcium scoring in patients with breast cancer to assess the risk of heart disease following adjuvant radiation therapy.

AIM: Validation of coronary artery calcium (CAC) scores as prognostic factors of acute coronary events (ACE) development in breast cancer patients are demanded. We investigated prognostic impact of CAC on ACE development with cardiac exposure to radiation. METHODS: We evaluated breast cancer patients with (n = 511) or without (n = 600) adjuvant radiotherapy (RT) between 2005 and 2013. CAC Agatston scores were analyzed using a deep-learning-based algorithm. Individual mean heart dose (MHD) was calculated, and no RT was categorized as 0 Gy. The primary endpoint was the development of ACE following breast surgery. RESULTS: In the RT and no-RT cohorts, 11.2% and 3.7% exhibited CAC >0, respectively. Over a 9.3-year follow-up period, the 10-year ACE rate was 0.7%. In the multivariate analysis, the CAC score was a significant risk factor for ACE (CAC >0 vs CAC = 0, 10-year 6.2% vs 0.2%, P < 0.001). In the subgroup with CAC >0, the 10-year ACE rates were 0%, 3.7%, and 13.7% for patients receiving mean heart doses of 0 Gy, 0-3 Gy, and >3 Gy, respectively (P = 0.133). Although CAC score was not predictive for non-ACE heart disease risk (P > 0.05), the 10-year non-ACE heart disease rates were 1.7%, 5.7%, and 7.1% for patients with CAC = 0 receiving MHD of 0 Gy, 0-3 Gy, and >3 Gy, respectively (P < 0.001). CONCLUSIONS: The CAC score was a significant predictor of ACE in patients with breast cancer. Although further studies are required, CAC score screening on simulation CT in patients undergoing breast RT can help identify those with high risk for ACE on a per-patient basis.

Metastasis-Directed Radiotherapy for Oligoprogressive or Oligopersistent Metastatic Colorectal Cancer.

INTRODUCTION: Some patients with cancer may present with progressive or persistent disease at a limited number of sites following a period of treatment response. We evaluated the safety and effectiveness of metastasis-directed radiotherapy (MRT) for oligoprogressive or oligopersistent disease in patients receiving systemic treatment for metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: Patients with mCRC who received 5-fluorouracil, leucovorin, and oxaliplatin; 5-fluorouracil, leucovorin, and irinotecan; and/or capecitabine chemotherapy between 2011 and 2020 at a single institution were identified. Then, those who underwent MRT for five or fewer lesion sites while receiving systemic treatment for other metastases were categorized. The primary endpoint was time to change to systemic therapy. Secondary endpoints included MRT-related toxicity, overall survival, and local control. RESULTS: Among 4157 patients included, 91 (2%) received MRT to limited lesion sites (55 oligoprogressive and 36 oligopersistent) during systemic treatment following a period of treatment response. The median time to change to next-line systemic therapy was 5 months in the overall cohort (measured from the current chemotherapy session) and 9.5 (range, 6.0-40.6) months in the MRT group (measured from the MRT session). No severe toxicity or systemic treatment interruption was observed following MRT. The 1-year local control and overall survival rates were 69% and 99%, respectively. CONCLUSION: In patients with oligoprogressive or oligopersistent mCRC, MRT may be performed safely in conjunction with systemic treatment to maximize the benefit of systemic therapy and to prolong the time to change to systemic therapy. Further prospective studies should confirm these findings.

Treatment outcomes and radiotherapy deintensification strategies in human papillomavirus-associated tonsil cancer.

BACKGROUND: Human papillomavirus (HPV)-positive tonsil cancer has a better prognosis than HPV-negative tonsil cancer. Deintensification strategies to reduce or avoid radiotherapy (RT) for patients with HPV-associated tonsil cancer have been suggested. This study investigated the treatment outcomes of patients with HPV-associated tonsil cancer and suggested RT deintensification strategies. METHODS: A cohort of 374 patients with HPV-associated tonsil cancer treated with primary surgery or RT between 2008 and 2020 was retrospectively evaluated. Survival and locoregional control rates after primary surgery or RT were analyzed, and propensity score matching was performed to adjust for clinical factors. Pearson's chi-square or Fisher's exact test was used to compare categorical variables, and Student's t-test was used to compare continuous variables. The Kaplan-Meier method and log-rank test were used to assess overall survival, progression-free survival, and locoregional failure (LRF). RESULTS: No significant differences in survival or LRF were observed between the primary surgery and RT groups. Subgroup analysis was conducted for patients who underwent primary surgery. Advanced pathological N stage, negative contralateral nodes at diagnosis, abutting or positive surgical margins, and no adjuvant RT were independent risk factors for LRF. Advanced pathological T stage was an independent risk factor for LRF in patients who underwent primary surgery without subsequent adjuvant RT. None of the patients with pathological complete remission (CR) after induction chemotherapy died or experienced LRF. CONCLUSIONS: Our study revealed that the outcomes of primary surgery and primary RT in HPV-positive tonsil cancer were similar after adjusting for clinical factors. Primary RT might be considered instead of surgery in patients with advanced pathological T stage. In the case of pathological CR after induction chemotherapy, deintensification for adjuvant RT should be considered.

Efficacy of Local Therapy for Oligometastatic Hepatocellular Carcinoma: A Propensity Score Matched Analysis.

PURPOSE: With respect to various solid cancers, patients with oligometastasis may benefit from local therapy. However, this approach is not widely accepted for hepatocellular carcinoma. This study investigated the efficacy of local therapy for oligometastatic lesions in patients with hepatocellular carcinoma. PATIENTS AND METHODS: The study included 69 hepatocellular carcinoma patients presenting with oligometastasis to the lung. Characteristics of the patients and treatment options for metastatic lesions were reviewed, and a survival analysis was performed. After propensity score matching, overall survival and progression-free survival were calculated from the time of pulmonary metastasis detection. Factors predicting prognosis were analyzed using a multivariate Cox regression analysis. RESULTS: After propensity score matching, 58 patients with Child-Pugh grade A disease were selected. Among them, 22 patients were treated with systemic therapy alone while 36 patients received local therapy or a combination of local and systemic therapies for metastatic lesions. Survival rates were higher in patients receiving local therapy than in those receiving systemic therapy (2-year overall survival rate, 66.6 vs 31.2%, p<0.001; 2-year progression-free survival rate, 47.0 vs 10.6%, p=0.005). In the multivariate Cox regression analysis, alpha-fetoprotein levels less than 400 ng/mL and the use of local therapy for metastatic lesions were found to be significant favorable prognostic factors. CONCLUSION: Local therapy for metastatic lesions improved the oncologic outcomes of patients with hepatocellular carcinoma with pulmonary oligometastasis.

Predictive factors of symptomatic radiation pneumonitis in primary and metastatic lung tumors treated with stereotactic ablative body radiotherapy.

PURPOSE: Although stereotactic ablative body radiotherapy (SABR) is widely used therapeutic technique, predictive factors of radiation pneumonitis (RP) after SABR remain undefined. We aimed to investigate the predictive factors affecting RP in patients with primary or metastatic lung tumors who received SABR. MATERIALS AND METHODS: From 2012 to 2015, we reviewed 59 patients with 72 primary or metastatic lung tumors treated with SABR, and performed analyses of clinical and dosimetric variables related to symptomatic RP. SABR was delivered as 45-60 Gy in 3-4 fractions, which were over 100 Gy in BED when the α/ß value was assumed to be 10. Tumor volume and other various dose volume factors were analyzed using median value as a cutoff value. RP was graded per the Common Terminology Criteria for Adverse Events v4.03. RESULTS: At the median follow-up period of 11 months, symptomatic RP was observed in 13 lesions (12 patients, 18.1%), including grade 2 RP in 11 lesions and grade 3 in 2 lesions. Patients with planning target volume (PTV) of ≤14.35 mL had significantly lower rates of symptomatic RP when compared to others (8.6% vs. 27%; p = 0.048). Rates of symptomatic RP in patients with internal gross tumor volume (iGTV) >4.21 mL were higher than with ≤4.21 mL (29.7% vs. 6.1%; p = 0.017). CONCLUSIONS: The incidence of symptomatic RP following treatment with SABR was acceptable with grade 2 RP being observed in most patients. iGTV over 4.21 mL and PTV of over 14.35 mL were significant predictive factors related to symptomatic RP.

In vivo dosimetry and acute toxicity in breast cancer patients undergoing intraoperative radiotherapy as boost.

PURPOSE: To report the results of a correlation analysis of skin dose assessed by in vivo dosimetry and the incidence of acute toxicity. This is a phase 2 trial evaluating the feasibility of intraoperative radiotherapy (IORT) as a boost for breast cancer patients. MATERIALS AND METHODS: Eligible patients were treated with IORT of 20 Gy followed by whole breast irradiation (WBI) of 46 Gy. A total of 55 patients with a minimum follow-up of 1 month after WBI were evaluated. Optically stimulated luminescence dosimeter (OSLD) detected radiation dose delivered to the skin during IORT. Acute toxicity was recorded according to the Common Terminology Criteria for Adverse Events v4.0. Clinical parameters were correlated with seroma formation and maximum skin dose. RESULTS: Median follow-up after IORT was 25.9 weeks (range, 12.7 to 50.3 weeks). Prior to WBI, only one patient developed acute toxicity. Following WBI, 30 patients experienced grade 1 skin toxicity and three patients had grade 2 skin toxicity. Skin dose during IORT exceeded 5 Gy in two patients: with grade 2 complications around the surgical scar in one patient who received 8.42 Gy. Breast volume on preoperative images (p = 0.001), ratio of applicator diameter and breast volume (p = 0.002), and distance between skin and tumor (p = 0.003) showed significant correlations with maximum skin dose. CONCLUSIONS: IORT as a boost was well-tolerated among Korean women without severe acute complication. In vivo dosimetry with OSLD can help ensure safe delivery of IORT as a boost.