5-year Local Control Rates Research Articles

Distinct patterns of osteoradionecrosis after photon-based radiotherapy and carbon ion radiotherapy for unresectable adenoid cystic carcinoma of the head and neck: case series from two institutions.

To present the clinical outcomes of two series of patients treated with carbon-ion radiotherapy (CIRT) and definitive photon radiotherapy (RT) for adenoid cystic carcinoma of the head and neck (HN-ACC). The first cohort of six patients was referred from Oslo University Hospital (OUS) to Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy) for CIRT in 2014-2017. The second cohort included 18 patients treated with definitive photon RT at OUS in 2005-2017. The primary endpoint was an evaluation of osteoradionecrosis (ORN) in the two cohorts. The secondary endpoints were treatment efficacy by local control (LC), progression-free survival (PFS), and overall survival (OS). The tumor stage was T4 for all the patients in the CIRT group and 15 (84%) in the photon group. There were three (50%) patients with grade 3 ORN in the CIRT group compared to one (6%) with grade 3 ORN in the photon group (p = 0.05). The 5-year LC (95% CI), PFS, and OS rates in the CIRT group and the photon group were 33% (11-100) and 39% (19-76), 17% (9-100) and 23% (2-59), and 80% (52-100) and 50% (31-82), respectively. Half of the patients in the CIRT cohort experienced ORN requiring surgical management during the follow-up. Patients with ACC referred for CIRT often have a worse prognosis and more advanced disease than patients treated with photons. When returning from the referring center, these patients need close follow-up often in collaboration with treating centers to manage toxicity that impacts quality of life.

Transoral Laser Microsurgery Versus Radiotherapy for T1-T2 Glottic Cancer with Anterior Commissure Involvement: A Systematic Review and Meta-Analysis.

To identify the most effective treatment modality for achieving favorable outcomes in early glottic tumors with anterior commissure involvement (ACI). PubMed, Embase, Web of Science, and ScienceDirect. Random-effects proportional meta-analysis model is used to evaluate the oncological and functional outcomes of transoral laser microsurgery (TLM) versus radiation therapy (RT) in early glottic (T1-T2) cancer with ACI. From a total of 736 studies, 40 studies were included, comprising 2666 early glottic tumor patients with ACI. TLM (52%) and upfront RT (48%) were the primary treatment groups. TLM had better 5-year overall survival (OS) (84.5% [80.3%-88.0%] vs. 79.4% [75.7%-82.7%]). Similarly, TLM-treated patients had better 3-year pooled disease-free survival (DFS) compared with RT-treated patients (82.7% [77.1%-87.1%] vs. 73.3% [23.8%-96.0%]). TLM exhibited a better 5-year local control rate (LCR) than RT (77.2% vs. 71.6%). In our temporal analysis, TLM had a higher 5-year LCR than RT (78.2% vs. 63.5%) in 2001-2012, with similar rates in 2013-2024 (76.8% vs. 78.4%). TLM-treated patients had higher laryngeal preservation rates compared with RT patients (93% [90.6%-94.8%] vs. 87.6% [82.8%-91.2%]). Our meta-analysis is the first in the literature to compare the outcomes between TLM and RT-treated patients with ACI in early glottic tumors. TLM-treated patients appear to have superior 5-year OS and laryngeal preservation compared with upfront RT-treated patients. However, both TLM and RT exhibited comparable oncological outcomes in early glottic tumor patients with ACI during the recent period from 2013 to 2024. Laryngoscope, 2025.

Radiotherapy & total neoadjuvant therapy for recurrent rectal cancer in previously irradiated patients, (RETRY): a multicenter prospective observational study

BackgroundLocal recurrence of rectal cancer (LRRC) previously treated with radiotherapy is associated with a poor prognosis. Historically, the integration of radiotherapy (RT) with surgery has improved the likelihood of complete resections (R0) and, consequently, enhanced survival. Unfortunately, many LRRC cases are not amenable to surgical intervention. The inclusion of chemotherapy (CHT) alongside advanced RT techniques including proton and carbon ion RT (CIRT) and stereotactic body radiation therapy (SBRT), has generated new treatment options. Therefore, there is a need for improved stratification of LRRC patients to enhance treatment outcomes. The RETRY is an integrated trial with the primary aim to explore if combining CHT with RT in all available modalities can enhance local control (LC) in LRRC patients, consequently improving survival.MethodsExperts from Italian centers specializing in rectal cancer and LRRC management collaborated to design a prospective multicenter observational study within the AIRO group for gastrointestinal malignancies. Eligible participants are adult LRRC patients who previously had pelvic RT, meet specific criteria, and are affiliated with the participating Italian centers. Specific criteria must be met for CIRT referral. A total of 88 patients will be enrolled over three years. The primary objective is to determine the 3-year LC rate. Secondary outcomes include assessing survival, quality of life, and R0 resection rates in surgery cases. A minimum dose of 40 Gy, conventional fractionation with concomitant fluoropyrimidine—with/without oxaliplatin-based CHT (CRT) is prescribed in neoadjuvant setting. Alternatively, the dose will vary from 35 to 40 Gy in 5 fractions based on clinical judgment, by SBRT. Both proton and photon therapies will be evaluated in these approaches. Surgery will be considered if deemed operable. In inoperable cases, CIRT with a dose of 40–60 Gy relative biological effectiveness (RBE) will be administered with a daily dose fraction ranging between 3 and 4.8 Gy RBE.DiscussionThe RETRY trial aims to investigate the combined effects of RT and CHT and when feasible the addition of surgery, to determine whether this comprehensive approach can result in improved survival and quality of life for LRRC patients.Trial registration number ClinicalTrials.gov (No. NCT05984576).

Stereotactic ablative radiotherapy for pulmonary metastasis from sarcoma: a retrospective comparison with metastasectomy.

Recent studies report excellent local control (LC) and favorable toxicities of stereotactic ablative radiotherapy (SABR) for pulmonary metastasis (PM) from sarcoma. This study compared the LC and survival of SABR and metastasectomy for sarcoma PM. We analyzed the LC rates of 54 PMs treated with SABR between 2008 and 2022. For survival analysis, we compared 14 patients who received SABR as first-line treatment with 61 patients who underwent metastatectomy. For SABR-treated PMs, a median total dose of 55Gy (range, 48-60) was administered over 3-10 fractions. Median follow-up for LC in SABR-treated PMs was 19.2months (range, 0.8-124.0), and the 2-year LC rate was 92.2%. No patients experienced toxicities of grade 3 or higher. The median age of the patients in the survival analysis was 73years (range, 42-83) in the SABR group and 54years (range, 19-78) in the metastasectomy group (p < 0.001). PMs in the "gray zone" were more common in the SABR group (35.7%) than in the metastasectomy group (8.2%) (p = 0.029). The median follow-up for survival analysis was 44.8months (interquartile range, 21.5-66.4). The 3-year rates of LC and overall survival were 92.3% and 57.3% in the SABR group and 89.2% and 75.9% in the metastasectomy group (p = 0.807, 0.224), respectively. The out-of-field intrapulmonary failure-free survival and extrapulmonary systemic failure-free survival rates at 3years were not significantly different (p = 0.673, 0.386). SABR for sarcoma PM demonstrated excellent LC with acceptable toxicity. Survival rates of SABR were comparable to those of metastasectomy.

ESHO 2-85. Hyperthermia as an adjuvant to radiation therapy in the treatment of advanced neck nodes: A randomized multicenter study by the European Society for Hyperthermic Oncology.

European Society for Hyperthermic Oncology (ESHO) 2-85 is a multicenter randomized trial investigating hyperthermia (HT) as an adjuvant to radiotherapy (RT) in treatment of locally advanced neck nodes. The trial never fulfilled recruitment and was stopped prematurely, and has not previously been published. Between January 1987 and February 1993, 64 evaluable neck nodes in 54 patients were included. Tumors were stratified according to institution and nodal size and randomly assigned to receive RT alone (2 Gy/fx, 5 fx/wk) to a total dose of 60-70 Gy, including boost, or the same RT followed once weekly by HT (aimed for 43°C for 60 min). The primary endpoint was persistent complete response (local control). Sixty-four tumors in 54 patients were evaluable, with a median observation of 17 months. Thirty-four tumors were randomized to RT alone and 30 to RT+HT. Compliance with RT was good. HT was associated with moderate to severe pain and discomfort in 38% of the treatments. In 57% of the heated patients at least one treatment achieved the target temperature. HT did not significantly increase radiation morbidity. The complete response rate was 53% in the RT versus 80% in the RT+HT group, and 3-year persistent local control rate was 32% for RT alone versus 53% for RT+HT; HR: 0.48 [0.23-0.98]. The ESHO 2-85 study demonstrated that addition of a weekly HT treatment to RT of advanced neck nodes significantly enhanced the persistent tumor control. The results substantiate the potential clinical benefit of hyperthermic oncology.

Application of spiral tracheoplasty in thyroid cancer with tracheal invasion

Objective: To explore the application of spiral tracheoplasty in the repair of large tracheal defects after the resection of trachea invaded by thyroid cancer. Methods: A retrospective analysis was performed on the clinical data of 11 patients, including 4 males and 7 females, aged from 36 to 67 years old, with large tracheal defects after tracheal resection due to thyroid papillary carcinoma invading the trachea in the Department of Otorhinolaryngology Head and Neck Surgery, Second Xiangya Hospital, Central South University from January 2019 to January 2022. The range of tracheal defects, time of tracheal reconstruction, postoperative complications and airway were recorded, and the patients were followed up for more than 24 months. Results: All patients underwent total thyroidectomy and tracheal resection and spiral reconstruction, and 2 of the cases underwent cricoid cartilage resection on the invaded side of cartilage. The tracheal defect accounted for 40%-60% of the circumference, and the lengths of the tracheal defects were 5.0 cm×7.5 cm and 6-9 tracheal rings, with 2 cases combined with partial defects of the cricoid cartilage. The reconstruction time was 30-60 min, with an average of 41.81 min. Among the 11 patients, 3 had recurrent laryngeal nerve paralysis, and 2 underwent tracheotomy. Four patients presented with hypocalcemia within one month after the operation. Followed up for 24-60 months, no tracheal stenosis occurred, the 2-year survival rate was 100%, the 2-year local control rate of the trachea was 100%, and the 2-year tumor-free survival rate was 81.8%. Conclusion: Spiral tracheoplasty is a safe and effective method that can reduce the tension at the tracheal anastomosis and expand the tracheal cavity, which can be used for tracheal reconstruction after extensive resection of trachea invaded by locally advanced thyroid cancer.

Outcomes of Management of Progressive Radiosurgery-Treated Brain Metastasis With Resection Followed by Pathology-Informed Management: A Retrospective Study

BACKGROUND AND OBJECTIVES: In patients treated with stereotactic radiosurgery (SRS) for brain metastases, follow-up imaging demonstrating progression may result from treatment effect/radionecrosis (RN) or tumor progression. We report long-term outcomes for a cohort of patients who demonstrated radiological progression on serial imaging after initial radiation and who underwent resection, at which point histology informed further management. METHODS: A retrospective chart review identified 76 patients with an associated 82 brain lesions between 2009 and 2022, that were initially treated with SRS, and then demonstrated suspicious imaging developing through at least 2 scan time points with either pathologic confirmation of tumor or RN. RESULTS: Of the 82 lesions, 55 lesions (67.1%) were found to be tumor and were treated with repeat radiation and 27 (32.9%) were found to have pathologically confirmed RN and conservatively managed. 14/27 lesions ultimately found to be radionecrotic required steroids preoperatively due to neurological symptoms. None of these lesions required further intervention with median postsurgery follow-up of 24.4 months (range 1-104 months). There were 55 instances (in 51 patients) of confirmed recurrent/progressive tumor who we treated with repeat aggressive radiation with either Cs-131 brachytherapy (12 [21.8%]) or SRS (43 [78.2%]). Among patients treated with reirradiation, the median follow-up to local failure was 15.2 months (95% CI 7.3-26.6 months). The 2-year local control rate was 79.5% (95% CI 68.3%-92.5%). CONCLUSION: These results support resection of radiosurgery-treated lesions with progression continuing through serial imaging, and this pathology-informed management results in excellent control of both RN and tumor progression after radiosurgery.

Final Results of a Multicenter Prospective Study of Stereotactic Body Radiation Therapy for Previously Untreated Solitary Primary Hepatocellular Carcinoma (The STRSPH Study).

To report final results of a prospective study of stereotactic body radiation therapy (SBRT) in patients with previously untreated solitary primary hepatocellular carcinoma (HCC). This prospective, single-arm, multicenter phase 2 trial recruited patients with HCC who were unsuitable for, or refused, surgery and radiofrequency ablation, with 3-year overall survival rates as the primary endpoint and survival outcomes and adverse events as secondary endpoints. The prescribed SBRT dose was 40 Gy in 5 fractions. The final data were analyzed in November 2022. Between 2014 and 2018, 36 patients (median age, 73.5 years) were registered; enrollment was closed before full recruitment due to slow accrual. Overall, 34 patients were analyzed for efficacy evaluation after excluding 2 patients. The median tumor size was 2.3 cm. The median follow-up times for all patients and for survivors were 49 and 56 months, respectively. The 3-year overall survival rate was 82% (95% confidence interval, 65%-92%). The 3-year local control rate was 93% (95% confidence interval, 76%-98%). Grade 3 or higher SBRT-related nonlaboratory toxicities were observed in 4 patients (11%). No grade 5 adverse events were observed. Final results of this phase 2 trial suggest the efficacy and safety of SBRT for newly diagnosed early-stage HCC that is unfit for other local therapies. Although this study was underpowered by the small number of registrations, the excellent results indicate that SBRT may be an alternative option for the management of early-stage HCC.

Postoperative high-dose-rate brachytherapy alone in stage T1-3N0M0 oral cancer with negative prognostic factors: a retrospective study

To evaluate treatment outcomes and toxicity in patients with stage T1-3N0M0 oral cancer treated with surgery followed by high-dose-rate brachytherapy (HDR-BT). Retrospective study of 50 patients with stage T1-T3N0 tongue and floor-of-mouth cancer who underwent tumour excision (+ elective neck dissection) followed by postoperative HDR-BT due to the presence of negative prognostic factors (close or positive resection margins, lymphovascular and/or perineural invasion, deep invasion). The plastic tube technique (dose: 18 x 3 Gy b.i.d.) was used. Survival outcomes, toxicity, and prognostic factors were evaluated. At a median follow-up of 81 months (range, 4-121), actuarial 5-year local control (LC), nodal control (NC) and progression-free survival (PFS) rates were 79%, 69%, and 64%. After salvage treatment (surgery + external beam radiotherapy), LC, NC, and PFS increased to 87%, 77%, and 72.3%, respectively. Five-year overall survival and cancer-specific survival (CSS) rates were 73% and 77%. Treatmentrelated toxicity included two cases of mandibular osteoradionecrosis and five cases of small soft tissue necrosis. T stage was significantly correlated with nodal control (p=0.02) and CSS (p=0.04). Tumour grade correlated with DFS (p=0.01). Postoperative HDR-BT 18 x 3 Gy b.i.d. seems to be an effective method in patients with T1-3N0M0 oral cancer with negative prognostic factors after tumour resection.

Evaluating the efficacy of low-kV X-ray intraoperative radiotherapy in the treatment of locally advanced rectal cancer: a retrospective cohort study.

Patients with locally advanced rectal cancer (LARC) treated with surgery have a high risk of local recurrence. Intraoperative radiotherapy (IORT) is a promising method for treating locally advanced solid tumors, but there is limited research on the efficacy of IORT in treating LARC. This study aimed to evaluate the long-term efficacy of low-kV X-ray IORT in the treatment of LARC. In total, 69 LARC patients with stage tumor3-4node0-2metastasis0 (T3-4N0-2M0) treated with radical resection and low-kV X-ray IORT at our center from December 2015 to August 2023 were consecutively included in this retrospective cohort study. Basic patient characteristics, intraoperative and postoperative data, and early and late complications were recorded. A Kaplan-Meier (K-M) survival analysis was performed to analyze the overall survival (OS) and disease-free survival (DFS) of the patients. In total, 69 patients (median age, 64 years; 69.6% male) were enrolled in the study, and the median follow-up time was 47.5 months (range, 6.5-98.5 months). At the time of analysis, 15 patients had died (21.74%), 6 patients (8.70%) had been lost to follow-up, and 48 patients (69.57%) were alive. The 3-year OS and DFS rates were 89.42% and 71.47%, respectively. The local recurrence rate was 26.09%, and the 5-year local control, OS, and DFS rates were 78.90%, 68.59%, and 66.91%, respectively. The T stage of tumors was not predictive of either OS or DFS (P>0.05). However, different N stages and nerve/vascular invasion were found to be positively correlated with OS and DFS (P<0.05). Mortality within 30 days post-surgery was 0%. Early complications included anastomotic leak (5 cases, 7.25%), urinary retention (4 cases, 5.80%), diarrhea (7 cases, 10.14%), and bowel obstruction (4 cases, 5.80%), all of which were cured by conservative treatment. Late complications included ureteral obstruction (3 cases, 4.35%), bladder dysfunction (2 cases, 2.90%), sexual dysfunction (5 cases, 7.24%), and bowel obstruction (6 cases, 8.70%). Our findings suggest that low-kV X-ray IORT enhances local control and survival in LARC patients. Further research should be conducted in larger, prospective trials.

Outcomes After Stereotactic Body Radiation for Hepatocellular Carcinoma in Patients With Child-Pugh A Versus Child-Pugh B/C Cirrhosis

For patients with hepatocellular carcinoma (HCC), stereotactic body radiation therapy (SBRT) has emerged as a locoregional treatment. Our purpose was to report outcomes in patients with HCC with Child-Pugh A (CP A) versus Child-Pugh B or C (CP B/C) liver dysfunction treated with SBRT. A retrospective analysis of 80 patients with HCC, with a total of 94 tumors treated with SBRT, was conducted at a single institution. Outcomes were compared between patients with CP A (n = 51) and CP B/C (n = 29) liver dysfunction. Outcomes of interest included local control, overall survival (OS), and toxicity. Median tumor size was 3.2 cm. There were 59 tumors included in the CP A cohort and 35 tumors in the CP B/C cohort. Median radiation dose was 50 Gy in 5 fractions for the CP A cohort and 40 Gy in 5 fractions for the CP B/C cohort. The rates of pathologic complete response were similar between the 2 groups at 63% for the CP A group and 61% for the CP B/C group. The estimated 1-year local control rates were similar between the 2 groups at 93% for the CP A group and 91% for the CP B/C group (P = .59). The 1-year OS for the CP A group was 85%, whereas the 1-year OS for the CP B/C group was 61% (P = .19). There was a 5.9% rate of grade 3+ toxicity in the CP A group and a 20.7% rate of grade 3+ toxicity in the CPB/C group. Our findings suggest that SBRT is feasible and effective in patients with both CP A and CP B/C liver dysfunction with similar rates of local control and pathologic complete response despite lower radiation doses in the CP B/C cohort. In patients with more advanced CP B/C cirrhosis, toxicities were higher and must be weighed against possible treatment benefits. Further studies characterizing the optimal role of SBRT in patients with advanced cirrhosis are warranted.

A systematic review of stereotactic radiosurgery for metastatic spinal sarcomas.

Sarcomas metastasizing to the spine are a rare entity. Ideally an En-bloc resection is necessary to achieve durable local control (LC) rates. However, anatomical constraints often limit the degree of tumor resection. Because of this, other therapeutic modalities either replacing or as an adjuvant to resection are necessary. Stereotactic radiosurgery (SRS) is a reasonable candidate therapy. We conducted a systematic review of the literature using the following databases: PubMed, Science Direct, and Cochrane library. We used a combination of the following terms connected by boolean operators: "Metastatic Sarcoma, Sarcoma of the Spine, Spine Sarcoma, Metastasis, stereotactic radiosurgery, SRS." All retrospective and prospective cohorts, as well as randomized control trials reporting on patients with histopathologically confirmed metastatic sarcomas of the bony elements of the vertebrae, thecal sac, cord, or associated soft tissues of the spine were included. We excluded animal studies, case reports, case series, patients < 18 (pediatric cohorts), review articles and meta-analyses. No date filters were applied to our search. Our final analysis included 5 studies ranging from 2009 to 2024 reporting on 260 patients and 371 associated lesions. Leiomyosarcoma was the most frequently reported histologic subtype (60%). Most lesions were localized to the thoracic spine (48.6%). 75% of studies reported a median dose < 30Gy, and achieved biologically equivalent doses (BEDs) ranging from < 50-100. Pooled 1-year median survival was 64.5% (IQR: 61.8-75.10). Pooled 1-year median LC was 86% (IQR: 79.4-88.5). Three of five studies (60%) for OS and 4/5 (80%) for LC had data availability suitable for meta-analysis. The 1-year OS and LC rates proportions across these studies were 67% (proportion = 0.67, 95% CI: 0.57-0.75, p = 0.07, I2 = 63%), and 84% (proportion = 0.84, 95% CI: 0.78-0.89, p = 0.10, I2 = 52%) respectively. Median follow up across all studies was 18 months (IQR:12.7-31.3). SRS is a reasonable alternative therapy in either the up front, salvage or adjuvant setting which can facilitate durable LC.

Respiratory-gated proton beam therapy for intrahepatic cholangiocarcinoma without fiducial markers

BackgroundIntrahepatic cholangiocarcinoma (ICC) is a challenging primary liver cancer with a poor prognosis, especially in unresectable cases. Traditional palliative irradiation is limited in reducing liver doses. This study aimed to evaluate the efficacy and toxicity of respiratory-gated proton beam therapy without fiducial markers for intrahepatic cholangiocarcinoma.MethodsBetween October 2011 and February 2022, 24 patients (median [range] age, 71 [41–88] years) were evaluated at our institution. Twelve patients were pathologically diagnosed with ICC. All patients underwent respiratory-gated proton beam therapy at a dose of 48–83.6 (relative biological effectiveness) in 20–38 fractions with four-dimensional computed tomography planning. The median follow-up period was 18.5 (range, 2.0–74.0) months. The median tumor size was 41 (range, 10–134) mm. Twenty-one patients were classified as having Child–Pugh class A, and three patients were classified as having Child–Pugh class B. Local progression was defined as any growth of the irradiated tumor.ResultsThe median survival time was 28 months for all patients. The Kaplan–Meier estimates of the 2-year overall survival, progression-free survival, and local tumor control rates were 51%, 26%, and 73%, respectively. Local tumor control rates were non-inferior to those reported in previous studies using fiducial markers. One patient had grade 4 pleural effusion; however, whether this was an adverse event due to the proton beam therapy was unclear.ConclusionsRespiratory-gated proton beam therapy without fiducial markers is an effective and less invasive treatment option for ICC, showing potential for improved local control and tolerable adverse effects.

RADT-15. THE ROLE OF STEREOTACTIC RADIOSURGERY IN WHO GRADE II MENINGIOMAS: RESULTS FROM A LARGE EUROPEAN MULTICENTER STUDY

Abstract BACKGROUND This study evaluates the outcomes of WHO grade II meningiomas treated with stereotactic radiosurgery (SRS) using a large, multi-institutional European database. We aim to investigate the long-term tumor control rate and morbidity associated with SRS. METHODS Data from 355 consecutive patients treated between 1992 and 2022 at 16 European radiosurgery centers were retrospectively analyzed. After excluding 40 patients due to loss to follow-up, results from 315 patients were included. Clinical and imaging data were independently collected by each center and uniformly entered into a multicenter database. RESULTS The median age of patients was 56 years, with 54% being female. The median follow-up duration was 46.3 ± 36.9 months. Tumors had prior surgical treatment and biopsy in 99% and 1% of cases, respectively. Tumors received previous radiotherapy or SRS in 27.4% of cases. SRS was performed due to local progression in 89.6% of cases, residual tumor in 6.4%, and distant progression in 4.0%. SRS characteristics included a median target volume of 5.1 cm³ and a median margin dose of 16 Gy (53.5% isodose). The 3-year local control rate was 72.0%, with a progression-free survival rate of 66.6% and an overall survival rate of 89.7%. Transient and permanent morbidity rates were 6.4% and 3.5%, respectively. Multivariate analysis identified previous radiotherapy and age as significant factors influencing these outcomes. CONCLUSIONS This study is the largest to date on SRS in WHO grade II meningiomas. Our data shows that SRS is a viable and safe treatment option for residual and recurrent WHO grade II meningiomas

RADT-50. CLINICAL OUTCOME OF DAILY 5-FRACTIONATED GAMMA KNIFE RADIOSURGERY FOR LARGE BRAIN METASTASES

Abstract INTRODUCTION With the introduction of the Gamma Knife Icon, hypo-fractionated Gamma Knife radiosurgery (GKRS) for large brain metastases (LBMs) is beginning to be performed. This study aimed to assess the clinical outcome and risk of the daily 5-fractionated GKRS for LBMs. METHODS A total of 100 patients who underwent 5-fractionated GKRS for LBMs (&amp;gt; 14cm3) were enrolled. Forty-six were male patients, and the median age was 60 years. Most common primary cancer sites were lung (41 non-small cell cancers), breast (24), and kidney (14). The median tumor volume was 22cm3 (14 – 69cm3) and marginal dose was 35Gy (50% isodose line) in 5 fractions. Median follow-up duration was 18 months (3 – 72 months). RESULTS The last follow-up showed local tumor control in 74 cases. The cumulative 1, 2, and 3-year local tumor control rates were 73, 65, and 60%, respectively. Eighty-six tumors showed best MRI response in a year, and median tumor volume decrease rate was 80% (22 – 100%). Thirty patients experienced dramatically tumor volume decrease (&amp;gt; 95%). Median progression free and overall survival were 7 and 16 months, respectively. Radiation necrosis occurred in 24 patients, of which only 9 had neurological symptoms and treated with steroid and bevacizumab. CONCLUSIONS The daily 5-fractionated GKRS for very LBMs showed favorable local tumor control and acceptable radiation necrosis, but questionable survival benefit. In the future, prospective multi-center study is needed.

SURG-53. LONG TERM FOLLOW-UP OF RESECTION PLUS CESIUM-131 BRACHYTHERAPY FOR PREVIOUSLY IRRADIATED RECURRENT BRAIN METASTASES

Abstract BACKGROUND Recurrent brain metastases (rBM) after previous radiosurgery present a clinical dilemma, as the advantages of reirradiation need to be weighed against the potential of significant radiation toxicity. Salvage resection with Cs-131 brachytherapy offers improved dosimetry due to reduced integral dose to healthy brain compared to repeat radiosurgery. We previously reported initial results of rBM treated with resection and salvage Cs131 brachytherapy; we present an updated analysis of tumor control with extended follow-up. METHODS We analyzed consecutive patients with rBM previously treated with radiosurgery, who underwent salvage resection plus implantation of Cs131 seeds (GammaTile, GT Medical Technologies). The prescribed brachytherapy dose was 60 Gy at 5mm from the cavity. Median follow-up was calculated using reverse Kaplan-Meier. Local recurrence was defined by new nodular contrast enhancement with hyperperfusion within 5mm of the resection cavity. Marginal recurrence was defined as &amp;gt;5mm but not beyond 1cm from the cavity. Local control and overall survival (OS) from brachytherapy were analyzed using Kaplan-Meier. RESULTS Twenty-five patients underwent Cs131 implantation in 30 tumor cavities. The median presurgical rBM maximal diameter was 2.95 cm (range 1.1-6.3). The most common histology was lung adenocarcinoma (n=8, 27%) followed by breast (n=7, 23%) and renal cell (n=3, 10%). Radiographic gross- or near-total resection was achieved in 80% of lesions. The median number of Cs131 seeds implanted was 17, (range 6-30), (median strength 3.5 U/seed). With median follow-up of 37 months (95%CI:29-45), twelve and 24-month OS was 55% and 41%, respectively. Four tumors recurred (3 in-field, one marginal) for a 1- and 2-year local control rate of 87% and 81%, respectively. Data for adverse radiation effects is under analysis and will be presented. CONCLUSIONS With over 3 years of follow-up, intraoperative brachytherapy with collagen-embedded Cs131 implants was associated with durable local control for this challenging clinical scenario. A randomized Phase II trial of Cs131 vs. standard of care for rBM (NCT04690348) is actively accruing.

RTID-05. STUDY PROTOCOL: A MULTICENTER, INTERNATIONAL RANDOMIZED CONFIRMATORY TRIAL: LOW-ENERGY X-RAY INTRAOPERATIVE RADIATION THERAPY (LEX-IORT) VS. ADJUVANT FRACTIONATED STEREOTACTIC RADIOTHERAPY (FSRT) IN THE MANAGEMENT OF BRAIN METASTASES (LEXIMATE)

Abstract BACKGROUND Fractionated stereotactic radiotherapy to the resection cavity boosts local control of resected brain metastases significantly. However, start of systemic tumor-directed treatment may be protracted and in-hospital times prolonged. Lately, lex-ioRT of BM has been described as a safe and effective one stop-shop treatment modality with a 1-year local control rate of up to 98% while potentially improving patient convenience. Study Design: The LEXIMATE-trial is a multicenter, international, randomized open-label confirmatory trial comparing lex-IORT with FSRT of resected BM. In the experimental arm, INTRABEAM (Carl Zeiss Meditec AG) is used to deliver IORT by application of 50-kV photons at a standard dose of 30 Gy prescribed to the applicator surface. Standard linear accelerator or Gamma Knife based FSRT (3-7 fractions) to the surgical bed is used in the control arm. The primary endpoint is the cumulative incidence of local recurrences (as per RANO-BM) considering death without prior local recurrence as competing event. Inclusion criteria include histologically confirmed BM with indication for resection according to EANO-ESMO/ASCO-SNO-ASTRO guidelines, ≤5 other brain lesions compatible with BM and amenable to radiosurgery and history of solid cancer or CT scan suggestive for localized or metastasized solid cancer (except germ cell tumors, lymphoma, small-cell lung cancer). The resection cavity must be &amp;lt;5cm in size, IORT doses to brainstem or optical tract may not exceed 8 Gy. Study design: Randomized, open-label, non-inferiority. Sample size: 70 patients per group to show a non-inferiority of the experimental therapy compared to the control therapy with a power of approximately 80%. DISCUSSION The best radio-oncologic procedure for resected BM remains under debate. The LEXIMATE-trial offers an opportunity to provide more solid prospective data on effectiveness, safety and patient comfort both for established and new RT techniques.

Radiofrequency Ablation Therapy versus Stereotactic Body Radiation Therapy for Naive Hepatocellular Carcinoma (≤5cm): A Retrospective Multi-Center Study.

Radiofrequency ablation (RFA) is a micro-invasive treatment for early-stage HCC patients. Stereotactic body radiation therapy (SBRT) has also been proven an effective and safe treatment for HCC patients. This multi-center study is to compare the efficacy of computed tomography (CT)-guided RFA and CT-based SBRT in naïve HCC patients with tumor diameters ≤5 cm. This retrospective cohort study included 1001 treatment-naïve HCC patients from three hospitals or medical centers. The patients received RFA (n = 481) or SBRT (n = 520) treatment between December 2011 and May 2019. Furthermore, subgroup analyses of all patients were conducted based on Couinaud's classification of liver segments. After matching, the local control (LC) rates of the SBRT group were better than those of the RFA group (p=0.024*), which mainly referred to the patients whose tumors were located in the S7/S8 (p=0.006*). Among patients with tumors located in S1, nineteen patients (19/21) underwent SBRT. The 1-, 3- and 5-year LC rates were 100%, 87.8% and 87.8% in the SBRT group, and the 1-, 3- and 5-year OS rates were 100%, 69.8% and 69.8%, respectively. Moreover, the OS rates in S5/S6 group in RFA were higher than those in SBRT group. The LC rates were better in the SBRT group than in the RFA group for the patients with lesions localized in S7/S8, and SBRT could also be a therapeutic option for patients with lesions in S1. Moreover, patients with tumors located in S5/S6 were better candidates for RFA treatment than SBRT.

Risk-adapted stereotactic body radiation therapy delivered in four fractions in patients with non-small cell lung cancer.

Risk-adapted stereotactic body radiation therapy is preferred over conventional radiotherapy at the authors' institution based on the hypothesis that even with a lower than recommended dose, stereotactic body radiation therapy would yield better local control than conventional radiotherapy. This retrospective study was performed to verify the hypothesis. Data from 34 patients with non-small cell lung cancer, who underwent risk-adapted stereotactic body radiation therapy delivered in 4 fractions between 2012 and 2018, were analyzed. The 3-year local control rate for patients receiving 42-44 Gy, 40 Gy, and 32-38 Gy was 80.8%, 75.0%, and 66.7%, respectively. The 3-year overall survival rate was 63.5%, 63.5%, and 40.0%, respectively. Three patients experienced grade 3 toxicities, with no toxicities > grade 3 observed. The results support the use of risk-adapted stereotactic body radiation therapy, both with a relatively high dose and a low dose.

External beam radiotherapy followed by image-guided adaptive brachytherapy in locally advanced cervical cancer: a multicenter retrospective analysis.

To evaluate oncological outcomes and toxicities in patients with locally advanced cervical cancer (LACC) treated with concurrent chemoradiotherapy followed by image-guided adaptive brachytherapy at two Italian centres. A retrospective analysis was conducted on 122 patients with LACC treated between 2010 and 2022. Primary endpoints were local control (LC), pelvic control (PC), and nodal control (NC). Secondary endpoints included disease-free survival (DFS), metastasis-free survival (MFS), overall survival (OS), and late toxicity. Correlations between patient characteristics and oncological outcomes were conducted. Brachytherapy planning was CT and MRI-based in 88 (72.1%) and 34 patients (27.9%), respectively. The mean total dose (EQD2) delivered to high-risk clinical target volume was 82Gy. Overall treatment time was ≤ 50days and > 50days in 48 (39.3%) and 74 patients (60.7%), respectively. At a mean follow up of 101months, 3 and 5-year LC rates were 87% and 85%, respectively. Five-year PC and NC rates were 77% and 85.1%. Five-year DFS and OS were 61% and 65.4%, respectively, with significant correlations between these outcomes and FIGO stage and nodal status at diagnosis. Gastrointestinal, genitourinary and vaginal adverse effects were the most reported late toxicities and 8 (6.5%) grade 3-5 events were observed. 32 patients (26.2%) had vaginal stenosis and it was significantly related to 3D imaging used for brachytherapy planning. The study confirmed the efficacy and safety of chemoradiotherapy and IGABT for LACC. Full implementation of MRI treatment planning and interstitial techniques could further enhance personalized treatment and outcomes.