Current practices of craniospinal irradiation techniques in Turkey: a comprehensive dosimetric analysis.

OBJECTIVE: This study evaluates various craniospinal irradiation (CSI) techniques used in Turkish centers to understand their advantages, disadvantages and overall effectiveness, with a focus on enhancing dose distribution. METHODS: Anonymized CT scans of adult and pediatric patients, alongside target volumes and organ-at-risk (OAR) structures, were shared with 25 local radiotherapy centers. They were tasked to develop optimal treatment plans delivering 36 Gy in 20 fractions with 95% PTV coverage, while minimizing OAR exposure. The same CT data was sent to a US proton therapy center for comparison. Various planning systems and treatment techniques (3D conformal RT, IMRT, VMAT, tomotherapy) were utilized. Elekta Proknow software was used to analyze parameters, assess dose distributions, mean doses, conformity index (CI), and homogeneity index (HI) for both target volumes and OARs. Comparisons were made against proton therapy. RESULTS: All techniques consistently achieved excellent PTV coverage (V95 > 98%) for both adult and pediatric patients. Tomotherapy closely approached ideal Dmean doses for all PTVs, while 3D-CRT had higher Dmean for PTV_brain. Tomotherapy excelled in CI and HI for PTVs. IMRT resulted in lower pediatric heart, kidney, parotid, and eye doses, while 3D-CRT achieved the lowest adult lung doses. Tomotherapy approached proton therapy doses for adult kidneys and thyroid, while IMRT excelled for adult heart, kidney, parotid, esophagus, and eyes. CONCLUSION: Modern radiotherapy techniques offer improved target coverage and OAR protection. However, 3D techniques are continued to be used for CSI. Notably, proton therapy stands out as the most efficient approach, closely followed by Tomotherapy in terms of achieving superior target coverage and OAR protection.

Feasibility and tolerability of breath-hold in liver stereotactic body radiotherapy with surface guided radiotherapy.

Purpose: Intrafractional motion constitutes a significant challenge in SBRT (Stereotactic Body Radiotherapy).The breath-hold (BH) technique is employed to mitigate tumor motion; however, ensuring reproducibility and consistency remains critically important. Surface tracking systems, integrated into the treatment process, facilitate motion tracking through three-dimensional camera technology. Surface guidance has been incorporated with Varian EDGE (Varian Medical Systems, Palo Alto, CA, USA) and has been utilized at multiple treatment sites within our department since 2018. Drawing on four years of experience, this study aims to publish patient experience, assess the feasibility, and evaluate the tolerability of breath-hold during SBRT with surface guided radiotherapy (SGRT), particularly focusing on a specific subgroup: patients with liver metastases. Methods: Prospective evaluation was conducted on patients with liver metastases undergoing breath-hold SBRT with SGRT. A two-step survey consisting of seven questions was administered after CT simulation and treatment. Treatment duration and the number of breath-holds were recorded. Additionally, factors potentially influencing SGRT and treatment time were assessed. Results: Between April 2021 and May 2022, a total of 41 patients underwent 171 fractions of treatment. According to the questionnaire, prior training was found to be beneficial, and breath-holding during the procedure was tolerable. Patients reported experiencing slight stress due to their active participation in the treatment. Factors such as Karnofsky Performance Status (KPS), age, lung volume, conditions affecting lung capacity, previous breath-hold history, and being a native speaker showed no correlation with treatment time. Moreover, these factors did not correlate with the tolerability of breath-hold during SGRT. However, female patients showed better breath-holding performance in SGRT treatments compared to male patients (p: 0.02). Conclusions: The application of breath-hold with SGRT procedures is tolerable and feasible in liver SBRT treatments. There exists no specific subgroup that cannot tolerate this method.

Evaluation of clinically involved lymph nodes with deformable registration in breast cancer radiotherapy.

OBJECTIVES: Modern radiotherapy (RT) techniques require careful delineation of the target. There is no particular RT contouring guideline for patients receiving neoadjuvant chemotherapy (NACT). In this study, we examined the distribution of pre-chemotherapy clinically positive nodal metastases. METHODS: We explored the coverage rate of the RTOG breast contouring guideline by deformable fusion of 18-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) scan. We retrospectively evaluated neoadjuvant chemotherapy patients. All PET-CT images were imported into the planning software. We combined the planning CT and the CT images of PET-CT with rigid and then a deformable registration. We manually contoured positive lymph nodes on the CT component of the PET-CT data set and transferred them to planning CT after fusion. We evaluated whether previously contoured lymphatic CTVs, according to the RTOG breast atlas, include GTV-LNs. RESULTS: All breast cancer patients between October 2018 and February 2021 were evaluated from the electronic database. There were 142 radiologically defined positive lymph nodes in 31 patients who were irradiated after NACT. Most LNs (70%) were in the level I axilla. Only 71.1% (n:101) of the whole lymph nodes in 10 patients were totally covered, 22.5% (n:32) partially covered and 6.4% %(n:9) totally undercovered. CONCLUSIONS: The extent of regional nodal areas in the RTOG atlas may be insufficient to cover positive lymph nodes adequately. For patients with nodal involvement undergoing neoadjuvant chemotherapy, PET-CT image fusions can be helpful to be sure that positive lymph nodes are in the treatment volume. ADVANCES IN KNOWLEDGE: RTOG contouring atlas may be insufficient to cover all involved lymph nodes after NACT. For patients with nodal involvement undergoing neoadjuvant chemotherapy, PET-CT image fusions may help to be sure that positive lymph nodes are in the treatment volume.

Stereotactic body radiotherapy in patients with adrenal gland metastases of oligometastatic and oliogoprogressive lung cancer.

Objective: To evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) in patients with adrenal gland metastasis (AGM) of oligometastatic lung cancer. Methods: Between June 2013 and May 2021, 44 patients with oligometastatic lung cancer (51 AGMs) were treated with SBRT. Forty-six (90%) lesions received a biological effective dose (BED10, α/ß = 10) of 100 Gy. The primary endpoint was local control (LC). Local control (LC), overall survival (OS), and progression-free survival (PFS) curves were calculated by the Kaplan-Meier method. Results: The median follow-up was 23 months. The most common histology was non-small cell lung cancer (88.6%). The 1- and 2-year LC rates were both 95% and 91%, respectively. Overall survival was better in patients with solitary AGMs in univariate analysis. Conclusion: This study demonstrated that SBRT with higher BED is associated with satisfactory LC and low toxicity rates in patients with AGM of oligometastatic lung cancer.