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Preoperative or postoperative radiation therapy is broadly employed in patients with rectal carcinoma. Radiotherapy directs high-energy beams of ionizing radiation toward the tumor area to destroy cancer cells. High radiation doses are needed for cell killing. The radiation exposure of the healthy tissues/organs may lead to carcinogenesis. This study describes the evolving role of radiotherapy in rectal cancer management. The present report also reviews epidemiological and dosimetric studies related to the radiation-induced second malignancies from pelvic radiotherapy. Some epidemiological studies have concluded that the second-cancer risk in patients subjected to radiation therapy does not increase compared to unexposed rectal cancer patients. Other researchers found an elevated or a marginally increased probability for second-cancer induction. Dosimetric studies reported cancer risk estimates for critical organs or tissues in the near and far periphery of the treatment volume. Useful information about the effect of the treatment parameters such as the irradiation technique, photon beam energy, and fractionation schedule on the organ-specific second-cancer risk was derived from the dose data analysis. The knowledge of these effects is needed for the selection of the optimal treatment parameters enabling a reduction in the resultant risk of carcinogenesis.

Objectives: To evaluate the effectiveness of different optimization parameters on radiotherapy plan quality for seventeen head and neck cancer patients. Methods: Volumetric Modulated Arc Therapy with Simultaneous Integrated Boost (VMAT-SIB) plans, involving up to three tumors, were generated. For each participant, a reference plan (Plan_Ref) was created using dual-arc with 180 control points, 20° gantry-angle increment and 1 cm minimum segment width. Modified plans were developed with dose constraints and optimization settings constant by changing to single-arc, 150 and 200 control points, 0.5 cm minimum segment width, and 30° and 40° gantry-angle increments. These plans were referred to as Plan_Arc1, Plan_CP150, Plan_CP200, Plan_SW0.5, Plan_Inc30, and Plan_Inc40, respectively. D95% of planning target volumes (PTVs), homogeneity index (HI), monitor units (MUs), maximum dose (Dmax) of spinal cord, mandible, and brainstem were recorded. Statistical and Bland–Altman analysis was performed comparing the modified plans to Plan_Ref. Results: Average D95% values for PTV1, PTV2, and PTV3 ranged from 93.13 to 98.82%. Plan_SW0.5 provided superior target coverage and homogeneity with higher MUs than Plan_Ref. Plan_Arc1 significantly reduced PTV coverage and dose homogeneity, while increasing MUs compared with Plan_Ref (p < 0.05). The average Dmax as derived from all planning approaches was up to 43.86 Gy, 65.86 Gy, and 48.85 Gy for spinal cord, mandible and brainstem, respectively. For spinal cord, Plan_Ref led to significantly lower doses compared to Plan_Arc1 and Plan_Inc30, while the brainstem recorded statistically higher Dmax doses than Plan_Arc1. Significantly higher Dmax was observed for the mandible using Plan_SW0.5 (p < 0.05). However, for Dmax, the comparison plans showed good agreement with Plan_Ref based on Bland–Altman analysis. Conclusions: The VMAT plan quality is strongly affected by the minimum segment width whereas no differences were observed with the modification of the number of control points.

This study aimed to evaluate the placement accuracy and reproducibility of Surface Guided Radiotherapy (SGRT) compared with the conventional tattoo/laser method in patients undergoing radiotherapy for abdominal malignancies. A retrospective analysis was conducted on 43 patients treated with either SGRT (Group A) or the tattoo/laser technique (Group B). Patients in both groups underwent CBCT to quantify the positioning shifts in the vertical (Svrt), lateral (Slat) and longitudinal (Slng) axes, as well as the total shift. Statistical indicators including median, interquartile range (IQR), and range were calculated, and Mann–Whitney U tests were performed due to non-normal data distribution. Median values in all axes were same between groups: Svrt = 0.4 cm, Slat = 0.2 cm, Slng = 0.4 cm. Group A showed a higher total median shift equal to 0.8 cm versus 0.7 cm of Group B. However, IQRs were smaller in the Group B for all directions and total shift, indicating greater method consistency. Statistically significant differences (p < 0.05) were observed in all axes, except the vertical. These findings suggest that, while SGRT achieves comparable median alignment, its use in a highly variable anatomical region such as the abdomen may be associated with greater setup variability.

This study compared the risks for developing second primary cancers and cardiotoxicity following radiotherapy for thymoma. Three different 3D-CRT, IMRT, and VMAT plans were generated with 6 MV photons for 12 females with thymoma. Dose-volume histogram data were employed to estimate the second cancer risks using a mechanistic non-linear model. The radiation doses to the heart and cardiac substructures were combined with linear models to assess the probability of cardiotoxicity. The mean lifetime risk for lung, esophageal, thyroid, left breast, and right breast cancer induction was 4.34–4.49%, 0.30–0.31%, 0.05–0.07%, 2.06–2.30%, and 2.04–2.34%, respectively, depending upon the radiotherapy technique. The relative risk for major cardiac events, including myocardial infarction, coronary revascularization, and death, was 1.43–1.55, whereas that for chronic heart failure was 1.20–1.29. The IMRT and VMAT significantly reduced the risk for cardiotoxicity with respect to 3D-CRT (p ≤ 0.023). Small but significant reductions were observed for most organ-specific cancer risks with IMRT compared to conformal treatment (p ≤ 0.008). Similar decreases were detected only for esophageal and thyroid cancer with VMAT (p ≤ 0.033). No difference was found in the probability for radiation-induced lung cancer with the three techniques (p ≥ 0.06). Healthcare professionals may use these data to select the appropriate radiotherapy technique and restrict the risk of late effects.

Cutaneous sarcomas are a heterogeneous group of rare mesenchymal neoplasms representing less than 1% of malignant tumors. Histology report remains the cornerstone for the diagnosis of these tumors. The most important clinicopathologic parameters related to prognosis include larger tumor size, high mitotic index, head and neck location, p53 mutations, depth of infiltration and histological grade, vascular and perineural invasion as well as the surgical margins status. Applying advanced biopsy techniques might offer more precise assessment of surgical margins, which constitutes a significant precondition for the management of these tumors. The management of cutaneous soft tissue sarcomas requires a multidisciplinary approach. Surgery remains the standard treatment, nonetheless adjuvant therapy may be required, consisting of radiotherapy, chemotherapy, and molecular targeted therapies to improve treatment outcomes. The role of molecular profiling in the treatment of uncontrolled disease is promising, but it may be offered to a relatively small proportion of patients and its use is still considered experimental in this setting. Due to the rarity of the disease, there is a need for knowledge and experience to be shared, pooled, organized and rationalized so that recent developments in medical science can have a major impact on the disease course. Multicenter clinical trials are needed to improve the care of patients with cutaneous sarcomas.

(1) Aim: This study was conducted to radiobiologically compare radiotherapy plans for gastric cancer with a newly developed software tool. (2) Methods: Treatment planning was performed on two computational phantoms simulating adult male and female patients. Three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans for gastric cancer were generated with three-photon beam energies. The equivalent uniform dose (EUD), tumor control probability (TCP) of the target and normal tissue control probability (NTCP) of eight different critical organs were calculated. A new software was employed for these calculations using the EUD-based model and dose-volume-histogram data. (3) Results: The IMRT and VMAT plan led to TCPs of 51.3–51.5%, whereas 3D-CRT gave values up to 50.2%. The intensity-modulated techniques resulted in NTCPs of (5.3 × 10−6–3.3 × 10−1)%. The corresponding NTCPs from 3D-CRT were (3.4 × 10−7–7.4 × 10−1)%. The above biological indices were automatically calculated in less than 40 s with the software. (4) Conclusions: The direct and quick radiobiological evaluation of radiotherapy plans is feasible using the new software tool. The IMRT and VMAT reduced the probability of the appearance of late effects in most of the surrounding critical organs and slightly increased the TCP compared to 3D-CRT.

This study aims to optimize the stereological method for estimating left-ventricular (LV) parameters from retrospectively electrocardiography-gated 16-row MDCT and to compare stereological estimations with those by MRI. MDCT was performed in 17 consecutive patients with known or suspected coronary disease. Stereological measurements based on point counting were optimized by determining the appropriate distance between grid points. LV parameters were evaluated by standard CT analysis using a semi-automatic segmentation method. Two independent observers evaluated the reproducibility of the stereological method. End-diastolic volume (EDV) and end-systolic volume (ESV) estimations with a coefficient of error below 5% were obtained in a mean time of 2.3 ± 0.5 min with a point spacing of 25 and 15 pixels, respectively. The intra- and interobserver variability for estimating LV parameters was 2.6–4.4 and 4.9–8.2%, respectively. MRI estimations were highly correlated with those by standard CT analysis ( R  > 0.82) and stereology ( R  > 0.84). Stereological method significantly overestimated EDV and ESV compared to MRI (EDV: P  = 0.0011; ESV: P  = 0.0013), whereas for stroke volume (SV) and ejection fraction (EF), no difference was observed ( P  > 0.05). For standard CT analysis and MRI, significant differences were found except for SV and EF (EDV: P  = 0.0008; ESV: P  = 0.0004; EF: P  = 0.051; SV: P  = 0.064). The time-efficient optimized stereological method enables the reproducible evaluation of LV function from MDCT.

The objective of this study was to estimate the risk of developing second malignancies to partially in‐field organs from volumetric modulated arc therapy (VMAT) of cervical cancer and to compare the above risks with those from the conventional three‐dimensional conformal radiotherapy (3D‐CRT). Seventeen consecutive patients with uterine cervix carcinoma were selected. VMAT and 3D‐CRT plans were generated with 6 and 10 MV photons, respectively. The prescribed tumor dose was 45 Gy given in 25 fractions. Differential dose‐volume histogram data from the treatment plans were obtained for the partially in‐field organs such as bladder and rectum. These data were used to estimate the patient‐specific lifetime attributable risk (LAR) for bladder and rectal cancer induction with a non‐linear model based on a mixture of plateau and bell‐shaped dose–response relationships. The estimated risks per 10000 people were compared with the baseline risks for unexposed population. The patient‐specific rectal cancer risk estimates from VMAT were significantly lower than those from 3D‐CRT (P = 0.0144). The LARs for developing bladder malignancies from VMAT were significantly high compared to those from conventional irradiation (P = 0.0003). The mean difference between the patient‐specific LARs for radiation‐induced bladder and rectal malignancies as derived from 3D‐CRT and VMAT plans was 6.6% and 2.0%, respectively. The average LAR for developing bladder and rectal malignant diseases due to VMAT was 9.2 × 10‐4 and 43.7 × 10‐4, respectively. The corresponding risks following 3D‐CRT were 8.6 × 10‐4 and 44.6 × 10‐4. These average risks showed that pelvic irradiation increases the baseline probability for cancer induction by 12.6‐19.1%. The differences in the second cancer risks associated with the VMAT and 3D‐CRT for cervical cancer were found to be small. Both treatment techniques resulted in considerable increased probabilities for developing bladder and rectal malignancies relative to those of unirradiated population.

The aim of the present study was to examine the effect of the photon beam energy on the volumetric modulated arc therapy (VMAT) plan quality for prostate cancer and on the risk of secondary carcinogenesis. Separate VMAT plans with 6-MV and 10-MV photons were created for 11 low-risk patients with prostate cancer. The prescribed tumor dose was 70 Gy delivered in 28 fractions. The normal tissue integral dose and parameters associated with planning target volume and organs at risk were determined by the treatment planning data. A non-linear mechanistic model considering the effects of tumor dose fractionation and cell proliferation was employed for estimating the patient-specific lifetime attributable risk (LAR) for bladder and rectal cancer induction. Data from differential dose-volume histograms were used for these risk assessments. The mean values of the planning parameters from 6-MV treatment plans differed by 0.2-3.4% from those associated with irradiation using 10-MV photons. The LAR range for developing secondary bladder malignancies varied between 0.041 and 0.129% by the patient under investigation and the beam energy used. The corresponding range for the appearance of rectal malignant diseases was 0.047-0.153%. The mean percentage difference between the bladder cancer risks from VMAT with 6-MV and 10-MV photons was 2.6±2.3%. The corresponding difference for secondary rectal malignancies was 0.7±0.6%. Therefore, VMAT for prostate cancer with both 6-MV and 10-MV photons leads to clinically equivalent treatment plans and to similar secondary bladder and rectal cancer risks.

Background Advanced radiotherapy techniques such as single‐isocenter volumetric modulated arc therapy (VMAT) and simultaneous integrated boost (SIB‐VMAT) require precise quality assurance (QA) due to their complexity and sensitivity to geometric and dosimetric uncertainties, especially for multi‐target configurations. Purpose To evaluate and compare two dosimetric systems—a diode array and a polymer gel dosimeter—for quality assurance in single‐isocenter multi‐target VMAT and SIB‐VMAT plans through 3D gamma index and statistical agreement analysis. Methods A diode array system (Delta⁴—Scandidos, Uppsala, Sweden) and a 3D printed phantom (Prime—RTsafe, Athens, Greece) embedded with in‐house polymer gel were utilized. The treatment plans for VMAT and SIB‐VMAT were created using the Monaco treatment planning system (TPS) and irradiations were performed with the Elekta Infinity linear accelerator with a 6‐MV photon beam on both Prime and Delta⁴. Analyses of the irradiated gels were performed using a 1.5T clinical MRI system. Additionally, 3D gamma indexes and Bland‐Altman analyses were conducted to evaluate the agreement between relative doses from MRI‐derived gel data and diode array's detector measurements. Results Diode array system achieved gamma passing rates (GPRs) >99%, while polymer gel showed >95% GPR for both irradiation plans. Bland–Altman analysis indicated minimal bias (mean difference: 0.1%) and narrow limits of agreement (−1.9% to 2.2%), confirming good consistency between the two dosimetric methods for both plans delivered. Conclusions Acceptable agreement between the two systems was observed. Both demonstrated complementary capabilities, making both essential tools for ensuring precision in advanced radiotherapy techniques. The polymer gel system offers more detailed insights compared to the diode array method, showing increased sensitivity in challenging cases that involve small targets at greater distances from the isocenter.