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Oral cavity squamous cell carcinoma (SCC) is conventionally treated with surgery followed by adjuvant radiation therapy. Multiple studies have demonstrated clinical utility of interstitial brachytherapy (BT) alone or external beam radiotherapy (EBRT) with BT boost for T1-T2N0 cancers of lip and buccal mucosa. In case of combined EBRT and BT, dose summation and optimizing doses received by planning target volume (PTV) and organs at risk (OARs) remains challenging.The aim of this study was to generate and evaluate dosimetric parameters of PTV and OARs as a sum of high-dose-rate (HDR)-BT boost and EBRT in early T1-T2N0 cancers of lip and buccal mucosa, using deformable image registration (DIR) software (Velocity ). 2 Gy equivalent dose (EQD ) calculated manually (EQD -D BT + EQD -D EBRT) was compared with that estimated using DIR. An analysis was performed in patients with histopathologically proven T1-T2N0 SCC of lip and buccal mucosa, who underwent interstitial BT boost followed by EBRT. Planning computed tomography (CT) images and respective treatment plans of both BT and EBRT were imported into Velocity software, and DIR was employed to fuse these images for all patients. A synthetic plan incorporating both plans was generated. Dosimetric parameters of both PTV and OAR (mandible) were analyzed. This study included a total of 10 patients (cT1N0: = 6, and cT2N0: = 4), with median age of 57 years (range, 30-69 years) and male : female ratio of 7 : 3. The median dose to PTV using HDR-BT was 21 Gy (range, 20-21 Gy), delivered in 5-6 fractions, 3.5-4 Gy per fraction. The median dose to PTV using EBRT was 44 Gy (range, 40-46 Gy), delivered in 20-23 fractions, 1.8-2 Gy per fraction. DIR software-based dose summation provides accurate dose delivery to target and OARs. If performed prospectively, it can potentially enable optimization of limiting the doses to critical OARs, thus, reducing post-RT morbidity.

Purpose To observe the effect of different high-dose-rate (HDR) intracavitary brachytherapy dose schedules on equieffective dose in 2 Gy per fraction (EQD2). Material and methods It is a retrospective study involving 50 cervical cancer patients, who received external radiotherapy of 45 Gy in 25 fractions and underwent intracavitary brachytherapy (ICBT). Computed tomography (CT) simulation was done after insertion of the applicators. High-risk clinical target volume (CTVHR) and organs at risk (OARs) such as bladder, rectum, and sigmoid were contoured. Four different plans were generated for each patient, with dose prescriptions of 5.5 Gy × 5 fractions (plan A), 6.5 Gy × 4 fractions (plan B), 7 Gy × 4 fractions (plan C), and 9 Gy × 2 fractions (plan D), delivered to CTVHR. The total EQD2 for 0.1 cm3 and 2 cm3 of bladder, rectum, and sigmoid as well as dose received by 90% of the CTVHR (D90) and point A were calculated. The values were analyzed and compared with available literature. Results The mean CTVHR volume was 47.12 ±13.8 cm3. All plans delivered similar EQD2 for 0.1 cm3 and 2 cm3 of sigmoid. Plan D delivered lesser EQD2 compared to other plans for bladder, rectum, D90 CTVHR, and point A (p = 0.0001). Plan C delivered higher EQD2 to OARs compared to other plans (p = 0.001). Plan A, B, and plan C delivered similar EQD2 for D90 CTVHR and point A. Conclusions EQD2 of bladder, rectum, sigmoid, D90 CTVHR, and point A were similar with 5.5 Gy × 5 fractions, 6.5 Gy × 4 fractions, and 7 Gy × 4 fractions, whereas EQD2 of 9 Gy × 2 fractions was significantly unfavorable compared to other schedules. Further clinical studies are recommended to observe clinical outcomes.

BackgroundCancer is one of the leading causes of death worldwide. According to GLOBOCAN estimates, there were 341,831 deaths from cervical cancer in 185 countries in 2020. The aim of this study was to compare equieffective dose (EQD2) at 2 Gy per fraction by using dose volume histograms (DVHs) derived from external beam radiotherapy (EBRT) and high-dose rate brachytherapy (HDR-BRT) treatment plans used in cervical cancer radiotherapy.MethodsFifteen patients with stage IIB-IIIB cervical cancer were included in this retrospective study. Treatment with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) was planned for all patients in 28 fractions, with a total of 50.4 Gy to be delivered to the whole pelvic region. After EBRT, manual optimization (MO) or inverse optimization (IO) HDR-BRT plans were created in 4 fractions with a total of 28 Gy. The plans obtained were grouped as IMRT + IO, IMRT + MO, 3DCRT + IO, and 3DCRT + MO by calculating EQD2s among these plans. D90, D95, and D98 values were compared in all plans for CTVHR total EQD2. In addition, EQD2 values ​for critical organs at risk (OARs) such as rectum, bladder, small intestine, and sigmoid were compared in all plans for volumes of 2 cm3, 1 cm3, and 0.1 cm3, respectively.ResultsThere was no significant difference between the treatment groups in terms of CTVHR D90 and CTVIR D90 values; However, CTVHR D95 (p = 0.000) and CTVHR D98 (p = 0.000) values ​were found to be better in IMRT + IO technique. The IMRT + IO technique provided better protection for 2 cm3, 1 cm3, and 0.1 cm3 volumes of OARs compared to other techniques.ConclusionsConsidering all parameters such as CTVHR, CTVIR, rectum, bladder, small intestine, and sigmoid, combination of IMRT + IO treatment option was found to be significantly superior in total EQD2 calculations compared to other plans.

The volume of Venezia applicator with vaginal caps can be relatively large compared to target volumes. This study investigated the dosimetric and radiobiological effects of applicator volume removal for cervical cancer patients treated with Venezia (VZ) and tandem and split-ring (TSR) applicators used in the clinic. A total of 40 patients (101 plans) with stage IIA-IIIC cervical cancer were retrospectively reviewed. Thirty patients were treated with VZ and ten patients were treated with TSR. Applicators were contoured on planning CTs where target contours were involved. Applicator contours were subtracted from the target contours. External beam radiation therapy (EBRT) and brachytherapy doses were calculated in biologically equivalent doses in 2 Gy fractions (EQD ) and combined using full parameter addition for dose-volume histogram (DVH) parameters of composited dose. D , D , V , V , V , and tumor control probability (TCP) were evaluated and compared for targets after applicator exclusion. The average volume changes in gross tumor volume (GTV), high-risk clinical target volume (HR-CTV), and intermediate-risk clinical target volume (IR-CTV) after VZ applicator exclusion were 1.4 ±1.5 cm , 15.7 ±6.6 cm , and 33.8 ±15.1 cm , respectively. VZ exclusion resulted in significant changes ( < 0.05) in small volume parameters (D ) and high-dose parameters (V and V ) for HR-CTV and IR-CTV. Dosimetric impact of TSR exclusion on targets was not significant. There was no significant change in TCP after applicator exclusion. Venezia applicator with vaginal caps has significant impact on small volume and high-dose DVH parameters of the target. Applicator contour exclusion is recommended for dosimetric evaluation when Venezia applicator is used.

High dose rate (HDR) image-guided brachytherapy with Cobalt-60 isotope is a relatively recent approach. The aim of the study is to evaluate the clinical and dosimetric parameters in terms of tumour response, bladder, and rectal toxicity in patients undergoing Co-60 HDR brachytherapy. All patients were initially treated with chemoradiation (CT-RT) at our center or other referral centers with external beam radiation therapy (EBRT) for a dose of 45 Gy-60 Gy at 1.8-2Gy/fraction (including nodal boost) with concomitant chemotherapy with either cisplatin or carboplatin. Patients were then scheduled for brachytherapy within 1 week after completion of CT-RT and are assessed by local examination. Depending on local examination parameters at the time of brachytherapy they were eligible either for intracavitary brachytherapy (ICBT) or interstitial brachytherapy (ISBT). The complete response (CR) observed in stage I, II, III, IVA were 60%, 79.4%, 86% and 76.2% respectively. Complete response was seen in patients with mean EQD2 of 78.67 Gy , 83.33 Gy , 84.23 Gy , 85.63 Gy in stages I, II, III, IVA respectively. 79.2% of cisplatin-treated patients and 87.5% of carboplatin-treated patients had a complete response indicating that patients treated with either chemotherapy had similar response rates. According to results obtained from the study we conclude by saying that higher rates of complete response to treatment in cervical cancer is seen in patients with shorter overall treatment time (OTT), shorter interval between end of definitive CT-RT and beginning of brachytherapy and squamous cell histology. The study also noted the trend of increasing mean EQD2 to tumor with increasing stage for achieving complete response. Higher acute bladder and rectal toxicity is seen in patients who received EQD2 of ¿70-90Gy and ¿70Gy respectively. The study findings suggest that the clinical outcomes and the toxicities are clinically comparable with other radioisotope based HDR brachytherapy treatment.

External beam radiotherapy (EBRT) combined with brachytherapy (BT) is the standard mode of radical radiotherapy for locally advanced cervical cancer. The cumulative equivalent doses in 2 Gy per fraction (EQD ) is an important basis for estimating the probability of local control of tumors and monitoring the occurrence of side effects in normal tissues. The purpose of this study was to explore the predictive value of Excel forms based on an automatic calculation in radical adaptive BT for cervical cancer. A retrospective analysis of 119 patients suffering from cervical cancer, treated with radical radiotherapy. All patients were treated with EBRT and adaptive BT. EBRT prescribed dose was 42.0-50.4 Gy in 21-28 fractions. BT nominal prescribed dose was 28 Gy in 4 fractions, separated by one week. Total EQD prediction at nth ( = 1-3) BT (TEPB ) or actual cumulative EQD (ACEQD ) can be calculated automatically by inputting the physical dose based on an in-house designed application. The relationship between TEPB and ACEQD was evaluated, and the predictive value of Excel forms based on the automatic calculation was analyzed. For the volume of high-risk clinical target, there was a significant decrease between BT1 and BT2. Similarly, for the volume of intermediate-risk clinical target, there was a significant decrease between BT2 and BT3. The sensitivity ranges of TEPB , TEPB , and TEPB prediction were 74.5-91.3%, 83.7-95.7%, and 92.9-99.1%, respectively, and the specificity ranges were 46.7-80.0%, 53.3-90.5%, and 66.7-90.5%, respectively. The in-house designed application has the function of quickly reading dose-volume histogram (DVH) parameters from the treatment planning system, which allows for balance between the total dose to target volumes and organs at risk (OARs). Excel forms based on EQD automatic calculation presents high predictive accuracy.

Background/purpose To establish regression models of physical and equivalent dose in 2 Gy per fraction (EQD 2 ) plan parameters of two kinds of hybrid planning for stage III NSCLC. Methods Two kinds of hybrid plans named conventional fraction radiotherapy & stereotactic body radiotherapy (C&S) and conventional fraction radiotherapy & simultaneous integrated boost (C&SIB) were retrospectively made for 20 patients with stage III NSCLC. Prescription dose of C&S plans was 2 Gy × 30f for planning target volume of lymph node (PTV LN ) and 12.5 Gy × 4f for planning target volume of primary tumor (PTV PT ), while prescription dose of C&SIB plans was 2 Gy × 26f for PTV LN and sequential 2 Gy × 4f for PTV LN combined with 12.5 Gy × 4f for PTV PT . Regression models of physical and EQD 2 plan parameters were established based on anatomical geometry features for two kinds of hybrid plans. The features were mainly characterized by volume ratio, min distance and overlapping slices thickness of two structures. The possibilities of regression models of EQD 2 plan parameters were verified by spearman’s correlation coefficients between physical and EQD 2 plan parameters, and the influence on the consistence of fitting goodness between physical and EQD 2 models was investigated by the correlations between physical and EQD 2 plan parameters. Finally, physical and EQD 2 models predictions were compared with plan parameters for two new patients. Results Physical and EQD 2 plan parameters of PTV LN CI 60Gy have shown strong positive correlations with PTV LN volume and min distance (PT to LN) , and strong negative correlations with PTV PT volume for two kinds of hybrid plans. PTV (PT+LN) CI 60Gy is not only correlated with above three geometry features, but also negatively correlated with overlapping slices thickness (PT and LN) . When neck lymph node metastasis was excluded from PTV LN volume, physical and EQD 2 total lung V 20 showed a high linear correlation with corrected volume ratio (LN to total lung). Meanwhile, physical total lung mean dose (MLD) had a high linear correlation with corrected volume ratio (LN to total lung) , while EQD 2 total lung MLD was not only affected by corrected volume ratio (LN to total lung) but also volume ratio (PT to total lung). Heart D 5 , D 30 and mean dose (MHD) would be more susceptible to overlapping structure (heart and LN) . Min distance (PT to ESO) may be an important feature for predicting EQD 2 esophageal max dose for hybrid plans. It’s feasible for regression models of EQD 2 plan parameters, and the consistence of the fitting goodness of physical and EQD 2 models had a positive correlation with spearman’s correlation coefficients between physical and EQD 2 plan parameters. For total lung V 20 , ipsilateral lung V 20 , and ipsilateral lung MLD, the models could predict that C&SIB plans were higher than C&S plans for two new patients. Conclusion The regression models of physical and EQD 2 plan parameters were established with at least moderate fitting goodness in this work, and the models have a potential to predict physical and EQD 2 plan parameters for two kinds of hybrid planning.

Concomitant chemo‐radiotherapy (cCRT) with 60 Gy in 30 fractions is the standard of care for stage 111 non‐small cell lung cancer (NSCLC). With a median overall survival of 28.7 months at best and maximum locoregional control rates of 70% at two years, the prognosis for these patients is still dismal. This systematic review summarizes data on dose escalation by alternative fractionation, which has been explored as a primary strategy to improve both local control and overall survival over the past three decades. A Pubmed literature search was performed according to the PRISMA guidelines. Because of the large variety of radiation regimens total doses were converted to EQD2,T. Only studies using an EQD2,T of at least 49.5 Gy, which corresponds to the conventional 60 Gy in six weeks, were included. In a total of 3256 patients, the median OS was 17 months (range 7.4–30 months). While OS was better for patients treated after the year 2000 (P = 0.003) or with a mandatory 18F‐FDG‐PET‐CT in the diagnostic work‐up (P = 0.001), treatment sequence did not make a difference (P = 0.106). The most commonly reported toxicity was acute esophagitis (AE) with a median rate of 24% (range 0%–84%). AE increased at a rate of 0.5% per Gy increment in EQD2,T (P = 0.016). Dose escalation above the conventional 60 Gy using modified radiation fractionation schedules and shortened OTT yield similar mOS and LRC regardless of treatment sequence with a significant EQD2,T dependent increase in AE. Key points Significant findings Modified radiation dose escalation sequentially combined with chemotherapy yields similar outcome as concomitant treatment. OS is better with the mandatory inclusion of FDG‐PET‐CT in the diagnostic work‐up. The risk of acute esophagitis increases with higher EQD2,T. What this study adds Chemo‐radiotherapy (CRT) with modified dose escalation regimens yields OS and LC rates in the range of standard therapy regardless of treatment sequence. This broadens the database of curative options in patients who are not eligible concomitant CRT.

Background Currently, the standard treatment for locally advanced cervical cancer patients is concurrent chemoradiotherapy. Here we aim to evaluate therapeutic efficacy, treatment failure, toxicity and prognostic factors for FIGO IIIB cervical cancer patients. Methods A comprehensive retrospective analysis was performed to understand various factors which contribute to IIIB cervical cancer prognosis. In total 223 well defined patients were assigned according to their pathological subtype, age, pre-treatment HGB level, tumor size, pelvic lymph node (LN) metastasis, para-aortic LN metastasis as well as external irradiation technologies, treatment duration, point A EQD2 dose and concurrent chemotherapy cycles. We then performed correlation studies of these factors and OS, DFS, LCR, DMFS using univariate and multivariate analysis respectively. Results We managed to achieve 207 (92.8%) complete response (CR) and 16 (7.2%) partial response (PR) with acceptable adverse effects. Notably, the 5 years OS, DFS, LCR, DMFS for these patients were 61.1, 55.2, 83.6 and 66.4% respectively. Importantly, our studies suggest that escalated point A EQD2 can significantly improve OS, DFS and LCR for FIGO IIIB cervical cancer patients, furthermore, patients without para-aortic LN metastasis who received prophylactic extended field irradiation have significant survival advantage for DFS and a tendency to improve OS and DMFS. Conclusions Our results suggest that FIGO IIIB cervical cancer patients should receive higher EQD2 (≥98Gy 10 ) radiotherapy, moreover, patients without para-aortic LN metastasis should receive prophylactic extended field nodal irradiation to improve prognosis.

This study aimed to provide accurate dose distribution profiles of radiotherapy for cervical cancer when treated with the central shielding technique by analysing the composite 3D EQD2 dose distribution of external beam radiotherapy (EBRT) plus intracavitary brachytherapy (ICBT). On a phantom, four patterns of the combinations of whole pelvis irradiation (WP) (4 fields), pelvis irradiation with central shielding technique (CS) [anterior–posterior/posterior–anterior (AP-PA fields), shielding width of 3 or 4 cm] and ICBT using Point-A prescription were created: 30 Gy/15 fractions + 20 Gy/10 fractions + 24 Gy/4 fractions [Plan (30 + 20 + 24)], 40 Gy/20 fractions + 10 Gy/5 fractions + 18 Gy/3 fractions [Plan (40 + 10 + 18)], 40 Gy/20 fractions + 10 Gy/5 fractions + 24 Gy/4 fractions [Plan (40 + 10 + 24)] and 45 Gy/25 fractions + 0 Gy + 28 Gy/4 fractions [Plan (45 + 0 + 28)]. The composite EQD2 dose distributions of the complete treatment were analysed. The Point-A dose of Plan (30 + 20 + 24), Plan (40 + 10 + 18), Plan (40 + 10 + 24) and Plan (45 + 0 + 28) were 78.0 Gy (CS 3 cm)/71.8 Gy (CS 4 cm), 72.1 Gy (CS 3 cm)/69.0 Gy (CS 4 cm), 80.1 Gy (CS 3 cm)/77.0 Gy (CS 4 cm) and 84.1 Gy, whereas it has been previously reported to be 62 Gy, 64 Gy, 72 Gy and 84 Gy, respectively. For all the treatment plans with CS, equivalent or wider coverage of 60 Gy (EQD2) was achieved in the right–left direction, while coverage in the anterior–posterior direction decreased in plans with CS. There were no irregularly ‘cold’ regions around the central target. The use of CS in radiotherapy for cervical cancer resulted in tumor coverage in the lateral direction with doses higher than the previously reported Point-A doses.