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Objective:To evaluate the efficacy and safety of hippocampal avoidance whole-brain irradiation with simultaneous integrated boost in the treatment of brain metastases of lung cancer.Methods:Forty lung cancer patients with brain metastases who received whole-brain radiotherapy with simultaneous integrated boost and hippocampal avoidance in Cancer Hospital, Chinese Academy of Medical Sciences from 2014 to 2020 were enrolled in this study. Brain MRI, survival follow-up and evaluation of side effects were performed before radiotherapy and at 1, 3, 6 and 12 months after radiotherapy, respectively. Overall survival (OS), progression-free survival (PFS) and changes in cognitive function were analyzed. Continuous data were described as Mean ± SD. Categorical data were described by frequency and composition ratio or percentage. Survival analysis was conducted by Kaplan-Meier method. Influencing factors of survival were identified by univariate and multivariate Cox's regression analyses.Results:A total of 40 patients were enrolled in the study. The median follow-up time was 14.2 months and the median OS, PFS and intracranial PFS of all patients were 14.8 months, 6.7 months and 14.8 months, respectively. Multivariate analysis showed that male gender and newly diagnosed stage Ⅳ disease were associated with worse OS and PFS, respectively. The Hopkins verbal learning test-revised (HVLT-R) scores at baseline and 1, 3 and 6 months after radiotherapy were 21.94±2.99, 20.88±3.12, 20.03±3.14, and 19.78±2.98, respectively. The HVLT-R score at 6 months after radiotherapy was decreased by approximately 9.8% compared with the baseline. No grade 3 or above toxic and side effect occurred in the entire cohort.Conclusion:Hippocampal avoidance whole-brain irradiation with simultaneous integrated boost is a safe and effective treatment for brain metastases of lung cancer, which is expected to reduce the impact of radiotherapy on cognitive function.
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Objective:To explore the effects of Onodera′s prognostic nutritional index (PNI) on the prognosis of locally advanced oropharyngeal squamous cell carcinoma (LA-OPSCC) after induction chemotherapy followed by sequential chemoradiotherapy.Methods:A retrospective analysis was conducted on the clinical data of 52 LA-OPSCC patients receiving induction chemotherapy followed by sequential chemoradiotherapy in The Affiliated Cancer Hospital of Guizhou Medical University during 2014-2018. The PNI values of all the patients at different treatment phases were statistically analyzed, and the ROC curve was employed to determine the optimal critical value of PNI. The patients in this study were divided into a well-nourished group ( n = 27) and a poorly-nourished group ( n = 25). The Kaplan-Meier method was used for survival analysis. The Cox proportional hazards model was utilized to analyze the relationships between different nutritional status and prognosis. Clinical features and adverse reactions were compared between the two groups. Results:The PNI values decreased significantly after radiotherapy, with an optimal critical value of 42.4. The 5-year overall survival (OS) and progression-free survival (PFS) of the well-nourished group (PNI ≥ 42.4) were 62.6% and 60.9%, respectively, which were significantly higher than those (30.1% and 29.7%) of the poorly-nourished group (PNI < 42.4, χ2 = 11.12, 5.74, P < 0.05). The multivariate analysis showed that PNI was an independent prognostic factor for the OS after radiotherapy ( HR = 2.752, 95% CI: 1.095-6.917, P = 0.031). The LA-OPSCC patients aged over 60 years or those who did not respond to induction chemotherapy accounted for a higher proportion of malnutrition after chemoradiotherapy ( χ2 = 4.89, 5.05, P < 0.05). Conclusions:PNI after radiotherapy can be used as a prognostic factor in the evaluation of LA-OPSCC patients receiving induction chemotherapy followed by sequential chemoradiotherapy. The LA-OPSCC patients aged over 60 years or those who do not respond to induction chemotherapy should receive more nutritional support during the chemoradiotherapy.
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Objective:Based on radiomics characteristics, different machine learning classification models are constructed to predict the gamma pass rate of dose verification in intensity-modulated radiotherapy for pelvic tumors, and to explore the best prediction model.Methods:The results of three-dimensional dose verification based on phantom measurement were retrospectively analyzed in 196 patients with pelvic tumor intensity-modulated radiotherapy plans. The gamma pass rate standard was 3%/2 mm and 10% dose threshold. Prediction models were constructed by extracting radiomic features based on dose documentation. Four machine learning algorithms, random forest, support vector machine, adaptive boosting, and gradient boosting decision tree were used to calculate the AUC value, sensitivity, and specificity respectively. The classification performance of the four prediction models was evaluated.Results:The sensitivity and specificity of the random forest, support vector machine, adaptive boosting, and gradient boosting decision tree models were 0.93, 0.85, 0.93, 0.96, 0.38, 0.69, 0.46, and 0.46, respectively. The AUC values were 0.81 and 0.82 for the random forest and adaptive boosting models, respectively, and 0.87 for the support vector machine and gradient boosting decision tree models.Conclusions:Machine learning method based on radiomics can be used to construct a prediction model of gamma pass rate for specific dosimetric verification of pelvic intensity-modulated radiotherapy. The classification performance of the support vector machine model and gradient boosting decision tree model is better than that of the random forest model and adaptive boosting model.
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@#Performing external beam radiotherapy alone without chemotherapy or brachytherapy for locally advanced cervical cancer with multiple lymph node metastases is challenging. The purpose of this case report is to present the efficacy of high‑dose adaptive extended‑field intensity‑modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) in treating locally advanced cervical cancer with multiple lymph node metastases. A 67‑year‑old woman with locally advanced squamous cell carcinoma of the uterine cervix was treated by external beam radiotherapy alone due to the refusal of chemotherapy and intracavitary brachytherapy. In order to maximize the efficacy of treatment, extended‑field radiotherapy that includes the paraaortic lymph nodes as well as an adaptive IMRT‑SIB plan, was applied. The treatment was successful, resulting in complete tumor disappearance without severe adverse events. In conclusion, high‑dose adaptive IMRT‑SIB may be an alternative treatment option for locally advanced cervical cancer with multiple lymph node metastases.
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Radiation Dosage , Uterine Cervical NeoplasmsABSTRACT
Objective To analyze the effect of the fixed-jaw technique on dosimetric parameters during dynamic intensity-modulated radiotherapy (DIMRT) planning. Methods Ten patients each with nasopharyngeal carcinoma, postoperative cervical cancer, and right breast cancer after radical surgery were selected for this study; all patients underwent DIMRT in our hospital in 2020. After administration at the prescribed dose, two methods were used to design the radiotherapy plan for each patient: split-field technique (SFT) and fixed-jaw technique (FJT). The two plans were compared for the differences in the dosimetric parameters and plan verification pass rate. Results Compared with SFT, FJT showed significant decreases (P <0.05) in the following parameters for patients with nasopharyngeal carcinoma, postoperative cervical cancer, and right breast cancer after radical surgery: number of radiation fields (down by 41.5%, 47.3%, and 34.9%, respectively, t = 7.954, 24.2, and 4.949, respectively), total number of monitor units (MUs) (down by 5.6%, 5.3%, and 13.5%, respectively, t = 3.211, 2.423, and 5.481, respectively), and actual beam-on time (down by 25.3%, 23.8%, and 13.6%, respectively, t = 5.814, 9.208, and 5.655, respectively). There were significant differences in some of the dosimetric parameters for all three types of cancer patients between the two plans (P <0.05). There were no significant differences in the plan verification pass rate (P >0.05). Conclusion FJT can reduce the total number of MUs and actual beam-on time while meeting the requirements for clinically prescribed doses in DIMRT planning.
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Objective To investigate the effect of couch rotation angle on non-coplanar static intensity-modulated radiotherapy (IMRT) plan for gastric cancer and to provide a reference for clinical planning. Methods A retrospective analysis was conducted on patients who recently underwent postoperative IMRT for gastric cancer. Twenty patients who received radiotherapy in the centre of Radiation Oncology of Huanggang Central Hospital from August 2022 to January 2023 were selected. That were selected to receive a seven-field coplanar static IMRT plan based on a couch rotation angle of 0° as the control group. Then, based on the coplanar IMRT plan, only the couch rotation angle of gantry angles 30° and 330° was changed to 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, respectively, and nine different non-coplanar plans were established. The homogeneity index (HI), conformity index (CI) of the target volume, and monitor unit (MU), as well as Dmean, V20, and V30 of the left and right kidneys, Dmax, Dmean, V10, V20, and V30 of the spinal cord, and Dmax, Dmean, V10, V20, V30, and V40 of the small intestine and liver were compared among the 10 plans. The MU and the dosimetric parameters of the target volumes and When the couch rotation angle was 60°, the minimum HI and maximum CI of the target volume were 0.0714±0.0089 and 0.9271±0.0108, respectively, and the minimum MU was 438±26, with the best homogeneity and conformity in the target volume and the shortest machine treatment time (P＜0.05). When the couch rotation angle was 10°, the Dmax of the small intestine was lowest, being (4620.73±99.27) cGy. When the couch rotation angle was 60°, the Dmean of the left and right kidneys was lowest, being (1246.30±130.35) cGy and (1001.52±103.33) cGy, respectively; the V20 of the left and right kidneys was lowest, being 22.87±6.29 and 19.69±1.84, respectively; the V10 and V30 of the spinal cord were lowest, being 40.08±4.92 and 1.68±0.34, respectively (P＜0.05). Conclusion The couch rotation angle has some influence on the postoperative treatment planning for patients with gastric cancer. In the design of non-coplanar plan for gastric cancer, the couch rotation angle of 60° contributes to establishing a better radiotherapy plan.
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Objective:To explore the efficacy and adverse reactions of image-guided hypofractionated intensity-modulated radiotherapy (Ig-HypoRT) conbined with contralateral esophageal protection in treatment of patients with unresectable stage Ⅲ non-small cell lung cancer (NSCLC).Methods:The clinical data of 45 patients with unresectable stage Ⅲ NSCLC who were admitted to Xuzhou Cancer Hospital from January 2016 to January 2019 were retrospectively analyzed. Patients received induction chemotherapy with a platinum-based dual-drug combination regimen, followed by Ig-HypoRT with a total dose of tumor of 60-63 Gy/12- 18 times at 3.5-5.0 Gy/time. Contralateral esophagus was delineated as an organ at risk during radiotherapy, limiting V 45 Gy≤1.8 cc and V 55 Gy ≤0.4 cc. Patients' efficacy, survival and the occurrence of adverse reactions were observed. Results:Among 45 patients, there were 9 cases of complete remission, 31 cases of partial remission, 4 cases of stable disease and 1 case of disease progression, and the effective rate was 88.8% (40/45). The median follow-up time was 34 months, 45 patients had a median overall survival (OS) time of 25.0 months (95% CI 21.7-28.8 months), with 1-, 2-, and 3-year OS rates of 78.9%, 56.8% and 47.7%, respectively; the median progression-free survival (PFS) time was 18.5 months (95% CI 15.0-22.0 months), with 1-, 2- and 3-year PFS rates of 59.8%, 32.6% and 18.6%, respectively. The 3-year local recurrence rate was 9% (4/45). The incidence of grade 1-2 radioactive esophagitis was 80% (36/45); the incidence of grade 1-2 chest pain was 20% (9/45). The incidence of grade 3-4 adverse reactions were 13% (6/45), including 7% (3/45) of grade 3 pulmonary atelectasis, 4% (2/45) of grade 3 radioactive pneumonia, and 2% (1/45) of grade 4 hemoptysis. Conclusions:Ig-HypoRT combined with contralateral esophageal protection for unresectable stage Ⅲ NSCLC can improve survival rate and reduce esophageal adverse reactions of patients.
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Purpose: Data regarding the efficacy of various radiotherapy techniques for post mastectomy chest-wall radiotherapy (PMRT) using hypofractionation is scarce and cardiac toxicity remains a concern. This study aims to compare effect of IMRT (Intensity Modulated Radiation Therapy) and 3D-CRT (3-Dimensional Conformal Radiation Therapy) techniques on cardiac dose. Materials and Methods: In this retrospective study, we compared IMRT and 3DCRT plans of 20 patients who received PMRT to a dose of 42.56Gy/16# and the dosimetric parameters in terms of planning target volume (PTV) coverage and dose to organ at risk (OARs) including heart and ipsilateral lung were recorded and analyzed. Result: PTV coverage were comparable with both techniques. IMRT planning provided a better conformity index as compared with 3DCRT (0.95 vs 0.91, p<0.001). The mean dose to the heart significantly reduced with IMRT (4.36Gy vs 8.2Gy, p<0.00001). Conclusion: IMRT offers a significant reduction in mean heart dose than 3DCRT in patients treated with hypofractionated post-mastectomy irradiation.
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Objective:To compare three fixed-field intensity-modulated radiotherapy (IMRT) plans for nasal cavity and paranasal sinus tumors, including the coplanar IMRT (C-IMRT) plan and the non-coplanar IMRT(NC-IMRT) plan which were based on a conventional C-arm LINAC (Trilogy), and the coplanar IMRT (H-IMRT) plan based on an O-ring LINAC (Halcyon).Methods:Based on the data of 10 patients in the Ningbo First Hospital from December 2018 to December 2021 with nasal cavity and paranasal sinus tumors who underwent postoperative radiotherapy, this study redesigned three IMRT plans with the same prescribed doses and optimization objectives. Then, this study compared the doses of target volumes and organ at risks(OARs), the validation pass rates, and the execution time of these plans. Friedman test was employed in this study, and multiple comparisons were further made in cases of different results.Results:The differences in the conformal index (CI) of PTV and PTV boost of the three plans were statistically significant ( χ2 = 7.51, 9.69, P < 0.05). The multiple comparisons showed that the median CI of the H-IMRT plan was higher than that of the NC-IMRT plan ( Z = 2.53, 2.68, P < 0.05). The differences in other parameters of target volumes were not statistically significant. Compared with the C-IMRT plan, the H-IMRT plan reduced the Dmax of bilateral lenses, bilateral corneas, ipsilateral optic nerve, and ipsilateral eyeball ( Z = 2.80, 2.80, 2.80, 2.80, 2.81, 2.09, P < 0.05). Compared with the C-IMRT plan, the NC-IMRT reduced the Dmax of bilateral lenses, corneas, and eyeballs and contralateral optic nerve ( Z = 2.80, 2.66, 2.80, 2.70, 2.29, 2.29, 2.65, P < 0.05) and reduced the Dmean of bilateral eyeballs ( Z = 2.80, 2.80, P < 0.05). Compared with the NC-IMRT plan, the H-IMRT plan reduced the Dmax of the ipsilateral lens and cornea ( Z = 2.50, 2.08, P < 0.05), but increased the Dmax of the contralateral optic nerve and the Dmean of bilateral eyeballs ( Z = 2.80, 2.80, 2.80, P < 0.05). The validation pass rate of the three plans met the institutional standards, and the differences were not statistically significant. Moreover, the H-IMRT plan had the shortest median execution time (172.00 s), followed by the C-IMRT plan (337.50 s), and the NC-IMRT plan (388.00 s). Conclusions:The verification pass rate of the three plans can achieve the requirements of treatment implementation. The three plans had similar dosimetric differences in target volumes. However, the H-IMRT and NC-IMRT plans can protect the normal tissues (especially optical organs) more effectively than the C-IMRT plan, which is conducive to reducing the toxicity after radiotherapy and provides space for local dose increase or the radiotherapy for the treatment of tumor recurrence. The execution efficiency of the three plans is in the order of H-IMRT > C-IMRT > NC-IMRT. It is necessary to select appropriate radiotherapy equipment and technology according to actual situations.
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Objective To investigate the effects of bolus thickness and use frequency on skin dose in postmastectomy intensity-modulated radiotherapy. Methods We retrospectively reviewed 20 cases receiving postmastectomy fixed-field intensity-modulated radiotherapy, to analyze the homogeneity index (HI) and conformity index (CI) of the target volume and the skin dose (Dmax, Dmean, and Dmin) of radiotherapy plans with 0.5 cm-thick bolus or 1 cm-thick bolus alone at a use frequency of 5 F, 10 F, 15 F, 20 F, and 25 F versus a combination of 0.5 cm and 1 cm-thick bolus, and fit the relationship between skin dose and bolus use frequency. Results As the bolus use frequency increased, the skin dose increased, the hot spot of the target volume decreased, and the low-dose volume decreased. The HI of the target volume with the 1 cm bolus was better than that with the 0.5 cm bolus at all use frequencies (P < 0.05), and HI decreased with the increase of bolus use frequency. For both 0.5 cm and 1 cm bolus, the CI of the target volume increased initially and then decreased, reaching the maximum value at a frequency of around 15 F; the CI showed significant differences only at 20 F and 25 F between the two types of bolus (P < 0.05). The skin Dmax and Dmean were significant higher with the 0.5 cm bolus than with the 1 cm bolus (P < 0.05). The equation for the relationship between skin dose (D) and bolus use frequency (F) was D = A × F + B × F2 + C. The Dmax and HI with the combination of 0.5 cm bolus (6 F) plus 1 cm bolus (8 F) fell between those with the 0.5 cm bolus (15 F) and those with the 1 cm bolus (15 F) (P < 0.05). Conclusion In postmastectomy fixed-field intensity-modulated radiotherapy, skin dose can be calculated based on bolus use frequency. Mixed use of bolus may be more suitable than use of 0.5 cm bolus or 1 cm bolus alone.
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Objective To study the irradiation dose of organs at risk (OAR) in involved field radiation and extended field radiation in patients with thoracic esophageal cancer who received intensity modulated radiotherapy (IMRT). Methods A total of 40 patients with thoracic esophageal cancer were treated with IMRT. The involved field, extended field, and OAR were outlined to generate IMRT plans. The conformity index (CI) and homogeneity index (HI) of planning target volume (PTV) and the irradiation parameters of OAR were evaluated for the two plans. Paired t-test was used for comparison of irradiation parameters. Results The PTV of both plans received the prescribed dose. There were no significant differences in CI and HI of PTV between the two groups (P = 0.317, 0.130). There were significant differences in average lung dose, lung V5, lung V20, lung V30, spinal cord Dmean, heart Dmean, heart Dmax, heart V30, heart V40, and heart V60 between the two groups (P < 0.01). Conclusion Compared with the extended field, the involved field can reduce the irradiation dose of ORA in patients with thoracic esophageal cancer, thus reducing the risk of radiation.
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Objective To evaluate the clinical efficacy and safety of simultaneous enhanced accelerated radiation therapy for brain metastases (SMART-Brain) combined with functional area protection. Methods SMART-Brain was planned for 60 patients with multiple brain metastases. Using the whole brain intensity modulation technique, important functional areas such as hippocampus were protected against irradiation by delivering a dose of 30 Gy in 10 fractions. Meanwhile, a high dose of 40 Gy was delivered to brain metastases in 10 fractions. All patients were followed up to evaluate the efficacy, incidence of adverse reactions, median overall survival (OS), and intracranial progression-free survival (IPFS). Results The effective rate was 73.33% (44 cases), the disease control rate was 91.67% (55 cases), median OS was 15.2 months, and IPFS was 12 months. The 1 and 2-year OS was 66.7% and 26.4%, and the 1-year IPFS was 46.7%. The MMSE scores at 1, 3, and 6 months after SMART showed no significant differences compared with baseline scores (P > 0.05). Grade 2 and above inner ear damage such as otitis media, hearing loss, and dizziness was absent. Conclusion Smart-Brain can significantly reduce the treatment time and better protect the organs at risk, and serves as an economical, safe, and effective radiotherapy regimen in areas with limited technical conditions.
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Objective:To compare the efficacy and side effects between simultaneous and sequential integrated boost intensity-modulated radiotherapy after operation for high-grade glioma.Methods:We retrospectively analyzed 142 patients with high-grade glioma who underwent postoperative radiotherapy from January 2010 to December 2017. All patients were divided into the simultaneous and sequential integrated boost intensity-modulated radiotherapy groups. Concurrent temozolomide chemotherapy was delivered during radiotherapy in two groups. The follow-up outcomes were statistically compared between two groups.Results:For the whole group, the median overall survival (OS) was 24 months, the median progression-free survival (PFS) was 17 months, and the median disease-free survival (DFS) was 25 months. In the simultaneous and sequential integrated boost intensity-modulated radiotherapy groups, the median OS were 27.2 and 21.0 months ( P=0.950), the median PFS were 21.2 and 15.0 months ( P=0.21), and the median DFS were 28.0 and 18.0 months ( P=0.171), and the disease control rates were 92.86% and 85.17%( P=0.541), respectively. There was no statistical difference in OS, PFS, DFS, short-term efficacy and side effects between two groups. However, the conformity index in the simultaneous integrated boost intensity-modulated radiotherapy group was better than that in the sequential integrated boost intensity-modulated radiotherapy group ( P=0.032). Conclusions:Postoperative simultaneous and sequential integrated boost intensity-modulated radiotherapy yield no statistical differences in the survival, short-term efficacy and side effects in the treatment of high-grade glioma. However, the conformity index in the simultaneous integrated boost intensity-modulated radiotherapy group is significantly better, which can be recommended for postoperative radiotherapy of high-grade glioma.
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Accurate delineation of clinical target volume (CTV) of nasopharyngeal carcinoma is of significance to prevent local recurrence and improve the survival rate of patients. When intensity-modulated radiotherapy (IMRT) was first introduced, CTV was delineated based on two-dimensional radiotherapy experience. The local recurrence-free survival is high, but the adverse reactions induced by radiotherapy are severe and the patients’ quality of life is poor. How to reduce CTV to alleviate acute and late radiotherapy-induced adverse reactions without deteriorating therapeutic effect has currently become a research hotspot. Despite the 2010 Chinese Nasopharyngeal Carcinoma IMRT Target and Dose Design Guideline Expert Consensus and the International Guideline for the Delineation of the CTV for Nasopharyngeal Carcinoma as references, the optimal individualized and standardized delineation of CTV remains controversial. This review summarizes the progress on the delineation of CTV of primary tumour of nasopharyngeal carcinoma, aiming to provide practical reference for clinicians.
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Objective:To evaluate the pancreatic subclinical dysfunction after intensity-modulated radiation therapy (IMRT) for gastric cancer by analyzing biochemical indexes and pancreatic volume changes, and to reduce the dose of pancreas by dosimetric prediction and dose limitation.Methods:30 patients with gastric cancer who received 45 Gy postoperative adjuvant radiotherapy were retrospectively selected. The pancreas was delineated and its dose and anatomical relationship with planning target volume (PTV) were evaluated. Fasting blood glucose, serum lipase and amylase, and pancreatic volume changes before and after radiotherapy were analyzed. The correlation between the changes of biochemical indexes and volume and pancreatic dose was evaluated by Pearson analysis. The threshold of the dosimetric prediction was obtained by receiver operating characteristic (ROC) curve. Finally, the feasibility of dosimetric limitation in IMRT was assessed.Results:The pancreatic volume of 30 patients was 37.6 cm 3, and 89.0% of them were involved in PTV. D mean of the pancreas was 45.92 Gy, and 46.45 Gy, 46.46 Gy and 45.80 Gy for the pancreatic head, body and tail, respectively. The fasting blood glucose level did not significantly change. The serum lipase levels were significantly decreased by 66% and 77%(both P<0.001), and the serum amylase levels were significantly declined by 24% and 38%(both P<0.001) at 6 and 12 months after radiotherapy. Pancreatic volumes of 22 patients was decreased by 47% within 18 months after radiotherapy. ROC curve analysis showed that pancreatic V 45Gy had the optimal predictive value for the decrease by 1/3 of serum lipase and amylase levels at 6 months and serum amylase level at 12 months after radiotherapy, and the cut-off value was V 45Gy<85%. Pancreatic D mean yielded the optimal predictive value for the decrease by 2/3 of serum lipase level at 12 months after radiotherapy, and the cut-off value was D mean<45.01 Gy. After" whole pancreas" and" outside PTV pancreas" dose limit, V 45Gy of the pancreas was decreased by 11% and 7%, D mean of the pancreas was declined by 2% and 2%, and D mean of the pancreatic tail was decreased by 3%, respectively. Conclusions:Serum lipase and amylase levels significantly decline at 6 and 12 months after adjuvant radiotherapy for gastric cancer, and pancreatic volume is decreased significantly within 18 months after radiotherapy. Pancreatic V 45Gy<85% and D mean<45.01 Gy are the dose prediction values for the decrease of serum lipase and amylase levels. The dose can be reduced to certain extent by dosimetric restriction.
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Non-coplanar radiotherapy is a kind of radiotherapy technology which employs multiple non-coplanar fixed fields or non-coplanar arcs. The non-coplanar field can be defined that the central axis of each field is not on the same plane, while the non-coplanar arc can be described that the trajectory formed by each arc is not on the same plane. Compared with coplanar radiotherapy, non-coplanar radiotherapy can achieve multi-angle or multi-radian irradiation, which effectively improves the focusing level of ray and is beneficial to enlarge the radiation dose of the target area between the surrounding normal tissues. Its dosimetric advantages have been proven in multiple types of tumors, such as intracranial tumors, liver cancer and lung cancer, etc. Multiple approaches can be employed to realize non-coplanar radiotherapy, which can be divided into the non-coplanar conic radiotherapy, non-coplanar conformal radiotherapy, non-coplanar intensity-modulated radiotherapy and non-coplanar volumetric modulated arc therapy according to the established sequence. In this review, the development process and principal characteristics of these implementations were summarized.
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Objective:To explore a new technique for lung dose reduction in esophageal cancer radiotherapy based on the dose distribution characteristics of the half-field combined with intensity-modulated radiotherapy (IMRT) technique.Methods:A three-dimensional water tank was used to measure the dose distribution at the edge of the symmetrical field and half-field, which was then compared and analyzed. Twenty patients with the middle and lower thoracic esophageal cancer receiving radiotherapy with prescription doses of 50.4-60.0 Gy were selected. Based on the Varian Vital beam linear accelerator and Eclipse planning system, flattening filter (FF) technique symmetrical field and half-field beam design and the flattening filter-free (FFF) technique symmetrical field and half-field design were adopted to compare and analyze various dose data and treatment MU numbers for the target area and the endangered organs. The field settings were chosen in the front 1 and back 4 mode.Results:Compared with the symmetrical field plan, the half-field plan significantly improved the irradiated dose to the lung with a statistically significant difference ( P<0.05), and the half-field FFF was slightly better than the half-field FF mode. Compared with the total lung V 5Gy, V 20Gy, V 30Gy, and D mean dosimetric parameters (Gy), the FF symmetric field and FFF half-field were (49.64±5.39)% vs.(42.70±5.53)%, (15.99±3.93)% vs.(13.32±3.06)%, (9.24±2.77)% vs.(8.50±2.62)%, and (10.45±1.76)% vs.(9.50±1.53)%, respectively. There was a significant reduction in the volume dose values for all structures of the lung (all P<0.05). For other comparative data, the irradiated dose for the heart of the symmetrical field was better than that of the half-field mode ( P<0.05), and the differences in conformity index (CI) and homogeneity index (HI), number of treated MU, and spinal cord associated with the target area were not statistically significant (all P>0.05). Conclusions:During radiotherapy for esophageal cancer, target area coverage and dose volume data of the lung are the main parameters affecting the efficacy and side effects. IMRT treatment based on the half-field mode can give full play to the advantages of half-field and IMRT, and significantly improve the irradiated dose to the lung, which can offer an additional clinical option.
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Objective:To investigate the dosimetric differences between conventional IMRT and electron beam conformal radiotherapy (EBCRT) combined with IMRT for post-mastectomy left-sided breast cancer patients.Methods:A total of 20 post-mastectomy left-sided breast cancer patients who were treated in the Ningbo First Hospital from June 2018 to October 2021 were retrospectively studied. The planning target volume (PTV) included the supra-and infra-clavicular regions(PTV sc)and the ipsilateral chest wall (PTV cw), and the prescribed dose was 50 Gy/25 f. All radiotherapy plans were designed using the Varian Eclipse treatment planning system (TPS). After that, the dose distribution of the target volume and the dose exposure of organs at risk (OARs) were compared and analyzed. Results:All the IMRT plans met the clinical requirements, yet 2/20 of the EBCRT combined with IMRT plans were not clinically accepted. For these two patients, the maximum chest wall thickness was 3.7 cm and 4.4 cm each, and the designed electron beam energy was 12 MeV and 15 MeV, respectively. The dose to the ipsilateral lung of these two patients exceeded the institution-specific dose limit standard. For the remaining 18 patients whose chest wall thickness was 3 cm or less, the designed electron beams were 9 MeV or less. All the EBCRT combined with IMRT plans were clinically accepted. The target dose distribution of the conventional IMRT was better than that of the EBCRT combined with IMRT (uniformity index (HI): PTV sc: t = -10.20, P<0.05; PTV cw: t = -9.24, P<0.05; conformal index (CI): PTV all: t = 10.39, P <0.05). For OARs, the V5 Gy, V20 Gy, and Dmean of the ipsilateral lung of EBCRT combined with IMRT were lower than those of IMRT ( t = 5.98, 6.30, 11.30, P <0.05). Specifically, the V25 Gy and Dmean of heart decreased by 8.3% and 4.79 Gy, respectively ( t = 15.23, 15.76, P<0.05), the Dmean of the left anterior descending coronary artery (LADCA) decreased by 44.03% ( t = 11.69, P <0.05), and the V5 Gy and Dmean of the contralateral breast decreased by 7.9% and 0.8 Gy, respectively ( t = 3.66, 4.93, P<0.05). The dosimetric differences of other OARs were not statistically significant ( P > 0.05). Conclusions:For post-mastectomy left-sided breast cancer patients with a chest wall thickness of less than 3 cm, EBCRT combined IMRT can significantly reduce the exposure dose to the heart, the ipsilateral lung, and the contralateral breast, which is beneficial to reducing the potential risk of long-term complications after radiotherapy and can further improve the long-term overall survival rate of patients. For patients with thick chest wall, IMRT plans are more technologically ideal.
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Objective:To evaluate the effects of simultaneous integrated boost intensity-modulated radical radiotherapy (SIB-IMRT) on the long-term prognosis of patients with cervical and upper thoracic esophageal cancer.Methods:From January 2011 to December 2014, a retrospective analysis was performed in 172 patients with cervical and upper thoracic esophageal cancer who were eligible for IMRT. First, the prognosis of all the patients was evaluated using single factor and multivariate analyses. According to the different irradiation method of the patients, the patients were divided into two groups, one of which received conventional IMRT (C-IMRT) and the other of which received SIB-IMRT. Propensity score matching (PSM) analysis was applied to match the two groups of patients and to determine the treatment efficacy of patients after PSM, prognostic factors, failure modes, and side effects. SPSS19.0 statistical software was used to conduct statistical analysis.Results:The median overall survival (OS) and progression-free survival (PFS) times of all the patients were 30 months and 20 months, respectively. The fact whether the surrounding tissues and organs of esophageal lesions were invaded, clinical node staging (cN staging), chemotherapy, and GTV-maximum transverse diameter were observed to be independent influencing factors of OS and PFS in all the patients ( P<0.001, P=0.013, 0.005, 0.002; P<0.001, P=0.017, 0.034, 0.002). In addition, the independent influencing factors of PFS showed short-term efficacy ( P=0.036). After PSM, there were 54 patients in each of the two groups. The result of multivariate analysis showed that the fact whether the surrounding tissues and organs of esophageal lesions were invaded, cN staging, cTNM staging, prescribed dose, GTV-maximum transverse diameter, and irradiation method were independent factors affecting the OS ( P<0.001, P=0.008, 0.014, 0.021, 0.010, 0.008). Similarly, the fact whether the surrounding tissues and organs of esophageal lesions were invaded, cN staging, and GTV-maximum transverse diameter were observed to be independent factors that affect the PFS of patients ( P<0.001, P=0.044, 0.013). The difference in the total failure rate (70.4% vs. 50.0%) and the local regional recurrence rate (61.1% vs. 31.5%) between the C-IMRT and SIB-IMRT groups after treatment was significant ( χ2=4.68, 9.53, P=0.031, 0.002). The incidence of radiation pneumonitis of grade ≥ 1 in the C-IMRT group was significantly higher than that of the SIB-IMRT group ( χ2=6.16, P=0.046), whereas the leukocyte suppression of grade ≥ 2 in the C-IMRT group was significantly lower than that in the SIB-IMRT group ( χ2=12.77, P=0.005). Conclusions:As shown by the result of this study, compared with C-IMRT, SIB-IMRT can improve the OS of patients with cervical and upper thoracic esophageal cancer to a certain extent. Whether SIB-IMRT can improve the PFS of patients requires further research.
ABSTRACT
Objective To analyze the recurrence of breast cancer without use of chest wall bolus during adjuvant intensity modulated radiotherapy after modified radical mastectomy, so as to investigate the necessity of bolus use. Methods A total of 218 patients undergoing adjuvant intensity modulated radiotherapy after modified radical mastectomy during the period from January 2013 to June 2019 were enrolled as the study subjects. The chest wall bolus was not used during the whole period of radiotherapy after modified radical mastectomy, and the recurrence of breast cancer in the chest wall was analyzed after radiotherapy. Results The post-surgical follow-up through outpatient records, inpatients records, local residents’ health system and telephone was performed until June 31, 2021. The proportion of follow-up was 100%, and the mean follow-up period was 48.9 months. There were three cases with breast cancer recurrence in the chest wall, including one case with recurrence in the chest wall alone and two cases with recurrence in the chest wall and regional lymph nodes, and the overall recurrence of breast cancer was 1.4% in the chest wall. Among the 3 cases with breast cancer recurrence in the chest wall, there were two cases with N3 stage and positive for HER2, and one triple-negative breast cancer case, and all three cases developed distal metastases upon local recurrence. Among 218 study subjects, there were 5 cases with grade Ⅰ radioactive skin reaction, 3 cases with grade Ⅱ radioactive skin reaction, and no grade Ⅲ or Ⅳ radioactive skin reaction occurred. In addition, no grade Ⅲ or Ⅳ acute radioactive injury was seen in the chest wall skin among the 218 study subjects. Conclusion No use of chest wall bolus may be considered during adjuvant intensity modulated radiotherapy after modified radical mastectomy in presence of systemic therapy if tumor invasion into skin is not observed prior to therapy.