Evaluating the influence of 6MV and 10MV photon beams on cervical cancer volumetric-modulated arc therapy plans.

BACKGROUND: Cervical cancer is a common gynecological cancer among women worldwide. OBJECTIVE: To determine the effects of 6 MV and 10 MV volumetric-modulated arc therapy (VMAT) photon beams on the target volume (TV) planning and critical organs in cases of cervical cancer. METHODS: Fifty patients with carcinoma of the cervix who underwent radiotherapy were selected. The transverse diameter (T) of the cross section of the upper edge of the sacroiliac joint on computerized tomography (CT) images of the patients was measured, and the mean value was calculated as 34 cm. All patients were divided into two groups: Group A (T < 34 cm) and Group B (T > 34 cm). The VMAT plans were generated using 6 MV and 10 MV plans separately. The prescription dose was 47.5 Gy, and the daily dose was 1.9 Gy. RESULTS: In Group A, the planning target volume (PTV) dose assessment parameters of 6 MV and 10 MV plans and their homogeneity and conformity indices were not statistically significantly different. A significant difference was observed between the 6 MV and 10 MV plans for the PTV dose assessment parameters and the homogeneity index of the plans for Group B. The monitor units (MUs) of the 10 MV plans were lower than in the 6 MV plans in both Groups A and B, and the difference was statistically significant. The assessment parameter V40 Gy of both the rectum and bladder in the 6 MV plans was smaller than the corresponding parameter in the 10 MV plans in Group A; in Group B, the assessment parameter V50 Gy of the rectum in the 10 MV plans was smaller than in the 6 MV plans. CONCLUSION: When T < 34 cm, 6 MV energy is more suitable for the external irradiation of cervical cancer. When T > 34 cm, 10 MV energy is more suitable for cervical cancer radiotherapy. Therefore, 10 MV should be considered for patients with a large abdominal size.

Dosimetric analysis of postoperative radiotherapy for thymoma.

PURPOSE: To compare the dosimetric differences between intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) in the treatment of male and female thymoma. MATERIAL AND METHODS: This single-institutional analysis included 20 patients with thymoma treated with RT between January 2017 and December 2020. Twenty patients were retrospectively planned for IMRT (IMRT1 with an average field angle of 216°, 288°, 0°, 72°,and 144°; IMRT2 with fan-shaped field angles of 280°, 320°, 0°, 40°, and 80°) and VMAT (VMAT1 with two arcs ranging form 280° to 80°,clockwise and then counterclockwise; VMAT2 with two 360° arcs). The plans for all investigated RT modalities were optimized for a prescriptional dose of 50Gy and fractional dose of 2.0Gy. Planning target volume (PTV) and organs-at-risk (OARs: heart, breasts, lungs, spinal cord, and esophagus) dosimetric parameters were compared. RESULTS: All plans met the preparation aims for all the included metrics. There was little difference in the median values of PTV parameters (D2%, D98%, Dmean, homogeneity index[HI], and conformity index [CI]). The CI of the VMAT2 plan was the closest to 1 in both therapy groups. The monitor unit (MU) of IMRT2 and the estimated total delivery time of VMAT1 were the lowest in both therapy groups and were statistically significant. In the male group, the lung parameters (Dmean, V5Gy, V10Gy, and V20Gy) for VMAT1 were the lowest and showed statistical significance. In the female group, the lung parameters (Dmean, V5Gy, V10Gy, and V20Gy) and bilateral breast parameters (Dmean, V5Gy, V10Gy, and V20Gy) of IMRT2 were the lowest and showed statistical significance. CONCLUSIONS: In male thymoma patients undergoing postoperative RT (PORT) treatment, the choice of fan-shaped VMAT may be a better option for protecting the lungs. For female thymoma patients receiving PORT, fan-shaped IMRT can better protect the lungs and breasts. The fan-shaped field performed better than the average and the full arc fields in PORT for thymoma.

Optimization of Minimum Segment Width Parameter in the Intensity-Modulated Radiotherapy Plan for Esophageal Cancer.

PURPOSE: This study was designed to explore the optimal minimum segment width (MSW) in the intensity-modulated radiotherapy (IMRT) plan for esophageal cancer. PATIENTS AND METHODS: The imaging data of 20 esophageal cancer patients were selected for this study. Four IMRT plans were designed for each patient with MSWs of 0.5, 1.0, 1.5, and 2.0 cm. The conformity index (CI) and homogeneity index (HI) of the planning target volumes (PTV), organs at risk (OARs), control points (CP), monitor units (MU), plan delivery time (DT), and gamma passing rates (GPR) were collected and compared to appraise the treatment plan quality and delivery efficiency. RESULTS: Lower-MSW plans had larger CI and smaller HI values, and lower dose parameters of OARs and PTVs. The HI, CI, and dose parameter of OARs in the 0.5 and 1.0 cm MSW groups were similar and much better than those of the 1.5 and 2.0 cm MSW groups. Meanwhile, the plan in the 0.5 cm MSW group had significantly higher MUs, CPs, and DTs, and a significantly lower relative dose of GPR with a 3% dose difference and 3 mm distance to agreement criteria than the other three groups. CONCLUSION: The 0.5 and 1 cm MSW groups had better dosimetric parameters and IMRT plan quality than the other groups. However, plans with 0.5 cm MSW had worse delivery accuracy and efficiency than the other three groups. Thus, MSW of 1.0 cm was the optimal choice to ensure good quality, delivery accuracy, and treatment efficiency in IMRT plans for esophageal cancer.

Comparison of efficacy for postoperative chemotherapy and concurrent radiochemotherapy in patients with IIIA-pN2 non-small cell lung cancer: an early closed randomized controlled trial.

OBJECTIVE: The efficacy of postoperative concurrent radiochemotherapy (POCRT) on IIIA-pN2 non-small cell lung cancer (NSCLC) is still unclear. The aim of this randomized controlled trial was to compare POCRT with postoperative chemotherapy (POCT) alone in terms of survival and relapse patterns. METHODS: Patients with completely resected IIIA-pN2 NSCLC were randomized into POCRT or POCT groups. Chemotherapy consisted of paclitaxel (175 mg/m(2)) and cisplatin (60 mg/m(2)) administered intravenously for four cycles on day 1, 22, 43, and 64. Patients in the POCRT group received radiotherapy (50.4 Gy/28 fractions) concurrently with the first 2 cycles of chemotherapy. RESULTS: This study recruited 140 participants and was closed early because of slow accrual. Data were analyzed for 135 of them including 66 cases in the POCRT group and 69 cases in the POCT group. Patients were followed-up for a median period of 45 months. The POCRT group had a median survival (MS) of 40 months and a 5-year overall survival (OS) rate of 37.9%. The POCT group had a MS of 28 months and a 5-year OS rate of 27.5%. The hazard ratio for death in the POCRT group was 0.69 (95% CI: 0.457-1.044, P=0.073). We observed a disease-free survival (DFS) of 28 months and a 5-year DFS rate of 30.3% in the POCRT group. Likewise, we observed a DFS of 18 months and a 5-year DFS rate of 18.8% in the POCT group. The recurrence hazard ratio in the POCT group was 1.49 (95% CI: 1.008-2.204, P=0.041). Subgroup analysis revealed that POCRT significantly increased the OS rate of the patients with ≥2 pN2 lymph nodes (P=0.021). The POCRT group had a significantly lower local relapse (P=0.009) and distant metastasis (P=0.05) rates as compared to that of the POCT group. One case died of pyemia and 9 cases suffered from grade 3 and 4 acute radiation esophagitis. The two groups had similar and tolerable hematologic toxicities. CONCLUSIONS: Compared with POCT, POCRT increased both local/regional and distant DFS rate of the patients with IIIA-pN2 NSCLC, but not the OS rate. Considering the relatively small sample size of the current study, caution should be taken when adopting the conclusions.

[Application of simplified intensity modulated radiation therapy in gastric cancer after operation].

OBJECTIVE: To elucidate the application and the dosimetry characteristic of the simplified intensity modulated radiation therapy (sIMRT) for gastric cancer after operation, and to compare the dose distribution with intensity modulated radiation therapy (IMRT) and three-dimension conformal radiation therapy (3D-CRT). METHODS: Twelve patients with gastric cancer after operation were enrolled in this study. 3D-CRT plan, 5-field IMRT plans (20 degree, 80 degree, 180 degree, 280 degree, 340 degree) and 5-field sIMRT plans (20 degree, 80 degree, 180 degree, 280 degree, 340 degree) were performed for each patient. The conformal index (CI), heterogeneity index (HI) of the planning target volume (PTV) and the dose of normal organs were analyzed with the dose volume histogram (DVH). The total MU and treatment time were also compared. RESULTS: The sIMRT and IMRT plans had comparable CI (sIMRT>IMRT>3D-CRT), and showed better dose conformity but worse homogeneity than 3D-CRT. The percentage of volume receiving 20 Gy, 25 Gy, 30 Gy and 40 Gy by liver were significantly lower in sIMRT than that in 3D-CRT, and comparable to IMRT. All the dose volumes to kidneys with sIMRT were still significantly lower as compared to 3D-CRT, and comparable to IMRT. The sIMRT plan was better than IMRT plan in total MU and treatment time. CONCLUSIONS: sIMRT has comparable dose distribution in patients with gastric cancer to IMRT, but is significantly better than 3D-CRT. Treatment time of sIMRT is the shortest. So sIMRT technique can be applied more simply.

A randomized controlled study of single-agent cisplatin and radiotherapy versus docetaxel/cisplatin and radiotherapy in high-risk early-stage cervical cancer after radical surgery.

BACKGROUND: This study explored whether docetaxel/cisplatin and radiotherapy (TP-R) increases overall survival (OS) and recurrence-free survival (RFS) compared to single-agent cisplatin and radiotherapy (C-R) in patients with high-risk early-stage cervical cancer post surgery. METHODS: Patients with clinical stage IB and IIA carcinoma of the cervix, initially treated with radical hysterectomy and pelvic lymphadenectomy, and who had positive pelvic lymph nodes and/or positive margins and/or the diameter of the primary tumor ≥4 cm and/or depth of interstitial infiltration ≥1/2 and/or lymphovascular space invasion were eligible for this study. Patients were randomized to receive C-R or TP-R. Radiotherapy in both groups was external radiation (46-54 Gy) followed by high-dose rate brachytherapy (12-24 Gy). Patients were given cisplatin (40 mg/m(2)) every week for five cycles (C-R group) or docetaxel (30 mg/m(2)) and cisplatin (30 mg/m(2)) every week for five cycles (TP-R group). RESULTS: Between 2003 and 2008, 320 patients were entered onto the study. Final analyses included 285 patients. One hundred and forty patients comprised the C-R group and 145 were in the TP-R group. The 5-year OS were 74.3 % in the C-R group and 82.8 % in the TP-R group. The hazard ratio (HR) for death was 0.65 in the TP-R group (95 % CI: 0.39-1.09, P = 0.098). The RFS were 69.3 % in the C-R group and 79.3 % in the TP-R group, and the HR for recurrence was 0.64 in the TP-R group (95 % CI: 0.40-1.03, P = 0.061). Recurrence rates were similar in both groups (27 in the C-R group and 18 in the TP-R group, P = 0.112). The seriousness of late side effects was similar in the two groups, with a higher rate of reversible hematological effects in the TP-R group. CONCLUSIONS: Compared with single-agent cisplatin and radiotherapy, docetaxel/cisplatin in combination with radiotherapy does not increase OS but has the trend of increasing RFS in patients with high-risk early-stage cervical cancer. However, docetaxel/cisplatin in combination with radiotherapy is associated with a higher incidence of side effects, this effect was reversible, and the incidence of late side effects was similar in the two treatment groups.

A randomized, controlled, multicenter study comparing intensity-modulated radiotherapy plus concurrent chemotherapy with chemotherapy alone in gastric cancer patients with D2 resection.

BACKGROUND AND PURPOSE: The role of postoperative chemoradiotherapy in the treatment of patients with gastric cancer with D2 lymph node curative dissection is not well established. In this study, we compared postoperative intensity-modulated radiotherapy plus chemotherapy (IMRT-C) with chemotherapy-only in this patient population. MATERIALS AND METHODS: We randomly assigned patients with D2 lymph node dissection in gastric cancer to IMRT-C or chemotherapy-only groups. The adjuvant IMRT-C consisted of 400 mg of fluorouracil per square meter of body-surface area per day plus 20mg of leucovorin per square meter of body-surface area per day for 5 days, followed by 45 Gy of IMRT for 5 weeks, with fluorouracil and leucovorin on the first 4 and the last 3 days of radiotherapy. Two 5-day cycles of fluorouracil and leucovorin were given 4 weeks after the completion of IMRT. Chemotherapy-only group was given the same chemotherapy regimens as IMRT-C group. RESULTS: The median overall survival (OS) in the chemotherapy-only group was 48 months, as compared with 58 months in the IMRT-C group; the hazard ratio for death was 1.24 (95% confidence interval, 0.94-1.65; P=0.122). IMRT-C was associated with increases in the median duration of recurrence-free survival (RFS) (36 months vs. 50 months), the hazard ratio for recurrence was 1.35 (95% confidence interval, 1.03-1.78; P=0.029). COX multivariate regression analysis showed that lymph node metastasis and TNM stage were both the independent prognostic factors. Rates of all grade adverse events were similar in the two treatment groups. CONCLUSIONS: IMRT-C improved RFS, but did not significantly improve OS among patients with D2 lymph node dissection in gastric cancer. Using IMRT plus chemotherapy was feasible and well tolerated in patients with gastric cancer after D2 resection.

Efficacy analysis of simplified intensity-modulated radiotherapy with high or conventional dose and concurrent chemotherapy for patients with neck and upper thoracic esophageal carcinoma.

For patients with neck and upper thoracic esophageal carcinoma, it is difficult to control lymph node metastases with conventional dose therapy. In this study, we assessed the feasibility of simplified intensity-modulated radiotherapy (sIMRT) and concurrent chemotherapy for 44 patients and boosted high-dose to metastatic lymph nodes.Three radiation treatment volumes were defined: PGTVnd, with which 68.1 Gy was delivered in high dose group (hsIMRT group), and 60 Gy in the conventional dose group (csIMRT group); PTV1, featuring 63.9 Gy in the hsIMRT group and 60Gy in the csIMRT group; PTV2, with 54 Gy given to both groups. The sIMRT plan included 5 equi-angular coplanar beams. All patients received the cisplatin and 5-FU regimen concurrently with radiotherapy. The treatment was completed within six weeks and one case with grade three acute bronchitis was observed in hsIMRT group. For esophageal lesions, 80% complete response (CR) and 20% partial response (PR) rates were found in the hsIMRT group, and 79.2% CR, with 20.8% PR, in the csIMRT group; for lymph node lesions, 75% CR and 25% PR rates were observed in the hsIMRT group, with 45.8% and 37.5% respectively in the csIMRT group (P <0.05). The differences in 1-, 2- and 3-year relapse-free survival rates were all statistically significant (P <0.05). The major toxicity observed in both groups was Grade I~II leucopenia. sIMRT can generate a desirable dose distribution in treatment of neck and upper thoracic esophageal carcinoma with a better short-term efficacy. Boosted high dosing to metastatic lymph nodes can increase the relapse-free survival rate.

[Feasibility and short-term efficacy of simplified intensity-modulated radiotherapy and concurrent chemotherapy for neck and upper thoracic esophageal carcinoma].

BACKGROUND AND OBJECTIVE: For neck and upper thoracic esophageal carcinoma, three dimensional conformal radiation therapy (3D-CRT) does not necessarily meet all clinical requirements while intensity modulated radiation therapy (IMRT) may take up a lot of labour power and material resources. This study was to explore the feasibility of simplified IMPT(sIMRT) and concurrent chemotherapy for neck and upper thoracic esophageal carcinoma, and to investigate the acute toxicities and short-term efficacy of this treatment modality. METHODS: sIMRT plans were designed for 30 patients with neck and upper thoracic esophageal carcinoma. Two target volumes were defined: PTV1, which was designed to irradiate to 64 Gy (2.13 Gy x 30 fractions); PTV2, which was given to 54 Gy (1.8 Gy x 30). The sIMRT plan included five equiangular coplanar beams. All patients concurrently received DDP+5-FU regimen with radiotherapy on d1-5 and d29-33. Chemotherapy was repeated for two cycles 28 days after radiotherapy. RESULTS: The treatment was completed for all patients within 6 weeks, and only one patient had Grade 3 acute bronchitis. The complete response (CR) rate was 90.0% (27/30) and the partial response (PR) rate 10.0% (3/30). Overall response was 100% for esophageal lesions and the CR rate 76.5% (13/17). The PR rate was 23.5% (4/17) in lymph node lesions. The major toxicities observed were Grades I-II leukocytopenia. CONCLUSIONS: sIMRT can generate desirable dose distribution for neck and upper thoracic esophageal carcinoma, which is similar to sophisticated IMRT but obviously better than 3D-CRT. The short-term efficacy of sIMRT is satisfactory and its acute toxicities are tolerable.