Objective:To analyze the incidence and influencing factors of lymphopenia in prostate cancer patients undergoing pelvic radiotherapy.Methods:A retrospective analysis was conducted on 123 prostate cancer patients treated at the Department of Radiation Oncology, Peking University First Hospital, from November 2011 to May 2015. Radiotherapy was administered using conventional fractionated intensity-modulated radiotherapy. Blood routine, including absolute lymphocyte count (ALC), was performed on patients before radiotherapy, weekly during radiotherapy, and at the end of radiotherapy. Severe lymphopenia was defined as an ALC <500 cells/μl. Based on whether the minimum ALC during radiotherapy was lower than 500 cells/μl, the entire cohort and 55 patients (excluding those with undelineated pelvic bone marrow due to radiotherapy planning system issues) with delineated pelvic bone marrow (divided into pelvic bone marrow, iliac bone marrow, and lower pelvic bone marrow) were stratified into a severe lymphopenia group (33 cases and 16 cases, respectively) and a mild lymphopenia group (90 cases and 39 cases, respectively). Differences in clinical factors and dosimetric parameters were compared between the groups using the chi-square test (or Fisher's exact test), t-test, and Wilcoxon rank-sum test. Univariate and multivariate logistic regression analyses were performed to identify the clinical and dosimetric factors influencing severe lymphopenia. Results:All 123 prostate cancer patients experienced lymphopenia during radiotherapy, with a median minimum ALC of 0.6×10 9/L [range: (0.2-2.3)×10 9/L]. Severe lymphopenia occurred in 26.8% (33 cases) of patients. Univariate analysis of the entire cohort showed that pre-radiotherapy baseline ALC, initial neutrophil-to-lymphocyte ratio, prostate-specific antigen value, Gleason score, and pelvic radiotherapy were promoting factors for severe lymphopenia ( P<0.05). Multivariate analysis identified pre-radiotherapy baseline ALC ( OR=0.217, 95% CI: 0.072-0.650, P=0.006) and pelvic radiotherapy ( OR=23.852, 95% CI: 2.834-200.787, P=0.004) as promoting factors for severe lymphopenia. In patients with delineated pelvic bone marrow, univariate analysis showed that pelvic bone marrow V 30 Gy and V 40 Gy, iliac bone marrow V 30 Gy and V 40 Gy, lower pelvic bone marrow V 30 Gy and V 40 Gy were promoting factors for severe lymphopenia during treatment ( P<0.05). Conclusions:Lymphopenia is common in prostate cancer patients undergoing radiotherapy, with a high incidence of severe lymphopenia. Pre-radiotherapy baseline ALC, as well as pelvic, iliac, and lower pelvic bone marrow V 30 Gy and V 40 Gy, are promoting factors for severe lymphopenia during radiotherapy.

Objective:To compare the efficacy and safety of extended-field versus reduced-field radiotherapy in upper tract urothelial carcinoma (UTUC) patients after radical operation.Methods:A retrospective analysis was conducted on the data of 210 UTUC patients who underwent full-length nephrectomy and received postoperative adjuvant radiotherapy in Peking University First Hospital from January 2013 to November 2023, and follow-up continued until June 2024. According to the target area of postoperative radiotherapy, patients were divided into the extended-field radiotherapy group (127 cases) and the reduced-field radiotherapy group (83 cases). The overall survival (OS), distant metastasis free survival (DMFS), local recurrence free survival (LRFS) and adverse reactions were compared. In the same period, 114 patients with recurrent abdominal and pelvic lymph nodes who did not receive adjuvant therapy after surgery for UTUC in our center were prospectively collected, and the coverage of the reduced-field target area was analyzed. Chi square test was used to compare the clinical characteristics, Kaplan-Meier method was used to analyze survival outcomes, log-rank test was used to compare the survival rate, and Cox multivariate regression analysis was performed on the influencing factors of survival.Results:The median follow-up was 24.5 (range: 3-74) months. There were no significant differences between the extended-field and reduced-field radiotherapy groups in terms of 2-year LRFS (93.3% vs. 98.1%, P=0.156), 2-year DMFS (84.8% vs. 91.2%, P=0.176), and 2-year OS (90.4% vs. 90.7%, P=0.707). The most common toxicities of adjuvant radiotherapy were nausea and leukopenia, with significantly higher grade 1-2 incidence in the extended-field group compared to the reduced-field group ( P<0.05). According to the analysis of patients with retroperitoneal lymph node recurrence after surgery, the reduced-field target designed according to the location of the primary tumor can cover more than 90% of the postoperative metastatic lymph node area Multivariate analysis revealed that variant histology ( HR=2.180,95% CI: 1.021-4.658, P=0.044) was an independent predictor of worse DMFS, while variant histology ( HR=3.825,95% CI: 1.514-9.662, P=0.005) and T 3-4 stage ( HR=4.452,95% CI: 1.025-19.339, P=0.046) were independent predictors of poorer OS. Conclusions:Compared with extended-field radiotherapy, reduced-field radiotherapy designed based on primary tumor location significantly reduced treatment-related toxicities without compromising postoperative therapeutic efficacy, and the reduced-field can cover more than 90% of local recurrent lesions.

Objective:To analyze the incidence and influencing factors of lymphopenia in prostate cancer patients undergoing pelvic radiotherapy.Methods:A retrospective analysis was conducted on 123 prostate cancer patients treated at the Department of Radiation Oncology, Peking University First Hospital, from November 2011 to May 2015. Radiotherapy was administered using conventional fractionated intensity-modulated radiotherapy. Blood routine, including absolute lymphocyte count (ALC), was performed on patients before radiotherapy, weekly during radiotherapy, and at the end of radiotherapy. Severe lymphopenia was defined as an ALC <500 cells/μl. Based on whether the minimum ALC during radiotherapy was lower than 500 cells/μl, the entire cohort and 55 patients (excluding those with undelineated pelvic bone marrow due to radiotherapy planning system issues) with delineated pelvic bone marrow (divided into pelvic bone marrow, iliac bone marrow, and lower pelvic bone marrow) were stratified into a severe lymphopenia group (33 cases and 16 cases, respectively) and a mild lymphopenia group (90 cases and 39 cases, respectively). Differences in clinical factors and dosimetric parameters were compared between the groups using the chi-square test (or Fisher's exact test), t-test, and Wilcoxon rank-sum test. Univariate and multivariate logistic regression analyses were performed to identify the clinical and dosimetric factors influencing severe lymphopenia. Results:All 123 prostate cancer patients experienced lymphopenia during radiotherapy, with a median minimum ALC of 0.6×10 9/L [range: (0.2-2.3)×10 9/L]. Severe lymphopenia occurred in 26.8% (33 cases) of patients. Univariate analysis of the entire cohort showed that pre-radiotherapy baseline ALC, initial neutrophil-to-lymphocyte ratio, prostate-specific antigen value, Gleason score, and pelvic radiotherapy were promoting factors for severe lymphopenia ( P<0.05). Multivariate analysis identified pre-radiotherapy baseline ALC ( OR=0.217, 95% CI: 0.072-0.650, P=0.006) and pelvic radiotherapy ( OR=23.852, 95% CI: 2.834-200.787, P=0.004) as promoting factors for severe lymphopenia. In patients with delineated pelvic bone marrow, univariate analysis showed that pelvic bone marrow V 30 Gy and V 40 Gy, iliac bone marrow V 30 Gy and V 40 Gy, lower pelvic bone marrow V 30 Gy and V 40 Gy were promoting factors for severe lymphopenia during treatment ( P<0.05). Conclusions:Lymphopenia is common in prostate cancer patients undergoing radiotherapy, with a high incidence of severe lymphopenia. Pre-radiotherapy baseline ALC, as well as pelvic, iliac, and lower pelvic bone marrow V 30 Gy and V 40 Gy, are promoting factors for severe lymphopenia during radiotherapy.

Objective:To compare the efficacy and safety of extended-field versus reduced-field radiotherapy in upper tract urothelial carcinoma (UTUC) patients after radical operation.Methods:A retrospective analysis was conducted on the data of 210 UTUC patients who underwent full-length nephrectomy and received postoperative adjuvant radiotherapy in Peking University First Hospital from January 2013 to November 2023, and follow-up continued until June 2024. According to the target area of postoperative radiotherapy, patients were divided into the extended-field radiotherapy group (127 cases) and the reduced-field radiotherapy group (83 cases). The overall survival (OS), distant metastasis free survival (DMFS), local recurrence free survival (LRFS) and adverse reactions were compared. In the same period, 114 patients with recurrent abdominal and pelvic lymph nodes who did not receive adjuvant therapy after surgery for UTUC in our center were prospectively collected, and the coverage of the reduced-field target area was analyzed. Chi square test was used to compare the clinical characteristics, Kaplan-Meier method was used to analyze survival outcomes, log-rank test was used to compare the survival rate, and Cox multivariate regression analysis was performed on the influencing factors of survival.Results:The median follow-up was 24.5 (range: 3-74) months. There were no significant differences between the extended-field and reduced-field radiotherapy groups in terms of 2-year LRFS (93.3% vs. 98.1%, P=0.156), 2-year DMFS (84.8% vs. 91.2%, P=0.176), and 2-year OS (90.4% vs. 90.7%, P=0.707). The most common toxicities of adjuvant radiotherapy were nausea and leukopenia, with significantly higher grade 1-2 incidence in the extended-field group compared to the reduced-field group ( P<0.05). According to the analysis of patients with retroperitoneal lymph node recurrence after surgery, the reduced-field target designed according to the location of the primary tumor can cover more than 90% of the postoperative metastatic lymph node area Multivariate analysis revealed that variant histology ( HR=2.180,95% CI: 1.021-4.658, P=0.044) was an independent predictor of worse DMFS, while variant histology ( HR=3.825,95% CI: 1.514-9.662, P=0.005) and T 3-4 stage ( HR=4.452,95% CI: 1.025-19.339, P=0.046) were independent predictors of poorer OS. Conclusions:Compared with extended-field radiotherapy, reduced-field radiotherapy designed based on primary tumor location significantly reduced treatment-related toxicities without compromising postoperative therapeutic efficacy, and the reduced-field can cover more than 90% of local recurrent lesions.

Objective:To explore the effect of a new teaching mode, which includes bridge-in, outcome, pre-test, participation, post-test and summary (BOPPPS), on the online teaching of radiobiology related knowledge for cancer radiotherapy practitioners.Methods:Taking the cell survival curve, cell cycle and radiosensitivity as examples, the radiotherapy practitioners in multiple university-affiliated hospitals were organized to carry out a multicenter prospective randomized control study. All practitioners were randomly divided into BOPPPS group and control group. The courses for BOPPPS group were designed as an online classroom, consisting of pre-class preparation, online teaching and post-class stages. The online teaching stage included video viewing, basic knowledge learning, literature discussion, group discussion and others. The control group employed the traditional teaching mode. The χ2 test was used to compare the consistency of general conditions between the two groups, and nonparametric test was used to compare the differences in scores between two or more groups. Results:The score of the pre-class test was 58.56 ± 0.99. Post-class average score for BOPPPS group was 85.48±0.85 and for control group 77.79±1.10, with the former being higher 7.69 ( Z=5.31, P<0.001) than the latter. The average answer time was (296.62±15.40) s for BOPPPS group and (386.41±21.27) s for control group, with the former being shorter 89.79 s ( Z=3.34, P=0.001) than latter. Subgroup analysis shown that the scores of BOPPPS group were significantly rising, regardless of whether or not the students had studied radiobiology courses. Among the students who have not studied these courses, the scores were rising greatly. Moreover, From the analysis of different positions, it was found that both the scores of BOPPPS group and control group have risen, especially for doctors, deputy chief doctors, physicists and technicians. There were also statistically differences between different degrees, with significantly rise in scores for undergraduate and doctoral students ( Z=3.64, 4.18, P<0.001). Conclusions:The flexible application of BOPPPS teaching mode to the online education of such boring disciplines, like radiobiology, is of great significance to raise the theoretical basis of radiotherapy practitioners.

Objective:Partial stereotactic ablative boost radiotherapy(P-SABR)is a method to deliver SABR boost to the gross tumor boost volume(GTVb), followed by conventionally fractionated radiotherapy to the whole tumor area(GTV). GTVb is the max volume receiving SABR while ensuring the critical organ-at-risk(OAR)falloff to 3 GyE/f. We investigated the potential advantage of proton therapy in treating bulky non-small cell lung cancer(the tumor length greater than 8 cm).Methods:Nine patients with bulky NSCLC treated with photon P-SABR in our institute were selected. For the treatment planning of proton therapy, the GTVb target area was gradually outwardly expanded based on the photon GTVb target area until the dose to critical OARs reached 3 GyE/f. The GTV and CTV areas remained the same as photon plan. A proton intensity-modulated radiation treatment plan(proton-IMPT), a photon intensity-modulated radiation treatment plan(photon-IMRT)and a photon volumetric modulated arc therapy(photon-VMAT)were created for each patient, respectively. The dosimetric parameters of different treatment plans were compared.Results:The volume ratio of GTVb-photon and GTVb-proton to GTV was(25.4±13.4)% and(69.7±30.0)%,respectively( P<0.001). In photon-IMRT, photon-VMAT, and proton-IMPT plan groups, the mean dose of CTV was(76.1±4.9)Gy, (78.2±3.6)Gy, and(84.7±4.9)Gy, respectively; the ratio of tumor volume with Biologic Effective Dose(BED)≥ 90 Gy to GTV volume was(70.7±21.7)%, (76.8±22.1)%,and(97.9±4.0)%,respectively. The actual dose and BED to the tumor area of the proton-IMPT plan group were significantly higher than those of the photon plan group(both P<0.05). Besides, the OARs dose was significantly decreased in the proton-IMPT group, with(49.2±22.0)%, (56.8±19.0)% and(16.1±6.3)% of the whole lung V5 for photon-IMRT, photon-VMAT and proton-IMPT, respectively(all P<0.001). Conclusions:Larger GTV boost target volume, higher BED and reduced OARs dose can be achieved in proton plans compared with photon plans. Proton P-SABR is expected to further improve the local control rate of bulky NSCLC with fewer adverse effects.

GABA is the main inhibitory neurotransmitter in the CNS acting at two distinct types of receptor: ligand-gated ionotropic GABA

Objective:To explore the amplitude of normal kidney motion in the 3D direction and its influencing factors under free-breathing condition.Methods:Clinical data of 28 patients with a KPS score≥80 who received 4D CT scan from March 2018 to March 2019 were collected. All patients were diagnosed with liver, pancreatic or lung tumors. The kidney was outlined and the geometric center and 3D coordinate values were recorded. The motion of bilateral kidneys in each direction and the 3D direction was calculated. The volume of kidney and surrounding organs, age, sex, height and body mass index (BMI) were recorded. Clinical data were statistically compared by t-test or nonparametric test. Results:The motion of the left and right kidneys in the the sup-inf (SI) direction were the largest up to (8.39±3.18) mm and (7.71±3.55) mm. The motion amplitudes of bilateral kidneys in male patients were significantly larger than those of the female counterparts in the left-right (LR), SI and 3D directions (all P<0.05). The motion amplitudes of bilateral kidneys in patients taller than 165 cm were significantly larger than those of their counterparts with a height of ≤165 cm (all P<0.05). Patients with a BMI≥25 kg/m 2 had significantly larger motion amplitudes of the left kidney in the LR and ant-post (AP) directions compared with those of normal weight counterparts (all P<0.05). The motion amplitude of the left kidney in the AP direction in patients with the left kidney volume of >180 cm 3 was significantly larger than that of patients with smaller left kidney volume ( P=0.014). Age was not significantly associated with kidney motion in each direction ( P>0.05). Conclusions:Kidney motion mainly occurs in the SI direction. The kidney motion amplitudes in male and taller patients are larger. Special attention should be paid to the use of breath motion control device to decrease the normal tissue damage.

Objective:To investigate the efficacy and safety of radiotherapy for all metastases in patients with metachronous oligo-metastatic prostate cancer after radical treatment.Methods:From October 2011 to February 2021, 41 patients with prostate cancer with less than 5 metastases after radical treatment were retrospectively analyzed in a single center. The median age at radiotherapy was 68 (57-81) years. Forty patients (98%) received androgen deprivation therapy (ADT). There were 28 patients in the hormone sensitive (HSPC) group and 13 patients in the hormone resistant (CRPC) group. The median initial PSA was 24.4 (7.4-399.0) ng/ml. Tumor stage: T 2 stage 11 patients, T 3 stage 27 patients, T 4 stage 3 patients.30 patients were in N 0 stage and 11 patients in N 1 stage. Gleason score was 7 in 12 patients, 8 in 9 patients, 9 in 18 patients, and 10 in 2 patients.33 patients were treated with surgery, and 8 patients were treated with radiotherapy. The time span from diagnosis to metastasis was 3.1 (0.2-1.8) years. Conventional imaging examination (CT/ MRI/bone scan) before radiotherapy was used in 7 patients, and PSMA PET/CT examination was used in 34 patients.The median PSA before radiotherapy was 1.3(0.1-33.8) ng/ml. There were 62 metastases in 41 patients, including 1 lesion in 28 patients, 2 lesions in 9 patients, 3 lesions in 2 patients, and 5 lesions in 2 patients. Fifty-four patients had bone metastases and eight had retroperitoneal lymph node metastases. Twenty-two bone metastases were located in the pelvis, 18 in the vertebral body, 12 in the ribs, one in the femur and one in the sternum.The median metastatic volume was 5.8(0.2-81.7) cm 3.Daily image-guided rotational intensity modulated radiotherapy was used to cover all metastases.Dose segmentation modes include 37.5Gy/7.5Gy/5F, 60Gy/3Gy/20F, 65-70Gy/2.6-2.8Gy/25F.The median biological effective dose (BED 3) was 120 (67-147) Gy. The primary endpoint was biochemical progression-free survival (BPFS), the secondary endpoints were acute and late toxic side effects, local relapse-free survival (LPFS), and overall survival (OS). Results:The median follow-up time was 21 months (range 5-72 months). All patients completed radiotherapy, and 16 patients had grade 1 to 2 acute toxicity and side effects, and no grade 3 or above acute and late stage side effects. 1-year LPFS was 97.1%.The 1-year and 2-year BPFS were 77.5% and 59.2%, respectively. The median BPFS time was 29 months (range 13.9-44.2 months). Univariate analysis showed that the HSPC group ( P<0.001) and the group with total metastatic volume ≤ 5.8cm 3 ( P=0.010) had higher BPFS. The median BPFS time was 37 months in the retroperitoneal lymph node metastases subgroup and 17 months in the bone metastases subgroup ( P=0.141). In the HSPC group, the median BPFS was 30(22-38) months. After radiotherapy, PSA decreased in all 28 patients, and increased in 6 patients. The median BPFS was 12(4-18) months. In the CRPC group, the median BPFS was 4(0-8) months. PSA decreased in 10 patients (76.9%) after radiotherapy, and PSA decreased in 6 patients. The median BPFS was 5(3-28) months. Three patients’PSA did not decrease after radiotherapy, and they were treated with new endocrine therapy drugs, chemotherapy, immunotherapy and other systemic therapy. Conclusions:For patients with metachronous metastases after radical treatment, full coverage radiotherapy has good safety and high local control rate. HSPC patients and patients with low tumor load could be recommended to receive radiotherapy for all metastatic lesions preferentially, and patients with only retroperitoneal lymph node metastases may have better prognosis after radiotherapy than patients with bone metastases.

Objective:To evaluate the dosimetric properties of intensity-modulated proton therapy (IMPT) plans for simulated treatment planning in patients with ventricular tachycardia (VT) using stereotactic ablative body radiotherapy (SABR), in comparison with the volumetric-modulated arc therapy (VMAT).Methods:A total of 25 gross target volume (GTV) of the apical, anterior, septal, inferior and lateral wall of the left ventricle (LV) were delineated on the CT simulation images of 5 patients with complete data. An additional 5 mm GTV margin was added to the internal target volume (ITV), and an additional 3 mm ITV margin was added to the planning target volume (PTV). VMAT and IMPT plans were designed in each target area. Dose prescription was 25 Gy (RBE) in a single fraction. The dosimetric differences of ITV and organ at risk (OAR) were compared between VMAT and IMPT.Results:The median volume of ITV was 45.40 cm 3(26.72-67.59 cm 3). All plans had adequate target coverage(V 95%Rx≥99%). Compared with the VMAT plans, IMPT reduced the D mean of whole heart, pericardium and non-target cardiac tissues (relative difference) by 44.52%, 44.91% and 60.16%, respectively, which also reduced D 0.03 cm 3 of the left anterior descending artery by 17.58%( P<0.05). After stratified analysis according to the lesion sites, IMPT could still reduce the dose of most OAR. However, the D 0.03 cm 3 of LAD and LCX for the lesions in the anterior wall of LV, the D 0.03 cm 3 of LCX in the inferior wall and D 0.03 cm 3 of LAD in the apical wall did not significantly differ (both P>0.05). Conclusions:Both VMAT and IMPT plans can meet the clinical dosimetric requirements when SABR is simulated in patients with VT. However, IMPT can lower the dose of normal heart tissues, which has the potential benefit of reducing the risk of complications, such as ischemic heart disease, pericarditis/pericardial effusion, etc.