Radical chemoradiotherapy is the standard treatment for unresectable locally advanced esophageal carcinoma, but its efficacy needs to be further improved, and combined immunotherapy is a potential direction to solve this issue. At present, the combination of radical radiotherapy and chemotherapy with immunotherapy mainly includes three modes: induction chemotherapy combined with immunotherapy before radiotherapy and chemotherapy, concurrent immunotherapy during radiotherapy and chemotherapy, and immune maintenance therapy after radiotherapy and chemiotherapy. A number of phase I and Ⅱ clinical trials have shown that radiotherapy and chemotherapy combined with immunotherapy can be tolerated by patients with good clinical efficacy, and more research data and long-term follow-up results are expected. At the same time, the adverse reactions caused by immunotherapy still deserve attention. Finding the optimal combination therapy mode, screening the patient population suitable for the treatment mode, and predicting and identifying serious adverse reactions as early as possible are the directions that need to be explored continuously.

Cervical cancer is a malignant tumor of the female reproductive system, which is closely related to persistent infection with high-risk human papillomavirus (HPV). Locally advanced cervical cancer (LACC) refers to cervical cancer of stage IB3 to IVA [International Federation of Gynecology and Obstetrics (FIGO) 2018 staging], characterized by tumor diameter greater than 4 cm or invasion of adjacent tissues. The standard treatment for LACC is concurrent chemoradiotherapy, with cisplatin as the preferred chemotherapeutic agent. However, there is still a clinical need for further improvement of the overall prognosis of LACC, and exploring effective adjuvant treatment strategies after concurrent chemoradiotherapy to increase the cure rate and quality of life of LACC patients is an important topic in clinical practice. This article reviews the types, indications, effects and existing problems of adjuvant treatment after concurrent chemoradiotherapy for LACC.

Objective:To evaluate the effects of different imaging frequencies and matching strategies of cone-beam computed tomography (CBCT) on dose-volume parameters in target and organs at risk (OAR) during image-guided radiotherapy for prostate cancer.Methods:A total of 561 sets of CBCT images from 21 patients treated with radical prostate radiotherapy who were admitted to Peking University First Hospital from June 2022 to May 2023 were retrospectively analyzed. All patients received volumetric intensity modulated arc therapy (VMAT) at a prescribed dose of 70 Gy divided into 25 times, 2.8 Gy per time. Clinical target volume (CTV) and OAR were delineated by the same oncologist on each CBCT image. The planned CT (pCT) was rigorously registered to CBCT after calibration of positioning errors according to different image guidance modes and frequencies, and CT values and structures were propagated to CBCT through deformable image registration (DIR). The daily dose was mapped to pCT according to the deformation vector field (DVF) for dose accumulation. The actual cumulative dose of daily online CBCT validation was compared with the weekly CBCT validation regimen (days 1, 2, 3, 6, 11, 16 and 21 online imaging). The dosimetric comparison was also made between bone-based matching and soft tissue-based matching (after automatic bone-based matching, manual prostate-based matching was performed and fine-tuning was made regarding the anterior wall of rectum). Wilcoxon signed rank-sum test was utilized to analyze dose-volume parameters between planned and cumulative doses that exhibited non-normal distribution, while paired t-test was employed for assessing shift values and average dose parameters that demonstrated normal distribution. Results:Compared with daily CBCT image guidance, the CTV_D 98% in weekly CBCT was significantly reduced [(69.08±1.58) vs. (65.24±3.64) Gy, P<0.001]. The CTV_D 98% of bone-based matching was (69.27±2.14) Gy, but the high-dose volume of the rectum were significantly increased: V 60 Gy was 3.18%±3.10%, V 65 Gy was 0.77%±1.23%. The target area coverage using soft tissue-based matching is sufficient, with a CTV_D 98% of (69.08±1.58) Gy. And the percentage volume of high-dose volume of the rectum was significantly reduced, with V 60 Gy being 2.02%±2.42% and V 65 Gy being 0.34%±0.68%. Conclusions:In prostate cancer patients undergoing moderately-fractionated radiotherapy, daily CBCT image guidance demonstrates superior target coverage compared to a weekly scheme. Soft tissue-based matching, which is automatic bone-based matching followed by manual soft tissue-based matching and fine-tuning according to the anterior rectal wall, offers better rectal protection while maintaining target coverage.

Objective:To investigate the advantage of three dimensional(3D)-printed tissue compensators in radiotherapy for superficial tumors at irregular sites.Methods:A subcutaneous xenograft model of prostate cancer in nude mice was established. Mice were randomly divided into no tissue compensator group( n=6), common tissue compensator group( n=6), and 3D-printed tissue compensator group( n=6). Computed tomography (CT) images of nude mice in the 3D-printed tissue compensator group were acquired. Compensator models were made using polylactic acid, and material properties were evaluated by measuring electron density. CT positioning images of the three groups after covering the corresponding tissue compensators were acquired to delineate the gross tumor volume (GTV). Nude mice in the three groups were irradiated with 6 MV X-rays at the prescribed dose. The prescribed dose for the three groups was 1 500 cGy. The dose distribution in the GTV of the three groups was calculated and compared using the analytical anisotropic algorithm in the Eclipse 13.5 treatment planning system. The metal-oxide-semiconductor field-effect transistor was used to verify the actual dose received on the skin surface of nude mice. Results:The air gap in the 3D-printed tissue compensator group and the common tissue compensator group was 0.20±0.07 and 0.37±0.07 cm 3, respectively ( t=4.02, P<0.01). For the no tissue compensator group, common tissue compensator group, and 3D-printed tissue compensator group, the D95% in the target volume was (1 188.58±92.21), (1 369.90±146.23), and (1 440.29±45.78) cGy, respectively ( F=9.49, P<0.01). D98% was (1 080.13±88.30), (1 302.76±158.43), and (1 360.23±48.71) cGy, respectively ( F=11.17, P<0.01). Dmean was (1 549.08±44.22), (1 593.05±65.40), and (1 638.87±40.83) cGy, respectively ( F=4.59, P<0.05). The measured superficial dose was (626.03±26.75), (1 259.83±71.94), and (1 435.30±67.22) cGy, respectively ( F=263.20, P<0.001). The percentage variation in tumor volume growth after radiation was not significantly different between the common tissue compensator group and the 3D-printed tissue compensator group ( P>0.05). Conclusions:3D-printed tissue compensators fit well to the body surface, which reduces air gaps, effectively increases the dose on the body surface near the target volume, and provides ideas for radiotherapy for superficial tumors at some irregular sites.

Objective:To compare the efficacy and safety of standard treatment with or without adjuvant chemotherapy in patients with highly malignant non-metastatic prostate cancer.Methods:In this prospective non-randomized controlled study, consecutive non-metastatic prostate cancer patients with pathologically proven Gleason score of 9-10 or Gleason score of 5 admitted to Peking University First Hospital were enrolled. Four to six cycles of chemotherapy using docetaxel ± carboplatin regimen were added or not after standard radical therapy. The primary end point was 5-year event-free survival (EFS), and the secondary end points were distant metastasis-free survival (MFS), overall survival (OS), and treatment-related adverse events. The survival curve was drawn by Kaplan-Meier method. The differences between two groups were analyzed by log-rank test.Results:A total of 176 patients were consecutively enrolled from November 2019 to January 2022 of which 138 patients received only standard radical therapy (control group), and 38 patients received adjuvant chemotherapy after standard radical therapy (chemotherapy group). The median follow-up time was 13.4 (2.0-34.0) months. All patients survived. The 30-month EFS rates in the chemotherapy and control groups were 100% and 85.6%, respectively ( P=0.064). There were no events in the chemotherapy group, while there were 12 cases of events in the control group, including 6 cases of biochemical recurrence and 6 cases of imaging progression. The 30-month MFS rates in two groups were 100% and 91.9%, respectively ( P=0.205). After the 1 vs. 2 propensity score matching, the EFS and MFS rates in two groups were 100% vs. 85.7% ( P=0.056), and 100% vs. 92.2% ( P=0.209), respectively. The incidence rates of grade 2 and above urinary toxicity in the chemotherapy and control groups were 2.6% and 7.2% ( P=0.354), respectively. The incidence rates of grade 2 and above rectal toxicity were 5.3% and 5.1% ( P=0.711), respectively. Grade 3 and above chemotherapy-related toxicity in the chemotherapy group were leukopenia (31.6%), thrombocytopenia (2.6%) and alopecia (13.2%). Conclusion:The addition of adjuvant chemotherapy after standard radical therapy tends to improve the overall EFS of patients with highly malignant prostate cancer, and the adverse effects are tolerable, which should be confirmed by long-term follow-up results.

Objective:To investigate and understand current status of radiotherapy resources in the Association of Southeast Asian Nations (ASEAN) and analyze the radiotherapy needs of ASEAN countries, aiming to provide suggestions for China's radiotherapy technology international assistance work.Methods:We created a database of 10 ASEAN countries using open-source data, including data on population size, per capita gross national income, new cancer cases, and radiotherapy equipment (megavolt units). We also estimated the number of cases requiring radiotherapy and the demand for radiotherapy equipment. Descriptive statistics were used to present aggregate data and national data.Results:In 2020, the number of new cancer cases in ASEAN countries was 1.0992 million, and the estimated total number of cancer patients requiring radiotherapy was 700 300. The number of radiotherapy equipment required was 1 406. At present, the actual number of radiotherapy equipment in ASEAN countries is 564, and there is a certain gap between the existing radiotherapy resources in some ASEAN countries and the actual needs of cancer patients in their own countries. In 2040, the estimated number of new cancer cases in ASEAN countries will be 1.803 million, and the estimated total number of cancer patients who need radiotherapy in ASEAN countries will be 1.141 2 million. The number of required radiotherapy equipment will be 2 287. By 2040, the growth rate of radiation therapy equipment demand in ASEAN countries will be 305%, and all ASEAN countries need to allocate more radiotherapy resources to cope with the increase in the number of cancer patients and radiotherapy demand.Conclusions:ASEAN countries have a huge demand for radiotherapy in the next two decades, while there are significant differences among different countries. China's precision radiotherapy science and technology have huge potential for ASEAN countries. Radiotherapy science and technology international assistance work based on the needs of ASEAN countries will help China's radiotherapy continue to exert influence and promote the health and well-being of people in ASEAN countries.

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.

Objective:To evaluate the effect of setup errors from daily cone-beam computed tomography (CBCT) on the accumulated dose under different image-guidance (IG) strategies, aiming to investigate the appropriate IG strategies during radiotherapy for the spine metastases.Methods:A total of 720 CBCT scans of 36 vertebral lesions were obtained. All 36 lesions were divided into the simultaneous boosting (PTV 40 Gy/20f, GTV 60 Gy/20f, n=20) and conventional radiotherapy groups (PTV 40 Gy/20f, n=16). The actual fractionated plan was recalculated simulatively after transferring the isocenter of the initial plan according to the interfraction setup error. Under no daily image-guidance (no-DIG) strategies including twice imaging guidance weekly (TIG), initial 5 days then weekly imaging guidance (5D+ WIG), WIG and no imaging guidance (NIG), the dose deviation was calculated between the delivered dose accumulated by each actual fractionated plan and the dose distribution under DIG. The tolerance of dose deviation for the target was within ±5% and the D max of the spinal cord was limited below 45 Gy. Results:Under different image-guidance strategies of TIG, 5D+ WIG, WIG and NIG, the median dose deviation was approximately ±1% for the CTV D 95% and D max of spinal cord. However, the median dose deviation was beyond -5% for the PTV D 95% when conventional radiotherapy was given. The median dose deviation was approximately 10% for the D max of spinal cord and the proportion of cases whose maximum irradiated dose of spinal cord was more than 4500 cGy was ≥70%. Also, the median dose deviation was beyond -5% for the GTV D 95% and PTV D 95% when simultaneous boosting was delivered. Conclusions:Because the dose deviation of CTV and spinal cord is within the tolerance limit, the image-guidance strategies could be chosen according to the clinical practice when conventional radiotherapy is delivered. However, the dose deviation of spinal cord, GTV and PTV exceeds the tolerance limit under no-DIG strategies when simultaneous boosting is delivered. Hence, it is necessary to perform daily IGRT for the spine metastases.

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.