Objectives:To explore whether short-course radiotherapy (SCRT)-based total neoadjuvant therapy (TNT) combined with PD-1 inhibitors could further promote tumor regression and improve the prognosis.Methods:This is a prospective, multicenter, two-arm randomized controlled, seamless phase Ⅱ/Ⅲ trial for proficient mismatch repair or microsatellite stable (pMMR/MSS) locally advanced rectal cancer (LARC). Eligible patients were randomly assigned to the iTNT (TNT+PD-1) group or the TNT group. Patients in the TNT group received SCRT (5 Gy×5) followed by 4 cycles of CAPOX or 6 cycles of mFOLFOX chemotherapy, with the iTNT group receiving SCRT followed by the same regime in combination with 4 cycles of Sintilimab. Total mesorectal excision (TME) surgery or watch and wait (W&W) was performed after neoadjuvant therapy and then 2 cycles of same regimen as before were recommended. The primary endpoints are the complete response (CR) rate for phase Ⅱ trial and 3-year disease-free survival (DFS) for phase Ⅲ trial. A total of 588 patients will be enrolled for the phase Ⅱ/Ⅲ trial. Short-term efficacy and safety data from the initial 100 treated patients were analyzed as planned.Results:From 2022-8-31 to 2023-5-24 the initial 100 patients were enrolled from 10 hospitals in China, 76.0%(76/100) patients were male, and the median age was 61 years (21-74 years). More patients had tumors located in the lower rectum (78.0%, 78/100), staged T3-4 (97.0%, 97/100) and N1-2 (93.0%, 93/100), and about half of the tumors invaded the mesorectal fascia (52.0%, 52/100) and with extramural vascular invasion (51.0%, 51/100). Analyses were performed according to the per-protocal (PP) set. All patients in the iTNT group ( n=52) and the TNT group ( n=48) completed SCRT; The 4-cycle chemotherapy±Sintilimab completion rates were 86.5% and 100.0% in the iTNT and TNT groups, respectively. In the iTNT group, 82.7% (43/52), 11.5% (6/52), and 5.8% (3/52) of the patients received 4, 3, and 2 cycles of PD-1 inhibitor. After TNT, 68 patients underwent radical surgery and 15 patients achieved cCR and adopted W&W. The pathological complete response (pCR) rates were 48.5% (16/33) and 17.1% (6/35) in the iTNT and TNT groups, with CR rates of 50.0% (25/50) and 26.1% (12/46), respectively. The incidence of treatment-related grade 3-4 adverse events was 26.9% (14/52, iTNT group) and 18.8% (9/48, TNT group), with thrombocytopenia and leukopenia being the most common. Among patients receiving immunotherapy, grade 3 immunotherapy-related adverse events occurred in 2 (3.8%, 2/52) patients: one case was pancreatitis, another case was hepatitis combined with myositis and myocarditis. Conclusion:The preliminary results show that SCRT-based TNT combined with PD-1 inhibitors could further improve the CR rate for LARC without unexpected serious adverse events.

Objective:To investigate the long-term efficacy, safety and prognostic factors of intraoperative radiotherapy (IORT) for narrow-margin (resection margin < 1 cm) hepatectomy in patients with hepatocellular carcinoma (HCC) during radical surgery.Methods:A retrospective cohort study was conducted. The data of primary HCC patients undergoing radical surgery and narrow-margin hepatectomy IORT in the Cancer Hospital of the Chinese Academy of Medical Sciences from November 2009 to February 2019 were collected. IORT applied 6 MeV or 9 MeV electron beams and a single irradiation was given to the margin. Kaplan-Meier method was used for the overall survival (OS) and disease-free survival (DFS) analysis; log-rank test was used for survival comparison among subgroups. The recurrence patterns and adverse reactions were recorded. Univariate and multivariate Cox proportional hazards models were used to analyze the factors influencing the OS and DFS.Results:A total of 64 patients were enrolled, with the median age [ M ( Q1, Q3)] of 57 years (49, 63) years. All patients included 55 males (85.9%) and 9 females (14.1%). The median dose of IORT was 15 Gy (range: 12-17 Gy). The median follow-up time was 83.3 (64.4, 91.9) months. The 1-year, 3-year, 5-year, 7-year, 10-year OS rates were 90.4%, 80.6%, 75.5%, 71.4% and 47.6%, respectively; the 1-year, 3-year, 5-year, 7-year,10-year DFS rates were 77.8%, 68.1%, 59.6%, 57.6% and 38.4%, respectively. Univariate Cox regression analysis indicated that preoperative serum alpha-fetoprotein (AFP) > 400 ng/ml was an independent risk factor for poor OS (> 400 ng/ml vs. ≤ 400 ng/ml: HR = 6.57, 95% CI: 2.16-19.96, P < 0.001), while not the independent influencing factor of poor DFS ( HR = 1.71, 95% CI: 0.65-4.52, P = 0.277). The age ≤ 60 years or not, gender, viral hepatitis or not, American Joint Committee on Cancer stage, tumor diameter (> 5 cm or not), tumor number, degree of tumor differentiation, microvascular invasion or not, microsatellite nodules or not, anatomical liver resection or not, and the dose of IORT ≤15 Gy or not were not the independent influencing factors of poor OS and DFS (all P > 0.05). Kaplan-Meier method analysis showed that patients with preoperative serum AFP ≤ 400 ng/ml (48 cases) had better OS compared with those with preoperative serum AFP>400 ng/ml (16 cases) (5-year OS rate: 84.8% vs. 44.9%; 7-year OS rate: 79.9% vs.37.4%), and the difference was statistically significant ( P = 0.002). There was no statistically significant difference in the DFS between the 2 groups ( P = 0.134). During the follow-up, 28 patients (43.8%) relapsed, including 17 cases (26.6%) of early recurrence and 11 cases (17.2%) of late recurrence. No marginal recurrence was observed. There were 22 cases (34.4%) of intrahepatic recurrence alone, 2 cases (3.1%) of extrahepatic recurrence and 4 cases (6.3%) of stimutaneous recurrence inside and outside the liver. The 1-, 3-, 5- and 7-year cumulative recurrence rates inside the liver were 19.0%, 27.2%, 37.4% and 39.3% respectively, and the cumulative recurrence rates outside the liver were 6.4%, 8.0%, 9.6% and 9.6% respectively. There were no adverse reactions above grade 3 in the entire group. There were no surgery-related deaths within 30 d after the operation, and no radiation-induced liver disease occurred. Conclusions:Narrow-margin IORT helps HCC patients receiving hepatectomy to achieve favorable long-term survival and adverse reactions are tolerable. It can be used as a safe and effective adjuvant therapy alternative.

Objectives:To explore whether short-course radiotherapy (SCRT)-based total neoadjuvant therapy (TNT) combined with PD-1 inhibitors could further promote tumor regression and improve the prognosis.Methods:This is a prospective, multicenter, two-arm randomized controlled, seamless phase Ⅱ/Ⅲ trial for proficient mismatch repair or microsatellite stable (pMMR/MSS) locally advanced rectal cancer (LARC). Eligible patients were randomly assigned to the iTNT (TNT+PD-1) group or the TNT group. Patients in the TNT group received SCRT (5 Gy×5) followed by 4 cycles of CAPOX or 6 cycles of mFOLFOX chemotherapy, with the iTNT group receiving SCRT followed by the same regime in combination with 4 cycles of Sintilimab. Total mesorectal excision (TME) surgery or watch and wait (W&W) was performed after neoadjuvant therapy and then 2 cycles of same regimen as before were recommended. The primary endpoints are the complete response (CR) rate for phase Ⅱ trial and 3-year disease-free survival (DFS) for phase Ⅲ trial. A total of 588 patients will be enrolled for the phase Ⅱ/Ⅲ trial. Short-term efficacy and safety data from the initial 100 treated patients were analyzed as planned.Results:From 2022-8-31 to 2023-5-24 the initial 100 patients were enrolled from 10 hospitals in China, 76.0%(76/100) patients were male, and the median age was 61 years (21-74 years). More patients had tumors located in the lower rectum (78.0%, 78/100), staged T3-4 (97.0%, 97/100) and N1-2 (93.0%, 93/100), and about half of the tumors invaded the mesorectal fascia (52.0%, 52/100) and with extramural vascular invasion (51.0%, 51/100). Analyses were performed according to the per-protocal (PP) set. All patients in the iTNT group ( n=52) and the TNT group ( n=48) completed SCRT; The 4-cycle chemotherapy±Sintilimab completion rates were 86.5% and 100.0% in the iTNT and TNT groups, respectively. In the iTNT group, 82.7% (43/52), 11.5% (6/52), and 5.8% (3/52) of the patients received 4, 3, and 2 cycles of PD-1 inhibitor. After TNT, 68 patients underwent radical surgery and 15 patients achieved cCR and adopted W&W. The pathological complete response (pCR) rates were 48.5% (16/33) and 17.1% (6/35) in the iTNT and TNT groups, with CR rates of 50.0% (25/50) and 26.1% (12/46), respectively. The incidence of treatment-related grade 3-4 adverse events was 26.9% (14/52, iTNT group) and 18.8% (9/48, TNT group), with thrombocytopenia and leukopenia being the most common. Among patients receiving immunotherapy, grade 3 immunotherapy-related adverse events occurred in 2 (3.8%, 2/52) patients: one case was pancreatitis, another case was hepatitis combined with myositis and myocarditis. Conclusion:The preliminary results show that SCRT-based TNT combined with PD-1 inhibitors could further improve the CR rate for LARC without unexpected serious adverse events.

Objective:To investigate the long-term efficacy, safety and prognostic factors of intraoperative radiotherapy (IORT) for narrow-margin (resection margin < 1 cm) hepatectomy in patients with hepatocellular carcinoma (HCC) during radical surgery.Methods:A retrospective cohort study was conducted. The data of primary HCC patients undergoing radical surgery and narrow-margin hepatectomy IORT in the Cancer Hospital of the Chinese Academy of Medical Sciences from November 2009 to February 2019 were collected. IORT applied 6 MeV or 9 MeV electron beams and a single irradiation was given to the margin. Kaplan-Meier method was used for the overall survival (OS) and disease-free survival (DFS) analysis; log-rank test was used for survival comparison among subgroups. The recurrence patterns and adverse reactions were recorded. Univariate and multivariate Cox proportional hazards models were used to analyze the factors influencing the OS and DFS.Results:A total of 64 patients were enrolled, with the median age [ M ( Q1, Q3)] of 57 years (49, 63) years. All patients included 55 males (85.9%) and 9 females (14.1%). The median dose of IORT was 15 Gy (range: 12-17 Gy). The median follow-up time was 83.3 (64.4, 91.9) months. The 1-year, 3-year, 5-year, 7-year, 10-year OS rates were 90.4%, 80.6%, 75.5%, 71.4% and 47.6%, respectively; the 1-year, 3-year, 5-year, 7-year,10-year DFS rates were 77.8%, 68.1%, 59.6%, 57.6% and 38.4%, respectively. Univariate Cox regression analysis indicated that preoperative serum alpha-fetoprotein (AFP) > 400 ng/ml was an independent risk factor for poor OS (> 400 ng/ml vs. ≤ 400 ng/ml: HR = 6.57, 95% CI: 2.16-19.96, P < 0.001), while not the independent influencing factor of poor DFS ( HR = 1.71, 95% CI: 0.65-4.52, P = 0.277). The age ≤ 60 years or not, gender, viral hepatitis or not, American Joint Committee on Cancer stage, tumor diameter (> 5 cm or not), tumor number, degree of tumor differentiation, microvascular invasion or not, microsatellite nodules or not, anatomical liver resection or not, and the dose of IORT ≤15 Gy or not were not the independent influencing factors of poor OS and DFS (all P > 0.05). Kaplan-Meier method analysis showed that patients with preoperative serum AFP ≤ 400 ng/ml (48 cases) had better OS compared with those with preoperative serum AFP>400 ng/ml (16 cases) (5-year OS rate: 84.8% vs. 44.9%; 7-year OS rate: 79.9% vs.37.4%), and the difference was statistically significant ( P = 0.002). There was no statistically significant difference in the DFS between the 2 groups ( P = 0.134). During the follow-up, 28 patients (43.8%) relapsed, including 17 cases (26.6%) of early recurrence and 11 cases (17.2%) of late recurrence. No marginal recurrence was observed. There were 22 cases (34.4%) of intrahepatic recurrence alone, 2 cases (3.1%) of extrahepatic recurrence and 4 cases (6.3%) of stimutaneous recurrence inside and outside the liver. The 1-, 3-, 5- and 7-year cumulative recurrence rates inside the liver were 19.0%, 27.2%, 37.4% and 39.3% respectively, and the cumulative recurrence rates outside the liver were 6.4%, 8.0%, 9.6% and 9.6% respectively. There were no adverse reactions above grade 3 in the entire group. There were no surgery-related deaths within 30 d after the operation, and no radiation-induced liver disease occurred. Conclusions:Narrow-margin IORT helps HCC patients receiving hepatectomy to achieve favorable long-term survival and adverse reactions are tolerable. It can be used as a safe and effective adjuvant therapy alternative.

Objectives:To assess the prognostic impact of the neoadjuvant rectal (NAR) score following neoadjuvant short-course radiotherapy and consolidation chemotherapy in locally advanced rectal cancer (LARC), as well as its value in guiding decisions for adjuvant chemotherapy.Methods:Between August 2015 and August 2018, patients were eligible from the STELLAR phase III trial (NCT02533271) who received short-course radiotherapy plus consolidation chemotherapy and for whom the NAR score could be calculated. Based on the NAR score, patients were categorized into low (＜8), intermediate (8-16), and high (＞16) groups. The Kaplan-Meier method, log rank tests, and multivariate Cox proportional hazard regression models were used to evaluate the impact of the NAR score on disease-free survival (DFS).Results:Out of the 232 patients, 24.1%, 48.7%, and 27.2% had low (56 cases), intermediate (113 cases), and high NAR scores (63 cases), respectively. The median follow-up period was 37 months, with 3-year DFS rates of 87.3%, 68.3%, and 53.4% ( P＜0.001) for the low, intermediate, and high NAR score groups. Multivariate analysis demonstrated that the NAR score (intermediate NAR score: HR, 3.10, 95% CI, 1.30-7.37, P=0.011; high NAR scores: HR=5.44, 95% CI, 2.26-13.09, P＜0.001), resection status ( HR, 3.00, 95% CI, 1.64-5.52, P＜0.001), and adjuvant chemotherapy ( HR, 3.25, 95% CI, 2.01-5.27, P＜0.001) were independent prognostic factors for DFS. In patients with R0 resection, the 3-year DFS rates were 97.8% and 78.0% for those with low and intermediate NAR scores who received adjuvant chemotherapy, significantly higher than the 43.2% and 50.6% for those who did not ( P＜0.001, P=0.002). There was no significant difference in the 3-year DFS rate (54.2% vs 53.3%, P=0.214) among high NAR score patients, regardless of adjuvant chemotherapy. Conclusions:The NAR score is a robust prognostic indicator in LARC following neoadjuvant short-course radiotherapy and consolidation chemotherapy, with potential implications for subsequent decisions regarding adjuvant chemotherapy. These findings warrant further validation in studies with larger sample sizes.

Background::Biliary tract carcinoma (BTC) is relatively rare and comprises a spectrum of invasive tumors arising from the biliary tree. The prognosis is extremely poor. The incidence of BTC is relatively high in Asian countries, and a high number of cases are diagnosed annually in China owing to the large population. Therefore, it is necessary to clarify the epidemiology and high-risk factors for BTC in China. The signs associated with BTC are complex, often require collaborative treatment from surgeons, endoscopists, oncologists, and radiation therapists. Thus, it is necessary to develop a comprehensive Chinese guideline for BTC.Methods::This clinical practice guideline (CPG) was developed following the process recommended by the World Health Organization. The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess the certainty of evidence and make recommendations. The full CPG report was reviewed by external guideline methodologists and clinicians with no direct involvement in the development of this CPG. Two guideline reporting checklists have been adhered to: Appraisal of Guidelines for Research and Evaluation (AGREE) and Reporting Items for practice Guidelines in Healthcare (RIGHT).Results::The guideline development group, which comprised 85 multidisciplinary clinical experts across China. After a controversies conference, 17 clinical questions concerning the prevention, diagnosis, and treatment of BTC were proposed. Additionally, detailed descriptions of the surgical principles, perioperative management, chemotherapy, immunotherapy, targeted therapy, radiotherapy, and endoscopic management were proposed.Conclusions::The guideline development group created a comprehensive Chinese guideline for the diagnosis and treatment of BTC, covering various aspects of epidemiology, diagnosis, and treatment. The 17 clinical questions have important reference value for the management of BTC.

Objectives:To assess the prognostic impact of the neoadjuvant rectal (NAR) score following neoadjuvant short-course radiotherapy and consolidation chemotherapy in locally advanced rectal cancer (LARC), as well as its value in guiding decisions for adjuvant chemotherapy.Methods:Between August 2015 and August 2018, patients were eligible from the STELLAR phase III trial (NCT02533271) who received short-course radiotherapy plus consolidation chemotherapy and for whom the NAR score could be calculated. Based on the NAR score, patients were categorized into low (＜8), intermediate (8-16), and high (＞16) groups. The Kaplan-Meier method, log rank tests, and multivariate Cox proportional hazard regression models were used to evaluate the impact of the NAR score on disease-free survival (DFS).Results:Out of the 232 patients, 24.1%, 48.7%, and 27.2% had low (56 cases), intermediate (113 cases), and high NAR scores (63 cases), respectively. The median follow-up period was 37 months, with 3-year DFS rates of 87.3%, 68.3%, and 53.4% ( P＜0.001) for the low, intermediate, and high NAR score groups. Multivariate analysis demonstrated that the NAR score (intermediate NAR score: HR, 3.10, 95% CI, 1.30-7.37, P=0.011; high NAR scores: HR=5.44, 95% CI, 2.26-13.09, P＜0.001), resection status ( HR, 3.00, 95% CI, 1.64-5.52, P＜0.001), and adjuvant chemotherapy ( HR, 3.25, 95% CI, 2.01-5.27, P＜0.001) were independent prognostic factors for DFS. In patients with R0 resection, the 3-year DFS rates were 97.8% and 78.0% for those with low and intermediate NAR scores who received adjuvant chemotherapy, significantly higher than the 43.2% and 50.6% for those who did not ( P＜0.001, P=0.002). There was no significant difference in the 3-year DFS rate (54.2% vs 53.3%, P=0.214) among high NAR score patients, regardless of adjuvant chemotherapy. Conclusions:The NAR score is a robust prognostic indicator in LARC following neoadjuvant short-course radiotherapy and consolidation chemotherapy, with potential implications for subsequent decisions regarding adjuvant chemotherapy. These findings warrant further validation in studies with larger sample sizes.

Background::Magnetic resonance (MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation (UHF-WPRT) is a novel approach to radiotherapy for patients with high-risk (HR) and very high-risk (VHR) prostate cancer (PCa). However, the inherent complexity of adaptive UHF-WPRT might inevitably result in longer on-couch time. We aimed to estimate the delivered dose, study the feasibility and safety of adaptive UHF-WPRT on a 1.5-Tesla MR-Linac.Methods::Ten patients with clinical stage T3a-4N0-1M0-1c PCa, who consecutively received UHF-WPRT, were enrolled prospectively. The contours of the target and organ-at-risks on the position verification-MR (PV-MR), beam-on 3D-MR(Bn-MR), and post-MR (after radiotherapy delivery) were derived from the pre-MR data by deformable image registration. The physician then manually adjusted them, and dose recalculation was performed accordingly. GraphPad Prism 9 (GraphPad Prism Software Inc.) was utilized for conducting statistical analyses.Results::In total, we collected 188 MR scans (50 pre-MR, 50 PV-MR, 44 Bn-MR, and 44 post-MR scans). With median 59 min, the mean prostate clinical target volume (CTV)-V 100% was 98.59% ± 2.74%, and the mean pelvic CTVp-V 100% relative percentages of all scans was 99.60% ± 1.18%. The median V 29 Gy change in the rectal wall was -2% (-18% to 20%). With a median follow-up of 9 months, no patient had acute Common Terminology Criteria for Adverse Events (CTCAE) grade 2 or more severe genitourinary (GU) or gastrointestinal (GI) toxicities (0%). Conclusion::UHF-RT to the prostate and the whole pelvis with concomitant boost to positive nodes using an Adapt-To-Shape (ATS) workflow was technically feasible for patients with HR and VHR PCa, presenting only mild GU and GI toxicities. The estimated target dose during the beam-on phase was clinically acceptable based on the 3D-MR–based dosimetry analysis.Clinical trial registration::Chinese Clinical Trial Registry ChiCTR2000033382.

Background::Magnetic resonance (MR)-guided ultra-hypofractionated radiotherapy with whole-pelvic irradiation (UHF-WPRT) is a novel approach to radiotherapy for patients with high-risk (HR) and very high-risk (VHR) prostate cancer (PCa). However, the inherent complexity of adaptive UHF-WPRT might inevitably result in longer on-couch time. We aimed to estimate the delivered dose, study the feasibility and safety of adaptive UHF-WPRT on a 1.5-Tesla MR-Linac.Methods::Ten patients with clinical stage T3a-4N0-1M0-1c PCa, who consecutively received UHF-WPRT, were enrolled prospectively. The contours of the target and organ-at-risks on the position verification-MR (PV-MR), beam-on 3D-MR(Bn-MR), and post-MR (after radiotherapy delivery) were derived from the pre-MR data by deformable image registration. The physician then manually adjusted them, and dose recalculation was performed accordingly. GraphPad Prism 9 (GraphPad Prism Software Inc.) was utilized for conducting statistical analyses.Results::In total, we collected 188 MR scans (50 pre-MR, 50 PV-MR, 44 Bn-MR, and 44 post-MR scans). With median 59 min, the mean prostate clinical target volume (CTV)-V 100% was 98.59% ± 2.74%, and the mean pelvic CTVp-V 100% relative percentages of all scans was 99.60% ± 1.18%. The median V 29 Gy change in the rectal wall was -2% (-18% to 20%). With a median follow-up of 9 months, no patient had acute Common Terminology Criteria for Adverse Events (CTCAE) grade 2 or more severe genitourinary (GU) or gastrointestinal (GI) toxicities (0%). Conclusion::UHF-RT to the prostate and the whole pelvis with concomitant boost to positive nodes using an Adapt-To-Shape (ATS) workflow was technically feasible for patients with HR and VHR PCa, presenting only mild GU and GI toxicities. The estimated target dose during the beam-on phase was clinically acceptable based on the 3D-MR–based dosimetry analysis.Clinical trial registration::Chinese Clinical Trial Registry ChiCTR2000033382.

Objective:To explore the impacts of comprehensive geriatric assessment (CGA) on setup errors during the radiotherapy of elderly patients with rectal cancer.Methods:A total of 45 patients over 70 years of age and receiving radiotherapy were enrolled in the study. A comprehensive geriatric assessment was conducted before the radiotherapy. The enrolled patients had a median age of 77 years, including 28 male and 17 female cases. Meanwhile, 31 patients were determined to be in a good CGA status and 14 were determined to be in a poor CGA status, and 35 patients received radiotherapy in the prone position and 10 in the supine position. Cone beam CT (CBCT) was used for setup correction during radiotherapy. CBCT was performed daily in the first week and once a week from the second week. By fusing and aligning the CBCT images with simulation CT images according to the lumbar vertebra, setup errors in the left-right ( x axis), cranio-caudal ( y axis), and anterior-posterior ( z axis) directions were obtained. A total of 338 CBCT images were obtained. A generalized linear model was used to evaluate the effects of multiple factors on the setup errors. Results:During the radiotherapy, setup errors of all patients were (0.24±0.19) cm in the left-right direction, (0.33±0.25) cm in the cranio-caudal direction, and (0.19±0.15) cm in the anterior-posterior direction. The setup error in the cranio-caudal direction was more than that in the left-right direction and that in the anterior-posterior direction ( Z=-4.86, -7.72, P< 0.001). The setup error in the left-right direction was greater than that in the anterior-posterior direction ( Z=-2.79, P=0.005). The mean setup errors of the good and poor status groups in the left-right direction were (0.21 ± 0.17) and (0.30 ± 0.22) cm, respectively ( Z=2.16, P=0.031). There was no statistically significant difference in the setup errors between cranio-caudal direction and anterior-posterior direction ( P>0.05). The setup errors in the anterior-posterior direction were (0.17 ± 0.13) and (0.27 ± 0.19) cm, respectively for the prone and supine positions during the radiotherapy ( Z=2.85, P=0.004). There was no statistically significant difference in the setup errors between the left-right direction and the cranio-caudal direction ( P>0.05). Conclusion:The status of CGA elderly patients with rectal cancer affects the setup error in the left-right direction. It may be necessary to clinically adjust the PTV margin.