Objective: To explore the association between nap duration with anxiety and depressive symptoms among junior high school students, in order to provide evidence for mental health interventions for adolescents. Methods: From May to June 2022, a combination of convenience sampling and cluster sampling was used to select 2 491 students from 2 junior high schools in Haizhu District, Guangzhou City for questionnaire survey and physical examination. The questionnaire collected nap duration, night time sleep duration, bedtime, physical activity, and sedentary behavior. Anxiety and depressive symptoms were assessed using Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7), respectively. Log-binomial regression model was used to analyze the association of nap duration with anxiety and depressive symptoms, as well as comorbidity among junior high school students, and a restricted cubic spline (RCS) Log-binomial regression model was employed to analyze the non linear relationship after adjusting for covariates. Results: The detection rates of anxiety symptoms, depressive symptoms and comorbidity among junior high school students were 13.29%,14.65%,9.19%. After adjusting for covariates such as age, gender and nighttime sleep duration, compared with a school day nap duration of <30 min/d, a nap duration of 30-<60 min/d was associated with a reduced risk of anxiety symptoms ( APR =0.68, 95% CI =0.49-0.98) and comorbidity ( APR =0.56, 95% CI =0.39-0.87)(both P < 0.05 ). Compared with no napping on weekends, a nap duration of 30-<60 min/d was associated with a reduced risk of anxiety symptoms ( APR =0.62, 95% CI =0.41-0.88), depressive symptoms ( APR =0.52, 95% CI =0.34-0.75) and comorbidity ( APR = 0.52 , 95% CI =0.30-0.83)(all P <0.05). RCS curves showed a nonlinear relationship between weekend nap duration and the prevalence of anxiety, depressive symptoms and comorbidity among junior high school students(all P non linear <0.05); weekend nap duration of <120 min was associated with a lower risk of anxiety and depressive symptoms, and weekend nap duration of >180 min was associated with an increased risk. Conclusions Appropriate nap duration can help reduce the risk of anxiety, depressive symptoms, and the comorbidity among junior high school students. Adolescents should be guided to reasonably arrange nap duration for promoting physical and mental health.

Objective:To investigate the interactive effect of mismatch repair (MMR) protein status and adverse clinicopathological features on prognosis of stage Ⅰ-Ⅲ colon cancer.Methods:The retrospective cohort study was conducted. The clinicopathological data of 1 650 patients with colon cancer of stage Ⅰ-Ⅲ who were admitted to 7 hospitals in China from January 2016 to December 2017 were collected. There were 963 males and 687 females, aged 62(53,71)years. Patients were classified as 230 cases of MMR deficiency (dMMR) and 1 420 cases of MMR proficiency (pMMR) based on their MMR protein status. Observation indicators: (1) comparison of clinicopathological characteristics between patients of different MMR protein status; (2) analysis of factors affecting the survival outcomes of patients of dMMR; (3) analysis of factors affecting the survival outcomes of patients of pMMR; (4) interaction analysis of MMR and adverse clinicopathological features on survival outcomes. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was conducted using the Mann-Whitney U test. The random forest interpolation method was used for missing values in data interpolation. Univariate analysis was conducted using the COX proportional risk regression model, and multivariate analysis was conducted using the COX stepwise regression with forward method. The coefficient of multiplication interaction effect was obtained using the interaction term coefficient of COX proportional risk regression model. Evaluation of additive interaction effects was conducted using the relative excess risk due to interaction ( RERI). Results:(1) Comparison of clinicopathological characteristics between patients of different MMR protein status. There were significant differences in age, T staging, the number of lymph node harvest, the number of lymph node harvest <12, high grade tumor between patients of dMMR and pMMR ( P<0.05). (2) Analysis of factors affecting the survival outcomes of patients of dMMR. Results of multivariate analysis showed that T staging, N staging, the number of lymph node harvest <12 were independent factors affecting the disease-free survival (DFS) of colon cancer patients of dMMR ( hazard ratio=3.548, 2.589, 6.702, 95% confidence interval as 1.460-8.620, 1.064-6.301, 1.886-23.813, P<0.05). Age and N staging were independent factors affecting the overall survival (OS) of colon cancer patients of dMMR ( hazard ratio=1.073, 10.684, 95% confidence interval as 1.021-1.126, 2.311-49.404, P<0.05). (3) Analysis of factors affecting the survival outcomes of patients of pMMR. Results of multivariate analysis showed that age, T staging, N staging, vascular tumor thrombus were independent factors affecting the DFS of colon cancer patients of pMMR ( hazard ratio=1.018, 2.214, 2.598, 1.549, 95% confidence interval as 1.006-1.030, 1.618-3.030, 1.921-3.513, 1.118-2.147, P<0.05). Age, T staging, N staging, high grade tumor were independent factors affecting the OS of colon cancer patients of pMMR ( hazard ratio=1.036, 2.080, 2.591, 1.615, 95% confidence interval as 1.020-1.052, 1.407-3.075, 1.791-3.748, 1.114-2.341, P<0.05). (4) Interaction analysis of MMR and adverse clinicopathological features on survival outcomes. Results of interaction analysis showed that the multiplication interaction effect between the number of lymph node harvest <12 and MMR protein status was significant on DFS of colon cancer patients ( hazard ratio=3.923, 95% confidence interval as 1.057-14.555, P<0.05). The additive interaction effects between age and MMR protein status, between high grade tumor and MMR protein status were significant on OS of colon cancer patients ( RERI=-0.033, -1.304, 95% confidence interval as -0.049 to -0.018, -2.462 to -0.146). Conclusions:There is an interaction between the MMR protein status and the adverse clinicopathological features (the number of lymph node harvest <12, high grade tumor) on prognosis of colon cancer patients of stage Ⅰ-Ⅲ. In patients of dMMR, the number of lymph node harvest <12 has a stronger predictive effect on poor prognosis. In patients of pMMR, the high grade tumor has a stronger predictive effect on poor prognosis.

Objective To investigate the status quo of pain catastrophizing(PC)in the patients with di-abetic peripheral neuropathic pain(DPNP),and to analyze the influencing factors to provide reference for for-mulating clinical preventive intervention strategies.Methods A total of 206 patients with DPNP admitted and treated in the People's Hospital of Guangxi Zhuang Autonomous Region were selected as the research sub-jects by convenience sampling method.The general data questionnaire,Numerical Rating Scale(NRS),Pain Catastrophizing scale(PCS),Perceived Social Support Scale(PSSS)and diabetes distress scale(DDS)were used to conduct the investigation.Results The incidence rate of PC in 206 cases of DPNP patients was 44.66％(92/206),and the total score of PCS was(30.10±5.16)points.The results of multiple linear regres-sion analysis showed that the gender,duration of diabetes(≥10 years),multiple drug use,number of compli-cations(＞5),NRS score,PSSS score and scores of DDS dimensions were the main influencing factors of PC(all P＜0.05),which could explain 92.3％of the total variation of PC.Conclusion The PC incidence rate in the patients with DPNP is high.Clinical healthcare workers should pay attention to the evaluation of PC in these patients,and formulate the scientific and effective targeted intervention measures according to the main influen-cing factors to help the patients to reduce the pain burden in order to reduce the level of PC.

Objective:To analyze the clinical characteristics of novel coronavirus (COVID-19) infection in liver transplant recipients.Methods:Clinical data of 130 liver transplant recipients with COVID-19 infection followed in Hebei Medical University Third Hospital from November 2022 to January 2023 were retrospectively collected, including 103 males and 27 females, aged (53.6±11.4) years. The severity of COVID-19 infection, its clinical symptoms, and negative conversion time for each recipient were analyzed and compared.Results:For the disease severity, 121 (93.1%) were mild, 5 (3.8%) were moderate, 3 (2.3%) were severe, and 1 (0.8%) was critically severe. The most common symptoms in the 126 patients with mild to moderate COVID-19 infection were successively fever, fatigue, cough and myalgia, with a negative conversion time of (10.1±4.5) (3.0-29.0)d. In those who underwent transplantation less than 12 months ( n=28), those who were taking mycophenolate mofetil ( n=53) and those who were taking methylprednisolone ( n=10), the negative conversion time was (11.6±5.1) d, (11.4±5.4) d, and (13.4±6.4) d, respectively, longer compared to those who underwent transplantation more than 12 months (9.7±4.2 d, n=98), and who were not taking mycophenolate mofetil (9.2±3.4 d, n=73) or methylprednisolone (9.8±4.2 d, n=116, all P<0.05). The negative conversion times were longer in recipients with symptoms (eg. fatigue and cough) than those in asymptomatic recipients (11.0±5.1 d vs. 9.0±3.3 d, t=2.64, P=0.009, and 11.4±5.2 d vs. 9.0±3.4 d, t=2.92, P=0.004). Conclusion:The COVID-19 infection in liver transplant recipients was mainly mild and moderate. The most common symptoms are fever, fatigue, cough and myalgia. The short time (less than 12 months) after liver transplantation, oral mycophenolate mofetil and methylprednisolone, with symptoms (fatigue and cough) could be associated with a prolonged negative conversion time.

Objective:To investigate the expression of human epidermal growth factor receptor 2 (HER2) in pancreatic ductal adenocarcinoma(PDAC) and its relationship with the prognosis of patients with PDAC.Methods:From January 2001 to December 2012, 109 paraffin embedded PDAC tissue samples and 27 normal pancreatic tissue samples were collected from the Department of Pathology, Huadong Hospital Affiliated to Fudan University. The expression of HER2 protein in pancreatic tissue was detected by immunohistochemical Envision two-step method. HER2 expression was evaluated according to Hercept test, and its relationship with clinicopathological features and survival time was analyzed.Results:The expression of HER2 protein was negative (-) in 29.4% of PDAC tissues, weakly positive (+ ) in 35.8%, positive (+ + ) in 25.7% and strongly positive (+ + + ) in 9.2%, respectively, and the overexpression rate (+ + , + + + ) was 34.9%; the negative (-) and weakly positive (+ ) expression of HER2 protein in normal pancreatic tissues accounted for 88.9% and 11.1% respectively. There was no expression with positive (+ + ) or strongly positive (+ + + ), therefore, the overexpression rate was 0. The overexpression rate of HER2 protein in PDAC and normal pancreatic tissues was significantly different ( P=0.000). The expression of HER2 protein was significantly correlated with age, and the expression of HER2 protein in patients with PDAC over 65 years old was significantly higher than that in patients with PDAC under 65 years old ( P=0.043), but not with gender, tumor location, tumor grade, T stage, N stage and nerve invasion (all P>0.05). Univariate Cox proportional hazards analysis showed that HER2 expression was associated with postoperative survival time of patients with PDAC ( P=0.032). Multivariate Cox proportional hazards analysis showed that HER2 expression was an independent prognostic factor for survival of patients with PDAC ( P=0.040). The median survival period of patients with HER2 expression + + + was significantly longer than that of patients with HER2 expression -~+ + (128.4 months vs 21.5 months), and the difference was statistically significant ( P=0.038). Conclusions:The overexpression of HER2 in PDAC tissue was related to the age of patients. The survival time of patients with HER2 strongly positive PDAC was significantly longer. HER2 can be considered as an index to evaluate the biological behavior and prognosis of PDAC.

Objective: To evaluate the safety and preliminary efficacy of total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC) with high risk factors. Methods: Data of 101 patients who were diagnosed with stage II-III rectal cancer with high risk factors and received TNT between March 2015 and January 2018 at West China Hospital of Sichuan University were analyzed retrospectively. Inclusion criteria: (1) patients were diagnosed with stage II-III rectal cancer by high-resolution MRI combined with CT and endorectal ultrasound; (2) at least one high risk factor: cT4a, cT4b, cN2, EMVI+, CRM+ and lateral lymph node+; (3) distance from tumor to anal verge was within 15 cm; (4) Eastern Collaborative Oncology Group (ECOG) performance status score was 0-1; bone marrow function, liver function and kidney function were suitable for chemoradiotherapy; (5) patients were treated with TNT strategy; (6) the follow-up data and postoperative pathological data were complete. Patients with previous rectal cancer surgery (except prophylactic colostomy), pelvic radiotherapy, and systemic chemotherapy, those with distant metastases, those without neoadjuvant radiotherapy, those receiving less than 4 cycles of neoadjuvant chemotherapy were excluded. The regimen of TNT: 3 cycles of induction CAPOX (oxaliplatin plus capecitabine) were followed by pelvic radiotherapy and concurrent CAPOX, then 3 cycles of consolidation CAPOX were delivered after radiotherapy. Total mesorectal resection (TME) or watch-and-wait strategy was selected according to the therapeutic effect and patients' wishes. Short-term efficacy, including tumor regression grade (TRG), pathological complete response (pCR), clinical complete response (cCR), postoperative complications within 30 days of surgery, and adverse events (AE) to radiotherapy and chemotherapy (measured using CTCAE 4.0) was analyzed. Results: The 101 patients included 68 males (67.3%) and 33 females (32.7%) with a median age of 54 years. The proportion of patients with cT4a, cT4b, cN2 and enlarged lateral lymph node was 13.9%, 29.7%, 56.4% and 43.6%, respectively. The mean cycle of neoadjuvant chemotherapy was 6.0±1.3. Seventy-five patients (74.3%) received at least 6 cycles of neoadjuvant chemotherapy and 100 (99.0%) completed radiotherapy. The mean cycle of induction and consolidation chemotherapy was 2.0±0.9 and 2.8±1.0 respectively. Most common grade 3 AE was leucopenia (n=13, 12.9%) and thrombocytopenia (n=7, 6.9%). Grade 3 diarrhea and radiation dermatitis were observed in 5 cases (5.0%) respectively. Grade 3 anemia and rectal pain were observed in 4 cases (4.0%) respectively. And rectal mucositis was observed in 2 cases (2.0%). Most of the AE was observed during concurrent chemoradiotherapy. No grade 4 or higher AE was observed. After TNT, 32 patients (31.7%) achieved pCR or cCR, and 62 patients (60.4%) achieved partial response (PR). Only 2 patients (2.0%) developed distant metastasis after chemoradiotherapy, while the other patients did not show disease progression. Seven patients (6.9%) with cCR refused surgery and selected watch-and-wait, while 7 patients without cCR still refused surgery. The other 87 patients (86.1%) underwent TME successfully. The mean interval from the completion of chemoradiotherapy to surgery was (20.1±8.5) weeks. The R0 resection rate was 97.7% (85/87).The morbidity of surgical complication was 16.1% (14/87), including pelvic infection or abscess in 6 cases (6.9%), anastomotic leakage in 3 (3.4%), hemorrhage in 2 (2.3%), and gastrointestinal dysfunction in 3 (3.4%). Pathological findings revealed that 24 cases (27.6%) had TRG 0, 20 (23.0%) had TRG 1, 30 (34.5%) TRG 2, and 13 (14.9%) TRG 3. Conclusion TNT is safe and has good short-term efficacy for locally advanced rectal cancer patients with high risk factors.

Objective To evaluate the safety and preliminary efficacy of total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC) with high risk factors. Methods Data of 101 patients who were diagnosed with stage II?III rectal cancer with high risk factors and received TNT between March 2015 and January 2018 at West China Hospital of Sichuan University were analyzed retrospectively. Inclusion criteria: (1) patients were diagnosed with stage II?III rectal cancer by high?resolution MRI combined with CT and endorectal ultrasound; (2) at least one high risk factor: cT4a, cT4b, cN2, EMVI+, CRM+and lateral lymph node+; (3) distance from tumor to anal verge was within 15 cm;(4) Eastern Collaborative Oncology Group (ECOG) performance status score was 0?1; bone marrow function, liver function and kidney function were suitable for chemoradiotherapy; (5) patients were treated with TNT strategy; (6) the follow?up data and postoperative pathological data were complete. Patients with previous rectal cancer surgery (except prophylactic colostomy), pelvic radiotherapy, and systemic chemotherapy, those with distant metastases, those without neoadjuvant radiotherapy, those receiving less than 4 cycles of neoadjuvant chemotherapy were excluded. The regimen of TNT: 3 cycles of induction CAPOX (oxaliplatin plus capecitabine) were followed by pelvic radiotherapy and concurrent CAPOX, then 3 cycles of consolidation CAPOX were delivered after radiotherapy. Total mesorectal resection (TME) or watch?and?wait strategy was selected according to the therapeutic effect and patients' wishes. Short?term efficacy, including tumor regression grade (TRG), pathological complete response (pCR), clinical complete response (cCR), postoperative complications within 30 days of surgery, and adverse events (AE) to radiotherapy and chemotherapy (measured using CTCAE 4.0) was analyzed. Results The 101 patients included 68 males (67.3%) and 33 females (32.7%) with a median age of 54 years. The proportion of patients with cT4a, cT4b, cN2 and enlarged lateral lymph node was 13.9%, 29.7%, 56.4% and 43.6%, respectively. The mean cycle of neoadjuvant chemotherapy was 6.0 ± 1.3. Seventy?five patients (74.3%) received at least 6 cycles of neoadjuvant chemotherapy and 100 (99.0%) completed radiotherapy. The mean cycle of induction and consolidation chemotherapy was 2.0 ± 0.9 and 2.8 ± 1.0 respectively. Most common grade 3 AE was leucopenia (n=13, 12.9%) and thrombocytopenia (n=7, 6.9%). Grade 3 diarrhea and radiation dermatitis were observed in 5 cases (5.0%) respectively. Grade 3 anemia and rectal pain were observed in 4 cases (4.0%) respectively. And rectal mucositis was observed in 2 cases (2.0%). Most of the AE was observed during concurrent chemoradiotherapy. No grade 4 or higher AE was observed. After TNT, 32 patients (31.7%) achieved pCR or cCR, and 62 patients (60.4%) achieved partial response (PR). Only 2 patients (2.0%) developed distant metastasis after chemoradiotherapy, while the other patients did not show disease progression. Seven patients (6.9%) with cCR refused surgery and selected watch?and?wait, while 7 patients without cCR still refused surgery. The other 87 patients (86.1%) underwent TME successfully. The mean interval from the completion of chemoradiotherapy to surgery was (20.1±8.5) weeks. The R0 resection rate was 97.7% (85/87).The morbidity of surgical complication was 16.1% (14/87), including pelvic infection or abscess in 6 cases (6.9%), anastomotic leakage in 3 (3.4%), hemorrhage in 2 (2.3%), and gastrointestinal dysfunction in 3 (3.4%). Pathological findings revealed that 24 cases (27.6%) had TRG 0, 20 (23.0%) had TRG 1, 30 (34.5%) TRG 2, and 13 (14.9%) TRG 3. Conclusion TNT is safe and has good short?term efficacy for locally advanced rectal cancer patients with high risk factors.

Objective To evaluate the safety and preliminary efficacy of total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC) with high risk factors. Methods Data of 101 patients who were diagnosed with stage II?III rectal cancer with high risk factors and received TNT between March 2015 and January 2018 at West China Hospital of Sichuan University were analyzed retrospectively. Inclusion criteria: (1) patients were diagnosed with stage II?III rectal cancer by high?resolution MRI combined with CT and endorectal ultrasound; (2) at least one high risk factor: cT4a, cT4b, cN2, EMVI+, CRM+and lateral lymph node+; (3) distance from tumor to anal verge was within 15 cm;(4) Eastern Collaborative Oncology Group (ECOG) performance status score was 0?1; bone marrow function, liver function and kidney function were suitable for chemoradiotherapy; (5) patients were treated with TNT strategy; (6) the follow?up data and postoperative pathological data were complete. Patients with previous rectal cancer surgery (except prophylactic colostomy), pelvic radiotherapy, and systemic chemotherapy, those with distant metastases, those without neoadjuvant radiotherapy, those receiving less than 4 cycles of neoadjuvant chemotherapy were excluded. The regimen of TNT: 3 cycles of induction CAPOX (oxaliplatin plus capecitabine) were followed by pelvic radiotherapy and concurrent CAPOX, then 3 cycles of consolidation CAPOX were delivered after radiotherapy. Total mesorectal resection (TME) or watch?and?wait strategy was selected according to the therapeutic effect and patients' wishes. Short?term efficacy, including tumor regression grade (TRG), pathological complete response (pCR), clinical complete response (cCR), postoperative complications within 30 days of surgery, and adverse events (AE) to radiotherapy and chemotherapy (measured using CTCAE 4.0) was analyzed. Results The 101 patients included 68 males (67.3%) and 33 females (32.7%) with a median age of 54 years. The proportion of patients with cT4a, cT4b, cN2 and enlarged lateral lymph node was 13.9%, 29.7%, 56.4% and 43.6%, respectively. The mean cycle of neoadjuvant chemotherapy was 6.0 ± 1.3. Seventy?five patients (74.3%) received at least 6 cycles of neoadjuvant chemotherapy and 100 (99.0%) completed radiotherapy. The mean cycle of induction and consolidation chemotherapy was 2.0 ± 0.9 and 2.8 ± 1.0 respectively. Most common grade 3 AE was leucopenia (n=13, 12.9%) and thrombocytopenia (n=7, 6.9%). Grade 3 diarrhea and radiation dermatitis were observed in 5 cases (5.0%) respectively. Grade 3 anemia and rectal pain were observed in 4 cases (4.0%) respectively. And rectal mucositis was observed in 2 cases (2.0%). Most of the AE was observed during concurrent chemoradiotherapy. No grade 4 or higher AE was observed. After TNT, 32 patients (31.7%) achieved pCR or cCR, and 62 patients (60.4%) achieved partial response (PR). Only 2 patients (2.0%) developed distant metastasis after chemoradiotherapy, while the other patients did not show disease progression. Seven patients (6.9%) with cCR refused surgery and selected watch?and?wait, while 7 patients without cCR still refused surgery. The other 87 patients (86.1%) underwent TME successfully. The mean interval from the completion of chemoradiotherapy to surgery was (20.1±8.5) weeks. The R0 resection rate was 97.7% (85/87).The morbidity of surgical complication was 16.1% (14/87), including pelvic infection or abscess in 6 cases (6.9%), anastomotic leakage in 3 (3.4%), hemorrhage in 2 (2.3%), and gastrointestinal dysfunction in 3 (3.4%). Pathological findings revealed that 24 cases (27.6%) had TRG 0, 20 (23.0%) had TRG 1, 30 (34.5%) TRG 2, and 13 (14.9%) TRG 3. Conclusion TNT is safe and has good short?term efficacy for locally advanced rectal cancer patients with high risk factors.

Objective To explore the teaching effects of physiology lectures and students' attitude to lectures,their suggestions for contents,forms and other aspects of lectures.Methods Random sampling questionnaire survey was conducted among 500 students of 2008 grade and 2009 grade in Xiangya medical school of central south university.The percentage of the option in the questionnaire was calculated and the findings were directly described.Results All students thought that physiology lectures were necessary.Teachers should arrange lectures which students were interested in,pay attention to inspire thinking and enhance teacher-student interaction.67.6％ of students thought that the knowledge learned from lectures can be used in expanding scientific thinking.Conclusions The lectures are popular among most students,playing an important role in cultivating students' ability of strict scientific thinking.

Objective To determine the change of tumor bed volume during whole breast irradiation by repeated computed tomography scanning and to analyze the dosimetric impact of boost-planning on different CT images. Methods From July 2008 to Jan 2009, sixteen patients with early-stage breast cancer underwent breast conservative surgery (BCS) were enrolled in the study. All patients received whole breast irradiation and tumor bed boost, no adjuvant chemotherapy was given. Two additional CT scans were acquired in addition to the planning CT ( CT1 ), one in the course of radiotherapy ( CT2 ) and the other before the boost (CT3). Tumor beds were contoured in all CT images. Three-dimensional conformal radiotherapy planning for tumor bed boost was done on CT1 and CT3 respectively. Results The mean tumor bed volume on CT1, CT2 and CT3 were 49.5 cm3, 25.6 cm3 and 22. 2 cm3 ( F = 5. 63, P = 0. 007 ),respectively. Further analysis found statistically significant difference between CT1 and CT2 ( q = 0. 03, P =0. 010), CT1 and CT3 ( q = 0. 01, P = 0. 004), but not between CT2 and CT3 ( q = 1.00, P = 0. 333 ). The average reduction of tumor bed volume from CT1 to CT3 was 43.4%. A reduction of 20% or above was found in 88% of the patients ( n = 14), 50% or above in 38% of the patients (n = 6). In the boost-planning, the volume of the ipsilateral breast receiving 100% prescribed dose (V100%) on CT1 and CT3 was 183.5 cm3 and 144. 5 cm3, respectively ( t = 3.06, P = 0. 008 ). Conclusions Volume of tumor bed is dynamically reduced in the course of whole breast irradiation after BCS, with more important reduction in the early weeks after the beginning of irradiation. A second CT scan before tumor bed boost is warranted.