Stereotactic body radiotherapy in pancreatic adenocarcinoma

Background:Stereotactic body radiotherapy(SBRT)in pancreatic cancer allows high delivery of radiation doses on tumors without affecting surrounding tissue.This review aimed at the SBRT application in the treatment of pancreatic cancer.Data sources:We retrieved articles published in MEDLINE/PubMed from January 2017 to December 2022.Keywords used in the search included:“pancreatic adenocarcinoma”OR“pancreatic cancer”AND“stereotactic ablative radiotherapy(SABR)”OR“stereotactic body radiotherapy(SBRT)”OR“chemoradiotherapy(CRT)”.English language articles with information on technical characteristics,doses and fractionation,indications,recurrence patterns,local control and toxicities of SBRT in pancreatic tumors were included.All articles were assessed for validity and relevant content.Results:Optimal doses and fractionation have not yet been defined.However,SBRT could be the standard treatment in patients with pancreatic adenocarcinoma in addition to CRT.Furthermore,the combination of SBRT with chemotherapy may have additive or synergic effect on pancreatic adenocarcinoma.Conclusions:SBRT is an effective modality for patients with pancreatic cancer,supported by clinical practice guidelines as it has demonstrated good tolerance and good disease control.SBRT opens a possibility of improving outcomes for these patients,both in neoadjuvant treatment and with radical intent.

Impact of preoperative chemoradiotherapy using concurrent S-1 and CPT-11 on long-term clinical outcomes in locally advanced rectal cancer

BACKGROUND Preoperative chemoradiotherapy regimens using a second drug for locally advanced rectal cancer are still under clinical investigation.AIM To investigate the clinical outcomes of patients with locally advanced rectal cancer treated with preoperative chemoradiotherapy using tegafur/gimeracil/oteracil(S-1)plus irinotecan(CPT-11).METHODS This was a single-center retrospective study of 82 patients who underwent radical surgery for rectal cancer after chemoradiotherapy with S-1(80 mg/m2/d),CPT-11(60 mg/m2/d),and radiation(total 45 Gy)between 2009 and 2016.The median follow-up was 51 mo(range:17–116 mo).RESULTS Twenty-nine patients(35.4%)had T3 or T4 rectal cancer with mesorectal fascia invasion,36(43.9%)had extramural vascular invasion,24(29.8%)had N2 rectal cancer and eight(9.8%)had lateral lymph node swelling.The relative dose intensity was 90.1%for S-1 and 92.9%for CPT-11.Seventy-nine patients(96.3%)underwent R0 resection.With regard to pathological response,13 patients(15.9%)had a pathological complete response and 52(63.4%)a good response(tumor regression grade 2/3).The 5-year local recurrence-free survival,relapsefree survival and overall survival rates were 90.1%,72.5%and 91.3%,respectively.We analyzed the risk factors for local recurrence-free survival by Cox regression analysis and none were detected.Previously described risk factors such as T4 stage,mesorectal fascia invasion or lateral lymph node swelling were not detected as negative factors for local recurrence-free survival.CONCLUSION We demonstrated good compliance and favorable tumor regression in patients with locally advanced rectal cancer treated with preoperative S-1 and CPT-11.

Analysis of preoperative concurrent chemoradiotherapy for superior sulcus lung tumor

Objective： To compare the clinical effect and toxicities of preoperative concurrent chemoradiotherapy （CT/RT） with radiotherapy （RT） alone in patients with superior sulcus lung tumor. Methods： Fifty-six patients with superior sulcus lung tumor were divided randomly into two groups： twenty-six patients received concurrent chemoradiotherapy, the other thirty patients received only radiotherapy. For both groups, the same radiation technic was given with the convention fraction. The total dose was 45 Gy/25 Fr/5 Wk. For the CT/RT group, the patients were also given with concurrent chemotherapy （navelbine 15-18 mg/m^2 on the 1st and 8th day, cisplatin 60 mg/m^2 on the 1st day）. Results： The rate of complete resection in the CT/RT group was significantly higher than that in the RT group （92.3% vs 80%, P 〈 0.05）. The complete pathological response rate and 2-year survival rate in the CT/RT group were significantly higher than those in the RT group （P 〈 0.01, P 〈 0.01）. The incidences of grades Ill-IV radiation esophagitis and leukopenia in the CT/RT group were significantly higher than those in the RT group （23.1% and 23.1% vs 6.7% and 0, P 〈 0.01, P 〈 0.01）. Conclusion： Preoperative concurrent chemoradiotherapy has the potential of improving the survival rate of superior sulcus lung tumors. Though this treatment regimen also increases the acute toxic effect, all patients can tolerate it. It is expected to be a new ＂standard treatment＂ for this malignant tumor.

Tumor regression grades:Potential outcome predictor of locally advanced rectal adenocarcinoma after preoperative radiotherapy

AIM:To analyze tumor regression grade(TRG)for prognosis of locally advanced rectal adenocarcinoma(LARA)treated with preoperative radiotherapy.METHODS:One hundred and ninety patients with clinical stageⅡ/ⅢLARA were studied.All patients underwent radical surgery(between 2004 and 2010)after 30-Gy/10-fraction preoperative radiotherapy(preRT).All 190 patients received a short course of preRT and were reassessed for disease recurrence and survival;the slides of surgical specimens were reviewed and classified according to Mandard TRG.We compared patients with good response(Mandard TRG1 or TRG2)vs patients with bad/poor response(Mandard TRG3-5).Outcomes evaluated were 5-year overall survival(OS),5-year disease-free survival(DFS),and local,distant and mixed recurrence.Fisher’s exact test orχ2 test,logrank test and proportional hazards regression analysis were used to calculate the probability that Mandard TRG was associated with patient outcomes.RESULTS:One hundred and sixty-six of 190 patients(87.4%)were identified as Mandard bad responders(TRG3-5).High Mandard grade was correlated with tumor height(41.7%<6 cm vs 58.3%≥6 cm,P=0.050),yp T stage(75%yp T0-2 vs 25%yp T3-4,P=0.000),and yp N stage(75%yp N0 vs 25%yp N1,P=0.031).In univariate survival analysis,Mandard grade bad responders had significantly worse OS and DFSthan good responders(TRG1/2)(OS,83.1%vs 96.4%,P=0.000;DFS,72.3%vs 92.0%,P=0.002).In multivariate survival analysis,Mandard bad responders had significantly worse DFS than Mandard good responders(DFS 3.8 years(95%CI:1.2-12.2 years,P=0.026).CONCLUSION:Mandard grade good responders had a favorable prognosis.TRG may be a potential predictor for DFS in LARA after pre-RT.

Ratio of metastatic lymph nodes is more important for rectal cancer patients treated with preoperative chemoradiotherapy

AIM:To evaluate the predictive value of the lymph node(LN) ratio(LNR,number of metastatic LNs/ examined LNs) for recurrence in patients with rectal cancer and to compare its applicability according to preoperative chemoradiotherapy(PCRT).METHODS:From 2000 to 2009,967 patients with metastatic LNs after curative resection for locally advanced rectal cancer were identified.Patients were categorized according to PCRT(PCRT vs No PCRT).The cut-off LNR was determined based on the p N1 vs p N2 when the recommended number of LNs was harvested.The 5-year recurrence-free survival(RFS) rates using the Kaplan-Meier method were compared according to p/yp N stage and the LNR in each group.RESULTS:Among patients with the same p/yp N stage,the 5-year RFS rate differed according to the LNR.In addition,the 5-year RFS rate was significantly different between p N and LNR groups in patients with No PCRT.In PCRT group,however,only LNR was associated with prognosis.On multivariate analysis,both p N and LNR were significant independent prognostic factors for 5-year RFS in the No PCRT group.In the PCRT group,only LNR category was found to be associated with RFS(HR = 2.36,95%CI:1.31-3.84,and P = 0.001).CONCLUSION:The LNR is an important prognostic predictor of RFS in rectal cancer patients especially treated with PCRT.Current p N categories could not discriminate between prognostic groups of RFS after PCRT.

Phosphatidylinositol 3-kinase CB association with preoperative radiotherapy response in rectal adenocarcinoma

AIM: To examine the correlation of phosphatidylinositol 3-kinase (PIK3) CB expression with preoperative radiotherapy response in patients with stage II/III rectal adenocarcinoma.

Impression of prognosis regarding pathologic stage after preoperative chemoradiotherapy in rectal cancer

AIM: To ascertain pathologic stage as a prognostic indicator for rectal cancer patients receiving preoperative chemoradiotherapy(PCRT).METHODS: Patients with mid- and low rectal carcinoma(magnetic resonance imaging- based clinical stage Ⅱ or Ⅲ) between 2000 and 2009 and treated with curative radical resection were identified. Patients were divided into two groups: PCRT and No-PCRT. Recurrence-free survival(RFS) was examined according to pathologic stage and addition of adjuvant treatment.RESULTS: Overall, 894 patients were identified. Of these, 500 patients received PCRT. Adjuvant chemotherapy was delivered to 81.5% of the No-PCRT and 94.8% of the PCRT patients. Adjuvant radiotherapy was given to 29.4% of the patients in the No PCRT group. The 5-year RFS for the No-PCRT group was 92.6% for StageⅠ, 83.3% for Stage Ⅱ, and 72.9% for Stage Ⅲ. The 5-year RFS for the PCRT group was 95.2% for yp Stage 0, 91.7% for yp StageⅠ, 73.9% for yp Stage Ⅱ, and 50.7% for yp Stage Ⅲ.CONCLUSION: Pathologic stage can predict prognosis in PCRT patients. Five-year RFS is significantly lower among PCRT patients than No-PCRT patients in pathologic stage Ⅱ and Ⅲ. These results should be taken into account when considering adjuvant treatment for patients treated with PCRT.

Fluorouracil-based preoperative chemoradiotherapy with or without oxaliplatin for stage Ⅱ/Ⅲ rectal cancer:a 3-year follow-up study

Background： Fluorouracil-based preoperative chemoradiotherapy has become the standard treatment for stage Ⅱ/Ⅲ rectal cancer. In order to improve the overall survival （OS） and disease-flee survival （DFS）, we added oxaliplatin to the standard treatment, and compared the effectiveness of these two treatment patterns. Methods： A total of 206 patients enrolled in the prospective study had histologically confirmed rectal cancer of clinical stage Ⅱ/Ⅲ during July 2007 to July 2010. They were randomized into the experimental group received oxaliplatin and capecitabine in combination with radiotherapy, and the control group received capecitabine in combination with radiotherapy. All patients received surgery in 6-10 weeks after chemoradiotherapy and adjuvant chemotherapy with mFOLFOX6. The primary endpoints were DFS and OS, and the secondary endpoints included toxicity, compliance, and histopathological response. Results： The 3-year OS in the experimental group and the control group was 90.29% vs. 86.41% （P〉0.05）, and the 3-year DFS was 80.58% vs. 69.90% （P〉0.05）. The pathological complete remission （pCR） rates were 23.30% and 19.42%, respectively （P=0.497）. The 3-year local recurrence rates were 4.85% vs. 5.83% （P=0.694）, and the 3-year distant metastasis rates were 16.50% and 28.16%, respectively （P=0.045）. There were no significant differences in most grade 3-4 toxicities between two groups, however, grade 3-4 diarrhea occurred in 16.50% （17/103） of the experimental group, compared with 6.80% （7/103） of the control group （P=0.030）. Also, the total grade 3-4 acute toxicity showed a significant difference （10.68% vs. 21.36%, P=0.037）. Conclusions： The experimental treatment did not lead significantly improved OS and DFS, and thus longer follow-up is warranted for our patient cohort. Adding oxaliplatin to capecitabine-based preoperative chemoradiotherapy can significantly reduce metastasis, but has only minimal impact on local recurrence. Although grade 3-4 toxicity rate increased （primarily gastrointestinal toxicity）, patients can stand to be followed up with allopathic treatment.

Impact of simultaneous assay, the PCNA, cyclinDl, and DNA content with specimens before and after preoperative radiotherapy on prognosis of esophageal cancer-possible incorporation into clinical TNM staging system

AIM: The aim of the present study is to use immunohisto chemical methods to investigate the clinical implications of tumor markers in esophageal squamous cell carcinoma and evaluate their impact on prognosis. METHODS: From November 1990 to December 1996, 47 patients were treated with preoperative radiation followed by radical esophagectomy. All patients were confirmed pathologically as suffering from squamous cell carcinoma. Immunohistochemical stain was done for PCNA, cyclinDl protein expression and DNA content analyzed by image cytometry. Kaplan-Meier method for single prognostic factor and log-rank test was used to test the significant difference. Cox stepwise regression model and prognosis index model were used for survival analysis with multiple prognostic factors. RESULTS: Radio-pathological change, T stage and N stage, as the traditional prognostic factors had statistical difference in 3-, 5- and 10-year survival rates. While, tumor cell proliferating marked PCNA, cyclinDl and DNA content served as independent prognostic factors of esophageal carcinoma. There was definitely an identity between the single and multiple factor analyses. PI was more accurate to evaluate the prognosis of esophageal carcinoma. CONCLUSION: It is possible that tumor cell proliferating marked PCNA, cyclinD1 and DNA content would become the endpoints for evaluating the prognosis of esophageal carcinoma.

Current issues in locally advanced colorectal cancer treated by preoperative chemoradiotherapy

In patients with locally advanced rectal cancer, preoperative chemoradiotherapy has proven to significantly improve local control and cause lower treatment-related toxicity compared with postoperative adjuvant treatment. Preoperative chemoradiotherapy followed by total mesorectal excision or tumor specific mesorectal excision has evolved as the standard treatment for locally advanced rectal cancer. The paradigm shift from postoperative to preoperative therapy has raised a series of concerns however that have practical clinical implications. These include the method used to predict patients who will show good response, sphincter preservation, the application of conservative management such as local excision or &#x0201c;wait-and-watch&#x0201d; in patients obtaining a good response following preoperative chemoradiotherapy, and the role of adjuvant chemotherapy. This review addresses these current issues in patients with locally advanced rectal cancer treated by preoperative chemoradiotherapy.

Down-staging depth score could be a survival predictor for locally advanced gastric cancer patients after preoperative chemoradiotherapy

Objective:The predictive effect of preoperative chemoradiotherapy(CRT)is low and difficult in guiding individualized treatment.We examined a surrogate endpoint for long-term outcomes in locally advanced gastric cancer patients after preoperative CRT.Methods:From April 2012 to April 2019,95 patients with locally advanced gastric cancer who received preoperative concurrent CRT and who were enrolled in three prospective studies were included.All patients were stage T_(3/4) N_(+).Local control,distant metastasis-free survival(DMFS),disease-free survival(DFS)and overall survival(OS)were evaluated.Clinicopathological factors related to long-term prognosis were analyzed using univariate and multivariate analyses.The down-staging depth score(DDS),which is a novel method of evaluating CRT response,was used to predict long-term outcomes.Results:The median follow-up period for survivors was 30 months.The area under the curve(AUC)of the receiver operating characteristic(ROC)curve predicted by the DDS was 0.728,which was better than the pathological complete response(pCR),histological response and ypN0.Decision curve analysis further affirmed that DDS had the largest net benefit.The DDS cut-off value was 4.pCR and ypN0 were associated with OS(P=0.026 and 0.049).Surgery and DDS are correlated with DMFS,DFS and OS(surgery:P=0.001,<0.001 and<0.001,respectively;and DDS:P=0.009,0.013 and 0.032,respectively).Multivariate analysis showed that DDS was an independent prognostic factor of DFS(P=0.021).Conclusions:DDS is a simple,short-term indicator that was a better surrogate endpoint than pCR,histological response and ypN0 for DFS.

Effect of Tumor Infiltrating Lymphocyte on Local Control of Rectal Cancer after Preoperative Radiotherapy

Objective： To study the effect of tumor infiltrating lymphocytes at cancer nest on local control of rectal cancer after preoperative radiotherapy. Methods： From Jan. 1999 to Oct. 2007, a total of 107 patients with rectal cancer were reviewed. They were treated by preoperative radiotherapy, 30 Gy/10 fractions/12 days. Two weeks later, the patient underwent a surgical operation. Their pathological samples were kept in our hospital before and after radiotherapy. Lymphocyte infiltration （LI） degree, pathologic degradation and fibrosis degree after radiotherapy in paraffin section were evaluated under microscope. Results： After followed-up of 21 months （2-86 months）, a total of 107 patients were reviewed. Univariate analysis showed that lymphocyte infiltration （LI）, fibrosis and pathologic changes after radiotherapy were significant factors on local control. Logistic regression analysis showed that LI after radiotherapy was a significant effect factor on local control. Conclusion： LI, fibrosis and pathologic degradation after radiotherapy are significant for local control of rectal cancer after preoperative radiotherapy. LI after radiotherapy was a significantly prognostic index for local control of rectal cancer after preoperative radiotherapy.

Abdominoperineal excision following preoperative radiotherapy for rectal cancer: Unfavorable prognosis even with negative circumferential resection margin

AIM: To evaluate whether an abdominoperineal excision (APE) is associated with increased local recurrence (LR) and shortened disease-free survival (DFS) in mid-low rectal cancer with a negative circumferential resection margin (CRM).

Local advanced rectal cancer perforation in the midst of preoperative chemoradiotherapy:A case report and literature review

Standard chemoradiotherapy(CRT) for local advanced rectal cancer(LARC) rarely induce rectal perforation. Here we report a rare case of rectal perforation in a patient with LARC in the midst of preoperative CRT. A 56-year-old male was conveyed to our hospital exhibiting general malaise. Colonoscopy and imaging tests resulted in a clinical diagnosis of LARC with direct invasion to adjacent organs and regional lymphadenopathy. Preoperative 5-fluorouracil-based CRT was started. At 25 d after the start of CRT, the patient developed a typical fever. Computed tomography revealed rectal perforation, and he underwent emergency sigmoid colostomy. At 12 d after the surgery, the remaining CRT was completed according to the original plan. The histopathological findings after radical operation revealed a wide field of tumor necrosis and fibrosis without lymph node metastasis. We share this case as important evidence for the treatment of LARC perforation in the midst of preoperative CRT.

Adjuvant Therapy on Cancer of the Lower Rectum. Evaluation of the Effects of Preoperative Radiotherapy on the Prognosis of Patients with Cancer of the Lower Rectum

Aims: The prognosis on treatment of the cancer of the rectum has not changed in the last fifty years. Survival rates of 50 to 55% seems immutable in several published series. The main cause for those results is the high incidence of recurrence, either local or widespread. Local recurrence is directly related to the number of undifferentiated cells and to the grade of wall invasion. Widespread recurrence depends specifically on the lymphatic and vascular spreading. So any kind of treatment that would diminish the number of undifferentiated cells and the size or the tumor wall penetration would certainly decrease the local recurrence rate, lengthening the interval free from cancer and, perhaps, modifying the long term survival rate. Between 1978 and 2009, a total of 538 patients with adenocarcinoma of the lower rectum (from the pectinate line to 10 cm above) were treated by preoperative radiotherapy. Methodology: The same protocol was used in all the patients – 400 cGy, 200 cGy/day, during 4 consecutive weeks (anterior and posterior pelvic fields) by means of a Linear Megavoltage Accelerator (25 MeV). Surgery was performed 2 months after completion of the radiotherapy. Results: Statistical analysis of the whole group showed that preoperative radiotherapy does decrease frequency of undifferentiated cells. Moreover, the incidence of local recurrence diminished after irradiation by 3.4%. Preoperative radiotherapy reduces tumor volume (ERUS) and wall invasion, as well as the mortality rate due to local recurrence (2.4%) and alters long-term survival rate (80.1%). Conclusion: Preoperative radiotherapy is really effective in reducing the number of undifferentiated cells and in diminishing the tumor volume and the carcinomatous infiltration of the rectal wall.

Phase I/II Study of Gefitinib and Concomitant Preoperative Radiotherapy in Patients with Locally Advanced Rectal Cancer

Objective: To determine the recommended dose (RD) of gefitinib when combined with concomitant radiotherapy (RT) in a preoperative setting in patients with locally advanced rectal cancer. Secondary objectives were to evaluate acute toxicities, pathological response rate, progression-free and overall survival (OS). Materials and Methods: 20 patients with cT3-4 or cN+ cM0 tumors were enrolled. The planned RT consisted in 50 Gy given in 2 daily fractions of 1.25 Gy in 4 weeks. During RT, gefitinib was planned to be given orally once daily with 2 successive dose levels: 250 mg and 500 mg. Rectal surgery was scheduled 5 - 6 weeks after completion of RT. The median follow-up for all patients was 57 months. Results: Among the first cohort of 6 patients, 1 patient presented a dose limiting toxicity (DLT) (Grade 3 diarrhea/dehydration). In the second cohort, 2/6 patients presented with the same DLT so that 250 mg was considered as the RD. Main acute toxicities consisted in diarrhea (grade 2 - 3, 63%), and skin reaction (in RT fields grade 2 - 3 in 42%). The 5-year actuarial OS and loco-regional control rates were of 80% and 84% respectively. Conclusion: The concomitant daily administration of 250 mg of gefitinib with 50 Gy preoperative RT is feasible with manageable toxicity. The major pathologic response rate is encouraging, though it needs further confirmation. Distant metastasis still represents a concern and new strategies to overcome this issue are warranted.

Hemostatic radiotherapy for bleeding gastrointestinal

Hemostatic radiotherapy is a non-invasive treatment for bleeding gastrointestinal(GI)tumors,promoting tumor shrinkage,blood supply reduction,and fibrotic tissue formation.It is effective in cases where traditional interventions are insufficient or contraindicated and can prevent recurrent bleeding in patients with GI bleeding histories.Hypofractionation schedules are also effective for tumor control and patient compliance.

Radiotherapy for hyoid bone metastasis from lung adenocarcinoma:A case report

BACKGROUND Metastasis to the hyoid bone is an exceptionally rare occurrence,with documented cases limited to breast,liver,colon,skin,lung,and prostate cancers.This report highlights an unusual case involving the metastasis of lung adenocarcinoma to the hyoid bone,accompanied by a distinctive headache.Previous documentation involved surgical resection of the hyoid mass.We present a case displaying the benefits of palliative radiotherapy.CASE SUMMARY A 72-year-old non-smoking,non-alcoholic woman,initially under investigation for a year-long elevation in absolute lymphocyte count,presented with a monthlong history of intermittent throat pain.Despite negative findings in gastroenterological and otolaryngologic examinations,a contrast-enhanced chest computed tomography scan revealed a mediastinal mass and questionable soft tissue thickening in her left anterolateral neck.Subsequent imaging and biopsies confirmed the presence of lung adenocarcinoma metastasis to the hyoid bone.The patient was treated with platinum-based chemo-immunotherapy along with pembrolizumab.Ultimately,the lung cancer was unresponsive.Our patient opted for palliative radiation therapy instead of surgical resection to address her throat pain.As a result,her throat pain was alleviated,and it also incidentally resolved her chronic headaches.This is the second documented case of lung adenocarcinoma metastasizing to the hyoid bone.CONCLUSION Palliative radiotherapy may add to the quality of life in symptomatic patients with cancer metastatic to the hyoid bone.

Present situation and prospect of immunotherapy for unresectable locally advanced esophageal cancer during peri-radiotherapy

Four major studies(Checkmate577,Keynote-590,Checkmate649 and Attraction-4)of locally advanced esophageal cancer published in 2020 have established the importance of immunotherapy,represented by anti-programmed death protein(PD)-1 in postoperative adjuvant treatment and advanced first-line treatment of locally advanced or advanced esophageal cancer and esophagogastric junction cancer,from the aspects of proof of concept,long-term survival,overall survival rate and progression-free survival.For unresectable or inoperable nonmetastatic esophageal cancer,concurrent radiotherapy and chemotherapy is the standard treatment recommended by various guidelines.Because its curative effect is still not ideal,it is necessary to explore radical radiotherapy and chemotherapy in the future,and it is considered to be promising to combine them with immunotherapeutic drugs such as anti-PD-1.This paper mainly discusses how to combine radical concurrent radiotherapy and chemotherapy with immunotherapy for unresectable local advanced esophageal cancer.

Signal intensity changes of dentate nucleus on plain MR T1WI innasopharyngeal carcinoma patients after radiotherapy andmultiple injections of gadolinium-base contrast agent

Objective To observe changes of plain MR T1WI signal intensity of dentate nucleus in nasopharyngeal carcinoma patients after radiotherapy and multiple times of intravenous injection of gadolinium-based contrast agent(GBCA).Methods Fifty patients with pathologically confirmed nasopharyngeal carcinoma and received intensity-modulated radiotherapy were retrospectively enrolled as the nasopharyngeal carcinoma group,and 50 patients with other malignant tumors and without history of brain radiotherapy were retrospectively enrolled as the control group.All patients received yearly GBCA enhanced MR examinations for the nasopharynx or the head.T1WI signal intensities of the dentate nucleus and the pons on same plane were measured based on images in the year of confirmed diagnosis(recorded as the first year)and in the second to the fifth years.T1WI signal intensity ratio of year i(ranging from 1 to 5)was calculated with values of dentate nucleus divided by values of the pons(ΔSI i),while the percentage of relative changes of year j(ranging from 2 to 5)was calculated withΔSI j compared toΔSI 1(Rchange j).The values of these two parameters were compared,and the correlation ofΔSI and GBCA injection year-time was evaluated within each group.Results No significant difference of gender,age norΔSI 1 was found between groups(all P>0.05).The second to the fifth yearΔSI and Rchange in nasopharyngeal carcinoma group were all higher than those in control group(all P<0.05).Within both groups,ΔSI was positively correlated with GBCA injection year-time(both P<0.05).Conclusion Patients with nasopharyngeal carcinoma who underwent radiotherapy and multiple times of intravenous injection of GBCA tended to be found with gradually worsening GBCA deposition in dentate nucleus,for which radiotherapy might be a risk factor.