Implications of recent neoadjuvant clinical trials on the future practice of radiotherapy in locally advanced rectal cancer

Over the last two decades, the standard treatment for locally advanced rectal cancer(LARC) has been neoadjuvant chemoradiotherapy plus total mesorectal excision followed by adjuvant chemotherapy. Total neoadjuvant treatment(TNT) and immunotherapy are two major issues in the treatment of LARC. In the two latest phase Ⅲ randomized controlled trials(RAPIDO and PRODIGE23), the TNT approach achieved higher rates of pathologic complete response and distant metastasis-free survival than conventional chemoradiotherapy. Phase I/II clinical trials have reported promising response rates to neoadjuvant(chemo)-radiotherapy combined with immunotherapy. Accordingly, the treatment paradigm for LARC is shifting toward methods that increase the oncologic outcomes and organ preservation rate. However, despite the progress of these combined modality treatment strategies for LARC, the radiotherapy details in clinical trials have not changed significantly. To guide future radiotherapy for LARC with clinical and radiobiological evidence, this study reviewed recent neoadjuvant clinical trials evaluating TNT and immunotherapy from a radiation oncologist’s perspective.

Postoperative chemoradiotherapy with capecitabine and oxaliplatin vs.capecitabine for pathological stage N2 rectal cancer

Objective:Several studies have been conducted on the effects and toxicity of adding oxaliplatin to fluorouracilbased or capecitabine-based chemoradiotherapy(CRT)regimens as significantly increasing the toxic response without benefit to survival.In this study,we further explored the role of these two postoperative CRT regimens in patients with pathological stage N2 rectal cancer.Methods:This study was a subgroup analysis of a randomized clinical trial.A total of 180 patients with pathological stage N2 rectal cancer were eligible,85 received capecitabine with radiotherapy(RT),and 95 received capecitabine and oxaliplatin with RT.Patients in both groups received adjuvant chemotherapy[capecitabine and oxaliplatin(XELOX);or fluorouracil,leucovorin,and oxaliplatin(FOLFOX)]after CRT.Results:At a median follow-up of 59.2[interquartile range(IQR),34.0−96.8]months,the three-year diseasefree survival(DFS)was 53.3%and 64.9%in the control group and the experimental group,respectively[hazard ratio(HR),0.63;95%confidence interval(95%CI),0.41−0.98;P=0.04].There was no significant difference between the groups in overall survival(OS)(HR,0.62;95%CI,0.37−1.05;P=0.07),the incidence of locoregional recurrence(HR,0.62;95%CI,0.24−1.64;P=0.33),the incidence of distant metastasis(HR,0.67;95%CI,0.42−1.06;P=0.09)and grade 3−4 acute toxicities(P=0.78).For patients with survival longer than 3 years,the conditional overall survival(COS)was significantly better in the experimental group(HR,0.39;95%CI,0.16−0.96;P=0.03).Conclusions:Our results indicated that adding oxaliplatin to capecitabine-based postoperative CRT is safe and effective in patients with pathological stage N2 rectal cancer.

Radical radiotherapy without surgical tumor resection for rectal cancer

In this editorial,I would like to comment on the article,recently published in the World Journal of Clinical Oncology.The article focuses on non-surgical treatments for locally recurrent rectal cancer,including the watch-and-wait(WW)strategy after total neoadjuvant therapy(TNT)and particle beam therapy.As treatment options for rectal cancer continue to evolve,the high complete response rate achieved with TNT has led to the development of a new non-surgical approach:WW.Chemoradiotherapy followed by consolidation chemotherapy,in particular,has a low rate of tumor growth and is a treatment aimed at achieving a cure without surgery.However,the risk of recurrence within two years is significant,necessitating careful follow-up.Establishing standardized follow-up methods that can be implemented by many physicians is essential.Carbon ion radiotherapy has demonstrated high local control with a low incidence of severe late toxicities,even after previous pelvic radiotherapy.While these new non-surgical curative treatments for rectal cancer require further investigation,future advancements in this field are anticipated.

Neoadjuvant vs adjuvant pelvic radiotherapy for locally advanced rectal cancer: Which is superior?

The treatment of locally advanced rectal cancer including timing and dosage of radiotherapy, degree of sphincter preservation with neoadjuvant radiotherapy, and short and long term effects of radiotherapy are controversial topics. The MEDLINE, Cochrane Library databases, and meeting proceedings from the American Society of Clinical Oncology, were searched for reports of randomized controlled trials and meta-analyses comparing neoadjuvant and adjuvant radiotherapy with surgery to surgery alone for rectal cancer. Neoadjuvant radiotherapy shows superior results in terms of local control compared to adjuvant radiotherapy. Neither adjuvant or neoadjuvant radiotherapy impacts overall survival. Short course versus long course neoadjuvant radiotherapy remains controversial. There is insufficient data to conclude that neoadjuvant therapy improves rates of sphincter preserving surgery. Radiation significantly impacts anorectal and sexual function and includes both acute and long term toxicity. Data demonstrate that neoadjuvant radiation causes less toxicity compared to adjuvant radiotherapy, and specifically short course neoadjuvant radiation results in less toxicity than long course neoadjuvant radiation. Neoadjuvant radiotherapy is the preferred modality for administering radiation in locally advanced rectal cancer. There are significant side effects from radiation, including anorectal and sexual dysfunction, which may be less with short course neoadjuvant radiation.

Selective lateral lymph node dissection after neoadjuvant chemoradiotherapy in rectal cancer

BACKGROUND Lateral lymph node metastasis is one of the leading causes of local recurrence in patients with advanced mid or low rectal cancer.Neoadjuvant chemoradiotherapy(NCRT)can effectively reduce the postoperative recurrence rate;thus,NCRT with total mesorectal excision(TME)is the most widely accepted standard of care for rectal cancer.The addition of lateral lymph node dissection(LLND)after NCRT remains a controversial topic.AIM To investigate the surgical outcomes of TME plus LLND,and the possible risk factors for lateral lymph node metastasis after NCRT.METHODS This retrospective study reviewed 89 consecutive patients with clinical stage II-III mid or low rectal cancer who underwent TME and LLND from June 2016 to October 2018.In the NCRT group,TME plus LLND was performed in patients with short axis(SA)of the lateral lymph node greater than 5 mm.In the non-NCRT group,TME plus LLND was performed in patients with SA of the lateral lymph node greater than 10 mm.Data regarding patient demographics,clinical workup,surgical procedure,complications,and outcomes were collected.Multivariate logistic regression analysis was performed to evaluate the possible risk factors for lateral lymph node metastasis in NCRT patients.RESULTS LLN metastasis was pathologically confirmed in 35 patients(39.3%):26(41.3%)in the NCRT group and 9(34.6%)in the non-NCRT group.The most common site of metastasis was around the obturator nerve(21/35)followed by the internal iliac artery region(12/35).In the NCRT patients,46%of patients with SA of LLN greater than 7 mm were positive.The postoperative 30-d mortality rate was 0%.Two(2.2%)patients suffered from lateral local recurrence in the 2-year follow up.Multivariate analysis showed that cT4 stage(odds ratio[OR]=5.124,95%confidence interval[CI]:1.419-18.508;P=0.013),poor differentiation type(OR=4.014,95%CI:1.038-15.520;P=0.044),and SA≥7 mm(OR=7.539,95%CI:1.487-38.214;P=0.015)were statistically significant risk factors associated with LLN metastasis.CONCLUSION NCRT is not sufficient as a stand-alone therapy to eradicate LLN metastasis in lower rectal cancer patients and surgeons should consider performing selective LLND in patients with greater LLN SA diameter,poorer histological differentiation,or advanced T stage.Selective LLND for NCRT patients can have a favorable oncological outcome.

Down-staging depth score to predict outcomes in locally advanced rectal cancer achieving ypl stage after neoadjuvant chemo-radiotherapy versus de novo stage pl cohort:A propensity score-matched analysis

Objective：Prognosis of patients with locally advanced rectal cancer（LARC）but achieving yp T1–2N0 stage after neoadjuvant concurrent chemo-radiotherapy（CRT）has been shown to be favorable.This study aims to determine whether the long-term outcome of yp T1–2N0 cases can be comparable to that of p T1–2N0 cohort that received definitive surgery for early disease.Method：From January 2008 to December 2013,449 consecutive patients with rectal cancer were treated and their outcome maintained in a database.Patients with LARC underwent total mesorectal excision（TME）surgery at4–8 weeks after completion of CRT,and those achieving stage yp I were identified as a group.As a comparison,stage p I group pertains to patients whose initially limited disease was not upstaged after TME surgery alone.After propensity score matching（PSM）,comparisons of local regional control（LC）,distant metastasis-free survival（DMFS）,disease-free survival（DFS）and overall survival（OS）were performed using Kaplan-Meier analysis and log-rank test between yp I and p I groups.Down-staging depth score（DDS）,a novel method of evaluating CRT response,was used for subset analysis.Results：Of the 449 patients,168 matched cases were generated for analysis.Five-year LC,DMFS,DFS and OS for stage p I vs.yp I groups were 96.7%vs.96.4%（P=0.796）,92.7%vs.73.6%（P=0.025）,91.2%vs.73.6%（P=0.080）and 93.1%vs.72.3%（P=0.040）,respectively.In the DDS-favorable subset of the yp I group,LC,DMFS,DFS and OS resulted in no significant differences in comparison with the p I group（P=0.384,0.368,0.277 and0.458,respectively）.Conclusions：LC was comparable in both groups;however,distant metastasis developed more frequently in down-staged LARC than de novo early stage cases,reflecting the need to improve the efficacy of systemic treatment despite excellent pathologic response.DDS can be an indicator to identify a subset of the yp I group whose longterm oncologic outcomes are as good as those of stage p I cohort.

Lymphovascular invasion in rectal cancer following neoadjuvant radiotherapy: A retrospective cohort study

AIM: To investigate the meaning of lymphovascular invasion (LVI) in rectal cancer after neoadjuvant radiotherapy. METHODS: A total of 325 patients who underwent radical resection using total mesorectal excision (TME) from January 2000 to January 2005 in Beijing cancer hospital were included retrospectively, divided into a preoperative radiotherapy (PRT) group and a control group, according to whether or not they underwent preoperative radiation. Histological assessments of tumor specimens were made and the correlation of LVI and prognosis were evaluated by univariate and multivariate analysis. RESULTS: The occurrence of LVI in the PRT and control groups was 21.4% and 26.1% respectively. In the control group, LVI was signifi cantly associated with histological differentiation and pathologic TNM stage, whereas these associations were not observed in the PRT group. LVI was closely correlated to disease progression and 5-year overall survival (OS) in both groups. Among the patients with disease progression, LVI positive patients in the PRT group had a signifi cantly longer median disease-free period (22.5 mo vs 11.5 mo, P = 0.023) and overall survival time (42.5 mo vs 26.5 mo, P = 0.035) compared to those in the control group, despite the fact that no signifi cant difference in 5-year OS rate was observed (54.4% vs 48.3%, P = 0.137). Multivariate analysis showed the distance of tumor from the anal verge, pretreatment serum carcinoembryonic antigen level, pathologic TNM stage and LVI were the major factors affecting OS. CONCLUSION: Neoadjuvant radiotherapy does not reduce LVI significantly; however, the prognostic meaning of LVI has changed. Patients with LVI may benefi t from neoadjuvant radiotherapy.

Neoadjuvant Therapy for Advanced Rectal Carcinoma in China:Whether Radiochemotherapy Is Superior to Radiotherapy?

Objective： To verify whether the 30 Gy preoperative radiotherapy regimen is effective to advanced rectal cancer, and whether the preoperative chemoradiation offers an advantage in sphincter preservation and tumor control compared with irradiation alone. Methods： A total of 141 patients administered neoadjuvant treatment with resectable lower rectal carcinoma from 2002 to 2006 were collected retrospectively. The patients were divided into two groups： preoperative radiotherapy alone （30Gy by 10 fractions） （PRT group） and preoperative chemoradiotherapy （PCRT group）. All patients underwent radical surgery after neoadjuvant treatment. Results： The overall sphincter-preservation rate was 68.8% （97/141）, with no significant difference between the two groups. The overall downstaging rate was 48.2% （68/141）, including 4 patients completely response （2.8%）. The T and N downstaging rate were 30.5% （43/141） and 53.8% （57/106） respectively, showing no statistically difference between the two groups. The 2-year overall survival rate was 93.6%; no survival benefit were observed in PCRT group. The 2-year cumulative local recurrence rates were similar as well （4.2% vs 6.7%, P=0.63）. Two patients with severe marrow suppression higher than grade 3 and 1 patient with severe perineum ulcer was observed in PCRT group, which did not occur in PRT group. Conclusion： The preoperative adjuvant treatment of 30Gy radiotherapy alone may be an optional treatment for Chinese lower rectal carcinoma. Preoperative chemoradiotherapy does not show actual superiority compared with radiotherapy alone.

Neoadjuvant radiotherapy dose escalation for locally advanced rectal cancers in the new era of radiotherapy:A review of literature

BACKGROUND The standard treatment of locally advanced rectal cancers(LARC)consists on neoadjuvant chemoradiotherapy followed by total mesorectal excision.Different data in literature showed a benefit on tumor downstaging and pathological complete response(pCR)rate using radiotherapy dose escalation,however there is shortage of studies regarding dose escalation using the innovative techniques for LARC(T3-4 or N1-2).AIM To analyze the role of neoadjuvant radiotherapy dose escalation for LARC using innovative radiotherapy techniques.METHODS In December 2020,we conducted a comprehensive literature search of the following electronic databases:PubMed,Web of Science,Scopus and Cochrane library.The limit period of research included articles published from January 2009 to December 2020.Screening by title and abstract was carried out to identify only studies using radiation doses equivalent dose 2 Gy fraction(EQD2)≥54 Gy and Volumetric Modulated Arc Therapy(VMAT),intensity-modulated radiotherapy or image-guided radiotherapy(IGRT)techniques.The authors’searches generated a total of 2287 results and,according to PRISMA Group(2009)screening process,21 publications fulfil selection criteria and were included for the review.RESULTS The main radiotherapy technique used consisted in VMAT and IGRT modality.The mainly dose prescription was 55 Gy to high risk volume and 45 Gy as prophylactic volume in 25 fractions given with simultaneous integrated boosts technique(42.85%).The mean pCR was 28.2%with no correlation between dose prescribed and response rates(P value≥0.5).The R0 margins and sphincter preservation rates were 98.88%and 76.03%,respectively.After a mean follow-up of 35 months local control was 92.29%.G3 or higher toxicity was 11.06%with no correlation between dose prescription and toxicities.Patients receiving EQD2 dose>58.9 Gy and BED>70.7 Gy had higher surgical complications rates compared to other group(P value=0.047).CONCLUSION Dose escalation neoadjuvant radiotherapy using innovative techniques is safe for LARC achieving higher rates of pCR.EQD2 doses>58.9 Gy is associated with higher rate of surgical complications.

Neoadjuvant hyperfractionated accelerated radiotherapy plus concomitant 5-fluorouracil infusion in locally advanced rectal cancer: A phase Ⅱ study

AIM To evaluate the efficacy and tolerability of neoadjuvant hyperfractionated accelerated radiotherapy(HART)and concurrent chemotherapy in patients with locally advanced infraperitoneal rectal cancer. METHODS A total of 30 patients with histopathologically confirmed T2-3/N0+ infraperitoneal adenocarcinoma of rectum cancer patients received preoperative 42 Gy/1.5 Gy/18 days/bid radiotherapy and continuous infusion of 5-fluorouracil(325 mg/m^2). All patients were operated 4-8 wk after neoadjuvant concomitant therapy. RESULTS In the early phase of treatment, 6 patients had grade Ⅲ-Ⅳ gastrointestinal toxicity, 2 patients had grade Ⅲ-Ⅳ hematologic toxicity, and 1 patient had grade Ⅴ toxicity due to postoperative sepsis during chemotherapy. Only 1 patient had radiotherapy-related late side effects, i.e., grade Ⅳ tenesmus. Complete pathological response was achieved in 6 patients(21%), while near-complete pathological response was obtained in 9(31%). After a median follow-up period of 60 mo, the local tumor control rate was 96.6%. In 13 patients, distant metastasis occurred. Disease-free survival rates at 2 and 5 years were 63.3% and 53%, and corresponding overall survival rates were 70% and 53.1%, respectively.CONCLUSION Although it has excellent local control and complete pathological response rates, neoadjuvant HART concurrent chemotherapy appears to not be a feasible treatment regimen in locally advanced rectal cancer, having high perioperative complication and intolerable side effects. Effects of reduced 5-fluorouracil dose or omission of chemotherapy with the aim of reducing toxicity may be examined in further studies.

Fat clearance and conventional fixation identified ypN0 rectal cancers following intermediate neoadjuvant radiotherapy have similar long-term outcomes

BACKGROUND As a prognostic factor for colorectal cancer,lymph node(LN)status,particularly the number of LN harvested,has been demonstrated to be essential in the evaluation of quality control in terms of surgical specimen.Neoadjuvant chemoradiation,however,decreases the LN harvest.Therefore,certain approaches(such as fat clearance or methylene blue)has drawn significant attention in order to raise LN yield.AIM To compare the long-term oncologic outcome of ypN0 rectal cancer identified using fat clearance(FC)or conventional fixation(CF)following 30 Gy in 10 fractions(30 Gy/10f)of neoadjuvant radiotherapy(nRT).METHODS Three hundred and eighty-two patients with resectable and locally advanced rectal cancer were treated by 30 Gy/10f intermediate nRT(biologically equivalent dose of 36 Gy)plus total mesorectal excision.Two specimen fixation methods(FC or CF)were non-randomly used.The ypN0 status was identified in 124 and 101 patients in the FL and CF groups,respectively.Primary endpoints were local recurrence-free survival(LRFS)and cancer-specific survival(CSS).RESULTS The median follow-up of patients was 5.1 years.The median numbers of retrieved LNs in the FC and CF groups were 19.5(range,4-47)and 12(range,0-44),respectively,with a significant difference(P=0.000).The percentages of patients with 12 or more retrieved nodes were 82.3%and 50.5%(101/159)in the FC and CF groups,respectively,with a significant difference(P=0.000).The LRFS at 5 years were 95.7%and 94.6%in the FC and CF groups,respectively,without statistical difference(P=0.819).The CSS at 5 years were 92.0%and 87.2%in the FC and CF groups,respectively,without statistical difference(P=0.482).CONCLUSION For patients with ypN0 rectal cancer who underwent 30 Gy/10f preoperative radiotherapy,the increased retrieval of LNs using fat clearance is not associated with survival benefit.This time-consuming fixation method has a low efficacy as a routine practice.

Potential predictive factors for pathologic complete response after the neoadjuvant treatment of rectal adenocarcinoma:a single center experience

Objective:To assess the response rate of patients with rectal adenocarcinoma to neoadjuvant therapy and to identify the predictors of histological regression after neoadjuvant radiotherapy(RT)or concurrent chemoradiotherapy(CCRT).Methods:This study recruited 64 patients.The patients had resectable cancer of the lower and the middle rectum(T3/T4 and/or N+)without distant metastasis and received neoadjuvant RT or CCRT followed by radical surgery with total mesorectal excision(TME)between January 2006 and December 2011.The patients were classified into non-response(NR),partial response(PR),and pathologic complete response(p CR)based on the Dworak tumor regression grading system.Results:The median age of patients was 57 years(ranging from 22 to 85).A total of 24 patients were treated with neoadjuvant CCRT,whereas 40 patients were treated with RT alone.Abdominoperineal resection(APR)was performed on 29 patients(45%).Anterior resection with TME was performed on 34 patients(53%).One patient had local resection.Histologically,12(19%),24(73%),and 28(44%)patients exhibited p CR,PR,and NR,respectively.Univariate analysis revealed that the predictors of tumor regression were as follows:the absence of lymph node involvement from initial imaging(c N0)(P=0.021);normal initial carcinoembryonic antigen(CEA)level(P=0.01);hemoglobin level≥12 g/dl(P=0.009);CCRT(P=0.021);and tumor downstaging in imaging(P=0.001).Multivariate analysis showed that the main predictors of p CR were CT combined with neoadjuvant RT,c N0stage,and tumor regression on imaging.Conclusions:Identifying the predictors of p CR following neoadjuvant therapy aids the selection of responsive patients for nonaggressive surgical treatment and possible surveillance.

Three-dimensional conformal radiotherapy combined with FOLFOX4 chemotherapy for unresectable recurrent rectal cancer

AIM： To investigate the effect of three-dimensional conformal radiotherapy （3-DCRT） in combination with FOLFOX4 chemotherapy for unresectable recurrent rectal cancer. METHODS： Forty-eight patients with unresectable recurrent rectal cancer were randomized and treated by 3-DCRT or 3-DCRT combined with FOLFOX4 chemotherapy between September 2001 and October 2003. For the patients without prior radiation history, the initial radiation was given to the whole pelvis by traditional methods with tumor dose of 40 Gy, followed by 3-DCRT for the recurrent lesions to the median total cumulative tumor dose of 60 Gy （range 56-66 Gy）; for the post-radiation recurrent patients, 3-DCRT was directly given for the recurrent lesions to the median tumor dose of 40 Gy （36-46 Gy）. For patients in the study group, two cycles chemotherapy with FOLFOX4 regimen were given concurrently with radiotherapy, with the first cycle given simultaneously with the initiation of radiation and the second cycle given in the fifth week for patients receiving conventional pelvis radiation or given in the last week of 3-DCRT for patients receiving 3-DCRT directly. Another 2-4 cycles （average 3.6 cycles） sequential FOLFOX4 regimen chemotherapy were given to the patients in the study group, beginning at 2-3 wk after chemoradiation. The outcomes of symptoms relieve, tumor response, survival and toxicity were recorded and compared between the study group and the control group. RESULTS： For the study group and the control group, the pain-alleviation rates were 95.2% and 91.3%（P〉 0.05）; the overall response rates were 56.5% and 40.0% （P〉0.05）; the 1-year and 2-year survival rates were 86.9%, 50.2% and 80.0%, 23.9%, with median survival time of 25 mo and 16 mo （P〈 0.05）; the 2-year distant metastasis rates were 39.1% and 56.0% （P= 0.054）, respectively. The side effects, except peripheral neuropathy which was relatively severer in the study group, were similar in the the two groups and well tolerated. CONCLUSION： Three-dimensional conformal radiotherapy combined with FOLFOX4 chemotherapy for unresectable recurrent rectal cancer is a feasible and effective therapeutic approach, and can reduce distant metastasis rate and improve the survival rate.

Usefulness of two independent hist classifications of tumor regression iUsefulness of two independent histopathological classifications of tumor regression in patients with rectal cancer submitted to hyperfractionated pre-operative radiotherapy

AIM： To assess the usefulness of two independent histopathological classifications of rectal cancer regression following neo-adjuvant therapy. METHODS： Forty patients at the initial stage cT3NxM0 submitted to preoperative radiotherapy （42 Gy during 18 d） and then to radical surgical treatment. The relationship between ＂T-downstaging＂ versus regressive changes expressed by tumor regression grade （TRG 1-5） and Nasierowska-Guttmejer classification （NG 1-3） was studied as well as the relationship between TRG and NG versus local tumor stage ypT and lymph nodes status, ypN. RESULTS： Complete regression （ypT0, TRG 1） was found in one patient. ＂T-downstaging＂ was observed in 11 （27.5%） patients. There was a weak statistical significance of the relationship between ＂T-downstaging＂ and TRG staging and NG stage. Patients with ypT1 were diagnosed as TRG 2-3 while those with ypT3 as TRGS. No lymph node metastases were found in patients with TRG 1-2. None of the patients without lymph node metastases were diagnosed as TRG 5. Patients in the ypT1 stage were NG 1-2. No lymph node metastases were found in NG 1. There was a significant correlation between TRG and NG. CONCLUSION： Histopathological classifications may be useful in the monitoring of the effects of hyperfractionated preoperative radiotherapy in patients with rectal cancer at the stage of cT3NxM0. There is no unequivocal relationship between ＂Todownstaging＂ and TRG and NG. There is some concordance in the assessment of lymph node status with ypT, TRG and NG. TRG and NG are of limited value for the risk assessment of the lymph node involvement.

Modified simultaneous integrated boost radiotherapy for an unresectable huge refractory pelvic tumor diagnosed as a rectal adenocarcinoma

A clinical trial of radiotherapy with modified simultaneous integrated boost(SIB)technique against huge tumors was conducted.A 58-year-old male patient who had a huge pelvic tumor diagnosed as a rectal adenocarcinoma due to familial adenomatous polyposis was enrolled in this trial.The total dose of 77 Gy(equivalent dose in 2Gy/fraction)and 64.5 Gy was delivered to the center of the tumor and the surrounding area respectively,andapproximately 20%dose escalation was achieved with the modified SIB technique.The tumor with an initial maximum size of 15 cm disappeared 120 d after the start of the radiotherapy.Performance status of the patient improved from 4 to 0.Radiotherapy with modified SIB may be effective for patients with a huge tumor in terms of tumor shrinkage/disappearance,improvement of QOL,and prolongation of survival.

Dosimetric study of five-field intensity-modulated radiotherapy compared with conventional three-dimensional conformal radiotherapy for rectal cancer

Objective： The aim of the study was to compare the difference of dose distribution in clinical target volume and organ at risk （OAR） between five-field intensity-modulated radiotherapy （IMRT） and conventional three-dimensional conformal radiotherapy （3DCRT） in the radiotherapy of rectal cancer. Methods： Fifteen patients with rectal cancer treated with radio- therapy （RT） were retrospectively analyzed. Among the patients, seven received RT preoperatively and 8 postoperatively. The target volume and the OARs such as the small bowel, bladder and femoral heads were contoured for each patient. 3DCRT-plan and IMRT-plan were performed for each patient respectively, with the prescribed dose covering at least 95% of the planning target volume （PTV）. The conformity index （CI） and homogeneity index （HI） were used for evaluation of the dose distribution in the target volume, and the Dx% （the lowest dose to the x% volume of the OARs that received the highest dose of irradiation） and the mean dose were used for evaluation of the dose to OARs. Paired-T test was used for companson of the difference between the two plans. Results： In the IMRT-plan and 3DCRT-plan, the CI were 0.94 and 0.87 （P = 0.000） and the HI were 1.13 and 1.17, respectively （P = 0.001）. For small bowel, the D30%, D50% and the mean dose were 19.67 Gy, 15.13 Gy and 18.81 Gy in the IMRT-plan and 25.20 Gy, 22.20 Gy and 22.89 Gy in the 3DCRT-plan, respectively （P 〈 0.001 for all pairs of parameters）. For bladder, the D30%, D50%, and the mean dose were 24.80 Gy, 34.20 Gy and 28.70 Gy in the IMRT- plan, and 35.07 Gy, 44.67 Gy and 35.68 Gy in the 3DCRT-plan, respectively （P 〈 0.001 for all pairs of parameters）. For femoral heads, the D5% in the IMRT-plan and 3DCRT-plan were 40.6 Gy and 40.47 Gy, respectively （P = 0.936）, and the mean dose were 30.14 Gy and 25.57 Gy, respectively （P = 0.001）. Conclusion： Five-field IMRT-plan is better than 3DCRT-plan in the conformity and the dose homogeneity within target volume and also better in sparing the small bowel and bladder.

Feasibility and oncological outcomes of laparoscopic rectal resection following neo-adjuvant chemo-radiotherapy: A systematic review

AIM: To study the feasibility and oncological outcomesfollowing laparoscopic total mesorectal excision(LTME) in patients who have received Neo-adjuvant long course chemo-radiotherapy(LCRT). METHODS: A protocol driven systematic review of published literature was undertaken to assess the feasibility and oncological outcomes following LTME in patients receiving LCRT. The feasibility was assessed using peri-operative outcomes and short term results. The oncological outcomes were assessed using local recurrence, disease free survival and overall survival.RESULTS: Only 8 studies-1 randomized controlled trial, 4 Case Matched/Controlled Studies and 3 Case Series were identified matching the search criteria. The conversion rate was low(1.2% to 28.1%), anastomotic leak rates were similar to open total mesorectal excision(0%-4.1% vs 0%-8.3%). Only 3 studies reported on local recurrence rates(5.2%-7.6%) at median 34 mo follow-up. A single study described disease free survival and overall survival at 3 years as 78.8% and 92.1% respectively. CONCLUSION: LTME following LCRT is feasible in experienced hands, with acceptable short term surgical outcomes and with the usual benefits associated with minimally invasive procedures. The long term oncological outcomes of LTME after LCRT appear to be comparable to open procedures but need further investigation.

The clinical observation of three-dimensional conformal radiotherapy combined with FOLFOX chemotherapy for rectal cancer of postoperative local recurrence

Objective The aim of this study was to explore the three-dimensional conformal radiotherapy combined with FOLFOX scheme chemotherapy in the treatment of postoperative recurrence of rectal cancer.

鼻咽癌放化疗治疗患者外周血PD-1及免疫指标水平的变化及其临床意义

目的探讨鼻咽癌放化疗治疗患者外周血程序性死亡受体1(PD-1)及免疫指标水平的变化及其临床意义。方法回顾性选取2020年1月至2023年江苏省肿瘤医院收治的90例鼻咽癌患者,所有患者均经病理确诊并接受放化疗治疗,采集其血液样本之后采用流式细胞术对不同时间段(治疗前、新辅助化疗后、放疗后)外周血淋巴细胞亚群比例、外周血PD-1、CD8^(+)CD28^(+)细胞比例的水平变化予以动态监测并比较。结果鼻咽癌患者新辅助化疗后CD3^(+)、CD4^(+)细胞比例、CD4^(+)/CD8^(+)比值分别为(72.28±8.37)%、(39.27±8.58)%、1.58±0.67,均明显高于治疗前,CD3-CD16^(+)CD56^(+)、CD19^(+)细胞比例分别为(18.27±8.38)%、(7.87±4.08)%,均明显低于治疗前,差异均有统计学意义(P<0.05);新辅助化疗后与治疗前的CD8^(+)细胞比例比较,差异无统计学意义(P>0.05)。鼻咽癌患者新辅助化疗之后CD8^(+)CD28^(+)细胞比例为(10.68±3.87)%,明显高于治疗前,差异有统计学意义(P<0.05);新辅助化疗后与治疗前的外周血PD-1水平比较,差异无统计学意义(P>0.05)。放疗后与治疗前的CD3^(+)细胞比例比较,差异无统计学意义(P>0.05);鼻咽癌患者放疗后CD4^(+)细胞比例、CD4^(+)/CD8^(+)比值、CD19^(+)细胞比例分别为(26.68±6.09)%、0.88±0.29、(3.69±2.36)%,均明显低于治疗前,CD8^(+)、CD3-CD16^(+)CD56^(+)细胞比例分别为(31.03±8.08)%、(27.39±10.26)%,均明显高于治疗前,差异均有统计学意义(P<0.05)。鼻咽癌患者放疗后CD8^(+)CD28^(+)细胞比例为(7.08±2.57)%,明显低于治疗前,外周血PD-1水平为(13.38±6.27)%,明显高于治疗前,差异均有统计学意义(P<0.05)。结论新辅助化疗之后鼻咽癌患者外周血T细胞亚群比值处于持续上调趋势,而放疗完成后处于下降趋势,表明鼻咽癌患者于放疗完成后免疫功能受损;放疗完成后鼻咽癌患者T细胞PD-1表达水平明显上调,提示PD-1抑制剂最佳使用时间可能为放化疗完成时,抗PD-1维持治疗可发挥持久、高效的抗肿瘤作用。

基于MRI影像组学构建PD-1/PD-L1抑制剂治疗dMMR/MSI-H直肠癌疗效的预测模型

目的:探讨MRI影像组学模型在程序性细胞死亡蛋白-1(PD-1)/程序性细胞死亡-配体1(PD-L1)抑制剂联合全程新辅助治疗(TNT)局部进展期直肠癌(LARC)的疗效预测价值。方法:收集河南中医药大学第一附属医院PD-1/PD-L1抑制剂联合TNT治疗的80例错配修复基因缺陷(dMMR)/微卫星高度不稳定(MSI-H)基因型中低位LARC患者的临床和影像资料。将入组患者按7∶3比例分为训练集和测试集,提取影像组学特征,从中筛选并构建影像组学模型。描绘影像组学模型的Rad-score与病理金标准之间的受试者工作特征(ROC)曲线,计算曲线下面积(AUC),并评价模型的诊断效能。采用决策曲线分析(DCA)计算风险阈值的范围,并评估临床获益情况。收集湖南省人民医院25例dMMR/MSI-H基因型LARC患者的影像资料作为外部验证集。结果:训练集、测试集及外部验证集三者之间的临床特征无统计学差异(P>0.05)。经过降维处理、t检验及一致性检验以及LASSO交叉验证后,筛选出一阶偏度特征和体积2个特征构建影像组学模型。训练集、测试集和外部验证集的影像组学预测模型ROC曲线的AUC、灵敏度、特异度、阳性预测值和阴性预测值分别为0.920、97.1%、85.7%、91.9%、94.7%;0.885、80.0%、88.9%、92.3%、72.7%;0.875、87.5%、88.9%、93.3%、80.0%。DCA曲线显示,当风险阈值范围为0%~82%时,采用影像组学模型预测LARC患者为病理完全缓解(pCR)的获益大于将所有患者都视为pCR或者无病理完全缓解(npCR)。结论:基于MRI影像组学构建的dMMR/MSI-H型局部进展期直肠癌PD-1/PD-L1抑制剂联合全程新辅助放化疗疗效预测模型,有较大潜力为不同基因分型的直肠癌患者制定个体化治疗策略提供量化依据。