FDG-PET/CT imaging for staging and target volume delineation in preoperative conformal radiotherapy of rectal cancer

PURPOSE: To investigate the potential impact of using (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on staging and target volume delineation for patients affected by rectal cancer and candidates for preoperative conformal radiotherapy. METHODS AND MATERIALS: Twenty-five patients diagnosed with rectal cancer T3-4 N0-1 M0-1 and candidates for preoperative radiotherapy underwent PET/CT simulation after injection of 5.18 MBq/kg of FDG. Clinical stage was reassessed on the basis of FDG-PET/CT findings. The gross tumor volume (GTV) and the clinical target volume (CTV) were delineated first on CT and then on PET/CT images. The PET/CT-GTV and PET/CT-CTV were analyzed and compared with CT-GTV and CT-CTV, respectively. RESULTS: In 4 of 25 cases (24%), PET/CT affected tumor staging or the treatment purpose. In 3 of 25 cases (12%) staged N0 M0, PET/CT showed FDG uptake in regional lymph nodes and in a case also in the liver. In a patient with a single liver metastasis PET/CT detected multiple lesions, changing the treatment intent from curative to palliative. The PET/CT-GTV and PET/CT-CTV were significantly greater than the CT-GTV (p = 0.00013) and CT-CTV (p = 0.00002), respectively. The mean difference between PET/CT-GTV and CT-GTV was 25.4% and between PET/CT-CTV and CT-CTV was 4.1%. CONCLUSIONS: Imaging with PET/CT for preoperative radiotherapy of rectal cancer may lead to a change in staging and target volume delineation. Stage variation was observed in 12% of cases and a change of treatment intent in 4%. The GTV and CTV changed significantly, with a mean increase in size of 25% and 4%, respectively.     

Association of statin use with a pathologic complete response to neoadjuvant chemoradiation for rectal cancer

PURPOSE: To assess whether 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, might enhance the efficacy of neoadjuvant chemoradiation in rectal cancer. METHODS AND MATERIALS: Between 1996 and 2001, 358 patients with clinically resectable, nonmetastatic rectal cancer underwent surgery at Memorial Sloan-Kettering Cancer Center after neoadjuvant chemoradiation for either locally advanced tumors or low-lying tumors that would require abdominoperineal resection. We excluded 9 patients for radiation therapy dose <45 Gy or if statin use was unknown, leaving 349 evaluable patients. Median radiation therapy dose was 50.4 Gy (range, 45-55.8 Gy), and 308 patients (88%) received 5-fluorouracil-based chemotherapy. Medication use, comorbid illnesses, clinical stage as assessed by digital rectal examination and ultrasound, and type of chemotherapy were analyzed for associations with pathologic complete response (pCR), defined as no microscopic evidence of tumor. Fisher's exact test was used for categoric variables, Mantel-Haenszel test for ordered categoric variables, and logistic regression for multivariate analysis. RESULTS: Thirty-three patients (9%) used a statin, with no differences in clinical stage according to digital rectal examination or ultrasound compared with the other 324 patients. At the time of surgery, 23 nonstatin patients (7%) were found to have metastatic disease, compared with 0% for statin patients. The unadjusted pCR rates with and without statin use were 30% and 17%, respectively (p = 0.10). Variables significant univariately at the p = 0.15 level were entered into a multivariate model, as were nonsteroidal anti-inflammatory drugs (NSAIDs), which were strongly associated with statin use. The odds ratio for statin use on pCR was 4.2 (95% confidence interval, 1.7-12.1; p = 0.003) after adjusting for NSAID use, clinical stage, and type of chemotherapy. CONCLUSION: In multivariate analysis, statin use is associated with an improved pCR rate after neoadjuvant chemoradiation for rectal cancer. The low prevalence of statin use limits the power to detect a significant difference at a type I error threshold of p = 0.05 in this analysis. Although no definitive conclusions can be drawn on the basis of this retrospective study, the unusually high incidence of pCR after chemoradiation suggests that the use of statins in the treatment of rectal cancer warrants further evaluation.     

Complete clinical response after neoadjuvant chemoradiation for distal rectal cancer

Multimodality treatment of rectal cancer, with the combination of radiation therapy, chemotherapy, and surgery has become the preferred approach to locally advanced rectal cancer. The use of neoadjuvant chemoradiation therapy (CRT) has resulted in reduced toxicity rates, significant tumor downsizing and downstaging, better chance of sphincter preservation, and improved functional results. A proportion of patients treated with neoadjuvant CRT may ultimately develop complete clinical response. Management of these patients with complete clinical response remains controversial and approaches including radical resection, transanal local excision, and observation alone without immediate surgery have been proposed. The use of strict selection criteria of patients after neoadjuvant CRT has resulted in excellent long-term results with no oncological compromise after observation alone in patients with complete clinical response. Recurrences are detectable by clinical assessment and frequently amenable to salvage procedures.     

直肠癌新辅助放化疗后的非手术治疗

新辅助放化疗目前已成为临床Ⅱ、Ⅲ期直肠癌的标准辅助治疗方式。接受新辅助治疗的患者部分可达到病理完全缓解,即切除的样本中不存在癌细胞。达到临床完全缓解的患者,取消手术治疗后仍获得较好的生存率。临床是否可以通过筛选取消部分患者的手术治疗,以避免术中及术后可能存在的风险及不良反应成为值得探讨的问题。     

局部晚期直肠癌术前新辅助治疗

Preoperative radiotherapy combined with chemotherapy and (or) targeted therapy not only reduces the local recurrence of locally advanced rectal cancer and increases the rate of anal preservation and pathologic complete response, but also improves patient compliance. Preoperative neoadjuvant therapy will gradually become the standard treatment for locally advanced rectal cancer.     

Patterns of locoregional recurrence after surgery and radiotherapy or chemoradiation for rectal cancer

PURPOSE: To identify patterns of locoregional recurrence in patients treated with surgery and preoperative or postoperative radiotherapy or chemoradiation for rectal cancer. METHODS AND MATERIALS: Between November 1989 and October 2001, 554 patients with rectal cancer were treated with surgery and preoperative (85%) or postoperative (15%) radiotherapy, with 95% receiving concurrent chemotherapy. Among these patients, 46 had locoregional recurrence as the first site of failure. Computed tomography images showing the site of recurrence and radiotherapy simulation films were available for 36 of the 46 patients. Computed tomography images were used to identify the sites of recurrence and correlate the sites to radiotherapy fields in these 36 patients. RESULTS: The estimated 5-year locoregional control rate was 91%. The 36 patients in the study had locoregional recurrences at 43 sites. There were 28 (65%) in-field, 7 (16%) marginal, and 8 (19%) out-of-field recurrences. Among the in-field recurrences, 15 (56%) occurred in the low pelvis, 6 (22%) in the presacral region, 4 (15%) in the mid-pelvis, and 2 (7%) in the high pelvis. Clinical T stage, pathologic T stage, and pathologic N stage were significantly associated with the risk of in-field locoregional recurrence. The median survival after locoregional recurrence was 24.6 months. CONCLUSIONS: Patients treated with surgery and radiotherapy or chemoradiation for rectal cancer had a low risk of locoregional recurrence, with the majority of recurrences occurring within the radiation field. Because 78% of in-field recurrences occur in the low pelvic and presacral regions, consideration should be given to including the low pelvic and presacral regions in the radiotherapy boost field, especially in patients at high risk of recurrence.     

Positron emission tomography as predictor of rectal cancer response during or following neoadjuvant chemoradiation

Positron emission tomography (PET) shows great promise as a tool to evaluate the effectiveness of rectal cancer neoadjuvant therapy as it has demonstrated high predictive value in several studies. Creating a standardized method of using PET has the potential to reduce ineffective treatments. However, relevant studies have been heterogenous in approach, making any unified standard difficult to establish. PET related parameters used to assess treatment response include magnitude and change of standard uptake value, total lesion glycolysis, and visual response. Finding the best evaluation interval and parameters to use for interpreting PET results in the neo-adjuvant treatment of rectal cancer needs additional study.     

Predictive factors associated with complete pathological response after neoadjuvant treatment for rectal cancer

PurposeA proportion of 10 to 30% of patients treated by chemoradiotherapy followed by total mesorectal excision surgery for a locally advanced rectal cancer can achieve a complete pathological response. We aimed to identify predictive factors associated with complete pathological response or no response and to assess the impact of each response on survival rates.Patients and methodsPatients treated with long course chemoradiotherapy for locally advanced and/or node positive rectal cancer from 2010 to 2016 were retrospectively reviewed. Statistical analysis was carried out to determine predictors of tumor regression and treatment outcomes.ResultsRecords were available on 70 patients. In the univariate analysis, clinical factors associated with complete tumor response were tumor mobility in digital rectal examination (P = 0.047), a limited parietal invasion (P = 0.001), clinically negative lymph node (P < 0.001) and a circumferential extent greater than 50% (P = 0.001). On the other hand, a T4 classification and an endoscopic tumor size greater than 6 cm were associated with no response to treatment (P = 0.049 and P = 0.017 respectively). On multivariate analysis, T2 clinical classification and N0 statement before treatment were independent predictive factors of pathologic complete response (P < 0.001 and P = 0.001) and a delayed surgery after 12 weeks was associated with no response to treatment (P = 0.001).ConclusionThe identification of predictive factors of histological response may help clinicians to predict the prognosis and to propose organ preservation for good responders.     

Clinical value of F-FDG PET/CT in assessing suspicious relapse after rectal cancer resection

AIM: To evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in the restaging of resected rectal cancer.METHODS: From January 2007 to Sep 2008, 21 patients who had undergone curative surgery resection for rectal carcinoma with suspicious relapse in conventional imaging or clinical findings were retrospectively enrolled in our study. The patients underwent 28 PET/CT scans (two patients had two scans, one patient had three and one had four scans). Locoregional recurrences and/or distant metastases were confirmed by histological analysis or clinical and imaging follow-up.RESULTS: Final diagnosis was confirmed by histopathological diagnosis in 12 patients (57.1%) and by clinical and imaging follow-up in nine patients (42.9%). Eight patients had extrapelvic metastases with no evidence of pelvic recurrence. Seven patients had both pelvic recurrence and extrapelvic metastases, and two patients had pelvic recurrence only. ¹⁸F-FDG PET/CT was negative in two patients and positive in 19 patients. ¹⁸F-FDG PET/CT was true positive in 17 patients and false positive in two. The accuracy of ¹⁸F-FDG PET/CT was 90.5%, negative predictive value was 100%, and positive predictive value was 89.5%. Five patients with perirectal recurrence underwent ¹⁸F-FDG PET/CT image guided tissue core biopsy. ¹⁸F-FDG PET/CT also guided surgical resection of pulmonary metastases in three patients and monitored the response to salvage chemotherapy and/or radiotherapy in four patients.CONCLUSION: ¹⁸F-FDG PET/CT is useful for evaluating suspicious locoregional recurrence and distant metastases in the restaging of rectal cancer after curative resection.     

术前同步放化疗在局部晚期直肠癌治疗中的价值

目的 探讨术前放化疗联合手术治疗局部晚期直肠癌的临床价值。方法 对22 例术前应用放疗（剂量45Gy/5周）和mFOLFOX 方案（奥沙利铂130mg/m2,dl,静脉滴注;甲酞四氢叶酸钙200mg, dl～d3,静脉滴注;氟尿嘧啶500mg/m2, dl～d3,静脉滴注;每3 周重复,共行2 个周期）进行新辅助治疗的局部晚期直肠癌患者资料进行分析。结果 低位前切除术16 例,保肛率72.7%,腹会阴联合切除6例。肿瘤完全消退3例（13.6 %),肿瘤部分缓解10例（45.5%),治疗有效率为59.1% (13/22。肿瘤分期降低13例,降期率为59.1％。结论 对局部晚期直肠癌采用新辅助治疗可使肿瘤不同程度消退,分期降低,提高保肛率。     

Thymidylate synthase genotypes and tumour regression in stage II/III rectal cancer patients after neoadjuvant fluorouracil-based chemoradiation

Purpose

According to the CAO-/ARO-/AIO-94 trial of the German Rectal Cancer Study Group, pre-operative 5-fluorouracil (5-FU)-based long-term chemoradiotherapy (CT/RT) is recommended for patients with rectal cancer UICC stage II/III. However, despite the local benefit of neoadjuvant treatment, the overall prognostic value remains uncertain in comparison to adjuvant CT/RT. We assessed the impact of standardized pre-operative CT/RT and intratumoural mRNA levels and polymorphisms of the TS gene on histopathological tumour regression.

Patients and methods

40 patients with rectal cancer UICC stage II/III, receiving pre-operative 5-FU-based CT/RT followed by standardized surgery, including total mesorectal excision, were investigated. TS gene expression and TS polymorphisms of surgical specimens were correlated with the grade of histopathological tumour regression (0–4). Patients achieved regression grades 2–4 were determined as responders.

Results

TS polymorphisms (5′-28 bp repeat + G/C SNP and TS1494del6) could be determined in 39/40 (97.5%) and in 38/40 (95%) patients, respectively. Quantification of TS mRNA expression was successful in 36/40 (90%) patients. There was a highly significant linkage disequilibrium between 5′- and 3′-TS polymorphisms (p = 0.0013). Interestingly, the majority of patients (82.1%) with 5′-TS genotypes known to be associated with low mRNA expression (2R/2R, 2R/3RC, 3RC/3RC) also possessed the TS1494del6 +6 bp/+6 bp genotype correlating with high TS mRNA expression. TS1494del6 polymorphism was significantly associated with TS mRNA expression. Patients with TS1494del6 −6 bp/−6 bp or −6 bp/+6 bp genotypes showed significantly lower mean TS mRNA expression with 0.55 (range:0.33;0.84) as compared to +6 bp homozygotes with a mean expression of 0.90 (range:0.20;1.91) (p = 0.025). Furthermore, all patients with TS 3′-UTR −6 bp/−6 bp or −6 bp/+6 bp genotype (11/11) were responders as compared to only 20/26 (77%) of patients with TS 3′-UTR +6 bp/+6 bp genotype (p = 0.082). TS 5′-polymorphisms were not associated with neither tumour regression nor gene expression.

Conclusion

Our data suggest that the TS1494del6 polymorphism may be an important predictor for histopathological tumour regression in UICC II/III rectal cancer patients receiving neoadjuvant 5-FU-based CT/RT.     

Early local recurrence and one-year mortality of rectal cancer after restricting the neoadjuvant therapy regime

IntroductionTo reduce the risk of local recurrence after rectal cancer surgery, neoadjuvant radiotherapy (RT) can be applied. However, as this causes morbidity and increases mortality, new Dutch guidelines withhold RT in low-risk patients. The aim of this study is to investigate if early local recurrence and one-year mortality in rectal cancer patients has changed since this more restricting indication for neoadjuvant RT was introduced in 2014.MethodsThis retrospective study included all consecutive patients treated with a mesorectal excision for primary rectal cancer in the Amphia Hospital, the Netherlands, between January 2011 and July 2016. Data were extracted from the electronic patient records. Survival data were collected from the Municipal Personal Records Database.ResultsBetween 2011 and July 2016, 407 resections of primary rectal cancer without synchronic metastases were performed, 225 under the old guidelines and 182 under the new guidelines. Significantly fewer patients received neoadjuvant treatment under the new guidelines (89% vs 41%, p < 0.001). Both clinical tumour stage (p = 0.001) and clinical lymph node stage (p < 0.001) were lower in the new group, but no difference in pathologic TN-stage was found. There was no difference in one-year local recurrence (2.2% in both groups, p = 0.987), nor in one-year mortality (5.3% vs 3.8%, p = 0.479).ConclusionIntroducing a new guideline and thereby restricting the indication for neoadjuvant RT in rectal cancer patients did not increase the early local recurrence rate or decreased one-year mortality in our hospital.     

Diffusion-weighted magnetic resonance for prediction of response after neoadjuvant chemoradiation therapy for locally advanced rectal cancer: Preliminary results of a monoinstitutional prospective study

Purpose

To evaluate diffusion-weighted imaging (DWI) for assessment of treatment response in locally advanced rectal cancer (LARC) 8 weeks after neoadjuvant chemoradiotherapy (CRT).

Methods and materials

A total of 28 patients with LARC underwent magnetic resonance imaging (MRI) prior to and 8 weeks after CRT. Tumor volume (TV) was calculated on T2-weighted MRI scans as well as the apparent diffusion coefficient (ADC) was calculated using Echo-planar DWI-sequences. All data were correlated to surgical results and histopathologic tumor regression grade (TRG), according to Mandard's classification. Post-treatment difference ADC (%ΔADC) and TV (%ΔTV) changes at 8 weeks were compared complete response (CR; TRG1) and non-complete response tumors (non-CR; TRG2–5).

Results

The mean % ADC increase of CR group was significantly higher compared to non-CR group (77.2 ± 54.63% vs. 36.0 ± 29.44%; p = 0.05). Conversely, the mean % TV reduction did not significantly differ in CR group from non-CR group (73.7% vs. 63.77%; p = 0.21). Accordingly, the diagnostic accuracy of the mean % ADC increase to discriminate CR from non-CR group was significantly higher than that of the mean % TV reduction (0.913 vs. 0.658; p = 0.022). No correlation was found between mean % TV reduction and TRG (rho = 0.22; p = 0.3037), whereas a negative correlation between mean % ADC increase and TRG was recorded (r = −0.69; p = 0.006).

Conclusion

The mean % ADC increase appears to be a reliable tool to differentiate CR from non-CR after CRT in patients with LARC.     

Local excision and postoperative radiotherapy for distal rectal cancer

To assess the outcome following local excision and postoperative radiotherapy (RT) for distal rectal carcinoma.

Seventy-three patients received postoperative radiotherapy following local surgery for primary rectal carcinoma at Princess Margaret Hospital from 1983 to 1998. Selection factors for postoperative RT were patient preference, poor operative risks, and “elective” where conservative therapy was regarded as optimal therapy. Median distance of the primary lesion from the anal verge was 4 cm (range, 1–8 cm). There were 24 T1, 36 T2, and 8 T3 lesions. The T category could not be determined in 5. Of 55 tumor specimens in which margins could be adequately assessed, they were positive in 18. RT was delivered using multiple fields by 6- to 25-MV photons. Median tumor dose was 50 Gy (range, 38–60 Gy), and 62 patients received 50 Gy in 2.5-Gy daily fractions. The tumor volume included the primary with 3–5 cm margins. No patients received adjuvant chemotherapy. Median follow-up was 48 months (range, 10–165 months).

Overall 5-year survival and disease-free survival were 67% and 55%, respectively. Tumor recurrence was observed in 23 patients. There were 14 isolated local relapses; 6 patients developed local and distant disease; and 3 relapsed distantly only. For patients with T1, T2, and T3 lesions, 5-year local relapse-free rates were 61%, 75%, and 78%, respectively, and 5-year survival rates were 76%, 58%, and 33%, respectively. The 5-year local relapse-free rate was lower in the presence of lymphovascular invasion (LVI) compared to no LVI, 52% vs. 89%, p = 0.03, or where tumor fragmentation occurred during local excision compared to no fragmentation, 51% vs. 76%, p = 0.02. Eleven of 14 patients with local relapse only underwent abdominoperineal resection, 8 achieved local control, and 4 remained cancer free. The ultimate local control, including salvage surgery, was 86% at 5 and 10 years. The 5-year colostomy-free rate was 82%. There were 2 patients who experienced RTOG Grade 3 late complications, and 1 with Grade 4 complication (bowel obstruction requiring surgery).

The local relapse rate for patients with T1 disease was high compared to other series of local excision and postoperative RT. Patients with LVI or tumor fragmentation during excision have high local relapse rates and may not be good candidates for conservative surgery and postoperative RT.     

Prognostic importance of Mandard tumour regression grade following pre-operative chemo/radiotherapy for locally advanced rectal cancer

Purpose

To assess the prognostic value of the Mandard tumour regression score (TRG) following pre-operative chemo/radiotherapy in patients with locally advanced rectal cancer.

Methods and materials

The study involved 158 patients with locally advanced rectal cancer treated with pre-operative long course chemo/radiotherapy at Nottingham University Hospital between April 2001 and December 2008. Patients were treated with radiotherapy to a dose of 50 Gy in 25 fractions over 5 weeks with or without concurrent capecitabine chemotherapy at a dose of 1650 mg/m²/day. Surgery was normally performed after an interval of 6-10 weeks. The response to pre-operative treatment was carefully graded by a single pathologist using the five point Mandard score. The median follow-up was 40 months (range 3-90 months).

Results

Of the 158 patients 14% were TRG1, 41% were TRG2, 31% were TRG3, 13% were TRG4 and 1% were TRG5. The groups were combined into TRG1, TRG2 and TRG3-5 to simplify further analysis. The Mandard score was clearly related to both disease-free (p < 0.001) and overall survival (p = 0.012). On multivariate analysis perineural invasion, nodal status, TRG and circumferential resection margin status were the most powerful predictors of disease-free survival.

Conclusions

The Mandard tumour regression score is an independent prognostic factor and predicts for long-term outcome following pre-operative chemo/radiotherapy in rectal cancer.     

Blood biomarkers are helpful in the prediction of response to chemoradiation in rectal cancer: A prospective,hypothesis driven study on patients with locally advanced rectal cancer

Purpose/objective

Chemoradiation (CRT) has been shown to lead to downsizing of an important portion of rectal cancers. In order to tailor treatment at an earlier stage during treatment, predictive models are being developed. Adding blood biomarkers may be attractive for prediction, as they can be collected very easily and determined with excellent reproducibility in clinical practice. The hypothesis of this study was that blood biomarkers related to tumor load, hypoxia and inflammation can help to predict response to CRT in rectal cancer.

Material/methods

295 patients with locally advanced rectal cancer who were planned to undergo CRT were prospectively entered into a biobank protocol (NCT01067872). Blood samples were drawn before start of CRT. Nine biomarkers were selected, based on a previously defined hypothesis, and measured in a standardized way by a certified lab: CEA, CA19-9, LDH, CRP, IL-6, IL-8, CA IX, osteopontin and 25-OH-vitamin D. Outcome was analyzed in two ways: pCR vs. non-pCR and responders (defined as ypT0-2N0) vs. non-responders (all other ypTN stages).

Results

276 patients could be analyzed. 20.7% developed a pCR and 47.1% were classified as responders. In univariate analysis CEA (p = 0.001) and osteopontin (p = 0.012) were significant predictors for pCR. Taking response as outcome CEA (p < 0.001), IL-8 (p < 0.001) and osteopontin (p = 0.004) were significant predictors. In multivariate analysis CEA was the strongest predictor for pCR (OR 0.92, p = 0.019) and CEA and IL-8 predicted for response (OR 0.97, p = 0.029 and OR 0.94, p = 0.036). The model based on biomarkers only had an AUC of 0.65 for pCR and 0.68 for response; the strongest model included clinical data, PET-data and biomarkers and had an AUC of 0.81 for pCR and 0.78 for response.

Conclusion

CEA and IL-8 were identified as predictive biomarkers for tumor response and PCR after CRT in rectal cancer. Incorporation of these blood biomarkers leads to an additional accuracy of earlier developed prediction models using clinical variables and PET-information. The new model could help to an early adaptation of treatment in rectal cancer patients.     

局部晚期直肠癌新辅助治疗pCR相关因素研究

目的 评价局部晚期直肠癌新辅助治疗后pCR的相关影响因素。方法 回顾分析2011—2013年间收治的265例AJCC分期Ⅱ、Ⅲ期直肠癌患者资料。所有患者均接受新辅助治疗±等待手术间期化疗, 而后手术。运用单因素和二元Logistic回归多因素分析影响pCR的预测因素, 并根据预测危险因素进行归类后分为无风险组(无因素)、低风险组(1个因素)、高风险组(2个因素)。建立临床风险评估模型。因素分析运用二元Logistic回归模型。结果 达pCR者50例(18.9%)。单因素分析中新辅助治疗前CEA、放化疗前T分期、同期放化疗结束至手术间隔时间和放化疗前肿瘤最大厚度对pCR有影响(P=0.017、0.001、0.000、0.040), 多因素分析显示新辅助治疗前CEA水平和同期放化疗结束至手术间隔时间是pCR影响因素(P=0.021、0.001), 进一步分层分析表明只有非吸烟组中新辅助治疗前低水平CEA对pCR有影响(P=0.044)。临床风险评估模型诊断pCR的敏感性为80.5%, 特异性为46.0%, AUC为0.690, 阳性预测值为35.49%, 阴性预测值为86.5%, 准确性为73.9%。结论 新辅助治疗能使部分局部晚期直肠癌患者达pCR。新辅助治疗前低水平CEA和更长的同期放化疗结束至手术间隔时间是局部晚期直肠癌新辅助治疗pCR的预测因素, 而新辅助治疗前低水平CEA对pCR预测只在非吸烟人群中有效。根据新辅助治疗前CEA>5 ng/ml和同期放化疗结束至手术间隔时间≤8周的危险因素建立的临床风险评估模型可用于预测局部晚期直肠癌新辅助治疗pCR率。     

Endoscopic criteria to evaluate tumor response of rectal cancer to neoadjuvant chemoradiotherapy using magnifying chromoendoscopy

Background and aims

Precise endoscopic assessment of complete response to neoadjuvant chemoradiotherapy before surgery is important for optimizing surgical and non-surgical treatment. We prospectively evaluated the accuracy of the newly proposed endoscopic criteria to identify complete response, using magnifying chromoendoscopy.