Barium enema and CT volumetry for predicting pathologic response to preoperative chemoradiotherapy in rectal cancer patients

The predictive value of tumor volume reduction ratio on three-dimensional endorectal ultrasound for tumor response to chemoradiotherapy for locally advanced rectal cancer

Background

Preoperative chemoradiotherapy remains part of the standard treatment for patients with locally advanced rectal cancer. Subsequent treatment individualization requires accurate prediction of tumor response to chemoradiotherapy. Three-dimensional endorectal ultrasound (3D-ERUS) can automatically capture and store the images of the rectal wall and rectal cancer with high resolution. In this study, we aimed to assess the correlation and predictive value between tumor volume changes measured on 3D-ERUS and the histopathological tumor response after chemoradiotherapy for patients with locally advanced rectal cancer.

Methods

A total of 54 patients with locally advanced rectal cancer who underwent chemoradiotherapy and had complete 3D-ERUS data pre-and post-chemoradiotherapy were enrolled in the study. The tumor volume pre-and post-chemoradiotherapy was measured manually on 3D-ERUS, and the tumor volume reduction ratio was calculated. The histopathological tumor regression grade (TRG) was used to assess tumor response. The differences in volumetry parameters were compared between groups with varying tumor response. The diagnostic efficacy of the tumor volume reduction ratio was evaluated by the receiver operating characteristic (ROC) curve.

Results

The mean age of all patients was 55.19±12.46 years. The relative proportions of TRG 0–3 were 29.6% (16/54), 16.6% (9/54), 50% (27/54), and 3.8% (2/54), respectively. The median tumor volumes post-chemoradiotherapy in good responders (TRG 0–1, median tumor volume =3.26 cm³) and the complete response group (TRG 0, median tumor volume =2.61 cm³) were smaller than those in poor responders (TRG 2–3, median tumor volume =5.43 cm³) and the partial response group (TRG 1–3, median tumor volume =4.00 cm³), while tumor volume reduction ratios were higher than those of poor responders (79.32% vs. 59.67%) and the partial response group (82.22% vs. 61.64%), with significant differences (all P values <0.05). The ROC curves showed that the cut-off values of the tumor volume reduction ratio to predict good responders and complete response were 67.77% and 72.02%, respectively. The corresponding areas under the curve in the prediction of good responders and complete response were 0.830 and 0.829, respectively.

Conclusions

The tumor volume reduction ratio measured on 3D-ERUS might be a helpful indicator for tumor response in patients with locally advanced rectal cancer.

Computed tomographic colonography versus double-contrast barium enema for the preoperative evaluation of rectal cancer

PURPOSE

We investigated whether or not computed tomographic colonography (CTC) is a viable alternative to double-contrast barium enema (BE) for a preoperative rectal cancer evaluation.

METHODS

The size and distance from the anal canal to the lower or upper tumor borders were laterally measured in 147 patients who underwent CTC and BE. Measurements were grouped into early cancer, advanced, and after chemoradiation therapy (CRT).

RESULTS

In the early and advanced cancer groups, all lesions were visualized by BE. In contrast, 3 (7.8%) early and 8 (7.3%) advanced cases, located at the anterior wall near the anal canal, were not visualized by CTC because of liquid level formation. In the CRT group, 16 (23.5%) and 4 (5.8%) cases were not visualized by CTC and BE, respectively. The BE and CTC size measurements were similar among cohorts. However, the distance from the anal canal's superior margin tended to be longer with BE, especially in early cancer. The differences in distance from the anal canal were significantly larger in the early cancer group than in the other two groups (p = 0.0024).

CONCLUSION

CTC may be a viable alternative imaging modality in some cases. However, BE should be employed in anterior wall cases near the anal canal and CRT cases.

Locally advanced gastric cancer: total iodine uptake to predict the response of primary lesion to neoadjuvant chemotherapy

PURPOSE

Pathologic response to neoadjuvant chemotherapy is a prognostic factor in many cancer types. However, the existing evaluative criteria are deficient. We sought to prospectively evaluate the total iodine uptake derived from dual-energy computed tomography (DECT) in predicting treatment efficacy and progression-free survival (PFS) time in gastric cancer after neoadjuvant chemotherapy.

METHODS

From October 2012 to December 2015, 44 patients with locally advanced gastric cancer were examined with DECT 1 week before and three cycles after neoadjuvant chemotherapy. The percentage changes in tumor area (%ΔS), diameter (%ΔD), and density (%ΔHU) were calculated to evaluate the WHO, RESCIST, and Choi criteria. The percentage changes in tumor volume (%ΔV) and total iodine uptake of portal phase (%ΔTIU-p) were also calculated to determine cut-off values by ROC curves. The correlation between the different criteria and histopathologic tumor regression grade (Becker score) or PFS were statistically analyzed.

RESULTS

Forty-four patients were divided into responders and non-responders according to 43.34% volume reduction (P = 0.002) and 63.87% (P = 0.002) TIU-p reduction, respectively. The %ΔTIU-p showed strong (r = 0.602, P = 0.000) and %ΔV showed moderate (r = 0.416, P = 0.005), while the WHO (r = 0.075, P = 0.627), RECIST (r = 0.270, P = 0.077) and Choi criteria (r = 0.238, P = 0.120) showed no correlation with the Becker score. The differences in PFS time between the responder and non-responder groups were significant according to %ΔTIU-p and Choi criteria (P = 0.001 and P = 0.013, respectively).

CONCLUSIONS

The TIU-p can help predict pathological regression in advanced gastric cancer patients after neoadjuvant chemotherapy. In addition, the %ΔTIU-p could be one of the potentially valuable predictive parameters of the PFS time.

Phase II trial of capecitabine plus oxaliplatin (CAPOX) as perioperative therapy for locally advanced rectal cancer

PURPOSE

The standard strategy for locally advanced lower rectal cancer is chemoradiotherapy followed by total mesorectal excision (TME) in Western countries and TME followed by adjuvant chemotherapy without preoperative treatment in Japan.

METHODS

This phase II trial evaluated the efficacy of a preoperative CAPOX chemotherapy regimen without radiation therapy for patients with locally advanced rectal cancer. The primary endpoint was 2-year disease-free survival.

RESULTS

The trial enrolled 45 patients from 9 institutions between 2012 and 2014. The mean age was 63.5 (29-74) years; 31 patients were male. Most patients (n = 41) received preoperative chemotherapy (CTx), and the preoperative CTx completion rate was 95.2%. R0 resection after CTx was performed in 41 patients. The pathological complete response rate was 7.3% (3/41). After surgery, 35 patients (85.3%) received adjuvant CTx, and 22 of 35 completed the protocol treatment. The follow-up period ranged from 0.71 to 4.68 years (median 2.86 years). There was recurrence in 13 of 40 patients who underwent R0 resection, and the 2-year disease-free survival rate and overall survival rate were 71.6 and 92.7%, respectively.

CONCLUSIONS

Here we report the completion rates for neoadjuvant CTx and adjuvant CTx, the pathological complete response rate, and the mid-term prognosis. The results indicate that CAPOX followed by TME may be a safe treatment strategy for locally advanced rectal cancer.

Predictive clinical model of tumor response after chemoradiation in rectal cancer

Survival improvement in rectal cancer treated with neoadjuvant chemoradiotherapy (nCRT) is achieved only if pathological response occurs. Mandard tumor regression grade (TRG) proved to be a valid system to measure nCRT response. The ability to predict tumor response before treatment may significantly have impact the selection of patients for nCRT in rectal cancer. The aim is to identify potential predictive pretreatment factors for Mandard response and build a clinical predictive model design. 167 patients with locally advanced rectal cancer were treated with nCRT and curative surgery. Blood cell counts in peripheral blood were analyzed. Pretreatment biopsies expression of cyclin D1, epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) and protein 21 were assessed. A total of 61 single nucleotide polymorphisms were characterized using the Sequenom platform through multiplex amplification followed by mass-spectometric product separation. Surgical specimens were classified according to Mandard TRG. The patients were divided as: "good responders" (Mandard TRG1-2) and "poor responders" (Mandard TGR3-5). We examined predictive factors for Mandard response and performed statistical analysis. In univariate analysis, distance from anal verge, neutrophil lymphocyte ratio (NLR), cyclin D1, VEGF, EGFR, protein 21 and rs1810871 interleukin 10 (IL10) gene polymorphism are the pretreatment variables with predictive value for Mandard response. In multivariable analysis, NLR, cyclin D1, protein 21 and rs1800871 in IL10 gene maintain predictive value, allowing a clinical model design.

CONCLUSION

It seems possible to use pretreatment expression of blood and tissue biomarkers, and build a model of tumor response prediction to neoadjuvant chemoradiation in rectal cancer.

CT volumetric measurement of colorectal cancer helps predict tumor staging and prognosis

Purpose

To evaluate feasibility of CT colonography (CTC) volumetry of colorectal cancer (CRC) and its correlation with disease stage and patients’ survival.

Materials and methods

CTC volumetry was performed for 126 patients who underwent preoperative CTC. Reproducibility of tumor volume (Tvol) between two readers was assessed. One-way ANOVA and ROC analysis evaluated correlation between Tvol and pTNM staging. ROC analysis compared diagnostic performance to predict pTNM staging between Tvol and radiologist. Kaplan-Meier test compared overall survival.

Results

Reproducibility among readers was excellent (interclass correlation = 0.9829). Mean Tvol showed an incremental trend with T stage and Tvol of pT4b stage was significantly larger than other stages (P<0.0001). Az value (0.780) of Tvol to predict pT4b stage was significantly larger than that (0.591) of radiologist (P = 0.004). However, Tvol was not significantly different according to pN stage. Az values (0.723~0.857) of Tvol to predict M1 or M1b were comparable to those (0.772~0.690) of radiologist (P>0.05). Smaller tumor burden (≤12.85cm³), ≤T3, N0, M0 stages, and curative surgery were significantly associated with patients’ longer survival (P<0.05).

Conclusion

CT volumetry has a limited value to predict N stage; however, it may outperform the radiologist’s performance when predicting pT4b and M1b stage and can be a useful prognostic marker.

Defining the distal margin of rectal cancer for surgical planning

Accurate measurement of the distal rectal tumor margin is essential in selecting the appropriate surgical procedure. However, there is no standard measurement method. The National Cancer Institute consensus group recommends use of the anal verge (AV) as a landmark, and the European Society of Gastrointestinal and Abdominal Radiology recommends use of the anorectal ring (ARR). In addition, whether measurements should be made on double contrast barium enema (BE) radiographs or magnetic resonance (MR) images remains controversial. We measured the distal tumor margin on both BE and MR images obtained preoperatively from 52 patients who underwent sphincter-saving resection for rectal cancer. The distances from the distal end of the tumor to the AV and the ARR were measured on both types of images, and the variability was investigated by Bland-Altman analysis. The mean distance from the tumor to the AV was 8.9 cm on the BE radiographs and 7.7 cm on the MR images (P=0.013). The mean distances to the ARR were 6.8 and 5.6 cm, respectively (P=0.070). Significant proportional bias was shown as the measured distances increased, the difference between the BE- and magnetic resonance imaging (MRI)-based measurements increased. Use of one or the other landmark did not affect selection of the appropriate surgical procedure. We conclude that an approximate 1-cm underestimation should be taken into account when MRI-based measurement of the distal rectal tumor margin is used to choose between sphincter-saving resection and abdominoperineal resection.

A pilot phase II study of neoadjuvant triplet chemotherapy regimen in patients with locally advanced resectable colon cancer

Objective

This study aims to investigate the feasibility, safety and efficacy of triplet regimen of neoadjuvant chemotherapy in patients with locally advanced resectable colon cancer.

Methods

Patients with clinical stage IIIb colon cancer received a perioperative triple chemotherapy regimen (oxaliplatin 85 mg/m² and irinotecan 150 mg/m², combined with folinic acid 200 mg, 5-fluorouracil 500 mg bolus and then 2,400 mg/m² by 44 h infusion or capecitabine 1 g/m² or S-1 40–60 mg b.i.d orally d 1–10, repeated at 2-week intervals) for 4 cycles. Complete mesocolic excision was scheduled 2–6 weeks after completion of neoadjuvant treatment and followed by a further 6 cycles of FOLFOXIRI or XELOX. Primary outcome measures of this stage II trial were feasibility, safety, tolerance and efficacy of neoadjuvant treatment.

Results

All 23 patients received neoadjuvant chemotherapy and underwent surgery. Twenty-one patients (91.3%) had reductions in tumor volume after neoadjuvant treatment, and 13 patients (56.5%) had grade 3–4 toxicity. No patients had severe complications from surgery. Preoperative therapy resulted in significant down-staging of T-stage and N-stage compared with the baseline clinical stage including one pathological complete response.

Conclusions

Neoadjuvant triple chemotherapy has high activity and acceptable toxicity and perioperative morbidity, and is feasible, tolerable and effective for locally advanced resectable colon cancer.

Assessing pathological complete response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a systematic review

AIM

Pathological complete response to neoadjuvant chemoradiotherapy is found in 20% of patients with rectal cancer undergoing long-course chemoradiotherapy. Some authors have suggested that these patients do not need to undergo surgery and can be managed with careful follow-up, with surgery only used in the event of clinical failure. Widespread adoption of this regimen is limited by the accuracy of methods to confirm a pathological complete response (pCR).

METHOD

A systematic search of PubMed, Medline and Cochrane databases was conducted to identify clinical, histological and radiological features in those patients with rectal cancer who achieved a pCR following chemoradiotherapy. Searches were conducted with the following keywords and MeSH search terms: 'rectal neoplasm', 'response', 'neoadjuvant', 'preoperative chemoradiation' and 'tumour response'. After review of title and abstracts, 89 articles addressing the assessment of pCR were identified.

RESULTS

Histology and clinical assessment are the most effective methods of assessment of pCR, with histology considered the gold standard. Clinical assessment is limited to low rectal tumours and is open to significant inter-rater variability, while histological examination requires a surgical specimen. Diffusion-weighted MRI and (18) F-fluorodeoxyglucose positron emission tomography/CT demonstrate the greatest potential for the assessment of pCR, but both modalities have limited accuracy.

CONCLUSION

Determination of a pCR is crucial if a nonoperative approach is to be undertaken proactively. Various methods are available, but currently they lack sufficient sensitivity and specificity to define management. This is likely to be an area of further research in the future.

Chemoradiation provides a physiological selective pressure that increases the expansion of aberrant TP53 tumor variants in residual rectal cancerous regions

Neoadjuvant chemoradiotherapy has been introduced in patients with surgically resected rectal cancer and reduced the local recurrence. Heterogeneity exists in rectal cancer, and we hypothesized that there are subclones resistant to chemoradiotherapy within the cancer mass.

We performed DNA-targeted sequencing of pre- and post-treatment tumor tissues obtained from 20 rectal cancer patients who received chemoradiotherapy. The variant frequency of the mutant clones was compared between pre- and post-treatment samples of nine non-responder patients. RNA-targeted sequencing of 57 genes related to sensitivity to chemotherapy and radiotherapy was performed for the paired samples. Immunohistochemical analyses of p53 expression were also performed on the paired samples from the nine non-responder patients.

DNA-sequencing detected frequent mutations of suppressor genes including TP53, APC and FBXW7 in the post-treatment samples of the nine non-responders. The frequency of TP53 mutations showed significant increases after chemoradiotherapy. RNA-targeted sequencing of 29 tumor tissues demonstrated that decreased expression of three genes and increased expression of four genes were detected in the post-treatment samples. Significantly increased expression of TP53 was observed in the post-treatment samples. Immunohistochemical staining for p53 revealed that increased p53 intensity scores were observed after chemoradiotherapy. These results suggest that the tumors with TP53 mutations tend to accumulate through chemoradiotherapy.

Rectal cancer: a review

Rectal cancer is the second most common cancer in large intestine. The prevalence and the number of young patients diagnosed with rectal cancer have made it as one of the major health problems in the world. With regard to the improved access to and use of modern screening tools, a number of new cases are diagnosed each year. Considering the location of the rectum and its adjacent organs, management and treatment of rectal tumor is different from tumors located in other parts of the gastrointestinal tract or even the colon. In this article, we will review the current updates on rectal cancer including epidemiology, risk factors, clinical presentations, screening, and staging. Diagnostic methods and latest treatment modalities and approaches will also be discussed in detail.