Is radiochemotherapy necessary in the treatment of rectal cancer?

Staging of Locally Advanced Rectal Cancer Beyond TME

The management of rectal cancer is complex and continually evolving. With advancements in technology and the use of multidisciplinary teams to guide the treatment decision making, staging, oncologic, and functional outcomes are improving, and the management is moving toward personalized treatment strategies to optimize each individual patient's outcomes. Key in this evolution is imaging. Magnetic resonance imaging (MRI) has emerged as the dominant method of pelvic imaging in rectal cancer, and use of MRI for staging is best practice in multiple international guidelines. MRI allows a noninvasive assessment of the tumor site, relationship to surrounding structures, and provides highly accurate rectal cancer staging, which is necessary for determining the appropriate treatment strategy. However, the applications of MRI extend far beyond pretreatment staging. MRI can be used to predict outcomes in locally advanced rectal cancer and guide the surgical or nonsurgical plan, serving as a predictive and prognostic biomarker. With continued MRI hardware improvement and new sequence development, MRI may offer new perspectives in the assessment of treatment response and new innovations that could provide better insight into the staging, restaging, and outcomes with rectal cancer.

Magnetic resonance tumor regression grade (MR-TRG) to assess pathological complete response following neoadjuvant radiochemotherapy in locally advanced rectal cancer

This study aims to evaluate the feasibility of a magnetic resonance (MR) automatic method for quantitative assessment of the percentage of fibrosis developed within locally advanced rectal cancers (LARC) after neoadjuvant radiochemotherapy (RCT). A total of 65 patients were enrolled in the study and MR studies were performed on 3.0 Tesla scanner; patients were followed-up for 30 months. The percentage of fibrosis was quantified on T2-weighted images, using automatic K-Means clustering algorithm. According to the percentage of fibrosis, an optimal cut-off point for separating patients into favorable and unfavorable pathologic response groups was identified by ROC analysis and tumor regression grade (MR-TRG) classes were determined and compared to histopathologic TRG. An optimal cut-off point of 81% of fibrosis was identified to differentiate between favorable and unfavorable pathologic response groups resulting in a sensitivity of 78.26% and a specificity of 97.62% for the identification of complete responders (CRs). Interobserver agreement was good (0.85). The agreement between P-TRG and MR-TRG was excellent (0.923). Significant differences in terms of overall survival (OS) and disease free survival (DFS) were found between favorable and unfavorable pathologic response groups. The automatic quantification of fibrosis determined by MR is feasible and reproducible.

Defining response to radiotherapy in rectal cancer using magnetic resonance imaging and histopathological scales

AIM

To define good and poor regression using pathology and magnetic resonance imaging (MRI) regression scales after neo-adjuvant chemotherapy for rectal cancer.

METHODS

A systematic review was performed on all studies up to December 2015, without language restriction, that were identified from MEDLINE, Cochrane Controlled Trials Register (1960-2015), and EMBASE (1991-2015). Searches were performed of article bibliographies and conference abstracts. MeSH and text words used included “tumour regression”, “mrTRG”, “poor response” and “colorectal cancers”. Clinical studies using either MRI or histopathological tumour regression grade (TRG) scales to define good and poor responders were included in relation to outcomes [local recurrence (LR), distant recurrence (DR), disease-free survival (DFS), and overall survival (OS)]. There was no age restriction or stage of cancer restriction for patient inclusion. Data were extracted by two authors working independently and using pre-defined outcome measures.

RESULTS

Quantitative data (prevalence) were extracted and analysed according to meta-analytical techniques using comprehensive meta-analysis. Qualitative data (LR, DR, DFS and OS) were presented as ranges. The overall proportion of poor responders after neo-adjuvant chemo-radiotherapy (CRT) was 37.7% (95%CI: 30.1-45.8). There were 19 different reported histopathological scales and one MRI regression scale (mrTRG). Clinical studies used nine and six histopathological scales for poor and good responders, respectively. All studies using MRI to define good and poor response used one scale. The most common histopathological definition for good response was the Mandard grades 1 and 2 or Dworak grades 3 and 4; Mandard 3, 4 and 5 and Dworak 0, 1 and 2 were used for poor response. For histopathological grades, the 5-year outcomes for poor responders were LR 3.4%-4.3%, DR 14.3%-20.3%, DFS 61.7%-68.1% and OS 60.7-69.1. Good pathological response 5-year outcomes were LR 0%-1.8%, DR 0%-11.6%, DFS 78.4%-86.7%, and OS 77.4%-88.2%. A poor response on MRI (mrTRG 4,5) resulted in 5-year LR 4%-29%, DR 9%, DFS 31%-59% and OS 27%-68%. The 5-year outcomes with a good response on MRI (mrTRG 1,2 and 3) were LR 1%-14%, DR 3%, DFS 64%-83% and OS 72%-90%.

CONCLUSION

For histopathology regression assessment, Mandard 1, 2/Dworak 3, 4 should be used for good response and Mandard 3, 4, 5/Dworak 0, 1, 2 for poor response. MRI indicates good and poor response by mrTRG1-3 and mrTRG4-5, respectively.

Interobserver agreement of radiologists assessing the response of rectal cancers to preoperative chemoradiation using the MRI tumour regression grading (mrTRG)

AIM

To investigate whether the magnetic resonance imaging (MRI) tumour regression grading (mrTRG) scale can be taught effectively resulting in a clinically reasonable interobserver agreement (>0.4; moderate to near perfect agreement).

MATERIALS AND METHODS

This study examines the interobserver agreement of mrTRG, between 35 radiologists and a central reviewer. Two workshops were organised for radiologists to assess regression of rectal cancers on MRI staging scans. A range of mrTRGs on 12 patient scans were used for assessment.

RESULTS

Kappa agreement ranged from 0.14-0.82 with a median value of 0.57 (95% CI: 0.37-0.77) indicating good overall agreement. Eight (26%) radiologists had very good/near perfect agreement (κ>0.8). Six (19%) radiologists had good agreement (0.8≥κ>0.6) and a further 12 (39%) had moderate agreement (0.6≥κ>0.4). Five (16%) radiologists had a fair agreement (0.4≥κ>0.2) and two had poor agreement (0.2>κ). There was a tendency towards good agreement (skewness: 0.92). In 65.9% and 90% of cases the radiologists were able to correctly highlight good and poor responders, respectively.

CONCLUSIONS

The assessment of the response of rectal cancers to chemoradiation therapy may be performed effectively using mrTRG. Radiologists can be taught the mrTRG scale. Even with minimal training, good agreement with the central reviewer along with effective differentiation between good and intermediate/poor responders can be achieved. Focus should be on facilitating the identification of good responders. It is predicted that with more intensive interactive case-based learning a κ>0.8 is likely to be achieved. Testing and retesting is recommended.

Preoperative diffusion-weighted imaging value of rectal cancer: preoperative T staging and correlations with histological T stage

PURPOSE

To assess the ability of diffusion-weighted imaging (DWI) for evaluating T stage and correlation with histological T stage of rectal cancer.

METHOD

The diagnostic accuracy, sensitivity, and specificity of T2WI and DWI combined with T2WI for T stage were evaluated. Mean tumor apparent diffusion coefficient (ADC) was compared with histological T stage.

RESULT

There were no significant differences in the diagnostic accuracy, sensitivity, and specificity no matter what kind of T stage was concerned. The difference between ADC values and histological T stage were significantly different.

CONCLUSION

DWI was useful for evaluating T stage of rectal cancer. The ADC may predict the histological grade.

Biomarkers for radiation-induced small bowel epithelial damage: An emerging role for plasma Citrulline

Reduction of cancer treatment-induced mucosal injury has been recognized as an important target for improving the therapeutic ratio as well as reducing the economic burden associated with these treatment related sequellae. Clinical studies addressing this issue are hampered by the fact that specific objective parameters, which enable monitoring of damage in routine clinical practice, are lacking. This review summarizes pros and cons of currently available endpoints for intestinal injury. The metabolic background and characteristics of plasma citrulline, a recently investigated biomarker specifically for small intestinal injury, are discussed in more detail.

Analysis of clinical outcomes and prognostic factors of neoadjuvant chemoradiotherapy combined with surgery: intraperitoneal versus extraperitoneal rectal cancer

Neoadjuvant chemoradiotherapy (CRT) is a widely purposed and performed treatment for rectal cancer. Downstaging effects possibly enhance the rate of curative surgery and may enable sphincter preservation in low-lying tumours. The current study examines the clinical outcomes in patients enrolled in a neoadjuvant CRT-surgery protocol for rectal cancer, distinguishing between intraperitoneal and extraperitoneal cancer. From 1994 to 2003, 58 patients with a primary diagnosis of rectal cancer were enrolled in a single-centre, not randomized study based on 5-week sessions of radiotherapy associated with a 30-day protracted venous 5-FU infusion followed by surgical resection. The study population was divided into two groups according to the localization of the tumour: 18 intraperitoneal and 40 extraperitoneal (EPt). Fifty-eight patients were treated with neoadjuvant CRT and surgery. Overall mortality rate was 25.9%, no deaths were recorded during hospitalization; 10 patients (all EPt) died because of recurrence. Significant differences in disease-free survival and overall survival rates were found between intraperitoneal vs. extraperitoneal tumours (P = 0.006), both intraperitoneal vs. extraperitoneal tumours N(0) (P = 0.04 and P < 0.05) and intraperitoneal vs. extraperitoneal tumours N(+) (P < 0.05). We diagnosed all local recurrence and liver metastasis in extraperitoneal tumours (t = 0.02 and t = 0.04), and only one case of lung metastasis arose from intraperitoneal cancer. Extraperitoneal tumours could be more aggressive than intraperitoneal ones, spreading more precociously, and/or less responsive to the neoadjuvant CRT because of their localization rather than biological differences. Aside from lymph node status, the location of the tumour with respect to the peritoneum border, is also a prognostic factor of survival in rectal cancer treated by neoadjuvant CRT and surgery.

Instrumental clinical restaging, pathological evaluation, and tumor regression grading: how to assess the response to neoadjuvant chemoradiotherapy for rectal cancer

INTRODUCTION

The object of neoadjuvant chemoradiotherapy regimens is a downstaging or downsizing of advanced rectal tumor to increase the rate of curative resection and reduce loco-regional failure. A reliable method of assessing response to adjuvant therapies is required to help standardize the assessments of new multimodality therapies. The purpose of this study was to evaluate the role played by tumor regression grading on the evaluation of pathological response to chemoradiotherapy, compared with both the predicting value of the clinical response to neoadjuvant therapy and pathologic response evaluation.

METHODS

From 1994 to 2003, 58 patients with a primary diagnosis of rectal cancer were studied at our department and enrolled in a single center, not randomized study based on 5-week sessions of radiotherapy associated with a 30-day 5-fluorouracil (FU) infusion, followed by surgical resection. Instrumental restaging and routine histological examination, including tumor regression grading, were performed to asses the response to neoadjuvant therapy.

RESULTS

The cCR rate corresponds to pCR rate, while a 3.5% of cPR and a 3.4% of cSD corresponded to a pPD. cPR and cSD show a PPV of 92.8% and 90.9% respectively, while cPD NPV is 20%. No case was found with no regression (grade 0). Tumor regression was defined grade 1 in 24.5% of cases, grade 2 was found in 58.5% of cases, 7.5% were grade 3, and 9.5% showed complete regression (grade 4). Pathologic response resulted to be associated with regression grade (p=0.006). Tumor regression grading is an independent variable for pT (p=0.0002), pN status (p=0.00004), pathologic staging (p=0.000001) and local recurrence (p=0.003).

CONCLUSION

Our results lead us to consider only pathologic evaluation to determine the response to neoadjuvant treatment: the application of tumor regression grading on the specimens obtained after combined neoadjuvant chemoradiotherapy and surgery is useful to plan a better therapeutic strategy on the ground of a quantitative evaluation of the response to neoadjuvant treatment; it shows it is an important comparable pathological feature, useful in comparing different protocols' results and differences between patient's response as well as prognostic factors.

Prognostic value of tumour regression grading and depth of neoplastic infiltration within the perirectal fat after combined neoadjuvant chemo-radiotherapy and surgery for rectal cancer

OBJECTIVE

To evaluate histological variables correlated with pathological response to chemo-radiotherapy protocols for rectal cancer and with local recurrence and survival.

METHODS

From 1994 to 2003, 58 patients with rectal cancer were enrolled in a non-randomised study based on standardised treatment with radiotherapy, 5-fluorouracil, and surgical resection, followed by histological examination, including tumour regression grading and depth of neoplastic infiltration within the perirectal fat. All patients were followed up. Mean (SD) length of follow up was 55.3 (28.1) months, range 5 to 108.

RESULTS

No case was found with no regression (grade 0). Tumour regression was defined as grade 1 in 24.5% of cases, grade 2 in 58.5%, grade 3 in 7.5%, and grade 4 (complete regression) in 9.5%. Neoplastic infiltration of >4 mm within the perirectal fat was found in 25.6% of cases in grade 1, 55.8% in grade, 2.7% in grade 3, and 11.6% in grade 4. In 80% cases of pT4 depth of neoplastic infiltration within the perirectal fat was >4 mm (100% were pN+), and the same spread was also found in 53.4% of pT2 and 86.2% of pT3. Pathological response was associated with regression grade (p = 0.006) and depth of neoplastic infiltration within the perirectal fat (p = 0.04). Tumour regression grading was an independent variable for pT (p = 0.0002), pN status (p = 0.00004), pathological staging (p = 0.000001), and local recurrence (p = 0.003).

CONCLUSIONS

Involvement of the lateral resection margins correlates with a poor prognosis and indicates the likelihood of local recurrence of rectal cancer. Tumour regression grading and the depth of neoplastic infiltration within the perirectal fat are important prognostic factors that need to be evaluated routinely.

Monitoring myeloablative therapy-induced small bowel toxicity by serum citrulline concentration: a comparison with sugar permeability tests

BACKGROUND

Intestinal mucositis is an important cause of cancer treatment-related morbidity and mortality, carrying a serious economic burden. Currently, objective parameters are lacking that would enable the monitoring of gut damage in routine clinical practice, thus hindering the development of clinical studies designed to investigate potential new strategies aimed at reducing or preventing this side effect. The authors investigated the characteristics of serum citrulline concentration compared with sugar permeability tests with respect to its use as a marker for cancer treatment-induced small bowel injury.

METHODS

In this prospective study, 10 patients with hematologic malignancies who were receiving myeloablative therapy had gut toxicity assessed with sugar permeability tests. Serum citrulline concentrations also were determined using archival serum samples. The association between both parameters and their respective characteristics were analyzed and compared with data from the literature.

RESULTS

Sensitivity and specificity were better for the citrulline assay compared with sugar permeability tests. Maximum gut damage assessed with the citrulline assay was observed 1-2 weeks earlier compared with the sugar permeability test. Similarly, citrulline indicated recovery of gut damage at 3 weeks after transplantation, whereas most sugar permeability tests remained abnormal.

CONCLUSIONS

The simplicity of the method, the low costs, and the lack of drawbacks to the method make the citrulline assay the first choice for measuring and monitoring treatment-related gut damage and provides an objective parameter for cancer treatment-related gut toxicity.

Plasma citrulline concentration: a surrogate end point for radiation-induced mucosal atrophy of the small bowel. A feasibility study in 23 patients

PURPOSE

Plasma citrulline, a nitrogen end product of glutamine metabolism in small-bowel enterocytes, was suggested as a marker of radiation-induced small-bowel epithelial cell loss in mice after single-dose whole-body irradiation. Our objective was to evaluate the feasibility of citrulline as a marker for radiation-induced small-intestinal mucosal atrophy in patients during and after abdominal fractionated radiotherapy.

METHODS AND MATERIALS

Twenty-three patients were studied weekly during treatment and at intervals of 2 weeks and 3 and 6 months after treatment by postabsorptive plasma citrulline concentration and clinical toxicity grading. The interrelationship between these variables and the correlation with small-bowel dose and volume parameters were investigated.

RESULTS

During fractionated radiotherapy, citrulline concentration significantly decreased as a function of the radiation dose (p < 0.001) and the volume of small bowel treated (p = 0.001). The plasma citrulline concentration correlated with clinical toxicity during the last 3 weeks of treatment. As a whole, citrulline concentration correlated better with radiation dose and volume parameters than clinical toxicity grading.

CONCLUSIONS

In patients treated with fractionated radiation therapy for abdominal or pelvic cancer sites, plasma citrulline concentration may be a simple objective marker for monitoring epithelial cell loss, a major event in acute radiation-induced small-bowel toxicity.

Effectiveness of preoperative staging in rectal cancer: digital rectal examination, endoluminal ultrasound or magnetic resonance imaging?

In rectal cancer, preoperative staging should identify early tumours suitable for treatment by surgery alone and locally advanced tumours that require therapy to induce tumour regression from the potential resection margin. Currently, local staging can be performed by digital rectal examination (DRE), endoluminal ultrasound (EUS) or magnetic resonance imaging (MRI). Each staging method was compared for clinical benefit and cost-effectiveness. The accuracy of high-resolution MRI, DRE and EUS in identifying favourable, unfavourable and locally advanced rectal carcinomas in 98 patients undergoing total mesorectal excision was compared prospectively against the resection specimen pathological as the gold standard. Agreement between each staging modality with pathology assessment of tumour favourability was calculated with the chance-corrected agreement given as the kappa statistic, based on marginal homogenised data. Differences in effectiveness of the staging modalities were compared with differences in costs of the staging modalities to generate cost effectiveness ratios. Agreement between staging and histologic assessment of tumour favourability was 94% for MRI (κ=0.81, s.e.=0.05; κ_W=0.83), compared with very poor agreements of 65% for DRE (κ=0.08, s.e.=0.068, κ_W=0.16) and 69% for EUS (κ=0.17, s.e.=0.065, κ_W=0.17). The resource benefits resulting from the use of MRI rather than DRE was £67164 and £92244 when MRI was used rather than EUS. Magnetic resonance imaging dominated both DRE and EUS on cost and clinical effectiveness by selecting appropriate patients for neoadjuvant therapy and justifies its use for local staging of rectal cancer patients.

Adjuvant and neoadjuvant radiotherapy and concurrent radiochemotherapy for rectal cancer

Radical surgery with negative margins remains the most important prognostic factor in the treatment of rectal cancer. Combined modality treatment is the recommended standard adjuvant therapy for patients with locally advanced rectal cancer in the USA and in Germany. During the last decade substantial progress has been made in treatment modalities: surgical management currently includes a broad spectrum of operative procedures ranging from radical operations to innovative sphincter-preserving techniques. Specialized groups have reported excellent local control rates with total mesorectal excision (TME) alone. New and improved radiation techniques (conformal radiotherapy, intraoperative radiotherapy) and innovative schedules (protracted intravenous infusion, chronomodulated infusion) and combinations (oxaliplatin, irinotecan) of chemotherapy may have the potential to further increase the therapeutic benefit of adjuvant treatment. Moreover, the basic issue of timing of radio-(chemo-)therapy - preoperative versus postoperative - within a multimodality regimen is currently being addressed in prospective trials. Evidently, the current monolithic approaches, established by studies conducted more than a decade ago, to apply either the same schedule of postoperative radiochemotherapy to all patients with stage II/III rectal cancer or to give preoperative intensive short-course radiation according to the Swedish concept for all patients with resectable rectal cancer irrespective of tumor stage and treatment goal (e.g. sphincter preservation), need to be questioned. This review will discuss different irradiation settings in more recent and ongoing studies of perioperative radiotherapy for rectal cancer and will focus on the issue which patient should receive radiotherapy at all, and if so, how and when?

Role of the surgeon as a variable in the treatment of rectal cancer

Increasingly, data are being accumulated on the influence of intersurgeon variability on outcome after curative surgical treatment of rectal carcinoma. Thus, today the individual surgeon has to be considered as an independent factor influencing locoregional recurrence, as well as survival rates. In general, higher local control and survival can be expected for specialized colorectal surgeons. There are no clear correlations between surgical volume and outcome. Interinstitutional variability in treatment results reflects intersurgeon variability, but analysis is generally more difficult because of a lack of homogeneity with respect to different confounding factors. There are several factors in surgical technique that are important for long-term outcome. Of greatest apparent importance is the adequacy of mesorectal excision (for carcinomas of the middle and lower third, total mesorectal excision; for carcinomas of the upper third, mesorectal excision down to a mesorectal plane 5 cm distal to the gross tumor margin detected by the surgeon in situ). Furthermore, intraoperative local tumor spillage (tumor perforation during mobilization, incision into the tumor), en bloc resection technique, skill, and the extent of regional lymphadenectomy may influence outcome. For quality assurance, detailed operative reports are required, as well as histopathology examinations concerning indicators of surgical oncologic quality discernable from the resection specimens. In future clinical trials of multimodal treatment of rectal cancer, quality assurance of surgery and pathology is necessary for consideration of the surgeon and surgical technique prognostic factors.

Preoperative combined radiotherapy and chemotherapy for middle and lower rectal cancer: preliminary results

BACKGROUND

Adjuvant treatment for rectal cancer is still controversial. This study reports on overall survival and disease-free survival, toxicity, downstaging, and surgical morbidity in rectal cancer patients who received combined chemoradiation therapy followed by curative surgery.

METHODS

Between 1993 and 1998, 51 patients (31 males and 20 females; median age, 60 years; range, 33-73 years) underwent chemoradiation therapy followed by radical surgery for middle and lower rectal adenocarcinoma. Criteria for giving preoperative radiotherapy (total 45 Gy in 25 fractions of 1.8 Gy/day for 5 weeks) and chemotherapy (5-fluorouracil 350 mg/m2/day and leucovorin 10 mg/m2/day, bolus on days 1-5 and 29-33) were an age younger than 75 years; an Eastern Cooperative Oncology Group performance status score of 0 to 2; and clinical preoperative stage II-III. Forty-three low anterior and eight abdominoperineal resections were performed. Median follow-up time was 29 (range, 3-63) months.

RESULTS

Although grade 3 to 4 toxicity occurred in 14 cases (27.4%), all patients completed the planned adjuvant therapy. At pathology, a complete response was found in eight (15.7%) cases. Of the remaining 43 cases, 22 were stage I, 12 were stage II, and 9 were stage III. Five-year actuarial disease-free survival and overall survival rates were 86.4% and 85.5%, respectively. Whereas no local recurrences were found, 4 patients had distant metastases. Three patients died (1 of cancer-related causes), 45 are alive and disease free, and 3 are alive with disease.

CONCLUSIONS

The combined preoperative chemoradiation approach used by us seems to improve the disease-free survival and overall survival of selected patients with rectal cancer. However, a longer follow-up time is required to confirm these preliminary results.