Pre-operative imaging of rectal cancer and its impact on surgical performance and treatment outcome

Preoperative radiotherapy and curative surgery for the management of localised rectal carcinoma

BACKGROUND

This is an update of the original review published in 2007.Carcinoma of the rectum is a common malignancy, especially in high income countries. Local recurrence may occur after surgery alone. Preoperative radiotherapy (PRT) has the potential to reduce the risk of local recurrence and improve outcomes in rectal cancer.

OBJECTIVES

To determine the effect of preoperative radiotherapy for people with localised resectable rectal cancer compared to surgery alone.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library; Issue 5, 2018) (4 June 2018), MEDLINE (Ovid) (1950 to 4 June 2018), and Embase (Ovid) (1974 to 4 June 2018). We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) for relevant ongoing trials (4 June 2018).

SELECTION CRITERIA

We included randomised controlled trials comparing PRT and surgery with surgery alone for people with localised advanced rectal cancer planned for radical surgery. We excluded trials that did not use contemporary radiotherapy techniques (with more than two fields to the pelvis).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the 'Risk of bias' domains for each included trial, and extracted data. For time-to-event data, we calculated the Peto odds ratio (Peto OR) and variances, and for dichotomous data we calculated risk ratios (RR) using the random-effects method. Potential sources of heterogeneity hypothesised a priori included study quality, staging, and the use of total mesorectal excision (TME) surgery.

MAIN RESULTS

We included four trials with a total of 4663 participants. All four trials reported short PRT courses, with three trials using 25 Gy in five fractions, and one trial using 20 Gy in four fractions. Only one study specifically required TME surgery for inclusion, whereas in another study 90% of participants received TME surgery.Preoperative radiotherapy probably reduces overall mortality at 4 to 12 years' follow-up (4 trials, 4663 participants; Peto OR 0.90, 95% CI 0.83 to 0.98; moderate-quality evidence). For every 1000 people who undergo surgery alone, 454 would die compared with 45 fewer (the true effect may lie between 77 fewer to 9 fewer) in the PRT group. There was some evidence from subgroup analyses that in trials using TME no or little effect of PRT on survival (P = 0.03 for the difference between subgroups).Preoperative radiotherapy may have little or no effect in reducing cause-specific mortality for rectal cancer (2 trials, 2145 participants; Peto OR 0.89, 95% CI 0.77 to 1.03; low-quality evidence).We found moderate-quality evidence that PRT reduces local recurrence (4 trials, 4663 participants; Peto OR 0.48, 95% CI 0.40 to 0.57). In absolute terms, 161 out of 1000 patients receiving surgery alone would experience local recurrence compared with 83 fewer with PRT. The results were consistent in TME and non-TME studies.There may be little or no difference in curative resection (4 trials, 4673 participants; RR 1.00, 95% CI 0.97 to 1.02; low-quality evidence) or in the need for sphincter-sparing surgery (3 trials, 4379 participants; RR 0.99, 95% CI 0.94 to 1.04; I² = 0%; low-quality evidence) between PRT and surgery alone.Low-quality evidence suggests that PRT may increase the risk of sepsis from 13% to 16% (2 trials, 2698 participants; RR 1.25, 95% CI 1.04 to 1.52) and surgical complications from 25% to 30% (2 trials, 2698 participants; RR 1.20, 95% CI 1.01 to 1.42) compared to surgery alone.Two trials evaluated quality of life using different scales. Both studies concluded that sexual dysfunction occurred more in the PRT group. Mixed results were found for faecal incontinence, and irradiated participants tended to resume work later than non-irradiated participants between 6 and 12 months, but this effect had attenuated after 18 months (low-quality evidence).

AUTHORS' CONCLUSIONS

We found moderate-quality evidence that PRT reduces overall mortality. Subgroup analysis did not confirm this effect in people undergoing TME surgery. We found consistent evidence that PRT reduces local recurrence. Risk of sepsis and postsurgical complications may be higher with PRT.The main limitation of the findings of the present review concerns their applicability. The included trials only assessed short-course radiotherapy and did not use chemotherapy, which is widely used in the contemporary management of rectal cancer disease. The differences between the trials regarding the criteria used to define rectal cancer, staging, radiotherapy delivered, the time between radiotherapy and surgery, and the use of adjuvant or postoperative therapy did not appear to influence the size of effect across the studies.Future trials should focus on identifying participants that are most likely to benefit from PRT especially in terms of improving local control, sphincter preservation, and overall survival while reducing acute and late toxicities (especially rectal and sexual function), as well as determining the effect of radiotherapy when chemotherapy is used and the optimal timing of surgery following radiotherapy.

Intersphincteric resection for very low rectal cancer: A review of the updated literature

Intersphincteric resection (ISR) has rapidly increased worldwide including laparoscopic surgery. However, there are some concerns for the definition of ISR, surgical technique, oncological outcome, anal function, and quality of life (QoL). The aim of the present study is to evaluate those issues. A review of this surgical technique was carried out by searching English language literature of the PubMed online database and appropriate articles were identified. With regard to open‐ISR, the morbidity rate ranged from 7.5% to 38.3%, with lower mortality rates. Local recurrence rates varied widely from 0% to 22.7%, with a mean follow‐up duration of 40–94 months. Disease‐free and overall 5‐year survival rates were 68–86% and 76–97%, respectively. Those outcomes were equivalent to laparoscopic‐ISR. Surgical and oncological outcomes of ISR were generally acceptable. However, accurate evaluation of anal function and QoL was difficult because of a lack of standard assessment of various patient‐related factors. The surgical and oncological outcomes after ISR seem to be acceptable. The ISR technique seems to be valid as an alternative to abdominoperineal resection in selected patients with a very low rectal cancer. However, both necessity for ISR and expectations of QoL impairment as a result of functional disorder should be fully discussed with patients before surgery.

Prediction of tumor stage and lymph node involvement with dynamic contrast-enhanced MRI after chemoradiotherapy for locally advanced rectal cancer

PURPOSE

The usefulness of restaging by magnetic resonance imaging (MRI) after chemoradiotherapy (CTx/RTx) in patients with locally advanced rectal cancer has not yet been established, mostly due to the difficult differentiation between viable tumor and fibrosis. MRI with dynamic contrast-enhanced (DCE) sequences may be of additional value in distinguishing malignant from nonmalignant tissue. The aim of this study was to assess the accuracy of tumor, nodal staging, and circumferential resection margin (CRM) involvement by MRI with DCE sequences after CTx/RTx.

METHODS

The accuracies were assessed by MRI on T2-weighted magnetic resonance (MR) images with DCE sequences in patients with locally advanced rectal cancer after a long course of CTx/RTx. MR images were assessed by two independent radiologists.

RESULTS

For tumor staging and CRM involvement, MRI with DCE sequences had an accuracy of 45 and 60 %, respectively. The accuracy for nodal staging was 93 %. On MRI, malignant lymph nodes had a median diameter of 8 mm (range, 4-18) and benign lymph nodes a median diameter of 4 mm (range, 3-11). A significant indicator for benign nodes was hypointensity on T2-weighted images (p < 0.001) and early complete arterial phase enhancement on DCE-weighted images (p < 0.001). A significant indicator for malignant nodes was heterogeneity on T2-weighted images (χ (2), p < 0.000) and early incomplete arterial phase enhancement on DCE (p < 0.001).

CONCLUSIONS

MRI with DCE is a useful tool for nodal staging after CTx/RTx. The addition of DCE sequences did not improve the accuracy of determining the tumor stage, CRM involvement, and in detecting complete response.

Preoperative chemoradiation versus radiation alone for stage II and III resectable rectal cancer

BACKGROUND

Preoperative radiotherapy (RT) decreases local recurrence rate and improves survival in stage II and III rectal cancer patients. The combination of chemotherapy with RT has a sound radiobiological rationale, and phase II trials of combined chemoradiation (CRT) have shown promising activity in rectal cancer.

OBJECTIVES

To compare preoperative RT with preoperative CRT in patients with resectable stage II and III rectal cancer.

SEARCH METHODS

We searched the Cochrane Register of Controlled Trials, Web of Science, Embase.com, and Pubmed from 1975 until June 2012. A manual search was performed of Ann Surg, Arch Surg, Cancer, J Clin Oncol, Int J Radiat Oncol Biol Phys and the proceedings of ASTRO, ECCO and ASCO from 1990 until June 2012.

SELECTION CRITERIA

Relevant studies randomized resectable stage II or III rectal cancer patients to at least one arm of preoperative RT alone or at least one arm of preoperative CRT.

DATA COLLECTION AND ANALYSIS

Primary outcome parameters included overall survival (OS) at 5 years and local recurrence (LR) rate at 5 years. Secondary outcome parameters included disease free survival (DFS) at 5 years, metastasis rate, pathological complete response rate, clinical response rate, sphincter preservation rate, acute toxicity, postoperative mortality and morbidity, and anastomotic leak rate. Outcome parameters were summarized using the Odds Ratio (OR) and associated 95% confidence interval (CI) using the fixed effects model.

MAIN RESULTS

Five trials were identified and included in the meta-analysis. From one of the included trials only preliminary data are reported. The addition of chemotherapy to preoperative RT significantly increased grade III and IV acute toxicity (OR 1.68-10, P = 0.002) and marginally affected postoperative overall morbidity (OR 0.67-1.00, P = 0.05) while no differences were observed in postoperative mortality or anastomotic leak rate. Compared to preoperative RT alone, preoperative CRT significantly increased the rate of complete pathological response (OR 2.12-5.84, P < 0.00001) although this did not translate into a higher sphincter preservation rate (OR 0.92-1.30, P = 0.32). The incidence of local recurrence at five years was significantly lower in the CRT group compared to RT alone (OR 0.39-0.72, P < 0.001). No statistically significant differences were observed in DFS (OR 0.92-1.34, P = 0.27) or OS (OR 0.79-1.14, P = 0.58) at five years.

AUTHORS' CONCLUSIONS

Compared to preoperative RT alone, preoperative CRT enhances pathological response and improves local control in resectable stage II and III rectal cancer, but does not benefit disease free or overall survival. The effects of preoperative CRT on functional outcome and quality of life are incompletely understood and should be addressed in future trials.

Intersphincteric resection for very low rectal cancer: a systematic review

Radical surgical treatment for very low rectal cancer near the anus has generally involved abdominoperineal resection. Various sphincter-saving operations have been developed for such tumors to optimize the patients' postoperative quality of life. Current protocols focus on intersphincteric resection (ISR), which differs from conventional hand-sewn coloanal anastomosis (CAA) after low anterior resection. However, the efficacy of ISR remains unclear. The surgical, oncologic, and functional outcomes after intersphincteric resection (ISR) were reviewed. This review of the current literature was conducted by searching the PubMed online database. Articles focusing specifically on conventional hand-sewn CAA were excluded from this study. The mean mortality rate is <2 %, and the mean morbidity rate ranges from 7.7 to 38.3 %. The mean local recurrence rate varies widely from 0 to 22.7 %, with a mean follow-up duration of 40-94 months. The mean disease-free and overall 5-year survival rates are 69-86 and 79-97 months, respectively. Functional outcomes are generally acceptable, but accurate evaluation is extremely difficult due to the absence of unified appraisal methods. ISR appears surgically, oncologically and functionally acceptable. However, more experience and better understanding of the oncology, anal physiology, and pelvic anatomy are necessary to achieve successful outcomes without complications, and to improve patient survival.

Local staging of rectal cancer: a review of imaging

During the past decades the management of patients with rectal cancer has substantially changed, with a significant reduction in local recurrence rates following the introduction of better imaging, better surgery, and more efficient neoadjuvant therapy. This review discusses the clinically relevant information radiologists should know on staging of rectal cancer patients. The crucial role of the radiologist in patient management is explained. Furthermore, the evidence for the use of magnetic resonance imaging (MRI) in staging and restaging of rectal cancer patients as well as the main features that need to be evaluated when interpreting rectal cancer MRI are given. New diagnostic challenges as a result of new treatment options are also discussed.

Preoperative radiotherapy combined with total mesorectal excision for resectable rectal cancer: 12-year follow-up of the multicentre, randomised controlled TME trial

BACKGROUND

The TME trial investigated the value of preoperative short-term radiotherapy in combination with total mesorectal excision (TME). Long-term results are reported after a median follow-up of 12 years.

METHODS

Between Jan 12, 1996, and Dec 31, 1999, 1861 patients with resectable rectal cancer without evidence of distant disease were randomly assigned to TME preceded by 5 × 5 Gy radiotherapy or TME alone (ratio 1:1). Randomisation was based on permuted blocks of six with stratification according to centre and expected type of surgery. The primary endpoint was local recurrence, analysed for all eligible patients who underwent a macroscopically complete local resection.

FINDINGS

10-year cumulative incidence of local recurrence was 5% in the group assigned to radiotherapy and surgery and 11% in the surgery-alone group (p<0·0001). The effect of radiotherapy became stronger as the distance from the anal verge increased. However, when patients with a positive circumferential resection margin were excluded, the relation between distance from the anal verge and the effect of radiotherapy disappeared. Patients assigned to radiotherapy had a lower overall recurrence and when operated with a negative circumferential resection margin, cancer-specific survival was higher. Overall survival did not differ between groups. For patients with TNM stage III cancer with a negative circumferential resection margin, 10-year survival was 50% in the preoperative radiotherapy group versus 40% in the surgery-alone group (p=0·032).

INTERPRETATION

For all eligible patients, preoperative short-term radiotherapy reduced 10-year local recurrence by more than 50% relative to surgery alone without an overall survival benefit. For patients with a negative resection margin, the effect of radiotherapy was irrespective of the distance from the anal verge and led to an improved cancer-specific survival, which was nullified by an increase in other causes of death, resulting in an equal overall survival. Nevertheless, preoperative short-term radiotherapy significantly improved 10-year survival in patients with a negative circumferential margin and TNM stage III. Future staging techniques should offer possibilities to select patient groups for which the balance between benefits and side-effects will result in sufficiently large gains.

FUNDING

The Dutch Cancer Society, the Dutch National Health Council, and the Swedish Cancer Society.

Pretherapy imaging of rectal cancers: ERUS or MRI?

ERUS and MRI should be seen more as complementary rather than competitive techniques. Each has its own strengths and weaknesses. ERUS is better in showing the tumor extent in small superficial tumors, whereas MRI is superior in imaging the more advanced tumors. The choice of imaging technique depends also on the amount of information that is required for choosing certain treatment strategies, like the distance to the mesorectal fascia for a short course of preoperative radiotherapy. For lymph node imaging, both techniques are at present only moderately accurate, although this could change with advances in new MR techniques.

Benefits and challenges in bowel MR imaging at 3.0 T

Abdominal imaging at 3.0 T has shown to be challenging because of a number of artifacts and effects related to the physics at higher field strength. For bowel imaging at 3.0 T, artifacts due to magnetic field inhomogeneities, standing waves, increased susceptibility, and greater chemical shift effects are of particular concern because they are likely to affect the assessment of relevant structures and counterbalance the benefits of higher signal-to-noise ratio. Regarding small- and large-bowel magnetic resonance imaging, the benefits of higher field strengths translate mainly in better contrast-to-noise ratio of contrast-enhanced T1-weighted gradient echo and T2-weighted imaging, whereas steady-state free precession sequences seem to suffer from serious degradation of image quality. The present article summarizes the technical challenges in bowel imaging at 3.0 T, provides an overview of performance compared with 1.5 T in small- and large-bowel diseases including the rectum, and revises the current literature.

Preoperative decision making for rectal cancer

BACKGROUND

Rectal cancer treatment has become multimodal as a result of significant advances in imaging, staging, surgery, radiotherapy, and chemotherapy. Multidisciplinary teams can incorporate these developments into tailor-made treatment plans and offer state-of-the-art services for rectal cancer patients.

METHODS

We searched the MEDLINE and PubMed databases using the following keywords: "rectal cancer," "total mesorectal excision," "multidisciplinary treatment/team," "radiotherapy," "chemotherapy," and their combinations. There were no language or publication year restrictions. References in published articles also were reviewed.

RESULTS

Total mesorectal excision surgery, high-resolution pelvic magnetic resonance imaging, preoperative chemoradiotherapy, and pathologic reports according to Quirke protocol are preconditions for the initiation of an effective multidisciplinary team. Common topics for discussion are the status of the circumferential margin, the type of radiotherapy and surgery required, and the chemotherapeutic agent to be used.

CONCLUSIONS

This review focuses on this issue based on two main principles. First, the status of the circumferential margin dictates the use of preoperative chemoradiotherapy. Second, preoperative chemoradiotherapy is superior in terms of free circumferential resection margin rate, local recurrence rate, and toxicity.

Extended total mesorectal excision in locally advanced rectal cancer (T4a) and the clinical role of MRI-evaluated neo-adjuvant downstaging

OBJECTIVE

To compare the clinical ability of MRl taken before and after neo-adjuvant treatment in locally advanced rectal cancer (LARC) to predict the necessary extension of TME (ETME) and the possibility to achieve a R0 resection.

METHOD

Prospective registration of 92 MRI evaluated T4a cancers undergoing elective surgery between 2002 and 2007 in a tertiary referral centre for multimodal treatment of rectal cancer.

RESULTS

MRI identified patients in need of neo-adjuvant treatment and predicted T-downstaging in 10% and N-downstaging in 59%. Seventy-nine percent R0 resections, 18% R1 and 3% R2 were obtained after ETME in 95% of the patients and TME in the rest. Higher tumour regression grade (TRG) was achieved in higher ypT-stage (P < 0.01). Preoperative chemo radiotherapy resulted in that more patients obtained TRG1-3 compared to those receiving radiotherapy (79% vs. 57%, P = 0.02). The pelvic wall was the area of failure in 70% of the R1 resections. Tumour cells outside the mesorectal fascia scattered within fibrosis was found in 18 TRG2-3 among 33 ypT4 tumours (55%).

CONCLUSION

MRl cannot discriminate tumour within fibrosis. Therefore, if a R0 resection is the goal, we advocate optimal surgery in accordance with the pre-treatment MRI. Post treatment MRI is a poor predictor of final histology and should not be relied upon to guide the extent of surgical resection. The study has initiated a new approach to histopathological classification of the removed specimen where we introduce a MRI assisted technique for investigating the areas at risk outside the mesorectal fascia in the specimen.

Total mesorectal excision for rectal cancer in an unselected population: quality assessment in a low volume center

OBJECTIVE

The aim of this study was to review the results and long-term outcome after total mesorectal excision (TME) for adenocarcinoma of the rectum in an unselected population in a community teaching hospital.

MATERIALS AND METHODS

Between 1996 and 2003, 210 patients with rectal cancer were identified in our prospective database, containing patient characteristics, radiotherapy plans, operation notes, histopathological reports, and follow-up details. An evaluation of prognostic factors for local recurrence, distant metastases, and overall survival was performed.

RESULTS

The mean age at diagnosis was 69 years (range 40-91 years). A total of 145 patients were treated by anterior rectal resection; 65 patients had to undergo an abdominoperineal resection (APR). Anastomotic leakage rate was 5%. Postoperative mortality was 3%. After a median follow-up of 3.6 years, the local recurrence-free rate in patients with microscopically complete resections was 91%. The 5-year overall survival rate was 58%. An increased serum carcinoembryonic antigen, an APR, positive lymph nodes, and an incomplete resection all significantly influenced the 5-year overall survival and local recurrence rate. In a multivariate analysis, age was the most important prognostic factor for overall survival.

CONCLUSIONS

Patients with rectal cancer can safely be treated with TME in a community teaching hospital and leads to a good overall survival and an excellent local control. In patients aged above 80, treatment-related mortality is an important competitive risk factor, which obscures the positive effect of modern rectal cancer treatment.

Preoperative chemoradiation versus radiation alone for stage II and III resectable rectal cancer

BACKGROUND

Preoperative radiotherapy (RT) decreases local recurrence rate and improves survival in stage II and III rectal cancer patients. The combination of chemotherapy with RT has a sound radiobiological rationale, and phase II trials of combined chemoradiation (CRT) have shown promising activity in rectal cancer.

OBJECTIVES

To compare preoperative RT with preoperative CRT in patients with resectable stage II and III rectal cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, Web of Science, Embase.com, and Pubmed from 1975 until june 2007. A manual search was performed of Ann Surg, Arch Surg, Cancer, J Clin Oncol, Int J Radiat Oncol Biol Phys and the proceedings of ASTRO, ECCO and ASCO from 1990 until june 2007.

SELECTION CRITERIA

Relevant studies randomized resectable stage II or III rectal cancer patients to at least one arm of preoperative RT alone or at least one arm of preoperative CRT.

DATA COLLECTION AND ANALYSIS

Primary outcome parameters included overall survival (OS) at 5 years and local recurrence (LR) rate at 5 years. Secondary outcome parameters included disease free survival (DFS) at 5 years, metastasis rate, pathological complete response rate, clinical response rate, sphincter preservation rate, acute toxicity, postoperative mortality and morbidity, and anastomotic leak rate. Outcome parameters were summarized using the Odds Ratio (OR) and associated 95% confidence interval (CI) using the fixed effects model.

MAIN RESULTS

Four trials were identified and included in the meta-analysis. The addition of chemotherapy to preoperative RT significantly increased grade III and IV acute toxicity (OR 1.68-10, P = 0.002) while no differences were observed in postoperative morbidity or mortality. Compared to preoperative RT alone, preoperative CRT significantly increased the rate of complete pathological response (OR 2.52-5.27, P < 0.001) although this did not translate into a higher sphincter preservation rate (OR 0.92-1.31, P = 0.29). The incidence of local recurrence at five years was significantly lower in the CRT group compared to RT alone (OR 0.39-0.72, P < 0.001). No statistically significant differences were observed in DFS (OR 0.92-1.34, P = 0.27) or OS (OR 0.79-1.14, P = 0.58) at five years.

AUTHORS' CONCLUSIONS

Compared to preoperative RT alone, preoperative CRT enhances pathological response and improves local control in resectable stage II and III rectal cancer, but does not benefit disease free or overall survival. The effects of preoperative CRT on functional outcome and quality of life are incompletely understood and should be addressed in future trials.

Randomized Phase III Study Comparing Preoperative Radiotherapy With Chemoradiotherapy in Nonresectable Rectal Cancer

Purpose

Preoperative chemoradiotherapy is considered standard treatment for locally advanced rectal cancer, although the scientific evidence for the chemotherapy addition is limited. This trial investigated whether chemotherapy as part of a multidisciplinary treatment approach would improve downstaging, survival, and relapse rate.

Patients and Methods

The randomized study included 207 patients with locally nonresectable T4 primary rectal carcinoma or local recurrence from rectal carcinoma in the period 1996 to 2003. The patients received either chemotherapy (fluorouracil/leucovorin) administered concurrently with radiotherapy (50 Gy) and adjuvant for 16 weeks after surgery (CRT group, n = 98) or radiotherapy alone (50 Gy; RT group, n = 109).

Results

The two groups were well balanced according to pretreatment characteristics. An R0 resection was performed in 82 patients (84%) in the CRT group and in 74 patients (68%) in the RT group (P = .009). Pathologic complete response was seen in 16% and 7%, respectively. After an R0 + R1 resection, local recurrence was found in 5% and 7%, and distant metastases in 26% and 39%, respectively. Local control (82% v 67% at 5 years; log-rank P = .03), time to treatment failure (63% v 44%; P = .003), cancer-specific survival (72% v 55%; P = .02), and overall survival (66% v 53%; P = .09) all favored the CRT group. Grade 3 or 4 toxicity, mainly GI, was seen in 28 (29%) of 98 and six (6%) of 109, respectively (P = .001). There was no difference in late toxicity.

Conclusion

CRT improved local control, time to treatment failure, and cancer-specific survival compared with RT alone in patients with nonresectable rectal cancer. The treatments were well tolerated.

Evidence and research in rectal cancer

The main evidences of epidemiology, diagnostic imaging, pathology, surgery, radiotherapy, chemotherapy and follow-up are reviewed to optimize the routine treatment of rectal cancer according to a multidisciplinary approach. This paper reports on the knowledge shared between different specialists involved in the design and management of the multidisciplinary ESTRO Teaching Course on Rectal Cancer. The scenario of ongoing research is also addressed. In this time of changing treatments, it clearly appears that a common standard for large heterogeneous patient groups have to be substituted by more individualised therapies based on clinical-pathological features and very soon on molecular and genetic markers. Only trained multidisciplinary teams can face this new challenge and tailor the treatments according to the best scientific evidence for each patient.

Can depth of tumour invasion predict lymph node positivity in patients undergoing resection for early rectal cancer? A comparative study between T1 and T2 cancers

OBJECTIVE

The present study investigated the risk of lymph node metastasis according to the depth of tumour invasion in patients undergoing resection for rectal cancer.

METHOD

The histology of patients undergoing oncological resection with regional lymphadenectomy for rectal cancer at St Marks Hospital from 1971 to 1996 was reviewed. Of the total number of 1549 patients, 303 patients with T(1) or T(2) rectal cancers were selected. The tumour type, grade, evidence of vascular invasion, depth of submucosal invasion (classed into 'sm1-3') were evaluated as potential predictors of lymph node positivity using univariate and multi-level logistic regression analysis.

RESULTS

Tumour stage was classified as T(1) in 55 (18.2%) and T(2) in 248 (81.2%) patients. The incidence of lymph node metastasis in the T(1) group was 12.7% (7/55), compared to 19% (47/247) in the T(2) group. The node positive and negative groups were similar with regard to patient demographics, although the former contained a significantly higher number of poorly differentiated (P = 0.001) and extramural vascular invasion tumours (P = 0.002). There was no significant difference in the number of patients with sm1-3, or T(2) tumour depths within the lymph node positive and negative groups. On multivariate analysis the presence of extramural vascular invasion (odds ratio = 10.0) and tumour grade (odds ratio for poorly vs well-differentiated = 11.7) were independent predictors of lymph node metastasis.

CONCLUSION

Whilst the degree of vascular invasion and poor differentiation of rectal tumours were significant risk factors for lymph node metastasis, depth of submucosal invasion was not. This has important implications for patients with superficial early rectal cancers in whom local excision is being considered.

Caspase-3 Activity Predicts Local Recurrence in Rectal Cancer

PURPOSE

Radiotherapy followed by total mesorectal excision surgery has been shown to significantly reduce local recurrence rates in rectal cancer patients. Radiotherapy, however, is associated with considerable morbidity. The present study evaluated the use of biochemical detection of enzymatic caspase-3 activity as preoperative marker for apoptosis to preselect patients that are unlikely to develop a local recurrence to spare these patients from overtreatment and the negative side effects of radiotherapy.

EXPERIMENTAL DESIGN

Nonirradiated freshly frozen tissue samples from 117 stage III rectal cancer patients were collected from a randomized clinical trial that evaluated preoperative radiotherapy in total mesorectal excision surgery. Additional frozen archival tissues from 47 preoperative biopsies and corresponding resected colorectal tumors were collected. Level of apoptosis was determined by measuring the enzymatic activity of caspase-3 in a biochemical assay.

RESULTS

In tumor tissue, caspase-3 activity lower than the median was predictive of 5-year local recurrence (hazard ratio, 7.4; 95% confidence interval, 1.7-32.8; P = 0.008), which was unaffected by adjustment for type of resection, tumor location, and T status (adjusted hazard ratio, 7.5; 95% confidence interval, 1.7-34.1; P = 0.009). Caspase-3 activity in preoperative biopsies was significantly correlated with caspase-3 activity in corresponding resected tumors (r = 0.56; P < 0.0001).

CONCLUSION

Detection of tumor apoptosis levels by measuring caspase-3 activity, for which a preoperative biopsy can be used, accurately predicted local recurrence in rectal cancer patients. These findings indicate that caspase-3 activity is an important denominator of local recurrence and should be evaluated prospectively to be added to the criteria to select rectal cancer patients in which radiotherapy is redundant.

Preoperative assessment of rectal cancer stage: state of the art

Rectal cancer is one of the most common tumors worldwide; it accounts for approximately 25-30% of cancers arising in the large bowel. Owing to greater distribution of screening programs and better attention from both patients and General Practitioners to this disease, in recent years we have observed an increasing number of cases diagnosed in the early stages, with a consequent better prognosis. The improved 5-year survival is also partially due to better, and more accurate, diagnostic techniques and to more curative treatments. In this review, the authors analyze and discuss the more recent diagnostic techniques for an accurate preoperative staging of rectal cancer, highlighting each method's advantages and limits for their routine use in clinical practice.

A prospective comparison study for predicting circumferential resection margin between preoperative MRI and whole mount sections in mid-rectal cancer: significance of different scan planes

AIM

The aim of this study is to evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in the prediction of circumferential resection margin (CRM) and to determine whether each different MRI scan plane provides an accurate CRM assessment.

METHOD

Fifty-seven consecutive patients with mid-rectal cancer were enrolled prospectively. The CRM measurement from each MRI plane according to tumor location was compared with CRM measurement on whole-mount sections with the definition of threatened CRM as 2 mm in distance. The difference in performance among the sagittal, axial and oblique MR images was analyzed by using receiver operating characteristic (ROC) curves (A(z)).

RESULTS

For anterior tumors (n = 17), the A(z) of the sagittal, axial and oblique MR planes were 0.66, 0.83 and 0.79, respectively. For lateral tumors (n = 17), the A(z) of the sagittal, axial and oblique MR planes were 0.53, 0.66 and 0.78, respectively. For posterior tumors (n = 23), the A(z) of the sagittal, axial and oblique MR planes were 0.76, 0.82 and 0.97, respectively.

CONCLUSIONS

MRI provides an accurate prediction of preoperative CRM. There exist differences in diagnostic accuracy according to each different scan plane of MRI and tumor location within the rectum.

Rectal Cancer: MR Imaging before Neoadjuvant Chemotherapy and Radiation Therapy for Prediction of Tumor-Free Circumferential Resection Margins and Long-term Survival1

PURPOSE

To retrospectively evaluate the prognostic importance of involvement of the circumferential resection margin predicted by using magnetic resonance (MR) imaging before neoadjuvant treatment in patients with rectal cancer.

MATERIALS AND METHODS

The local institutional review board approved the retrospective analysis of the data and waived informed consent. Sixty-eight patients (52 men, 16 women; mean age +/- standard deviation, 58.9 years +/- 9.4) with cT3 NX M0 tumors were included. T2-weighted MR images were analyzed in consensus by two radiologists with respect to the shortest distance between the outermost parts of the tumor to the adjacent mesorectal fascia (as the potential circumferential resection margin in total mesorectal excision). Histopathologic and follow-up data were available for all patients (mean follow-up time, 54 months; range, 31-77 months). To compare local recurrence and survival rates, the population was divided into three groups categorized according to the minimum distance of the tumor to the mesorectal fascia (group 1, <or=1 mm; group 2, >1 to 5 mm; group 3, >5 mm). Univariate Cox and multivariate proportional hazard regression models were used to test the prognostic importance of clinical, histopathologic regression, and histopathologic tumor parameters.

RESULTS

MR imaging led to accurate prediction of a histologically involved circumferential resection margin (sensitivity, 100%; specificity, 88%). The rates for local recurrence (group 1, 33%; group 2, 5%; group 3, 6%; P<.02) and 5-year overall survival (group 1, 39%; group 2, 70%; group 3, 90%; P<.001) differed significantly among the predefined groups. The distance to the mesorectal fascia was an independent prognostic parameter in multivariate analysis (P<.001), and histopathologic response to treatment provided no additional information.

CONCLUSION

Prediction of the tumor-free circumferential resection margin assessed with MR imaging before initiation of neoadjuvant chemotherapy and radiation therapy proved to be a prognostic factor in rectal cancer.

Prognostic value of apoptosis in rectal cancer patients of the dutch total mesorectal excision trial: radiotherapy is redundant in intrinsically high-apoptotic tumors

PURPOSE

The combination of radiotherapy and good quality surgery reduces local recurrence rate for rectal cancer patients. This study assesses the prognostic value of both intrinsic and radiotherapy-induced apoptosis and evaluates the relevance of radiotherapy for outcome of rectal cancer patients.

EXPERIMENTAL DESIGN

Tumor samples (1,198) were available from the Dutch Total Mesorectal Excision trial, in which rectal cancer patients were treated with standardized surgery and randomized for preoperative short-term radiotherapy or not. Tumor samples were obtained at time of surgery. Tissue microarrays were constructed and stained with the active caspase-specific M30 antibody to determine the amount of apoptotic epithelial tumor cells.

RESULTS

Nonirradiated patients with a negative circumferential margin displaying lower than median levels of apoptosis developed more local recurrences (10.5% versus 6.1%; P=0.06) and more rapidly after surgery than patients with high intrinsic apoptosis in their tumors (median time to recurrence, 13.0 versus 21.3 months; P=0.04). In multivariate analysis, intrinsic apoptosis was an independent predictor for the development of local recurrences (hazard ratio, 2.0; P=0.05). Radiotherapy increased apoptosis level (11 versus 23 apoptotic cells/mm2 tumor epithelium; P<0.001), but this apoptosis did not influence patients' prognosis.

CONCLUSIONS

Rectal cancer patients with low intrinsic apoptosis will benefit from radiotherapy with respect to the development of local recurrences. Because apoptosis is an inherent characteristic of tumors, patients who do not need radiotherapy may be selected based on the apoptotic index of the primary tumor.

New developments in MRI for target volume delineation in radiotherapy

MRI is being increasingly used in oncology for staging, assessing tumour response and also for treatment planning in radiotherapy. Both conformal and intensity-modulated radiotherapy requires improved means of defining target volumes for treatment planning in order to achieve its intended benefits. MRI can add to the radiotherapy treatment planning (RTP) process by providing excellent and improved characterization of soft tissues compared with CT. Together with its multiplanar capability and increased imaging functionality, these advantages for target volume delineation outweigh its drawbacks of lacking electron density information and potential image distortion. Efficient MR distortion assessment and correction algorithms together with image co-registration and fusion programs can overcome these limitations and permit its use for RTP. MRI developments using new contrast media, such as ultrasmall superparamagnetic iron oxide particles for abnormal lymph node identification, techniques such as dynamic contrast enhanced MRI and diffusion MRI to better characterize tissue and tumour regions as well as ultrafast volumetric or cine MR sequences to define temporal patterns of target and organ at risk deformity and variations in spatial location have all increased the scope and utility of MRI for RTP. Information from these MR developments may permit treatment individualization, strategies of dose escalation and image-guided radiotherapy. These developments will be reviewed to assess their current and potential use for RTP and precision high dose radiotherapy.