USPIO-enhanced MR imaging for nodal staging in patients with primary rectal cancer: predictive criteria

Preoperative staging and treatment options in T1 rectal adenocarcinoma

BACKGROUND

Major rectal resection for T1 rectal cancer offers more than 95% cancer specific five-year survival to patients surviving the first 30 days after surgery. A significant further improvement by development of the surgical technique may not be possible. Improvements in the total survival rate have to come from a more differentiated treatment modality, taking patient and procedure related risk factors into account. Subgroups of patients have operative mortality risks of 10% or more. Operative complications and long-term side effects after rectum resection are frequent and often severe.

RESULTS

Local treatment of T1 cancers combined with close follow-up, early salvage surgery or later radical resection of local recurrences or with chemo-radiation may lead to fewer severe complications and comparable, or even better, long-term survival. Accurate preoperative staging and careful selection of patients for local or non-operative treatment are mandatory. As preoperative staging, at present, is not sufficiently accurate, strategies for completion, salvage or rescue surgery is important, and must be accepted by the patient before local treatment for cure is initiated.

RECOMMENDATIONS

It is recommended that polyps with low-risk T1 cancers should be treated with endoscopic snare resection in case of Haggitt's stage 1 or 2. TEM is recommended if resection margins are uncertain after snare resection for Haggitt's stage 3 and 4, and for sessile and flat, low-risk T1 cancers. Average risk patients with high-risk T1 cancers should be offered rectum resection, but old and comorbid patients with high-risk T1 cancers should be treated individually according to objective criteria as age, physical performance as well as patient's preference. All patients treated for cure with local resection or non-surgical methods should be followed closely.

Locally advanced rectal cancer: MR imaging for restaging after neoadjuvant radiation therapy with concomitant chemotherapy. Part II. What are the criteria to predict involved lymph nodes?

PURPOSE

To prospectively determine diagnostic performance of predictive criteria for nodal restaging after radiation therapy with concomitant chemotherapy by using ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance (MR) imaging in patients with rectal cancer.

MATERIALS AND METHODS

After institutional review board approval and informed consent were obtained, 39 patients (24 men, 15 women; mean age, 64 years) with rectal cancer underwent USPIO-enhanced two-dimensional (2D) T2-weighted fast spin-echo, three-dimensional (3D) T1-weighted gradient-echo, and 3D T2*-weighted MR for restaging. Two observers evaluated nodes for border irregularity, short- and long-axis diameters, and estimated percentage of white region (<30%, 30%-50%, or >50%) within the node (3D T2*-weighted images). Ratio of the measured surface area of the white region within the black node to the measured surface area of the total node (Ratio(A)) was calculated. Signal intensity (SI) in gluteus muscle (SI(GM)) and in total node (SI(TN)) were used to calculate SI(TN)/SI(GM) ratio. Histopathologic findings were reference standard. Receiver operating characteristic (ROC) curves were compared and interobserver agreement was determined.

RESULTS

Lesion-by-lesion analysis was feasible in 201 lymph nodes. Area under the ROC curve (AUC) of border and short- and long-axis diameters for observer 1 were 0.85, 0.87, and 0.88 and for observer 2 were 0.70, 0.89, and 0.87, respectively. AUC for estimated percentage of white region within the node, Ratio(A), and SI(TN)/SI(GM) ratio for observer 1 were 0.98, 0.99, and 0.62 and for observer 2 were 0.97, 0.98, and 0.65, respectively. AUC for USPIO-enhanced MR criteria was significantly better than AUC for conventional MR criteria (P < .01). All criteria except border irregularity and SI(TN)/SI(GM) ratio showed high interobserver agreement (kappa > 0.79).

CONCLUSION

The most reliable predictors for identifying benign nodes after radiation therapy with concomitant chemotherapy by using USPIO-enhanced MR imaging for restaging in patients with rectal cancer were estimated percentage of white region within the node and Ratio(A). Measurements on standard 2D T2-weighted fast spin-echo images versus primary staging results offer reasonably good accuracy to identify benign lymph nodes after therapy.

Locally advanced rectal cancer: MR imaging in prediction of response after preoperative chemotherapy and radiation therapy

PURPOSE

To prospectively differentiate, at magnetic resonance (MR) imaging, patients with locally advanced nonmucinous rectal cancer who will respond to long-course chemotherapy and radiation therapy (CRT) from those who will not respond, with histopathologic results as the reference standard.

MATERIALS AND METHODS

Institutional review board approval for this study was obtained, and all patients provided written informed consent. High-spatial-resolution T2-weighted MR images were acquired before and 6-8 weeks after CRT in 53 patients (33 men, 20 women; mean age, 63 years; age range, 42-79 years). Patients were categorized as responders to CRT (patients with T3 cancer that converted to T2 or a lower stage, patients with T4 cancer that converted to T3 or a lower stage) or as nonresponders (patients with stable or progressive disease). At the posttreatment MR imaging examination, a decrease in signal intensity was considered to represent a morphologic response with fibrosis. Before CRT and surgery, tumor volume was calculated at MR imaging by multiplying cross-sectional area by section thickness. Tumor length was measured at MR imaging and in the histopathologic specimen. Nodal downstaging was evaluated. The relationship between pathologic response, morphologic MR imaging response, and percentage volume reduction was evaluated with the Mann-Whitney-Wilcoxon two-sample test.

RESULTS

Morphologic response assessment with MR imaging achieved a positive predictive value (PPV) of 84.2% (32 of 38) and a negative predictive value (NPV) of 66.7% (10 of 15). Volume reduction extent (> or = 70%) was significantly different between patients in whom disease was downstaged and those in whom it was not downstaged (P = .000005) and showed additional diagnostic value, with an overall accuracy of 86.8% (46 of 53). Presurgical MR imaging and histopathologic tumor length did not show a significant difference. MR imaging accuracy for lymph node (N) stage was 86.8% (46 of 53) on the basis of morphologic criteria.

CONCLUSION

After CRT, morphologic and volumetric evaluation at MR imaging had a high PPV and a low NPV for response assessment. The detection of small clusters of residual tumor cells within fibrosis remains a problem.

SUPPLEMENTAL MATERIAL

http://radiology.rsnajnls.org/cgi/content/full/250/3/730/DC1.

A comparison between the treatment of low rectal cancer in Japan and the Netherlands, focusing on the patterns of local recurrence

PURPOSE

Differences exist between Japan and The Netherlands in the treatment of low rectal cancer. The purpose of this study is to analyze these, with focus on the patterns of local recurrence.

METHODS

In The Netherlands, 755 patients were operated by total mesorectal excision (TME) for low rectal cancer, 379 received preoperative radiotherapy (RT+TME). Applying the same selection criteria resulted in 324 patients in the Japanese (NCCH) group, who received extended surgery consisting of lateral lymph node dissection and a wider abdominoperineal excision. The majority received no (neo) adjuvant therapy. Local recurrence images were examined by a radiologist and a surgeon.

RESULTS

Five-year local recurrence rates were 6.9% for the Japanese NCCH group, 5.8% in the Dutch RT+TME group, and 12.1% in the Dutch TME group. Recurrence rate in the lateral pelvis is 2.2%, 0.8%, and 2.7% in the Japanese, RT+TME group, and TME group, respectively. The incidence of presacral recurrences was low in the NCCH group (0.6%), compared with 3.7% and 3.2% in the RT+TME and TME groups, respectively.

CONCLUSIONS

Both extended surgery and RT+TME result in good local control, as compared with TME alone. Preoperative radiotherapy can sterilize lateral extramesorectal tumor particles. A wider abdominoperineal resection probably results in less presacral local recurrence. Comparison of the results is difficult because of differences in patient groups.

Magnetic resonance imaging in locoregional staging of rectal adenocarcinoma

A comprehensive overview of the current status of magnetic resonance imaging (MRI) in the locoregional assessment and management of rectal adenocarcinoma is presented. Staging systems for rectal cancer and treatment strategies in its management are discussed to give the reader the context that shapes MRI acquisition techniques and interpretation. Findings on MRI are detailed and their accuracy reviewed based on currently available evidence. Optimization of MRI acquisition and relevant pelvic anatomy are reviewed. A detailed description of our approach in interpreting MRI for locoregional staging of rectal cancer is given and future directions are also introduced.

Ultrasound staging of rectal cancer

Endorectal ultrasound (ERUS) is a primary imaging technique in the preoperative evaluation of patients with rectal adenocarcinoma. The purpose of this report is to review ultrasound staging with emphasis on technique and potential pitfalls. The role of ultrasound in multimodality staging and surveillance is also explored. An awareness of inherent imaging challenges and implications may optimize staging accuracy and resultant management of rectal cancer patients.

Patterns of local recurrence in rectal cancer: a single-center experience

A cohort of patients operated at the National Cancer Center Hospital in Tokyo for rectal carcinoma, at or below the peritoneal reflection, was reviewed retrospectively. The purpose was to study the risk factors for local relapse and the patterns of local recurrence. Three hundred fifty-one patients operated between 1993 and 2002 for rectal carcinoma, at or below the peritoneal reflection, were analyzed. One hundred forty-five patients, with preoperatively staged T1 or T2 tumors without suspected lymph nodes, underwent total mesorectal excision (TME). Lateral lymph node dissection (LLND) was performed in suspected T3 or T4 disease, or when positive lymph nodes were seen; 73 patients received unilateral LLND and 133 patients received bilateral LLND. Of the 351 patients 6.6% developed local recurrence after 5 years. TME only resulted in 0.8% 5-year local recurrence. In lymph-node-positive patients, 33% of the unilateral LLND group had local relapse, significantly more (p = 0.04) than in the bilateral LLND group with 14% local recurrence. Local recurrence in the lateral, presacral, perineal, and anastomotic subsites was lower in the bilateral LLND group as compared with in the unilateral LLND group. We conclude that, in selected patients, surgery without LLND has a very low local recurrence rate. Bilateral LLND is more effective in reducing the chance of local recurrence than unilateral LLND. Either surgical approach, with or without LLND, requires reliable imaging during work-up.

Faecal and urinary incontinence after multimodality treatment of rectal cancer

Marilyne Lange and Cornelis van de Velde discuss the differential diagnosis and management of incontinence after rectal cancer treatment.

The diagnosis and management of rectal cancer: expert discussion and recommendations derived from the 9th World Congress on Gastrointestinal Cancer, Barcelona, 2007

Knowledge of the biology and management of rectal cancer continues to improve. A multidisciplinary approach to a patient with rectal cancer by an experienced expert team is mandatory, to assure optimal diagnosis and staging, surgery, selection of the appropriate neo-adjuvant and adjuvant strategy and chemotherapeutic management. Moreover, optimal symptom management also requires a dedicated team of health care professionals. The introduction of total mesorectal excision has been associated with a decrease in the rate of local failure after surgery. High quality surgery and the achievement of pathological measures of quality are a prerequisite to adequate locoregional control. There are now randomized data in favour of chemoradiotherapy or short course radiotherapy in the preoperative setting. Preoperative chemoradiotherapy is more beneficial and has less toxicity for patients with resectable rectal cancer than postoperative chemoradiotherapy. Furthermore chemoradiotherapy leads also to downsizing of locally advanced rectal cancer. New strategies that decrease the likelihood of distant metastases after initial treatment need be developed with high priority. Those involved in the care for patients with rectal cancer should be encouraged to participate in well-designed clinical trials, to increase the evidence-based knowledge and to make further progress. Health care workers involved in the care of rectal cancer patients should be encouraged to adopt quality control processes leading to increased expertise.

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.

[Progress in diagnostics of anorectal disorders. Part II: radiology]

Diagnostics and therapy of anorectal disorders remain a surgical question. In close cooperation between different departments (radiology and gastroenterology, urology and gynecology, dermatology and psychology), the role of radiologic imaging is of growing importance. Exact knowledge of functional anatomy and precise clinical examination constitute the basis of the according therapeutic strategies. In this context radiology has contributed decisively. Developments in imaging techniques, e.g. dynamic MRI, highly contributed to better understanding of complex functional pelvic floor disorders. The combination of nanotechnology and high-resolution imaging allows precise staging, especially in rectal cancer. Furthermore, advances in virtual colonoscopy could lead to widely acceptable and patient-friendly screening for colorectal malignancies.