Diagnostic Imaging Pathways - Colorectal Cancer (Staging)
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This pathway provides guidance on imaging patients with proven colorectal cancer, indicating how imaging helps determine management.
Date reviewed: January 2012
Date of next review: 2017/2018
Published: January 2012
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The relative radiation level (RRL) of each imaging investigation is displayed in the pop up box.
| SYMBOL | RRL | EFFECTIVE DOSE RANGE |
 | None | 0 |
 | Minimal | < 1 millisieverts |
 | Low | 1-5 mSv |
 | Medium | 5-10 mSv |
 | High | >10 mSv |
Images
Image GalleryNote: These images open in a new page | ||
|---|---|---|
| 1 |  |
Rectal Carcinoma Image 1 (Computed Tomography): Thickened rectal wall with invasion of the mesorectal fascia on the right side (arrow). The mesorectal fascia on the left appears normal. |
| 2 |  |
Rectal Carcinoma Image 2 (Endorectal Ultrasound): Rectal carcinoma with infiltration into the perirectal fat (arrows) (T3 lesion). |
| 3a |  |
Colonic Carcinoma
Image 3a: Right hemicolectomy specimen showing a large ulcerated and exophytic caecal carcinoma. |
| 3b |  |
Image 3b (H&E, x2.5) and 3c (H&E, x10): Histological sections showing a moderately differentiated colorectal adenocarcinoma composed of malignant glands invading into the bowel wall (blue arrows). The glands are lined by cells showing marked nuclear atypia. Normal colonic mucosa is included for comparison (green arrow). |
| 3c |  |
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Teaching Points
Teaching Points
- The staging processes for colon cancer and rectal cancer are different
- In colon cancer, locoregional staging is often not indicated unless advanced disease is suspected. In this case, CT / ultrasound of the abdomen and chest radiogaphy may be performed if surgical or management decisions are likely to change
- In rectal cancer accurate staging pre-operatively is essential, as chemo-radiotherapy has been shown to be effective in certain groups
- Endorectal US and Pelvic MRI are complimentary investigations
col_c
Staging of Colon Cancer
- Surgery for colon cancer is not stage-dependent. The majority of patients with colon cancer will undergo surgical treatment whether with curative or palliative intent
- The purpose of preoperative imaging is to detect synchronous tumours, assess contiguous organ involvement and distant metastases. Generally this involves CT imaging of the chest, abdomen & pelvis
- Other preoperative workup includes physical examination and complete colonoscopy (or CT colonoscopy if the patient is unable to tolerate normal colonoscopy)
- A recent meta-analysis of CT imaging for colon cancer for local staging found that the sensitivity and specificity for T staging was 86% and 78% respectively and for N staging, 70% and 78% respectively. 44 CT is particularly useful for distinguishing advanced tumour invading beyond the muscularis propria (stage T3+). CT also has a high negative predictive value in clinically advanced disease 4,5,6
- CT has 70-80% sensitivity for the detection of hepatic metastases 3,4
- There is emerging evidence that CT is useful in aiding operative management and directly alters surgical management in a smaller number of cases. 8,9 Furthermore, CT has been used to prognosticate patients into “favourable” and “poor” groups, based on radiological characteristics 10
- There is no advantage of MRI over CT for local staging of tumour 2,7
- Limitations: CT is less reliable for local staging because of low sensitivity for detection of local tumour extent and lymph node metastases 4,6,7
colrect_c
Staging of Colorectal Cancer
- A careful pre-operative search for systemic metastases is rarely indicated in patients with colon cancer, as the initial management is often not altered. A CT scan of the abdomen should be considered, if there are clinical indications of a locally advanced cancer or systemic metastasis that may alter operative or management strategies 1
- Pre-operative identification of liver/lung metastases may be useful in 1
- Frail, elderly patients who may not need resection of a relatively asymptomatic primary tumour
- Patients with clinical indication of extensive local (>50%) liver metastases, as this carries a high operative morbidity and mortality
- Identifying the few selected cases, where synchronous liver resection for metastatic disease may be performed concurrently at the time of bowel resection
- Preoperative locoregional staging of patients with rectal cancer is important, both to plan surgery and to consider the possible need for adjuvant chemoradiotherapy. 1 Careful attention to staging is required, as local recurrence (and hence prognosis) is dependant on accurate staging 2
ct
Computed Tomography (CT)
- In the setting of rectal cancer staging, Computed Tomography (CT) scans of the chest & abdomen are appropriate for the detection of metastatic disease
- Despite significant advances in CT technology (multi-detectors, helical scanning), CT is still relatively poor at differentiating the layers of the rectum and identifying tumour involvement of the circumferential resection margin (compared with MRI and EUS). A meta-analysis of imaging for rectal cancer staging found that EUS and MRI had better diagnostic accuracy than CT for T & N staging. 46 The sensitivity and specificity of CT for T-staging was 72-79% and 78-96% respectively. Hence, CT is not recommended as the primary imaging for local staging
- CT has been shown to be able to identify mesorectal lymph nodes as small as 5mm. Currently, anatomical size criteria are used as a surrogate measure of lymph node metastases. This is an inaccurate method since lymph nodes may be enlarged due to benign reasons (resulting in false positives) or there may be micrometastatic deposits on normal sized lymph nodes (resulting in false negatives). 47 Nodal staging with CT has a sensitivity and specificity of 55% and 74% respectively 46
- CT can accurately stage distant metastases. Rectal cancer has a greater tendency for pulmonary spread compared to colon cancer (11.5% vs 3.5%). 48 Traditionally, chest radiography has been used to detect pulmonary metastases, but they can miss smaller nodules and nodules in shadowed areas (e.g. retro-cardiac space). In a recent prospective study, Choi et al. found that routine staging chest CT detected more lung metastases than chest radiography (9 vs 5 patients), and affected treatment in 3 of the 4 missed patients 48
dre
Digital Rectal Examination
- On the basis of fixity and presence of rectal tumour outside the rectal wall on DRE, it is possible to divide the lesion as ‘locally not extensive’ or ‘locally extensive’ 19
- This will dictate the most appropriate initial investigation in locoregional staging of rectal cancer
eus
Endorectal Ultrasound
- High accuracy (85 - 95%) in evaluation of tumour penetration and perirectal spread 20,21,35
- Staging is most accurate for T1 and T2 cancers. 22,36 This may facilitate local excision of the carcinoma, if distant metastasis are absent on the staging CT of the abdomen
- It is as accurate as MRI and MDCT in the detection of local nodal disease 23
- Limitations - it is less accurate in staging advanced tumours (especially in differentiating ‘early’ and ‘late’ T3 lesions) and is unable to visualise the mesorectal fascia. 2 It is also highly operator dependant, may not be able technically possible in high rectal cancers or a stenosing lesion and is limited by availability in some centres
mri
Magnetic Resonance Imaging (MRI)
- Pelvic MRI is used widely for the staging and treatment planning of rectal cancer 43
- MRI is superior to endorectal US for evaluation of the relationship of the tumour to the mesorectal fascia. 24,25 A meta-analysis has shown that MRI is the only modality that predicts the circumferential resection margin with good accuracy 23,37
- This is important with the surgical technique of TME, as one of the strongest predictors for local recurrence is the least distance between tumour and the circumferential resection margin. MRI can accurately predict the distance between the tumour edge and the mesorectal fascia 25,26,27,38,39 Various trials have validated pelvic MRI in being able to predict resection margin, when compared to the gold standard of histology 28,29,40,29
- One prospective trial showed that tumors of the distal sigmoid, rectosigmoid, and upper rectum can be staged accurately using high spatial resolution MRI 42
- Compared to endorectal US, MRI has a similar sensitivity for lymph node staging, but has a wider field-of-view and can therefore detect lymph nodes that are located further from the mesorectal fascia 24
- The use of MRI in post-radiotherapy patients to assess regression of tumour and nodal down staging prior to surgery, is compounded by the technical difficulty of differentiating fibrosis and tumour 31
rectal
Staging of Rectal Cancer
- Accurate local staging is very important in rectal cancer for optimal treatment. The treatment strategies range from transanal resection of superficial T1 tumours, to long-term chemoradiotherapy aimed at tumour debulking followed by extensive surgery
- Total mesenteric excision is now the gold standard curative treatment of rectal cancer. It involves careful dissection of specific embryologic avascular planes and has led to significantly reduced local recurrence rates and increased survival 43
- The presence of tumour within the circumferential resection margin (CRM) of the resected tissue is a predictor of poor prognosis and is associated with increased local recurrence and poorer survival
- Currently, MRI is the only imaging modality that can accurately predict CRM involvement. The presence of tumour 5mm or less from the mesorectal fascia is generally considered CRM positive. However, a recent trial by Taylor et al. suggests that a cut-off margin of 1mm can also accurately predicting CRM involvement. 45 Their prospective trial compared the outcomes of patients with CRMs of <1mm, 1-2mm, 2-5mm and >5mm, and found that only patients with a margin of <1mm had a significantly higher hazard ratio for local recurrence than the other groups 45
stent
Treatment
- Surgery + / - neoadjunctive chemotherapy or radiotherapy
- Chemotherapy or radiotherapy alone
- For obstructing or potentially obstructing colonic cancer
- Metallic self-expanding stents are used for 14,15,6
- Palliation in patients with inoperable disease or distant metastases or who are unfit for surgery
- Temporary relief of obstruction to allow colonic preparation and primary anastomosis
- Stents can be inserted colonoscopically, under fluoroscopic guidance or combination
- Metallic self-expanding stents are used for 14,15,6
References
References
References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document
- Clinical pactice guidelines for the prevention, early detection and management of colorectal cancer (CRC). National health and Medical Research Council Dec 2005.
- Engelen S, Beets G, Beets-Tan R. Role of preoperative local and distant staging in rectal cancer. Onkologie. 2007;30:141-5. (Review article)
- Kinkel K, Lu Y, Both M, et al. Detection of hepatic metastases from cancers of the gastrointestinal tract by using noninvasive imaging methods (US, CT, MRI imaging, PET): a meta-analysis. Radiology. 2002;224:748-56. (Level II evidence). View the reference.
- Balthazar EJ, Megibow AJ, Hulnick D, et al. Carcinoma of the colon: detection and preoperative staging by CT. AJR Am J Roentgenol. 1988;150:301-6. (Level II/III evidence). View the reference
- Cance WG, Cohen AM, Enker WE, et al. Predictive value of a negative computed tomographic scan in 100 patients with rectal carcinoma. Dis Colon Rectum. 1991;34:748-51. (Level II/III evidence). View the reference
- Freeny PC, Marks WM, Ryan JA, et al. Colorectal carcinoma evaluation with CT: preoperative staging and detection of postoperative recurrence. Radiology. 1986;158:347-53. (Level II/III evidence). View the reference
- Zerhouni EA, Rutter C, Hamilton SR, et al. CT and MR imaging in the staging of colorectal carcinoma: report of the Radiology Diagnostic Oncology Group II. Radiology. 1996;200:443-51. (Level II evidence). View the reference
- Barton J, Langdale B, Cummins J, et al. The utility of routine preoperative computed tomography scanning in the management of veterans with colon cancer. Am J Surg. 2002;183:499-503. (Level II evidence). View the reference
- Mauchley, Lynge D, Langdale L, et al. Clinical utility and cost-effectiveness of routine preoperative computed tomography scanning in patients with colon cancer. Am J Surg. 2005;189:512-17. (Level II evidence). View the reference
- Smith N, Bees N, Barbachano et al. Preoperative computed tomography staging of nonmetastatic colon cancer predicts outcome: implications for clinical trials. Br J Cancer. 2007;96:1030-6. (Level IV evidence)
- Valls C, Andia E, Sanchez A, et al. Hepatic metastases from colorectal cancer: preoperative detection and assessment of resectability with helical CT. Radiology. 2001;218:55-60. (Level II evidence). View the reference
- Valls C, Lopez E, Guma A, et al. Helical CT versus CT arterial portography in the detection of hepatic metastasis of colorectal carcinoma. AJR Am J Roentgenol. 1998;170:1341-7. (Level III evidence)
- Van Ooijen B, Oudkerk M, Schmitz PIM, et al. Detection of liver metastases from colorectal carcinoma: Is there a place for routine computed tomography arteriography? Surgery. 1996;119:511-6. (Level II evidence). View the reference
- Martinez-Santos C, Lobato RF, Fradejas JM, et al. Self expandable stent before elective surgery vs emergency surgery for the treatment of malignant colorectal obstructions: comparison of primary anastomosis and morbidity rates. Dis Colon Rectum. 2002;45:401-6. (Level II/III evidence). View the reference
- Wong KS, Cheong DMO, Wong D. Treatment of acute malignant colorectal obstruction with self-expandable metallic stents. ANZ J Surg. 2002;72:385-8. (Level III evidence)
- Vrazaz JI, Ferris S, Bau S, et al. Stenting for obstructing colorectal malignancy: an interim or definitive procedure. ANZ J Surg. 2002;72:392-6. (Level III evidence)
- Matsuoka H, Nakamura A, Masaki T, et al A prospective comparison between multidetector-row computed tomography and magnetic resonance imaging in the preoperative evaluation of rectal carcinoma. Am J Surg. 2003;185:556-9. (Level III evidence)
- Karantas A, Yarmentis S, Papanikolaou N, et al. Preoperative imaging staging of rectal cancer. Dig Dis. 2007;25:20-32. (Review article)
- Nicholls R, Galloway D, Mason A, et al. Clinical local staging of rectal cancer. Br J Surg. 1985;72:Suppl S51-2. (Level II evidence). View the reference
- Boyce GA, Sivak MV, Lavery IC, et al. Endoscopic ultrasound in the pre-operative staging of rectal carcinoma. Gastrointest Endosc. 1992;38:468-71. (Level II/III evidence). View the reference
- Nielsen MB, Qvitzau S, Pedersen JF, et al. Endosonography for preoperative staging of rectal tumours. Acta Radiologica. 1996;37:799-803. (Level II/III evidence). View the reference
- Siddiqui A, Fayiga Y, Huerta S. The role of endoscopic ultrasound in the evaluation of rectal cancer. Int Sem Surg Oncol. 2006;3:36-42. (Review article)
- Lahaye M, Engelen S, Nelemans P, et al. Imaging for predicting the risk factors. The circumferential resection margin and nodal disease of local recurrence in rectal cancer: a meta-analysis. Semin Ultrasound CT MR. 2005;26:259-68. (Level I evidence). View the reference
- Beets-Tan PGH, Beets GL. Rectal cancer: review with emphasis on MR imaging. Radiology. 2004;232:335-46. (Review article)
- Brown G, Richards CJ, Newcombe RG. Rectal carcinoma: thin-section MR imaging for staging in 28 patients. Radiology. 1999;211:215-22. (Level III evidence)
- Beets-Tan PGH, Beets GL, Vliegen RFA, et al. Accuracy of magnetic resonance imaging in prediction of tumour-free resection margin in rectal cancer surgery. Lancet. 2001;357:497-504. (Level II evidence). View the reference
- Goh V, Halligan S, Bartram CI. Local radiological staging of rectal cancer. Clin Radiol. 2004;59:215-26. (Review article)
- MERCURY Study Group. Extramural depth of tumour invasion at thin-section MR in patients with rectal cancer. Radiology. 2007;243:132-9. (Level II evidence). View the reference
- MERCURY Study Group. Diagnostic accuracy of pre-operative magnetic resonance imaging in predicting curative resection of rectal cancer: prospective observational study. BMJ. 2006;333:779-884. (Level II evidence). View the reference
- Koh DM, Brown G, Temple L, et al. Rectal cancer: mesorectal lymph nodes at MR imaging with USPIO versus histopathological findings - initial observations. Radiology. 2004;231:91-9. (Level IV evidence)
- Allen S, Padham A, Dzik-Jurasz A. Rectal carcinoma: MRI with histologic correlation before and after chemoradiation therapy. AJR Am J Roentgenol. 2007;188:442-51. (Level IV evidence)
- Matsuoka H, Nakamura A, Masaki T. Preoperative staging by multidetector-row computed tomography in patients with rectal carcinoma. Am J Surg. 2002;184;131-5. (Level III evidence)
- Sinha R, Verma R, Rajesh A, et al. Diagnostic value of multidector row CT in rectal cancer staging: comparison of multiplanar and axial images with histology. Clin Radiol. 2006;61:924-31. (Level IV evidence)
- Taylor A, Slater A, Mapstone N, et al. Staging rectal cancer: MRI compared to MDCT. Abdom Imaging. 2007;32:323-7. (Level IV evidence)
- Hsieh P S, Changchien C R, Chen J S, Tang R, Chiang J M, Yeh C Y, Wang JY. Comparing results of preoperative staging of rectal tumor using endorectal ultrasonography and histopathology. Chang Gung Med J. 2003;26(7):474-8. (Level III evidence)
- Chun HK, Choi D, Kim MJ, Lee J, Yun SH, Kim SH, et al. Preoperative staging of rectal cancer: comparison of 3-T high-field MRI and endorectal sonography. AJR Am J Roentgenol. 2006;187(6):1557-62. (Level II evidence)
- Purkayastha S, Tekki PP, Athanasiou T, Tilney HS, Darzi AW, Heriot AG. Diagnostic precision of magnetic resonance imaging for preoperative prediction of the circumferential margin involvement in patients with rectal cancer. Colorectal Dis. 2007;9(5):402-11. (Level I evidence). View the reference
- Allen S D, Padhani A R, Dzik-Jurasz A S, Glynne-Jones R. Rectal carcinoma: MRI with histologic correlation before and after chemoradiation therapy. AJR Am J Roentgenol. 2007;188(2):442-51. (Level III evidence)
- Kulkarni T, Gollins S, Maw A, Hobson P, Byrne R, Widdowson D. Magnetic resonance imaging in rectal cancer downstaged using neoadjuvant chemoradiation: accuracy of prediction of tumour stage and circumferential resection margin status. Colorectal Dis. 2008;10(5):479-89. (Level II evidence)
- Brown G, Radcliffe AG, Newcombe RG, Dallimore NS, Bourne MW, Williams GT. Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging. Br J Surg. 2003;90(3):355-64. (Level II evidence)
- Branagan G, Chave H, Fuller C, McGee S, Finnis D. Can magnetic resonance imaging predict circumferential margins and TNM stage in rectal cancer? Dis Colon Rectum. 2004;47(8):1317-22. (Level III evidence)
- Burton S, Brown G, Daniels I, Norman A, Swift I, Abulafi M, et al. MRI identified prognostic features of tumors in distal sigmoid, rectosigmoid, and upper rectum: treatment with radiotherapy and chemotherapy. Int J Radiat Oncol Biol Phys. 2006;65(2):445-51. (Level III evidence)
- Taflampas P, Christodoulakis M, de Bree E, Melissas J, Tsiftsis DDA. Preoperative decision making for rectal cancer. Am J Surg. 2010;200(3):426-32. (Review article)
- Leufkens AM, van den MA, van Leeuwen MS, Siersema PD. Diagnostic accuracy of computed tomography for colon cancer staging: a systematic review. Scand J Gastroenterol. 2011;46(7-8):887-94. (Level I evidence). View the reference
- Taylor FG, Quirke P, Heald RJ, Moran B, Blomqvist L, Swift I, et al. One millimetre is the safe cut-off for magnetic resonance imaging prediction of surgical margin status in rectal cancer. Br J Surg. 2011;98(6):872-9. (Level III evidence)
- Bipat S, Glas AS, Slors FJ, Zwinderman AH, Bossuyt PM, Stoker J. Rectal cancer: local staging and assessment of lymph node involvement with endoluminal US, CT, and MR imaging--a meta-analysis. Radiology. 2004;232(3):773-83. (Level II evidence)
- Yeung JMC, Ferris NJ, Lynch AC, Heriot AG. Preoperative staging of rectal cancer. Future Oncol. 2009;5(8):1295-306. (Review article)
- Choi DJ, Kwak JM, Kim J, Woo SU, Kim SH. Preoperative chest computerized tomography in patients with locally advanced mid or lower rectal cancer: its role in staging and impact on treatment strategy. J Surg Oncol. 2010;102(6):588-92. (Level III evidence)
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