Radiology Overview of Rectal Carcinoma.pptx

IMAGING MODALITIES IN DIAGNOSIS OF RECTAL CANCER

1. Radiology Overview of Rectal Carcinoma: Modern Imaging in Diagnosis BY DR. JURY D. SHIRA

2. Presentation Agenda Introduction to Rectal Carcinoma CRM & EMVI Tumour Staging Role of Radiology in Rectal Carcinoma Imaging Modalities and Case Discussions

3. The third most frequently diagnosed cancer globally Rectal cancer generally develops slowly and originates in the inner lining of the rectum. The rectum constitutes the final few inches of the large intestine, linking the colon to the anus. Introduction to Rectal Carcinoma The majority of rectal cancers begin as clusters of abnormal cells called adenomas, or polyps. These polyps may take between 10 and 15 years to develop into a malignant tumor in the rectum.

4. RISK FACTORS MODIFIABLE RISK FACTOR Diet & Lifestyle: High red/processed meat, low fiber , fruits & Veg. Obesity Smoking & Alcohol NON MODIFIABLE FACTORS Age > 50years Family History(Colorectal/rectal ca in family Congenital(Lynch syndrome/FAP) Inflammatory Bowel Diseases(Crohn’s disease/ulcerative colitis) Personal/past History( colorecatal polyp/other cancers)

5. SYMPTOMS

6. In radiology, rectal carcinoma is identified by its distance from the anal verge and location near pelvic structures. MRI is the preferred method for local staging, as it accurately shows the tumor's relation to nearby fascia and organs. LOCATION Rectum Segmentation for Staging Low Rectum: 0–5 cm from anal verge Mid Rectum: 5–10 cm from anal verge High Rectum: 10–15 cm from anal verge Tumors >15 cm classified as sigmoid colon cancers

7. Important MRI Landmarks for Cancer Sigmoid Take-off (STO) marks rectum's upper boundary Anorectal Junction identified by anorectal ring Anterior Peritoneal Reflection varies by gender Indicates T4a tumor invasion Mesorectal Fascia (MRF) surrounds mesorectum Tumor invasion near MRF affects prognosis Sphincter complex's muscle relation guides surgery decisions

8. LOCATION

9. TUMOUR STAGING Tumor Classification Stages Tx: Primary tumor can not be assessed T0: No evidence of primary tumor Tis: Carcinoma in situ or lamina propria invasion T1: Tumor invades submucosa T2: Tumor invades muscularis propria MRI cannot differentiate T1 and T2 lesions T3: Tumor invades beyond muscularis propria without reaching fascia T3a: Tumor extends less than 1 mm beyond muscularis propria T3b: Tumor extends 1-5 mm beyond muscularis propria T3c: Tumor extends 5-15 mm beyond muscularis propria T3d: Tumor extends more than 15 mm beyond muscularis propria T4: Tumor invades other organs or perforates peritoneum T4a: Tumor penetrates visceral peritoneum surface T4b: Tumor invades or adheres to other organs or structures

10. Regional Lymph Node Classification Nx : Regional nodes cannot be assessed N0: No metastases in regional lymph nodes N1: Metastasis in 1-3 regional lymph nodes N1a: Metastasis in 1 regional lymph node N1b: Metastasis in 2-3 regional lymph nodes N1c: Tumor deposits without regional nodal metastasis N2: Metastasis in 4 or more regional lymph nodes N2a: Metastasis in 4-6 regional lymph nodes N2b: Metastasis in 7 or more regional lymph nodes Nodes larger than 7 mm were associated with an increased risk of recurrence when treatment involved only chemoradiotherapy and rectal cancer surgery without pelvic sidewall dissection. MORPHOLOLOGY OF ABNORMAL NODES

11. Metastases (M) Classification Mx: Cannot be assessed M0: No distant metastasis M1: Distant metastasis M1a: Metastasis in one organ/site without peritoneal metastases M1b: Metastases in multiple organs M1c: Metastasis to peritoneum with or without other organs Stage groupings stage 0: Tis N0 M0 stage I: T1-2, N0 M0 stage II IIa : T3, N0, M0 IIb: T4a, N0, M0 IIc : T4b, N0, M0 stage III IIIa: T1-2, N1, M0 IIIb : T3-4, N1, M0 IIIc: T3-4b, N2, M0 stage IV: any T, any N, M1

12. CIRCUMFERENTIAL RESECTION MARGIN Drawing showing the mesorectum and rectum relationship with a rectal tumor. The mesorectal fascia acts as a natural barrier to tumor spread and also represents the circumferential resection margin (CRM). The mesorectal fascia represents the surgical excision plane in total mesorectal excision (TME). The extramural spread is measured from the level of the supposed muscularis propria (pink dashed line) to the maximal point of mesorectal involvement (pink arrow). The tumor is represented in purple

13. CRM Negative CRM Positive

14. Extramural Veinous Invasion (EMVI) In rectal cancer, EMVI (Extramural Venous Invasion) is the invasion of tumor cells into the blood vessels outside of the rectal wall. It is a critical finding that indicates a higher risk of metastasis and is associated with a poorer prognosis for patients

15. Tumour SIGNAL IN THE VESSEL IS SIMILAR TO THAT OF TUMOUR

16. Importance of Accurate Diagnosis Crucial Role of Diagnosis Accurate diagnosis helps determine disease extent and guides effective treatment decisions. Radiological Imaging Importance Radiological imaging is vital for detailed visualization aiding precise diagnosis and prognosis improvement.

17. Role of Radiology in Rectal Carcinoma

18. Objectives of Radiological Evaluation Identify Tumor Extent: Radiological evaluation helps determine the size and local extent of the tumor to guide treatment planning. Detect Nodal Involvement: Imaging identifies whether cancer has spread to nearby lymph nodes, crucial for staging and prognosis. Assess Distant Metastases: Radiological scans detect distant spread of disease to other organs, informing advanced treatment strategies. Tumor Staging via Imaging: Radiology provides critical imaging findings to accurately classify the stage of tumors. Guiding Treatment Decisions: Imaging results assist in planning surgical and non-surgical treatments for personalized care.

19. Imaging for Treatment Response and Follow-Up Assessing Tumor Regression Imaging helps evaluate how tumors shrink or respond after treatment. Detecting Recurrence Imaging techniques identify any return of cancer at early stages. Guiding Patient Care Post-treatment imaging supports ongoing management and personalized care decisions.

20. IMAGING MODALITIES

21. Endorectal Ultrasound and Other Specialized Techniques High-Resolution Imaging Endorectal ultrasound provides detailed images crucial for early detection of tumors. Enhanced Diagnostic Methods Specialized diagnostic techniques improve accuracy in complex or selected clinical cases. An endorectal ultrasound is a diagnostic technique that involves inserting a probe into the rectum to generate sonographic images of internal tissues and organs through the use of sound waves.

22. The procedure involves: Preparation: Patients might be instructed to adhere to a low-fiber diet for one day and may be required to undergo a mild enema prior to the procedure. Positioning: The patient is positioned lying on their side or back with their knees bent. Probe Insertion: A lubricated ultrasound probe is carefully introduced into the rectum. Image Generation: The probe emits sound waves, and the returning echoes create a sonographic image. Duration: The procedure is brief, usually lasting between 15 and 30 minutes.

23. Use of Endorectal Ultrasound (ERUS) CA RECTUM Utilizes to assess depth of rectal tumor invasion Carcinomas appear as hypoechoic areas disrupting layers Normal rectal wall has five alternating layers Layer 1: Hyperechoic, probe balloon to superficial mucosa Layer 2: Hypoechoic, mucosa and muscularis mucosae Layer 3: Hyperechoic, submucosa Layer 4: Hypoechoic, muscularis propria muscle layer

24. ERUS findings by TNM stage ERUS staging corresponds to the pathological TNM classification, with findings defined by the depth of disruption to the rectal wall layers Early-stage tumors T1: The hypoechoic tumor is confined to the submucosal layer (Layer 3), with the muscularis propria (outer hypoechoic layer) intact and distinct. T2: The tumor invades the muscularis propria (Layer 4), but the outer hyperechoic layer adjacent to perirectal fat remains intact. Locally advanced tumors T3: The tumor has spread through the muscular layer into the nearby perirectal fat. T4: The tumor has grown beyond the perirectal fat to invade surrounding pelvic organs like the bladder, uterus, or prostate.

25. T1

26. T4 HYPERVASCULARITY

27. Lymph node status (N-stage) ERUS detects suspicious perirectal lymph nodes but is less precise for N-staging compared to T-staging. Signs of malignancy include Size:  Larger than 5 mm in diameter. Echotexture:  Hypoechoic and nonhomogeneous. Shape:  More circular than oval. Margins:  Irregular borders. Blood flow:  Increased vascularity, visible with Doppler imaging

28. Limitations of ERUS in Ca Rectum Peritumoral inflammation causing overstaging Difficulty distinguishing deep T2 vs superficial T3 tumors Challenges with large, bulky or stenotic tumors Limited probe access to high rectal tumors Radiation-induced fibrosis confusing residual tumor detection

29. Computed Tomography (CT): Role in Detection and Staging Detection of Distant Metastases CT imaging effectively detects distant metastases, aiding in comprehensive cancer diagnosis and treatment planning. Evaluation of Regional Lymph Nodes CT helps evaluate regional lymph nodes, providing crucial information on cancer spread alongside MRI. Complementary Role to MRI CT imaging complements MRI by offering additional insights into tumor staging and metastasis detection.

30. A CT scan helps stage and evaluate rectal cancer but cannot confirm diagnosis, which requires a tumor biopsy typically done during a colonoscopy. Key Uses of CT Scans Identify tumor characteristics like focal mass or wall thickening Detect local invasion through rectal wall into surrounding tissue Assess lymph node involvement in pelvis or abdomen Find distant metastases in organs like liver and lungs Reveal tumor complications such as obstruction or perforation

31. EXAMPLES OF CASE STUDIES CASE 1 The patient presented with blood in the stools and changes in bowel habits. A rectal examination identified a growth within the rectum. Case Discussion Rectal cancer mainly occurs in older adults and is rare under 50, with a slight male bias, though this patient is female. Most rectal cancers, including this case, are adenocarcinomas, making up 98% of cases.

32. CASE 2 Abdominal pain and distention Case Discussion Obstructing rectal mass; path proven adenocarcinoma

33. CASE 3 Chronic constipation. Case Discussion Pathology confirmed rectal adenocarcinoma with nearby lymph node involvement. Colorectal cancer can occur throughout the colon, with the rectosigmoid region being the most common site (about 55%). While CT is often used for staging colorectal cancer, MRI is preferred for staging rectal cancer.

34. CASE 4

35. FOLLOW UP OF CASE 4 Follow up after 3x cycle of chemoRx Case Discussion Histopathological analysis confirmed grade II rectal adenocarcinoma with liver metastases, showing improvement following chemotherapy. The porta hepatis and portocaval lymph nodes, along with the left adrenal lesion, are likely incidental findings and not associated with the spread of rectal malignancy.

36. CASE 5 Right upper quadrant pain and deranged LFTs. Alcoholic, weight loss recently. Case Discussion This case involves a sizable primary rectal tumor accompanied by mesorectal lymph node involvement and a metastatic lesion in the right liver lobe, potentially invading the intrahepatic portal vein. It represents a textbook example for a viva examination.

37. CASE 6 Case Discussion Diverticulitis and colorectal cancer are the primary causes of colovesical fistula.

38. Limitations of CT Scans Less detail than pelvic MRI Inferior soft-tissue contrast Less accurate for early-stage tumors Weaker evaluation of tumor relationship to structures Cannot replace endoscopic procedures for biopsy

39. Magnetic Resonance Imaging (MRI): Protocol and Advantages Superior Soft Tissue Contrast MRI provides exceptional soft tissue contrast, enabling clear differentiation between normal and abnormal tissues. Accurate Tumor Assessment MRI accurately assesses tumor depth and invasion, crucial for effective local staging and treatment planning.

40. MRI is able not only to assess tumor stage but other important prognostic features such as extramural venous invasion (EMVI), tumor deposits and lymph node metastases. The key sequences are T2-weighted images parallel and perpendicular to the axis of the segment of the rectum containing the tumor Preparation for rectal MRI does not require bowel cleansing. Typically, scans are done without rectal distension to avoid inaccuracies in tumor measurement and staging. Antispasmodic drugs like hyoscine or glucagon help reduce motion artifacts. A standard protocol includes various T2-weighted sequences tailored to the tumor’s location, with diffusion-weighted imaging often added for restaging after chemoradiotherapy. Contrast is usually unnecessary except in cases of local recurrence or advanced cancer affecting nearby pelvic structures. MRI PROTOCOL

41. CHECKLIST Key Tumor Assessment Points Morphology of primary tumor : semi-annular, circumferential, ulcerating, polypoidal, villous, eroding, mucinous, signet, or unassessed Invading edge of tumor (e.g., x o'clock to y o'clock) Distance of distal edge from the anal verge Distance of distal edge from puborectalis sling Longitudinal extent of tumor Confirmation tumor is distal to sigmoid take-off (rectosigmoid junction) Location relative to peritoneal reflection with measurement or invasion status T stage: refers to tumor depth, including whether it involves the muscularis propria, extramural spread (T3), invasion of peritoneum (T4a) or other organs (T4b), distance from the mesorectal fascia, extramural venous invasion (EMVI), and presence of tumor deposits. N (locoregional) stage: It involves assessing regional lymph nodes based on size and morphology. For tumors above the dentate line, mesorectal , superior rectal, inferior mesenteric, internal iliac, and obturator nodes are considered regional, with the latter two known as lateral or pelvic sidewall nodes. Suspicious features include irregular margins, heterogeneous signals, and round shape. Evaluation includes the number of nodes, proximity to the mesorectal fascia, lateral node size, and any signs of peritoneal involvement.

42. CASE 1 Case Discussion Rectal cancer confirmed by pathology. The patient underwent radiotherapy before surgery, resulting in tumor reduction to T2 stage with clear margins.

43. CASE 2 Case Discussion MRI is preferred for local staging of rectal cancer, with T2-weighted images taken in three planes aligned parallel and perpendicular to the rectum's long axis.

44. There is extensive rectal and peritoneal cancer with multiple concerning features. The tumor spans about 12 cm, starting 5 cm from the anal verge and extending from the lower rectum to the sigmoid. It invades the muscularis propria, anterior mesorectal fascia, and peritoneal reflection, causing thickening. Multiple abnormal mesorectal and vascular nodes are present, along with evidence of EMVI. Radiological staging is T4, N2, M1, EMVI positive, with CRM involvement. CASE 3

45. MRI REPORTING FORMAT(Sample)

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