Colorectal Cancer Imaging and Treatment PDF

C O LO R E C TA L CANCER IMAGING AND T R E AT M E N T DR TEMBA MUDARIKI  LEARNING OUTCOMES Understand the purpose of liver cell-specific contrast agent-enhanced MRI in diagnosing liver metastases in colorectal cancer post-chemotherapy. Recognize the significance of ma...

C O LO R E C TA L CANCER IMAGING AND T R E AT M E N T DR TEMBA MUDARIKI  LEARNING OUTCOMES Understand the purpose of liver cell-specific contrast agent-enhanced MRI in diagnosing liver metastases in colorectal cancer post-chemotherapy. Recognize the significance of marking the location and quadrant of rectal tumors to predict positive pathological circumferential resection margin (pCRM). Explain the role of short diameter, irregular shape, and unclear boundary in diagnosing lymph node metastasis in rectal cancer. Identify the recommended imaging modality (axial small FOV high-resolution T2WI nonfat-suppressed sequence) to evaluate the therapeutic effect of chemoradiotherapy for rectal cancer. Understand the purpose of high-resolution MRI in determining the safe surgical resection plane in colorectal cancer. Recognize the significance of the NICHE trial in demonstrating the feasibility of neoadjuvant immunotherapy for dMMR/MSI-H CRC. Understand the benefit of neoadjuvant sintilimab monotherapy in achieving higher rates of pathological complete response (pCR) in dMMR/MSI-H locally advanced rectal cancer.  LEARNING OUTCOMES Recognize the criterion for using PD-1 blockade with toripalimab with or without celecoxib in treating dMMR/MSI-H advanced CRC (RAS mutation status). Understand the role of the combination of TAS-102 and bevacizumab in prolonging overall survival in metastatic CRC. Recognize the benefit of the combination of TAS-102 plus bevacizumab in prolonging progression-free survival (PFS) according to the CSCO guideline. Determine the next recommended step (liver cell-specific contrast agent-enhanced MRI) for evaluating liver metastases in a patient with colorectal cancer post-chemotherapy. Identify the factor (distance between tumor and external sphincter) to mark for predicting the risk of positive pCRM in rectal cancer surgery according to the CSCO guideline. Identify the factor (invasion of the bladder) that may lead to the diagnosis of T4b rectal cancer during T staging. Understand the criteria (short diameter >5mm, irregular shape) for diagnosing lymph node metastasis in rectal cancer according to the CSCO guideline.  LEARNING OUTCOMES Recognize the appropriate timing (6-8 weeks after completion of neoadjuvant therapy) for imaging evaluation to assess the efficacy of neoadjuvant chemoradiotherapy in rectal cancer. Understand the recommendation to consider neoadjuvant immunotherapy for non-metastatic dMMR/MSI-H CRC based on the updated CSCO guideline. Recognize the class I recommendation for first-line palliative treatment of metastatic dMMR/MSI-H CRC (pembrolizumab) according to the CSCO guideline. Understand the recommendation for third-line palliative treatment (TAS-102 plus bevacizumab) for metastatic CRC progression after two lines of therapy. Identify the primary recommendation for second-line palliative treatment of metastatic dMMR/MSI-H CRC (pembrolizumab) according to the CSCO guideline. Understand the primary benefit of using TAS-102 plus bevacizumab in palliative treatment of metastatic CRC (prolonged overall survival) according to the CSCO guideline. OVERVIEW Introduction Imaging Techniques for Colorectal Cancer Diagnosis and Evaluation Advances in Neoadjuvant and Palliative Treatment Treatment Guidelines for Colorectal Cancer  INTRODUCTION Colorectal cancer, also known as bowel cancer Malignant tumour that develops in the colon or rectum Most common types of cancer worldwide A leading cause of cancer-related deaths Starts as a small growth known as a polyp Risk factors for CRC Age, family history, certain genetic conditions, inflammatory bowel disease, sedentary lifestyle, obesity, smoking, and a diet high in red and processed meats.  I M P O R TA N C E O F I M A G I N G T E C H N I Q U E S I N C R C D I A G N O S I S A N D T R E AT M E N T Imaging techniques play a crucial role Diagnosis, staging, and treatment evaluation of colorectal cancer Valuable information Extent of the disease, presence of metastasis, and help guide treatment decisions. Physicians to accurately assess the tumour Tumour location, size, and involvement of nearby structures Aiding in surgical planning and determining the appropriate treatment approach. Monitoring  BRIEF OVERVIEW OF CSCO GUIDELINES F O R C O L O R E C TA L C A N C E R - V E R S I O N 2 0 2 3 The CSCO (Chinese Society of Clinical Oncology) Evidence-based recommendations and expert consensus on the diagnosis, staging, and treatment of CRC. The version 2023 of the CSCO guidelines Focuses on optimizing the management of CRC Offering guidance on diagnosis, treatment strategies, and surveillance Guidelines cover a wide range of topics Imaging evaluation for CRC, neoadjuvant and palliative treatment options Surgical considerations, and follow-up recommendations.  BRIEF OVERVIEW OF CSCO GUIDELINES F O R C O L O R E C TA L C A N C E R - V E R S I O N 2 0 2 3 They aim to standardize practices Improve patient outcomes Promote the delivery of high-quality care across different healthcare settings Help clinicians make informed decisions regarding imaging techniques Treatment modalities Follow-up protocols based on the specific characteristics of the disease and individual patient factors.  I M A G I N G T E C H N I Q U E S F O R C O L O R E C TA L C A N C E R D I A G N O S I S A N D E VA L U AT I O N A. Liver Cell-Specific Contrast Agent-Enhanced MRI for Diagnosing Liver Metastases Post-Chemotherapy Assessment Liver metastases are common in colorectal cancer patients Accurate detection and assessment of their response to chemotherapy –crucial Liver cell-specific contrast agent-enhanced MRI Gadoxetic acid-enhanced MRI – Recommended for post-chemotherapy Allows for the identification and characterization of liver metastases Enhances the contrast between tumour cells and normal liver tissue. Provides detailed information- Number, size, location, and viability of liver metastases  PURPOSE AND BENEFITS OF MRI IN LIVER M E TA S TA S E S D E T E C T I O N MRI offers several advantages Excellent soft tissue contrast - better visualization and characterization of lesions. Liver cell-specific contrast agents -enhance the detection and characterization of liver metastases Selectively accumulating in functioning hepatocytes Highlighting the contrast between normal liver tissue and metastatic lesions. MRI can accurately detect small liver metastases Early diagnosis and intervention MRI can help differentiate between benign liver lesions and metastases  M A R K I N G T H E L O C AT I O N A N D Q U A D R A N T O F R E C TA L T U M O U R S Predicting Positive Pathological Circumferential Resection Margin (pCRM) The circumferential resection margin (CRM) refers  The radial margin of normal tissue around the tumour in rectal cancer surgery. A positive CRM (pCRM) indicates the presence of tumour cells  At the resection margin  Associated with an increased risk of local recurrence. Accurate preoperative marking of the location and quadrant of rectal tumours  Essential for predicting pCRM status. Imaging techniques, such as MRI  Can precisely localize the tumour and provide information about its relationship to adjacent structures  Allowing surgeons to plan the appropriate surgical approach and achieve negative CRM  S I G N I F I C A N C E A N D I M P L I C AT I O N S F O R SURGICAL PLANNING The pCRM status is a critical factor  Determining the extent of surgery and the need for adjuvant therapy in rectal cancer A positive pCRM is associated with a higher risk of local recurrence and poorer prognosis Imaging techniques aid in predicting pCRM involvement  Help surgeons plan the optimal surgery  Such as total mesorectal excision (TME) -to achieve negative margins. Achieving negative CRM is crucial for reducing local recurrence rates  Improving patient outcomes, and guiding subsequent treatment decisions  D I A G N O S I N G LY M P H N O D E M E TA S TA S I S I N R E C TA L C A N C E R Factors: Short Diameter, Irregular Shape, and Unclear Boundary Lymph node metastasis is an important prognostic factor Significantly impacts treatment decisions Imaging plays a crucial role in diagnosing lymph node metastasis  Evaluating various factors, including short diameter, irregular shape, and unclear boundary of lymph nodes.  Raise suspicion for metastatic involvement Enlarged lymph nodes with a short diameter greater than 5mm Irregular shape, or an unclear boundary on imaging studies, such as MRI or CT These factors help differentiate between benign and malignant lymph nodes  Assisting in treatment planning and determining the need for neoadjuvant therapy or surgical intervention  R O L E O F I M A G I N G I N LY M P H N O D E M E TA S TA S I S A S S E S S M E N T Accurate assessment of lymph node metastasis Essential for determining the stage and prognosis of rectal cancer Imaging techniques, particularly MRI with high-resolution and multiplanar capabilities Allow for detailed evaluation of the regional lymph nodes. Identifying suspicious lymph nodes based on size, shape, and boundary characteristics Helps guide decisions regarding neoadjuvant therapy and surgical management. Allows for a more personalized approach Identifying patients who may benefit from preoperative treatment to downstage the disease and improve surgical outcomes  R E C O M M E N D E D I M A G I N G M O DA L I T Y F O R E VA LUAT I N G THERAPEUTIC EFFECT OF CHEMORADIOTHERAPY Axial Small FOV High-Resolution T2WI Non-fat-Suppressed Sequence Evaluation of the therapeutic effect of neoadjuvant chemoradiotherapy is crucial  Crucial for determining the subsequent treatment plan in rectal cancer patients. MRI is the recommended imaging modality for assessing the response to chemoradiotherapy.  Specifically, the axial small field-of-view (FOV), high-resolution T2-weighted imaging (T2WI) non-fat-suppressed sequence is preferred  Provides detailed information about the tumour and surrounding tissues  Allowing for accurate assessment of treatment response, including tumour regression, fibrosis, and residual disease. Helps determine the need for additional therapy, such as surgery or further neoadjuvant treatment adjustments  I M P O R TA N C E O F E VA L U AT I N G T R E AT M E N T RESPONSE Evaluating the therapeutic effect of chemoradiotherapy is crucial for tailoring subsequent treatment strategies in rectal cancer patients. Determine the need for surgical intervention, the extent of surgical resection, and the potential for organ preservation Accurately assessing treatment response Imaging techniques assist in identifying patients who may benefit from a watch-and-wait approach, where surgery is deferred in favour of close surveillance Suitable for patients who achieve a complete or near-complete response to neoadjuvant therapy Sparing them from the potential morbidity associated with surgery. Patients with inadequate treatment response may require additional therapy Adjustments to the treatment plan to optimize outcomes  HIGH-RESOLUTION MRI FOR DETERMINING SAFE SURGICAL RESECTION PLANE Purpose and Role in Colorectal Cancer Treatment Determining the safe surgical resection plane in colorectal cancer Detailed anatomical information about the tumour, its relationship with adjacent structures, and the extent of local invasion  BENEFITS AND SURGICAL PLANNING C O N S I D E R AT I O N S Accurate tumour staging Identifying the depth of tumour invasion Involvement of adjacent structures Potential lymph node metastasis Determines the appropriate surgical approach TME or partial colectomy, and guides decisions regarding the extent of resection and the need for lymphadenectomy.  A D VA N C E S I N N E O A D J U VA N T A N D PA L L I AT I V E T R E AT M E N T NICHE Trial and Feasibility of Neoadjuvant Immunotherapy for dMMR/MSI-H CRC Significance of the Trial Explores the feasibility and efficacy of neoadjuvant immunotherapy in patients with deficient mismatch repair (dMMR) Microsatellite instability-high (MSI-H) colorectal cancer (CRC). Investigates the use of immune checkpoint inhibitors, specifically PD-1 inhibitors Aims to assess the response rates, pathological complete response (pCR) rates, and safety profile of neoadjuvant immunotherapy in this patient population.  I M P L I C AT I O N S F O R T R E AT M E N T A P P R O A C H NICHE trial will have important implications for the treatment approach in dMMR/MSI-H CRC If neoadjuvant immunotherapy demonstrates favourable response rates and pCR rates Neoadjuvant immunotherapy has the potential to downstage tumors Achieving complete Tumour eradication, and improve long-term outcomes Successful outcomes from the NICHE trial Pave the way for incorporating neoadjuvant immunotherapy into standard treatment protocols for dMMR/MSI-H CRC.  Neoadjuvant Sintilimab Monotherapy for dMMR/MSI-H Locally Advanced Rectal Cancer Achieving Higher Rates of Pathological Complete Response (pCR) Neoadjuvant sintilimab monotherapy, a PD-1 inhibitor, has shown promise Potential Benefits and Treatment Outcomes Patients with dMMR/MSI-H locally advanced rectal cancer Potential to improve patient outcomes by reducing the need for radical surgery, preserving sphincter function, and enhancing quality of life.  P D - 1 B L O C K A D E W I T H TO R I PA L I M A B W I T H O R W I T H O U T C E L E C O X I B I N T R E AT I N G D M M R / M S I - H A DVA N C E D C RC RAS Mutation Status as a Criterion  Important to consider the RAS mutation status (KRAS and NRAS) when selecting patients for this treatment approach  RAS mutation status is a predictive biomarker that helps identify patients who are more likely to benefit from anti-EGFR therapies  In patients with RAS wild-type tumours, the addition of anti-EGFR therapy to PD-1 blockade may further improve treatment outcomes. Treatment Considerations and Efficacy  Combination of PD-1 blockade with toripalimab and celecoxib in the treatment of dMMR/MSI-H advanced CRC  High response rates, prolonged progression-free survival (PFS), and improved overall survival (OS).  Celecoxib, a COX-2 inhibitor, may enhance the immune response and augment the efficacy of PD-1 blockade  TA S - 1 0 2 A N D B E VA C I Z U M A B C O M B I N AT I O N I N M E TA S TAT I C C R C Prolonging Overall Survival Combination of TAS-102, a cytotoxic agent, and bevacizumab TAS-102 is a nucleoside analog that inhibits DNA replication Bevacizumab targets vascular endothelial growth factor (VEGF) to inhibit tumour angiogenesis Benefits and Treatment Recommendations TAS-102 and bevacizumab combination offers several benefits Improves overall survival, delay disease progression, and increase the objective response rate(ORR). Addition of bevacizumab to TAS-102 provides enhanced anti-tumour activity TAS-102 and bevacizumab combination can be considered as a treatment option for patients with metastatic CRC  T R E AT M E N T G U I D E L I N E S F O R C O L O R E C TA L CANCER Imaging Evaluation for Liver Metastases Post-Chemotherapy Next Recommended Step: Liver Cell-Specific Contrast Agent-Enhanced MRI Importance of Assessing Treatment Response Factors for Predicting Positive Pathological Circumferential Resection Margin (pCRM) Distance Between Tumour and External Sphincter Implications for Surgical Planning and Outcomes Predicting a positive pCRM based on the distance between the tumor and the external sphincter helps guide surgical planning for rectal cancer If the risk of a positive pCRM is high -total mesorectal excision (TME) or even abdominoperineal resection (APR) to ensure complete tumor removal.  T S TA G I N G A N D D I A G N O S I S O F T 4 B R E C TA L CANCER Invasion of the Bladder as a Diagnostic Factor  Invasion of the bladder is an important diagnostic factor for T4b staging in rectal cancer  T4b stage indicates direct invasion of adjacent organs  Bladder involvement suggests the tumour has extended beyond the rectal wall Importance of Accurate Staging Accurate staging helps guide treatment decisions and allows for appropriate patient counselling Criteria for Diagnosing Lymph Node Metastasis in Rectal Cancer Short Diameter > 5mm and Irregular Shape -indicative of metastatic involvement Implications for Treatment Decision-Making -helps guide treatment selection and improves prognostic assessment  T I M I N G F O R I M A G I N G E VA L U AT I O N O F N EOA DJ U VA N T C H E M O R A D I OT H E R A PY E F F I C AC Y Recommended Timing: 6-8 Weeks After Completion of Neoadjuvant Therapy Timeframe allows for an adequate assessment of treatment response and tumour regression Imaging modalities such as MRI or CT scans can be used to evaluate tumour size, depth of invasion, lymph node involvement, and potential residual disease. Assessing Treatment Response and Adjustments Imaging assessment at the recommended timing –good response and candidates suitable for surgery Evaluating the efficacy of neoadjuvant chemoradiotherapy -determining the subsequent treatment plan  N EOA DJ U VA N T I M M U N OT H E R A PY FO R N O N - M E TA S TAT I C D M M R / M S I - H C R C Updated Recommendations and Considerations Potential Benefits and Treatment Outcomes -Neoadjuvant immunotherapy Palliative Treatment Guidelines for Metastatic CRC  First-Line Treatment: Pembrolizumab for dMMR/MSI-H CRC o In the palliative treatment of metastatic colorectal cancer (CRC) with deficient mismatch repair (dMMR) o Microsatellite instability-high (MSI-H) status Second-Line Treatment: TAS-102 plus Bevacizumab  Combination of TAS-102 (trifluridine/tipiracil) and bevacizumab has demonstrated efficacy Third-Line Treatment: Palliative Options After Progression  Include regorafenib, cetuximab or panitumumab (for RAS wild-type tumors), or chemotherapy agents such as irinotecan or fluoropyrimidines  SUMMARY Liver cell-specific contrast agent-enhanced MRI is recommended for imaging evaluation of liver metastases post-chemotherapy Distance between the tumour and external sphincter can predict a positive pathological circumferential resection margin (pCRM) Invasion of the bladder is a diagnostic factor for T4b staging in rectal cancer Criteria for diagnosing lymph node metastasis in rectal cancer include a short diameter > 5mm & irregular shape Timing for imaging evaluation of neoadjuvant chemoradiotherapy efficacy is recommended at 6-8 weeks after treatment completion Neoadjuvant immunotherapy for non-metastatic dMMR/MSI-H CRC is an area of ongoing research Palliative treatment options for metastatic CRC include pembrolizumab as a first-line treatment for dMMR/MSI- H CRC and TAS-102 plus bevacizumab as a second-line treatment