From the Guidelines
Rectal adenocarcinoma staging involves a combination of physical examination, imaging studies, and pathological assessment, with the most recent and highest quality study recommending a comprehensive approach including digital rectal examination (DRE), colonoscopy with biopsy, pelvic MRI for local staging, CT scan of chest, abdomen, and pelvis for distant metastasis evaluation, and carcinoembryonic antigen (CEA) blood test 1. The recommended approach is:
- Digital rectal examination (DRE) to assess tumor location and fixation
- Colonoscopy with biopsy to visualize the tumor and obtain tissue for pathological diagnosis
- Pelvic MRI for local staging to determine the depth of tumor invasion (T stage) and lymph node involvement (N stage) 1
- CT scan of chest, abdomen, and pelvis for distant metastasis evaluation (M stage)
- Carcinoembryonic antigen (CEA) blood test to provide a baseline for monitoring treatment response and recurrence This comprehensive approach allows for accurate TNM staging, which is essential for determining the appropriate treatment strategy, whether it be surgery, neoadjuvant chemoradiation, or palliative care 1. Proper staging also helps predict prognosis and guides follow-up protocols. The staging process should be completed within 2-3 weeks of initial presentation to avoid treatment delays. Multidisciplinary team involvement, including colorectal surgeons, radiologists, and oncologists, is crucial for optimal staging and treatment planning 1. It is also important to note that the choice of treatment according to risk category for primary rectal cancer without distant metastases should be based on the latest guidelines, which recommend preoperative chemoradiotherapy (CRT) for patients with T3,N0 disease and total neoadjuvant therapy (TNT) for locally advanced rectal cancer 1.
From the Research
Staging of Rectal Adenocarcinoma
The staging of rectal adenocarcinoma is a crucial process that determines the treatment approach and prognosis for patients. The following are key points related to the staging of rectal adenocarcinoma:
- Rectal MRI is an integral part of the multidisciplinary treatment of rectal adenocarcinoma, used to establish TNM stage and assess for prognostic factors such as circumferential resection margin status and presence of extramural vascular invasion 2.
- The TNM staging system is used to classify rectal adenocarcinoma, with MRI playing a key role in pre- and posttreatment evaluation, assisting the multidisciplinary team in tailoring the most appropriate treatment option 3.
- MRI accurately identifies important risk factors of local recurrence and distant metastasis, thus facilitating enhanced preoperative prognostic stratification and treatment 4.
- The benefits achieved with rectal MRI are strictly dependent on obtaining good-quality images, which is important for the characterization of the main anatomic structures and their relationship with the tumor 3.
Key Features in Staging
The following are key features that are assessed during the staging of rectal adenocarcinoma:
- Tumor location and morphology
- T and N categories
- Presence of extramural vascular invasion
- Relationship with surrounding structures, including the sphincter complex and involvement of the mesorectal fascia 3
- Status of the circumferential resection margin (CRM), extramural vascular invasion (EMVI), and tumor deposits (TD) 5
Role of MRI in Staging and Restaging
MRI plays a crucial role in both staging and restaging of rectal adenocarcinoma, with the following benefits:
- Helps in the assessment of treatment response, especially with the emergence of nonsurgical approaches such as "watch and wait" 2, 3
- Contributes to identifying "high" and "low" risk features that can be used to tailor and personalize patient treatment 5
- Plays a role in surgical planning, especially when the tumor is located in the low rectum, or in cases of locally advanced or recurrent tumors invading adjacent pelvic organs 5