Cohort Definition Name: Primary adenocarcinoma of the colon or rectum, MSI-L, MSI-indeterminate, MSS or pMMR
Contributor name: Andreas Weinberger Rosen
Contributor OrcId: 0000-0001-9990-8155
Logic Description: First event of primary adenocarcinoma of the colon or rectum, with a molecular subtype of MSI-L, MSI-indeterminate, MSS or pMMR
Recommended study application: exposure. Including patients who received a potentially curative treatment
Assertion statement: This cohort definition was executed on at least one real person-level observational health data source and resulted in a cohort with at least 1 person.
Submitted cohort definition:
Target Clinical Description
Colorectal cancer, primarily an adenocarcinoma, stands as the most prevalent malignant tumor affecting the intestinal tract. Originating in the epithelial cells that line the colon or rectum, the disease can escalate into a full-fledged malignant tumor through various molecular mechanisms. The disease manifests differently based on its anatomical location, its size, and its stage of development.
Presentation of Colorectal Cancer
Hematochezia or blood in the stool
Diarrheal episodes or constipation
Sensation of incomplete bowel evacuation
Abdominal discomfort or pain
Unintentional weight loss
Some patients may not display symptoms and are often diagnosed either via screening programs or incidental findings during other medical evaluations.
In some instances, colorectal cancer can escalate into an emergency scenario, leading to complications like bowel obstruction, acute lower gastrointestinal bleeding, or even bowel perforation.
Assessment for Colorectal Cancer
Colonoscopy for macroscopic evaluation and biopsy collection
Histopathology of the biopsy tissue serves as a cornerstone for diagnosis
Various imaging modalities such as CT, PET, and MRI for clinical staging
Histological evaluation of surgical or metastatic samples for pathological staging
Differential Diagnosis of Colorectal Cancer
Other intestinal neoplasms like neuroendocrine tumors or advanced polyps
Irritable Bowel Syndrome (IBS)
Inflammatory Bowel Disease (IBD)
Treatment Plan for Colorectal Cancer
For localized or regionally-confined cancers, surgical resection along with the affected intestinal segment remains the standard care, often supplemented by neoadjuvant or adjuvant therapies like chemotherapy or radiation.
In cases of solitary metastasis, radical surgery may be augmented by radiofrequency ablation, stereotactic radiation, or additional surgeries for metastatic lesions, aiming for curative outcomes.
For those without curative options, palliative measures, including oncological treatments and surgical interventions, are employed to improve symptoms and extend life expectancy.
Patients with specific molecular profiles, such as ‘deficient mismatch repair’ or high microsatellite instability, may benefit from treatments involving immune checkpoint inhibitors.
Prognosis for Colorectal Cancer
The prognosis hinges on multiple factors, most notably the stage at diagnosis and the treatment modality applied. Early-stage diagnosis followed by aggressive surgical intervention usually yields favorable outcomes. Conversely, a diagnosis at advanced stages or emergency presentations typically indicates a poorer prognosis.
Assignment for Peer Review:
Peer review of the phenotype would be more than welcome