Colorectal Cancer (Colon & Rectal) — Molecular Profiling & Precision Oncology Access

Colorectal cancer (CRC) refers to cancers arising from the inner lining of the colon or rectum. It is the third most commonly diagnosed cancer worldwide and the second most common cause of cancer death, with approximately 1.9 million new cases diagnosed globally each year. It is also one of the most preventable cancers — colonoscopy screening can identify and remove precancerous polyps before they become cancer, and when detected at an early stage, it is highly curable.

MSI-H stands for microsatellite instability-high, and dMMR stands for deficient mismatch repair — they refer to the same molecular finding in colorectal cancer. About 15% of CRC cases are MSI-H/dMMR. This status matters enormously because MSI-H/dMMR CRC responds exceptionally well to immune checkpoint inhibitors — specifically pembrolizumab, which is now approved as first-line treatment for MSI-H/dMMR metastatic CRC with better outcomes than standard chemotherapy. It also indicates that the patient may have Lynch syndrome (a hereditary cancer predisposition) and should receive genetic counselling. Testing for MSI/MMR status is mandatory for all metastatic CRC patients before treatment begins.

Colon cancer and rectal cancer are closely related but differ in their anatomical location, staging considerations, and treatment approach. Colon cancer arises in the colon (caecum through sigmoid colon) and is typically managed with surgical resection followed by adjuvant chemotherapy for Stage III disease. Rectal cancer arises in the rectum — the lower 15 cm of the large intestine — and locally advanced rectal cancer requires neoadjuvant treatment (chemoradiation or total neoadjuvant therapy) before surgery to reduce local recurrence. The complexity of rectal cancer surgery (total mesorectal excision, sphincter preservation decisions) also means that high-volume specialist surgical centres produce significantly better outcomes.

Molecular profiling is the foundation of treatment decision-making in metastatic colorectal cancer. Four biomarkers must be tested before any systemic therapy begins: (1) MSI/MMR status — determines pembrolizumab immunotherapy eligibility; (2) RAS mutations (KRAS/NRAS) — predicts whether anti-EGFR antibodies (cetuximab, panitumumab) will work; (3) BRAF V600E — identifies patients who need encorafenib + cetuximab combination; and (4) HER2 amplification — identifies patients for HER2-targeted therapy. Using the wrong regimen without molecular guidance will produce substantially worse outcomes and may expose patients to unnecessary toxicity.

Yes — a minority of Stage IV CRC patients can achieve long-term cure. Approximately 25–30% of patients with Stage IV CRC limited to liver or lung metastases have disease that is surgically resectable or can be converted to resectability with effective systemic therapy. Complete surgical resection of isolated liver metastases achieves 5-year survival rates of 30–40% in selected patients. This is why specialist HPB surgical review at an expert liver surgery centre is essential for all newly diagnosed Stage IV CRC patients — many patients incorrectly labelled 'unresectable' at non-specialist centres have resectable disease when reviewed by expert HPB surgeons.

Total neoadjuvant therapy (TNT) is an approach to locally advanced rectal cancer treatment where all systemic chemotherapy and radiotherapy are given before surgery, rather than saving the chemotherapy for the postoperative adjuvant setting. The two main TNT sequences are: induction FOLFOX/CAPOX followed by chemoradiation then surgery; or short-course radiotherapy followed by FOLFOX/CAPOX then surgery (RAPIDO trial approach). TNT achieves higher rates of pathological complete response (pCR) — meaning no cancer cells in the surgical specimen — compared to standard chemoradiation alone, and may enable watch-and-wait (avoiding surgery entirely) in clinical complete responders. TNT is now preferred for high-risk locally advanced rectal cancer at specialist centres.

Common symptoms of colorectal cancer include: change in bowel habit (persistent diarrhoea, constipation, or alternating pattern for more than 4 weeks); rectal bleeding (blood in or on the stool, or dark tarry stools); abdominal pain or cramping; unexplained iron-deficiency anaemia (particularly in older adults where right-sided colon cancer may bleed slowly without visible blood); feeling of incomplete bowel emptying; unexplained weight loss; and fatigue. Importantly, early colorectal cancer may cause no symptoms at all — which is why routine colonoscopy screening beginning at age 45 (or earlier for higher-risk individuals) is recommended.

Yes — colorectal cancer has some of the strongest diet and lifestyle associations of any cancer. Protective measures include: regular colonoscopy screening to detect and remove precancerous adenomas before they become cancer; a diet rich in vegetables, fruits, and fibre with limited red and processed meat; maintaining a healthy body weight; regular physical activity; limiting alcohol consumption; not smoking; and for selected high-risk individuals, aspirin chemoprevention (under physician guidance). Lynch syndrome and other hereditary CRC syndromes require specialist genetic counselling and surveillance colonoscopy at defined intervals to prevent CRC.

Yes. CancerFax provides comprehensive specialist support for colorectal cancer patients at all stages. We review pathology and molecular profiling reports (MSI/MMR, RAS, BRAF, HER2, NTRK), staging imaging, surgical reports, and treatment plans, then connect patients with specialist GI oncologists, colorectal and rectal cancer surgeons, HPB liver surgery teams, and molecular tumour boards — in India, Germany, South Korea, the UAE, and other countries with specialist colorectal cancer programmes. We assist with second opinions on resectability assessment, total neoadjuvant therapy planning, pembrolizumab and targeted therapy access, clinical trial identification, and international treatment coordination.