Colorectal Cancer

Colorectal cancer begins when abnormal cells in the colon or rectum grow and divide in an uncontrolled way. Because every patient’s situation is unique, our team at Illinois CancerCare focuses on early detection, accurate diagnosis, and personalized treatment plans designed to give you the best possible outcome. Many colorectal cancers start as polyps—small growths that can be found and removed before they become cancer.

Understanding the Colon & Rectum

The colon (large intestine) absorbs water and nutrients and forms stool; the rectum stores stool before it leaves the body. Most colorectal cancers are adenocarcinomas, which start in the inner lining of the colon or rectum and can grow through the wall and to nearby lymph nodes or distant organs if not treated.

Types of Colorectal Cancer

Adenocarcinoma

(most common)

Mucinous and signet‑ring

cell variants (less common subtypes of adenocarcinoma)

Neuroendocrine tumors, gastrointestinal stromal tumors (GISTs), and lymphomas

(rare in the colon/rectum)

Your pathology report will also note biomarkers (such as MMR/MSI, RAS, BRAF, HER2) that help guide therapy, especially for advanced disease.

Signs & Symptoms

Early colorectal cancer may cause no symptoms—another reason screening is so important. Possible symptoms include:

Changes in bowel habits, diarrhea or constipation that doesn’t resolve
Blood in the stool or rectal bleeding
Abdominal pain, cramping, bloating, or a feeling of incomplete emptying
Unexplained anemia, fatigue, or weight loss

These symptoms can be caused by conditions other than cancer, but they should be evaluated by your clinician.

Risk Factors

Age (risk increases after 45–50), personal/family history of colorectal cancer or polyps
Hereditary syndromes (e.g., Lynch syndrome, FAP)
Inflammatory bowel disease (ulcerative colitis or Crohn’s colitis)
Lifestyle: smoking, heavy alcohol use, physical inactivity, excess body weight, diets high in red/processed meat

Talk with your care team about your personal risk and whether you need earlier or more frequent screening.

Prevention

Many colorectal cancers are preventable:

Get screened on time (polyps can be removed before they turn into cancer).
Maintain healthy weight, stay physically active, don’t smoke, and limit alcohol; aim for a diet rich in fruits, vegetables, and whole grains while limiting red/processed meats.

Screening

For people at average risk, the American Cancer Society recommends starting regular screening at age 45 with either a sensitive stool‑based test or a visual exam (choose the test you’re most likely to complete):

Stool-based tests

FIT (fecal immunochemical test) every year
gFOBT (high‑sensitivity guaiac) every year
Multitarget stool DNA (FIT‑DNA) every 3 years

Visual exams

Colonoscopy every 10 years
CT colonography every 5 years
Flexible sigmoidoscopy every 5 years

Anyone with an abnormal non‑colonoscopy test needs a timely colonoscopy for follow‑up. People at higher risk (family history, IBD, hereditary syndromes) may need earlier and more frequent screening—ask your clinician.

Diagnosis

If screening or symptoms suggest colorectal cancer, your team may use:

(often polyp removal at the same time)

for rectal cancers) to assess local spread and plan treatment

(CBC for anemia; CEA tumor marker for monitoring)

on tumor tissue for MMR/MSI and, when indicated, RAS, BRAF, and HER2—results can change treatment choices, especially in advanced disease

Staging

Colorectal cancer is staged using TNM (Tumor, Nodes, Metastasis):

Stage I–III

Cancer limited to colon/rectum and/or regional lymph nodes

Stage IV

Cancer has spread to distant sites (e.g., liver, lungs) Staging determines whether surgery, chemotherapy, radiation (especially for rectal cancer), or combinations are used.

Your team will explain your stage and how it impacts treatment planning.

Treatment Options

Treatment is personalized based on location (colon vs rectum), stage, pathology, biomarkers, overall health, and your goals. Care is coordinated by a multidisciplinary team.

For Early Colon Cancer (Stages I–III)

Surgery (segmental colectomy with lymph node evaluation) is the main treatment.
Adjuvant chemotherapy (e.g., CAPOX/FOLFOX) may be recommended for some stage II (high‑risk features) and most stage III colon cancers.
MSI‑H/dMMR stage II cancers often do not benefit from standard adjuvant 5‑FU–based therapy.

For Localized Rectal Cancer

Neoadjuvant therapy (chemoradiation or total neoadjuvant therapy) to shrink the tumor and lower recurrence risk, followed by surgery (total mesorectal excision).
Select centers may consider a non‑operative “watch‑and‑wait” approach after a documented complete clinical response—decisions are highly individualized.

For Advanced/Metastatic Disease (Stage IV)

Systemic therapy: combinations such as FOLFOX, FOLFIRI, CAPOX; plus targeted agents based on biomarkers.
Anti‑VEGF therapy (e.g., bevacizumab) can be used with chemotherapy.
Anti‑EGFR therapy (e.g., cetuximab or panitumumab) for left‑sided, RAS/NRAS/BRAF wild‑type tumors.
BRAF V600E tumors may benefit from BRAF‑targeted combinations.
HER2‑amplified tumors may be candidates for HER2‑targeted regimens.
Immunotherapy (e.g., pembrolizumab, nivolumab ± ipilimumab) for MSI‑H/dMMR cancers.
Local therapies for limited liver or lung metastases (surgery, ablation, stereotactic radiation) may be considered in select cases.

Your Illinois CancerCare team will discuss potential benefits and side effects of each option—and whether a clinical trial might be right for you.

Prognosis

Outcomes depend on stage at diagnosis, tumor biology, response to therapy, and overall health. Across the U.S., the 5‑year relative survival for colorectal cancer is about 65% overall—but is much higher when found early (around 89–91% for localized disease) and lower when cancer has spread distantly. Your doctor will explain what your individual features mean.

Follow Up Care

After treatment, follow‑up typically includes regular clinic visits, CEA monitoring (when appropriate), surveillance colonoscopy, and periodic imaging based on your stage and treatment. Your schedule will be tailored to your diagnosis and goals.

Living With Colorectal Cancer

Illinois CancerCare offers comprehensive support, including counseling, nutrition services, rehabilitation, survivorship programs, genetic counseling (for personal or family history suggesting a hereditary syndrome), caregiver resources, and access to clinical trials—all designed to help you and your loved ones navigate treatment and recovery. ACS provides additional education, tools, and support for patients and caregivers.

Why Choose Illinois CancerCare

Experienced multidisciplinary team in medical and radiation oncology, with surgical and GI partners
Advanced diagnostics and timely, coordinated care
Access to innovative treatments and clinical trials close to home
Compassionate, patient‑centered care focused on your goals and quality of life

Sources & Patient Friendly References

All information was taken from the NCI (National Cancer Institute) and ACS (American Cancer Society).