Rectal Cancer - Diagnosis and Treatment

Diagnosis

Examining the Colon and Rectum with a Camera

Doctors often use a colonoscopy to check for rectal cancer. They look at the inside of the colon and rectum using a thin, bendable tube with a tiny camera and light at the end, called a colonoscope.

During the test, patients usually receive medicine to help them relax and not feel pain.

The colonoscope shows the lining of the colon and rectum on a screen. Doctors look for anything strange, such as polyps, adenomas, or signs that could point to cancer.

Colonoscopy serves as one of the main screening tests for colorectal cancer and helps catch the disease early. It also gives doctors a way to remove small growths, like polyps, before they turn into cancer.

Other Screening and Exam Methods:

Flexible Sigmoidoscopy: Similar to a colonoscopy, but looks at only part of the colon.
Stool Tests: These include the fecal occult blood test and fecal immunochemical test, which check for hidden blood in the stool. Blood in the stool can be a sign of cancer or large polyps.
Physical Exam: A digital rectal exam is when the doctor uses a gloved finger to feel for lumps or other changes in the rectum.

Taking a Sample of Tissue for Testing

If doctors find something unusual during a colonoscopy or physical exam, they often perform a biopsy. They remove a small piece of tissue from the suspicious area so a lab can examine it under a microscope.

During the colonoscopy, the doctor uses special tiny tools passed through the colonoscope to take the tissue sample.

Pathologists examine this tissue and look for cancer cells or abnormal growths. The results confirm if cancer is present, what type it is, and how it might behave.

Other special lab tests may be performed on the sample:

Genetic and Molecular Tests: These tests look for changes in the cancer cells, like microsatellite instability (MSI) and specific gene mutations. These details help doctors make a treatment plan.
Tumor Marker Testing: The sample may be checked for markers such as carcinoembryonic antigen (CEA), which can sometimes be found at higher levels in people with colorectal cancer.

Checking if Cancer Has Spread Beyond the Rectum

Once doctors diagnose rectal cancer, they need to see if it has spread, a process called staging. The stage helps guide treatment decisions.

Doctors use a mix of blood tests and imaging tests for this:

Test	What It Checks For
Complete blood count (CBC)	Counts red/white blood cells and platelets; may show anemia or infection.
Organ function tests (Chemistry panel)	Measures chemicals in the blood to check how the liver and kidneys are working.
Carcinoembryonic antigen (CEA)	Measures tumor marker levels; higher amounts can mean more cancer activity.
CT scan (chest, abdomen, pelvis)	X-ray images to look for cancer in the lungs, liver, and other organs.
MRI of the pelvis	Detailed images of nearby tissues and lymph nodes.

Staging shows how far cancer has gone, from stage 0 (early and only in the lining) to stage 4 (spread to other parts of the body, like the liver).

Treatment

Operations to Remove the Cancer

Doctors often start treatment with surgery to physically remove rectal cancer from the body. The choice of operation depends on the size, location, and stage of the cancer:

Local removal with a scope. For cancers that are very small and limited to the inside of the rectum, doctors use a procedure called transanal local excision. This uses a special scope and tools inserted through the anus to cut out the tumor and some healthy tissue around it.
Taking out a part or all of the rectum. Larger cancers or those in a certain position may require more tissue to be removed. Surgeons perform a low anterior resection to remove the cancerous part of the rectum and some nearby lymph nodes, then reconnect the colon to the remaining rectum or anus. Sometimes, the whole rectum is taken out and the colon is attached to the anus.
Full rectal and anal removal with colostomy. For cancers close to the anus that can’t be removed without harming muscle control, surgeons perform an abdominoperineal resection (APR). This procedure removes the rectum, anus, and part of the colon, so waste exits through a new opening (colostomy) in the abdomen, collected in a bag.

Other surgical methods include:

Polypectomy: For very small, early cancers that appear as polyps, doctors can sometimes remove these during colonoscopy.
Local Excision: Doctors may recommend this for cancers that have not spread to lymph nodes.

Below is a summary table of common rectal cancer surgeries:

Name of Procedure	What It Removes	When It’s Used
Transanal local excision	Small, shallow cancers	Early, small, local cancers
Polypectomy	Small polyps	Early, polyp-type cancers
Low anterior resection	Part of rectum, nearby tissue, lymph nodes	Larger or higher-up rectal cancers
Coloanal anastomosis	Whole rectum, but connects colon to anus	Entire rectum needs removal
Abdominoperineal resection	Rectum, anus, part of colon; colostomy	Low rectal cancers near the anus

Many patients heal quickly and regain bowel function after surgery, but some may need a stoma (colostomy), temporary or permanent, depending on the operation and recovery.

Medicine to Destroy Cancer Cells

Doctors use chemotherapy to kill cancer cells or stop them from growing. They most commonly give it as a pill or through a vein (IV).

Doctors may use chemotherapy in several ways:

Before Surgery: To shrink the tumor, making it easier to remove surgically (neoadjuvant chemotherapy).
After Surgery: To kill any cancer cells left behind (adjuvant chemotherapy).
For Advanced Cancer: To slow cancer that has spread beyond the rectum or to ease symptoms.

Some commonly used treatments for rectal cancer include chemotherapy agents that interfere with cancer cell growth. These drugs may be used alone or in combination with other therapies.

Chemotherapy can cause side effects, such as tiredness, low blood counts, or nausea, but many people manage them with help from their care team.

High-Energy Beam Therapy

Doctors use radiation therapy to treat cancer by aiming high-energy beams, such as X-rays or protons, at the tumor to damage or destroy cancer cells.

For rectal cancer, external beam therapy is the most common form. The patient lies on a table while a machine targets the beams to specific parts of the pelvis where the tumor is located.

Doctors may use radiation:

Before Surgery: To shrink the tumor and make it easier to remove.
After Surgery: To kill remaining cancer cells.
Instead of Surgery: If surgery isn’t possible or the patient is not healthy enough for surgery.
To Control Symptoms: Such as pain or bleeding, in advanced cancer.

Side effects may include skin irritation, tiredness, or changes in bowel habits, but these are usually temporary.

Combining Chemotherapy and Radiation

When doctors give chemotherapy and radiation therapy together, they call this chemoradiation. This approach can be more effective at shrinking tumors or preventing their return than either treatment alone.

Doctors often use combined chemoradiation before surgery to reduce cancer size or as the main treatment if surgery is not an option.

While this combination increases the success of treatment, it can also cause more side effects such as bowel problems, skin reactions, and increased fatigue.

Chemoradiation Can Help:

Shrink tumors for easier surgical removal
Kill remaining cancer after surgery
Control symptoms when surgery isn’t possible

Drugs That Target Cancer Cells

Doctors use targeted therapies—medicines that focus on specific molecules or pathways that cancer cells use to grow and survive. These treatments differ from traditional chemotherapy because they attack cancer more precisely.

Some targeted therapies stop the signals that help tumors grow or cause cancer cells to die. Not every rectal cancer patient will benefit from these drugs. Doctors may do lab tests on cancer cells to see if a patient’s tumor is likely to respond.

In rectal cancer, doctors often use targeted therapies for:

Advanced cancers that can’t be removed with surgery
Cancers that have come back after treatment
Cancers with specific DNA changes

Common side effects may include skin problems, high blood pressure, or diarrhea, but most can be managed by the healthcare team. Doctors sometimes combine these medicines with chemotherapy.

Helping the Immune System Fight Cancer

Immunotherapy helps the immune system find and attack cancer cells. Normally, the immune system might not notice all cancer cells, as they can hide or put up barriers.

Doctors use special medicines in immunotherapy to change these signals and make immune cells attack the cancer. Immunotherapy is mainly used for rectal cancers with certain genetic features that make them more likely to respond.

Used in advanced cancers or those with special DNA test results.
Sometimes given before or after surgery.
Works for only a small number of patients, so testing is important.

Side effects can include tiredness, skin changes, or problems with organs like the lungs or liver, but most people can continue treatment with proper monitoring.

Symptom Relief and Comfort Care

Palliative care focuses on making people with rectal cancer feel better, even while they receive treatment for their cancer. This type of care helps control pain, manage symptoms, and provide emotional and practical support.

Palliative care teams work together with doctors, nurses, and families to support the patient’s needs. They may suggest medicines to reduce pain, treatments to control other symptoms, or services to help with difficult emotions.

People can get palliative care at the same time as other treatments like surgery, chemotherapy, or radiation therapy. This approach helps patients keep up their quality of life and may help them feel better during all stages of care.

Benefits of palliative care:

Less pain and discomfort
Better support for family and caregivers
More information and help making decisions

By working with a palliative care team, people with rectal cancer often have an easier time coping with treatment and its effects.

Coping and Support

Gather Information to Make Care Choices

Understanding rectal cancer can make it easier to face decisions. People should ask their medical team questions about test results, possible side effects, treatment steps, and how each option might affect daily life, including regular exercise and fertility.

Making informed choices often feels more manageable with accurate information. Some find it helpful to write down questions in advance or keep a care journal.

Tip:

What to Ask	Why It’s Helpful
Treatment Options	Helps compare benefits and risks.
Side Effects	Prepares for managing daily routines.
Impact on Fertility	For those who want children later.

Stay Connected with Loved Ones

Strong relationships offer both emotional comfort and practical help. Friends and family may assist with tasks at home or support appointments, especially during treatment or when side effects are challenging.

Staying socially active, such as joining family dinners or short walks, can help maintain a sense of normalcy.

Let people know what you need.
Share your thoughts openly.
Accept help when it’s offered.

Seek Emotional and Social Support

It is important to have someone to talk to about fears, hopes, and day-to-day worries. This can be a trusted friend, a family member, or a counselor.

Cancer support groups also provide a safe space to connect with others facing similar experiences.

Getting Ready for Your Medical Visit

Steps You Can Take Before Your Appointment

Taking time to prepare for a medical visit can help make the appointment more useful and less stressful. Here are some actions to consider:

Check for instructions. Call ahead or read appointment materials to find out if you need to follow any special steps, such as fasting or a restricted diet.
Make a note of all symptoms. Write down any symptoms, even if they seem minor or not directly linked to rectal cancer. Include changes in bowel habits, abdominal pain, or unexplained weight loss.
Record personal and family health history. Note any major life changes, recent stresses, or previous illnesses. Bring information about risk factors such as obesity, long-term bowel diseases (like Crohn disease or ulcerative colitis), or any past diagnosis of familial adenomatous polyposis or Lynch syndrome. Also, include any family history of colorectal cancer or hereditary nonpolyposis colorectal cancer.
List all medications. Write down prescription drugs, over-the-counter medicine, vitamins, and supplements, along with their dosages.
Bring someone with you. Invite a friend or family member to help you remember information and provide support.

Sample Table: Risk Factor Checklist

Risk Factor	Check if applies (✓)
Family history of colorectal cancer
Lynch syndrome or hereditary nonpolyposis colorectal cancer
Familial adenomatous polyposis
Obesity
Crohn disease or ulcerative colitis
Changes in bowel habits
Personal history of polyps or rectal cancer
High-fat, low-fiber diet

Prepare a set of questions: Make a list of questions for the healthcare team, ranking them by importance. Consider topics like the cancer’s exact location, stage, possible need for biomarker tests, treatment options, side effects, and follow-up plans. If you are concerned about inherited risks (such as Lynch syndrome), ask about genetic counseling.

Example questions to discuss:

What area does the cancer affect?
Has it spread elsewhere?
What are the treatment choices and their chances of success?
What are the risks or side effects?
Will treatment change my daily life?
Should I see a cancer specialist?

What the Doctor May Want to Know

During the visit, the doctor will likely ask for specific details. Being ready can help share information quickly and accurately.

Description of Symptoms: When did they start? Are they ongoing or do they come and go? How strong are they?
Effect of Changes: Do activities, foods, or medicines make symptoms better or worse?
Health Background: The doctor may ask about past illnesses, past colonoscopies, polyps, or any genetic conditions like Lynch syndrome or familial adenomatous polyposis.
Family Medical History: The doctor may ask if relatives have had colorectal cancer or related conditions.
Lifestyle: The doctor may ask about diet, physical activity, and history of obesity, as these can affect risk.
Medications: The provider wants to know about all medications you take, as some drugs may impact treatment plans.

Having these details close at hand, possibly written in a notebook or on a phone, helps use time efficiently and lowers stress.

Rectal Cancer – Diagnosis and Treatment