Rectal Cancer

Rectal cancer makes up around 3.7% of all global cancers and it is the 8th most commonly diagnosed cancer worldwide, with approximately 730,000 new cases per year. Rectal cancer is more common in men than women globally, with males consistently showing higher incidence and mortality rates, especially in patients age 40 or older. Rectal cancer is often preventable through screening, and when caught in its earliest stages there is a good chance of survival.

A concerning and accelerating trend is emerging globally among younger adults. People born in 1990 are four times as likely to develop rectal cancer as those born in 1950. By 2030, rectal cancer is projected to account for 23% of all colorectal cancer cases in adults younger than 50 worldwide. A major Swiss study analyzing nearly 100,000 cases over four decades found that the rise in early-onset colorectal cancer specifically concerns rectal cancers in both men and women, and right-sided colon cancers in young women in particular. Nearly 28% of patients under 50 already had metastatic disease at the time of diagnosis, compared with about 20% of older patients.

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What is rectal cancer?

The rectum is at the end of the large intestine, connected to the colon and the anus. The rectum  can expand to store the poop that gets formed as food and drink move through the colon. It’s about 5-6 inches long.

Rectal cancer forms in the cells lining the rectum and grows outward as it spreads.

While many people group them together, colon cancer and rectal cancer are technically two distinct cancers. Additionally, rectal cancer is not the same thing as anal cancer. Rectal cancers need unique treatment plans.

Types of rectal cancer

Most rectal cancers are adenocarcinomas. These are cancers that begin in glands that line internal organs and make mucus and other fluids. 

Adenocarcinomas

Most adenocarcinomas in the rectum grow from adenomatous polyps (adenomas). Screening for colorectal cancer through a colonoscopy is one way to identify and remove these polyps before they become cancer. Several new technologies—like non-invasive screening tests using stool and blood—are also able to identify if someone has adenomas.

If adenomas are caught and removed, in a pre-cancerous phase or in the earliest stages of becoming cancerous, the disease is very treatable and survival rates are high.

Rare types of rectal cancer

A few other very rare types of rectal cancer include carcinoid tumors (neuroendocrine), gastrointestinal stromal tumors (GISTs), non-Hodgkin lymphoma, leiomyosarcoma, squamous cell carcinoma, and melanomas. 

Staging rectal cancer

If you have rectal cancer, you need to know your stage. This helps you understand the size of your tumor, where the cancer is now, and the best treatment plan for your unique situation. 

Rectal cancer is staged on a scale from 0-4 (many researchers use roman numerals 0-IV) using the TNM staging system. In general:

• Stage 0 (carcinoma in situ): Abnormal cells are in the inner layer of the rectum.
• Stage 1: Cancer is in the submucosa and possibly the muscle layer of the rectum.
• Stage 2: Cancer has spread past the muscle layer of the rectum but not to lymph nodes.
• Stage 3: Cancer is in at least 1 lymph node.
• Stage 4 (also called “metastatic”): The cancer has spread to distant organs like the liver or lungs. It may also be in lymph nodes. 

What causes rectal cancer?

Risk factors put you at a higher risk of getting cancer. Some risk factors can be controlled with lifestyle changes, and others cannot. Older age, smoking, and obesity increase your risk of many cancers.

Just because you have a risk factor, that doesn’t mean you will get cancer. 

These are scenarios researchers have found that can increase your risk:

• Rectal polyps
• Family history of colorectal or other cancers like endometrial, ovarian, stomach, urinary tract, brain, and pancreatic 
• Personal history of colorectal cancer
• Certain genetic syndromes like familial adenomatous polyposis (FAP) and Lynch syndrome
• Inflammatory bowel disease (IBD): Crohn’s and ulcerative colitis

Preventing rectal cancer

Getting screened for rectal cancer is the No. 1 way to reduce your risk. Rectal cancer is one of the few cancers that can be prevented. There are several FDA-approved screening options:

• Colonoscopy
• Stool-based tests (like FIT and Cologuard)
• Blood-based tests (Shield)

It’s important to discuss your screening options with a doctor; each has pros and cons. Not all options are covered by insurance nor are all of them available to patients of every age. 

As with every cancer, there are steps you can take to adopt a healthy lifestyle and reduce your overall cancer risk, such as maintaining a healthy weight, not smoking, and limiting or eliminating alcohol. 

For colorectal cancer specifically, studies have shown that eating a lot of red and processed meats and drinking alcohol increases risk. Many researchers around the world are looking into why there’s been an increase of cancer cases among young adults since the early 1990s, and several are exploring the role of diet and environmental factors.

Learn more about cancer prevention from the American Institute for Cancer Research.

What are some rectal cancer statistics? 

According to GLOBOCAN data:

• Rectal cancer is the 8th most commonly diagnosed cancer worldwide, with approximately 730,000 new cases and an estimated 310,000 deaths globally in 2022.
• The global incidence rate of rectal cancer in men is 75% higher than in women (a larger sex disparity than is seen in colon cancer).
• The highest rectal cancer incidence rates in men are found in Eastern Europe (16.5 per 100,000), and in women in Australia and New Zealand (8.8 per 100,000).

According to the Lancet Commission on Colorectal Cancer (2026):

• The global burden of colorectal cancer is projected to reach more than 3.2 million new cases and 1.6 million deaths annually by 2040.
• The epidemiological landscape is shifting rapidly toward younger age at diagnosis, more advanced stage when diagnosed, and a higher proportion of left-sided and rectal tumors.
• Age-standardized incidence rates rose from approximately 22.2 to 26.7 per 100,000 population between 1990 and 2019
• There are rapid increases in cases amongst younger adults across all global regions. Global early-onset colorectal cancer cases nearly doubled from 1990 to 2021, rising from 107,309 to 211,890. By 2030, an estimated 23% of all rectal cancers worldwide will occur in adults under age 50.

According to a Swiss national study published in the European Journal of Cancer (May 2026):

• Nearly 28% of patients under 50 already had metastatic disease at diagnosis, compared with about 20% of older patients

What are my odds of surviving it?

Rectal cancer is highly treatable if caught early. Doctors use what’s called “survival statistics” to understand the likelihood of a patient beating the disease.

According to the National Cancer Institute, 65% of patients are alive five years after a colorectal cancer diagnosis. Survival statistics below are for colorectal cancer (colon and rectal combined) as reported by the National Cancer Institute.

Detailed survival statistics are based on where the cancer is located and if it has spread:

Localized

The cancer hasn’t spread

• 34% of cases
• 91.5% of patients are alive five years after diagnosis

Regional

The cancer spread to nearby lymph nodes

• 37% of cases
• 74.6% of patients are alive five years after diagnosis

Distant

The cancer has spread to lymph nodes and/or organs

• 23% of cases
• 16.2% of patients are alive five years after diagnosis

What types of tests should I expect to undergo?

Doctors typically use these tests to diagnose rectal cancer:

• Colonoscopy
• Blood tests
• Biopsy

Once you’ve been diagnosed, you may have these tests:

• Pelvic MRI
• Endorectal ultrasound
• CT scan
• Chest x-ray
• PET scan

Ask your doctor about these additional tests—ideally before you begin treatment.

• Biomarker testing
• Genetic testing

I’m facing a diagnosis: What are my next steps?

If you’re facing a diagnosis, the GI Cancers Alliance is here for you. 

If you’re newly diagnosed, work with your doctor to create a treatment plan. We encourage you to find a surgeon with a high volume of rectal surgeries and expertise with treating rectal cancer.

Rectal cancer treatment plans may include a combination of the following:

• Chemotherapy
• Radiation
• Surgery (total mesorectal excision (TME), possible ostomy)
• Targeted therapy
• Immunotherapy

About Ostomy

An ostomy is a surgical opening created in the abdomen that allows waste to exit the body into a pouch worn on the outside, when the normal path through the rectum is no longer possible. In rectal cancer, an ostomy may be needed temporarily while the bowel heals after surgery, or permanently if the tumor is very low in the rectum and the sphincter muscles cannot be preserved. Whether an ostomy is temporary or permanent depends on the location and stage of the tumor, the type of surgery performed, and your overall health. Many people live full, active lives with an ostomy, and ostomy nurses and support resources are available help you adjust.

ctDNA

A liquid biopsy is a blood test that detects fragments of tumor DNA circulating in the bloodstream, called circulating tumor DNA (ctDNA). In rectal cancer, liquid biopsy is increasingly being used in several important ways.

First, after surgery, a positive ctDNA result can indicate that the DNA of cancer cells remain in the body even if scans appear clear. This may guide a doctor to recommend chemotherapy after surgery.

Second, during and after treatment, ctDNA can be monitored over time to assess how well the cancer is responding to treatment or to detect early signs of recurrence (sometimes several months before a tumor would be visible on a scan).

Third, for patients who appear to have had a complete response to neoadjuvant chemoradiation or immunotherapy, ctDNA is being actively studied as a tool to help determine whether surgery can safely be avoided in rectal cancer patients. This is called the "watch and wait" approach. A negative ctDNA result after treatment may help confirm that no cancer cells remain, while a positive result may signal the need for closer monitoring or further treatment.

Liquid biopsy can also identify specific mutations and biomarkers of a tumor that may influence treatment choices, including resistance mutations that may develop over time. Liquid biopsy is not yet a universal standard of care and is still being studied in large clinical trials, but it is increasingly available and used at major cancer centers. Ask your care team whether ctDNA testing is appropriate for your situation.

We strongly encourage you to get a second opinion from another trusted doctor so you feel confident moving forward.