Diagnosis and Management of Rectum Cancer

In the diagnosis and management of rectum cancer, colonoscopy and biopsy confirm the cancer, pelvic MRI and chest and abdominal CT stage it, and the stage sets the treatment: surgery first for early tumours, chemotherapy and radiotherapy first for locally advanced low rectal tumours, and chemotherapy-led treatment for most stage 4 disease. In expert hands, most patients can now keep normal bowel passage rather than a permanent stoma.

That is the clinical arc set out by Dr. Kaushal Kishor Yadav, currently Director & Unit Head – Surgical Oncology, Max Hospital, Gurugram, India, in a Jivo Masterclass for international doctors on 15 June 2025. A graduate of PGIMS Rohtak, he highlighted a problem he sees in patients who travel for treatment: evaluation, diagnosis and referral take a very long time, and by the point they reach a surgical oncologist the disease is advanced and the options have narrowed.

This guide sets out the whole pathway. Two companion articles go deeper: the diagnostic workup, tests and staging for colon and rectum cancer, and sphincter-preserving surgery for low rectal cancer, which also covers complete mesocolic excision for colon cancer and the choice between open, laparoscopic and robotic operations.

How common is colorectal cancer, and why early diagnosis matters

Colorectal cancer is the third most commonly diagnosed cancer in the world and the second leading cause of cancer death. Cancer of the colon and cancer of the rectum together make up colorectal cancer, the cancer of the large intestine. Dr. Yadav's point to the audience was that no doctor, whatever their specialty, can afford to be unfamiliar with it.

The decisive fact is timing. In Dr. Yadav's account, 60 to 70% of patients present in stage 3 or stage 4, when the tumour is producing obvious symptoms. Those patients face long treatment. Patients diagnosed early have shorter treatment and good results. That is why he made prompt evaluation of the warning signs the key point for doctors at the first point of contact.

Colorectal cancer in young adults

Age no longer protects patients. Dr. Yadav now sees colon cancer in people in their thirties and even their twenties, and attributes the shift to habits and lifestyles changing everywhere in the world. Rectal bleeding in a young adult therefore deserves the same evaluation as in an older patient, rather than an assumption of haemorrhoids.

Risk factors for colorectal cancer

Dr. Yadav did not dwell on risk factors, noting that most doctors know them well. For completeness, the established risk factors for colorectal cancer include:

• Increasing age, although the incidence in younger adults is rising.
• Family history of colorectal cancer or adenomatous polyps, and inherited syndromes such as Lynch syndrome and familial adenomatous polyposis.
• Inflammatory bowel disease, particularly long-standing ulcerative colitis and Crohn's colitis.
• Diet and lifestyle: a diet high in red and processed meat and low in fibre, obesity, physical inactivity, smoking and heavy alcohol use.

Regular physical activity and a diet rich in fibre are associated with a lower risk.

For a broader view of colon cancer red flags and hereditary risk in the context of other common cancers, see Dr. Niti Raizada's guide to diagnostic red flags in lung, colon, liver and oral cancer.

Warning signs of colon and rectum cancer

Dr. Yadav named a short list of signs that should prompt investigation for colon and rectum cancer, and he was clear that the response to any of them is evaluation, not reassurance:

1. Bleeding from the bowel. This is the most common sign. It may be fresh red blood or a change in the colour of the stool from altered blood.
2. A fall in haemoglobin that no other cause explains. Unexplained anaemia in an adult is a reason to examine the colon.
3. A change in bowel habit that persists. Frequent constipation or diarrhoea that is not relieved and continues for more than three weeks warrants evaluation for early diagnosis.

Where the tumour sits changes how it shows itself. The classic signs of bleeding and altered bowel habit are more common with tumours of the distal colon, such as the sigmoid colon, and the rectum. Tumours of the proximal colon produce fewer of these signs. They tend to bleed in small amounts the patient never notices, so anaemia may be the only presentation, and once they grow large they can cause intestinal obstruction.

Dr. Yadav's instruction for primary care was direct. When these symptoms are present and abdominal symptoms are not settling, the patient should have a colonoscopy or a CT scan so that any doubt is resolved. If there is suspicion, the test should be done without delay, because it is the only way to make the diagnosis at an early stage.

Colorectal cancer screening: when to start and which tests

Dr. Yadav's screening advice for people beyond 40 years of age is a faecal occult blood test or a faecal immunochemical test (FIT) once a year, and colonoscopy once every ten years. A faecal occult blood test looks for traces of blood in the stool that cannot be seen; the immunochemical version detects human haemoglobin specifically. Major guidelines, such as those of the US Preventive Services Task Force, begin routine screening of average-risk adults at 45.

Colonoscopy is the reference test because it both finds and removes precancerous polyps. Where colonoscopy is available only at a tertiary hospital, stool-based testing at the primary or district level remains useful. As one general surgeon in the audience put it, the test is not very specific and may miss some cases, but it can pick up others that would otherwise go undetected until symptoms appear.

How rectum cancer is diagnosed: the workup at a glance

The ideal workup, in Dr. Yadav's words, combines four elements: colonoscopy (a camera examination of the colon and rectum) with biopsy to confirm the diagnosis, MRI of the pelvis to define a rectal tumour's local extent, CT of the thorax and abdomen (or PET-CT where available) to look for spread to the liver or lungs, and the blood tumour marker carcinoembryonic antigen (CEA). The detail, including when CT can stand in for MRI and how to sequence tests where resources are limited, is in the companion article on diagnosis, tests and staging.

Diagnosis and management of rectum cancer by stage

Once the workup has set the stage, the stage sets the order of treatment. Dr. Yadav laid out the sequence clearly.

Chemotherapy and radiotherapy before surgery for rectal cancer

Treatment given before surgery is called neoadjuvant therapy. Its purpose is to shrink a locally advanced tumour and reduce the risk of the cancer returning in the pelvis. Dr. Yadav's practice for lower rectal cancer is to give neoadjuvant chemotherapy and radiotherapy when the tumour is T3, meaning it has grown through the muscle wall of the rectum into the surrounding fatty tissue, or when the lymph nodes are involved. Early disease, T1 or T2 with no nodal involvement, goes directly to surgery.

For colon cancer the logic is different. In stages 1 to 3 there is, in Dr. Yadav's words, no role for neoadjuvant chemotherapy: the operation comes first, and the decision about chemotherapy afterwards rests on the final pathology. NCCN guidelines do allow chemotherapy before surgery for selected locally advanced colon cancers, such as those invading adjacent organs (T4b).

Stage 4: liver metastases

Spread to the liver does not automatically mean a patient cannot be cured. Answering a question about a patient with sigmoid colon cancer whose only metastases are in the liver, Dr. Yadav explained that when those metastases are limited, perhaps one, two or three deposits, they can be removed (liver metastasectomy) either at the time of the bowel operation or as a second-stage procedure. The condition is that the surgeon must be able to remove them completely.

When the liver is studded with disease in both lobes, there is no role for curative surgery, and treatment is palliative chemotherapy.

Stage 4: peritoneal disease

The peritoneum is the lining of the abdominal cavity, and colorectal cancer can seed small deposits across it. When the peritoneal seedings are the only site of spread, Dr. Yadav's approach is cytoreductive surgery with HIPEC. Cytoreductive surgery removes all visible tumour from the abdomen; HIPEC (hyperthermic intraperitoneal chemotherapy) then bathes the abdominal cavity in heated chemotherapy during the same operation. He described it as a good option that gives patients a survival advantage, with two conditions: the disease must be limited, and the surgery must be combined with chemotherapy before and after it. In the PRODIGE 7 trial, however, adding oxaliplatin-based HIPEC to complete cytoreductive surgery did not improve overall survival.

For the large majority of stage 4 patients, treatment is chemotherapy alone. The surgical options above are reserved for limited disease that can be cleared completely.

When to refer a colorectal cancer patient

Dr. Yadav's answer is to refer early to a centre that can complete the workup and treatment with precision whenever the necessary tests or surgery cannot be done locally. Much of the session's discussion turned on a practical dilemma raised by doctors in the audience. A doctor at a first-level hospital sees a patient with suspected colorectal cancer but must refer upwards, and even the highest level available locally may not be able to treat the disease. Some facilities cannot order a CT scan at all; colonoscopy may require travel to a tertiary hospital.

Dr. Yadav's observation from the other end of that pathway is sobering. Many patients from African countries who reach India have spent a very long time moving from evaluation to diagnosis to treatment, and did not receive a proper line of management early. By the time they present, the disease is advanced. That translates into a longer course of treatment, and in stage 4 it can mean that only limited options remain.

His advice to doctors working with few resources had three parts:

• Recognise the warning signs and act on them, regardless of the patient's age.
• Do what is achievable locally, such as a stool test for blood or a referral for colonoscopy, without waiting.
• Refer early to a centre that can complete the workup and treatment with precision when the necessary tests or surgery cannot be done locally. Doctors can describe the patient and symptoms to the treating team at the initial stage and ask which investigations to do first.

His reasoning was simple: cancer gives only one chance.

Can rectal cancer surgery avoid a permanent stoma?

In most cases today, yes. The fear many patients have is the permanent stoma: the rectum removed, and stool and wind passing into a bag attached to the abdomen. Dr. Yadav's message was that normal passage is now possible in most cases, even for tumours lying very low in the rectum. Surgeons achieve this by operating in the embryological plane around the rectum and, where the tumour allows, by intersphincteric resection, in which the dissection continues between the internal and external anal sphincters. Most of these patients need only a temporary stoma for about three months, which is then reversed.

He also noted that this approach is still not practised in many parts of the world; a participant had said that abdominoperineal resection (APR), the operation that removes the anus and leaves a permanent stoma, is the operation most commonly done for low tumours in their setting. The principles, margins and operative steps are explained in the companion article on sphincter-preserving surgery.

Open, laparoscopic or robotic surgery, and treatment costs

Dr. Yadav reported that open surgery gives good results in colon and rectum cancer, that laparoscopy achieves equal results with a shorter hospital stay and faster recovery, and that robotic surgery has proved equally effective; his team operates on colon and rectum cancer with a robotic surgical system at Max Hospital, Gurugram. Indicative costs for the main treatments are on the treatment-cost pages for colorectal resection surgery, liver resection (hepatectomy), cytoreductive surgery with HIPEC, chemotherapy and radiotherapy.

The questions doctors raised during the session, including how to secure clear margins without frozen section and what to do where diagnostic tests are unavailable, are answered in full on the live discussion page for this masterclass. Related material on gastrointestinal cancers is collected on the oncology specialty page, and Dr. Rajesh Kumar Jain's organ-by-organ guide to cancer warning signs places colorectal symptoms alongside those of other cancers.