Rectum, the last 15 cm portion of the large intestine, is where cancers that develop are referred to as rectal cancer.

Symptoms of Rectal Cancer

Symptoms such as difficult bowel movements, rectal bleeding, narrowing of stool diameter, episodes of diarrhea or constipation, and a sensation of incomplete emptying can indicate rectal cancer. However, in some patients, it can also be detected in screening colonoscopies or imaging studies such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography-computed tomography (PET-CT) conducted for other purposes.

Diagnosis of Rectal Cancer

The primary diagnostic method is colonoscopic examination. A biopsy is taken from the tumor tissue during colonoscopy to obtain a tissue sample for pathological examination.

Additionally, it is possible to determine whether the tumor is in its very early stage, identify the presence of accompanying lesions in other parts of the large intestine, or ascertain the existence of familial polyposis syndrome.

Before planning the treatment for rectal cancer, staging should be performed, as with any cancer patient. In the staging of rectal cancer:

• Pelvic magnetic resonance (MR) imaging (taken with a specific angle toward the rectum),
• Upper abdomen MR,
• Thoracic (lung) computed tomography should be conducted.

While guidelines recommend both upper and lower abdomen (abdomen) tomography and pelvic MR, in our country’s colorectal surgery practice, pelvic MR and upper abdomen MR are performed instead of tomography. This approach is effective in our country, where MR imaging is more widespread and conducted rapidly, providing information as clear as tomography.

PET-CT is not routinely recommended for rectal cancer staging; it is suggested only for evaluating patients with suspected metastasis.

In patients without advanced-stage disease (early stage), endorectal ultrasound (EUS/ERUS) may be utilized to assess the tumor’s spread in the rectum wall.

Although blood values coded as CEA and Ca 19-9 are not used in staging, it is recommended to be examined at the time of the initial diagnosis to predict the course of the disease and monitor the recurrence status after treatment.

Rectal Cancer Treatment

The treatment of rectal cancer is planned based on the stage of the tumor, as with all gastrointestinal tumors. Below, you can see the main treatment options according to stages:

• Stage 1,
  • Endoscopic intervention (endoscopic submucosal dissection – ESD)
  • Transanal minimal invasive approach (intervention through the anal canal under visual guidance with surgical instruments)
  • Colorectal surgery (open, laparoscopic, robotic)
• Stage 2,
  • Colorectal surgery (open, laparoscopic, robotic)
  • Surgery after radiotherapy
• Stage 3,
  • Radiotherapy ± Chemotherapy, followed by colorectal surgery, followed by chemotherapy
• Stage 4 (Distant organ metastasis),
  • Chemotherapy

Additional treatments can be considered depending on the region where metastasis has occurred. If complete removal is possible in cases with metastasis only to the lungs or liver, rectum surgery and removal of metastases can be planned simultaneously or at different times. For patients with peritoneal metastasis, hyperthermic intraperitoneal chemotherapy (HIPEC) can be applied in conjunction with cytoreductive surgery after chemotherapy or immediately following the diagnosis. Surgical interventions can be planned even in cases with simultaneous metastasis in many regions.

In all stages, treatment planning should be decided in a multidisciplinary oncology council where colorectal surgeons, medical oncologists, radiation oncologists, pathologists, radiologists, and other relevant specialists participate, considering the patient’s and tumor’s characteristics and current scientific data.

Rectal Cancer Surgery

The surgery for all rectal cancer patients, whether they have received additional treatment or not, requires specialized expertise. For successful rectal surgery, the rectum, surrounding fatty tissue, and the sheath enveloping it should be removed without disruption. This operation is referred to as total mesorectal excision (TME) with low anterior resection.

The placement of the rectum within the pelvis complicates rectal cancer surgery. In front of the rectum are the bladder, prostate, vessels, and nerves supplying the genital and urinary systems on the sides, and at the back, numerous vessels located in front of the hip bone. Striving to avoid these structures prevents potential injuries but tearing the rectum sheath to preserve it may lead to the violation of oncological surgery rules. On the other hand, cutting too far away to protect the rectum sheath can cause injuries to surrounding structures, leading to additional surgeries, serious bleeding that could be life-threatening, or functional impairments related to sexuality and urination.

Adhering to all these surgical principles, rectal cancer surgery can be performed by traditional (open) methods, laparoscopic, or robotic methods. Scientific data show that laparoscopic surgery provides an equally effective cancer surgery as open surgery, with many additional advantages. Although robotic surgery has a higher cost, it has not demonstrated significant superiority over laparoscopic surgery. Therefore, in contemporary colorectal surgery practice, laparoscopic surgery is primarily recommended for rectal cancer.