Practice Essentials
Rectal cancer is a disease in which cancer cells form in the tissues of the rectum; colorectal cancer occurs in the colon or rectum.
Adenocarcinomas comprise the vast majority (98%) of colon and rectal cancers; more rare rectal cancers include lymphoma (1.3%), carcinoid (0.4%), and sarcoma (0.3%).
Practice Essentials
Essential update: NCCN recommends Lynch syndrome screening in all CRC patients younger than 70 years
Practice Essentials
The National Comprehensive Cancer Network (NCCN) has issued a recommendation that all patients younger than 70 years with colorectal cancer be tested for Lynch syndrome, the most common inherited form of the cancer, whereas those 70 years and older should be tested only if they meet the Bethesda criteria for colorectal cancer.[1, 2]
Practice Essentials
The primary method for detecting Lynch syndrome in tumor tissue from biopsied or surgically resected specimens is with either immunohistochemistry or microsatellite instability testing.[1, 2]
Practice Essentials
The updated NCCN guidelines also indicates that genetic counseling is not necessary before “routine tumor testing” at a cente
Signs and symptoms
Bleeding is the most common symptom of rectal cancer, occurring in 60% of patients.
However, many rectal cancers produce no symptoms and are discovered during digital or proctoscopic screening examinations.
Signs and symptoms
Other signs and symptoms of rectal cancer may include the following:
Change in bowel habits (43%): Often in the form of diarrhea; the caliber of the stool may change; there may be a feeling of incomplete evacuation and tenesmus
Signs and symptoms
Occult bleeding (26%): Detected via a fecal occult blood test (FOBT)
Abdominal pain (20%): May be colicky and accompanied by bloating.
Back pain: Usually a late sign caused by a tumor invading or compressing nerve trunks.
Urinary symptoms: May occur if a tumor invades or compresses the bladder or prostate
Signs and symptoms
Malaise (9%) Pelvic pain (5%): Late symptom, usually
indicating nerve trunk involvement Emergencies such as peritonitis from
perforation (3%) or jaundice, which may occur with liver metastases (< 1%)
Diagnosis
Perform physical examination with specific attention to the size and location of the rectal tumor in addition to possible metastatic lesions, including enlarged lymph nodes or hepatomegaly.
In addition, evaluate the remainder of the colon.
Diagnosis
Examination includes the use of the following: Digital rectal examination (DRE): The average
finger can reach approximately 8 cm above the dentate line; rectal tumors can be assessed for size, ulceration, and presence of any pararectal lymph nodes, as well as fixation to surrounding structures (eg, sphincters, prostate, vagina, coccyx and sacrum); sphincter function can be assessed.
Diagnosis
Rigid proctoscopy: This examination helps to identify the exact location of the tumor in relation to the sphincter mechanism
Laboratory testsRoutine laboratory studies in patients with
suspected rectal cancer include the following: Complete blood count
Diagnosis
Serum chemistries Liver and renal function tests Carcinoembryonic antigen (CEA) test Cancer antigen (CA) 19-9 assay, if available:
May be useful for monitoring the disease Histologic examination of tissue specimens
Diagnosis
Screening tests may include the following: Guaiac-based FOBT Stool DNA screening (SDNA) Fecal immunochemical test (FIT)
Diagnosis
Rigid proctoscopy Flexible sigmoidoscopy (FSIG) Combined glucose-based FOBT and flexible
sigmoidoscopy Double-contrast barium enema (DCBE) Computed tomography (CT) colonography Fiberoptic flexible colonoscopy (FFC)
Diagnosis
Imaging studiesIf metastatic rectal cancer is suspected, the
following radiologic studies may be obtained: CT scanning of the chest, abdomen, and pelvis Endorectal ultrasonography
Diagnosis
Endorectal or pelvic magnetic resonance imaging (MRI)
Positron emission tomography (PET) scanning: Not routinely indicated
Management
A multidisciplinary approach that includes colorectal surgery, medical oncology, and radiation oncology is required for optimal treatment of patients with rectal cancer.
Surgical technique, use of radiotherapy, and method of administering chemotherapy are important factors.
Management
Strong considerations should be given to the intent of surgery, possible functional outcome, and preservation of anal continence and genitourinary functions.
The first step involves achievement of cure, because the risk of pelvic recurrence is high in patients with rectal cancer, and locally recurrent rectal cancer has a poor prognosis.
Management
Surgery Radical resection of the rectum is the
mainstay of therapy. The timing of surgical resection is dependent
on the size, location, extent, and grade of the rectal carcinoma.
Management
Operative management of rectal cancer may include the following:
Transanal excision: For early-stage cancers in a select group of patients
Transanal endoscopic microsurgery: Form of local excision that uses a special operating proctoscope that distends the rectum with insufflated carbon dioxide and allows the passage of dissecting instruments
Management
Endocavity radiotherapy: Delivered under sedation via a special proctoscope in the operating room
Sphincter-sparing procedures: Low anterior resection, coloanal anastomosis, abdominal perineal resection
Management
Adjuvant medical management Adjuvant medical therapy may include the
following: Adjuvant radiation therapy Intraoperative radiation therapy Adjuvant chemotherapy Adjuvant chemoradiation therapy Radioembolization
Management
PharmacotherapyThe National Comprehensive Cancer Network
guidelines recommend the use of as many chemotherapy drugs as possible to maximize the effect of adjuvant therapies for colon and rectal cancer.