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Rectal Cancer

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.

Management

The following agents may be used in the management of rectal cancer:

Antineoplastic agents (eg, fluorouracil, vincristine, leucovorin, irinotecan, oxaliplatin, cetuximab, bevacizumab, panitumumab)

Vaccines (eg, quadrivalent papillomavirus vaccine)