Part Three of Three-Part Series: Colorectal Surgery Review for Primary Care Providers

Abstract

Malignant colon and rectal disorders must be identified and treated. Timing and indication for diagnostic and screening colonoscopy are extremely important. A high index of suspicion to exclude malignancy is imperative. This paper will focus on the screening for and treatment of colorectal and anal cancers.

Screening for Colorectal Cancer

Colorectal cancer is common and deadly, ranking as the third most common cancer in both men and women. Fortunately, the implementation of widespread screening has directly led to a steady and ongoing decrease in incidence. A well-defined polyp to cancer progression, true for most colorectal cancers, allows detection and treatment of “pre-malignant” adenomatous polyps and early cancers before they become symptomatic and later stage.¹

“Screening” is testing asymptomatic patients to detect a disease before it becomes clinically apparent to allow intervention and prevent disease progression. Patients are classified as either average or high-risk. Average risk for colorectal cancer is defined as individuals 50 years or older without a personal or family history of colorectal polyps or cancer, and no at-risk diseases such as ulcerative colitis or Crohn’s disease.²

Primary care providers are vital to the success of any screening program. It is important to discuss with all patients that screening for colorectal cancer drastically reduces the chance of dying from colorectal cancer but a perfect test does not exist.

Summary of Recommendations and Considerations

1. Providers should begin screening for colorectal cancer at age 50 if no at-risk factors exist.

2. High-risk patients (personal or family history of polyps or colorectal cancer) should begin at age 40 years old or 10 years prior to the youngest first-degree affected relative.

3. Approved first-line screening should be either fecal testing or colonoscopy.

Colonoscopy

• Considered “best” but involves time off work, bowel prep, risks of procedural complications such as bleeding, bowel perforation³ (4 in 10,000 endoscopies performed) or sedation issues, and costs more.

• However, colonoscopy remains the most reliable method to prevent development of advanced polyps and cancers.

• Normal colonoscopy requires 10-year follow-up if the patient remains asymptomatic.⁴

• Abnormalities might require closer follow-up, ranging between three months to five years depending on the concern. This will be determined by the endoscopist.

• Fecal tests: FOBT, FIT or fecal DNA⁵ (“Cologuard”)

  • Less accurate: more false positives and false negatives.

  • Done more frequently (every two years at minimum).

  • Involves dietary or medication restrictions prior to test.

  • Compliance is also lower.

  • Abnormal results require follow-up colonoscopy.

  • Single digital exam in the office with FOBT cards is not adequate screening.

  • Fecal DNA test usage is likely to increase in the future, but it is currently hard to know their role.

  • Fecal tests are never appropriate for symptomatic patients, since a false test does not eliminate the need for colonoscopy to rule out an intermittently bleeding tumor.

4. All symptomatic and high-risk patients require diagnostic colonoscopy.

5. Incidence of colorectal cancer is increasing (for unknown reasons) in patients under the age of 50. All unexplained, persistent bowel symptoms require investigation (colonoscopy) regardless of age.

Common symptoms to watch for: bleeding, bowel changes (more or less frequent, change in caliber, feeling of incomplete emptying, etc…), abdominal bloating, abdominal pain, unexplained or unintentional weight loss, among others.

6. The development of concerning symptoms between screening exams mandates further investigation as no test is perfect, and polyps or cancers can be “missed” or develop in the interim.

7. It is reasonable to not screen patients with significant medical comorbidity, advanced age or frailty, which reasonably decreases their life expectancy to less than 5–10 years. Otherwise, screening should continue (the risk for colorectal cancer rises as age increases) despite age over 75.

8. Other options in certain circumstances include digital rectal exams, flexible sigmoidoscopy, barium enema, and CT colonography. However, they are often adjuncts to the standard tests previously mentioned and generally used only if fecal tests or colonoscopy are contraindicated or not possible.⁴

9. The suspicion of hemorrhoids, or the finding of hemorrhoids on exam, does not rule out the presence of colorectal cancer unless a colonoscopy has been performed recently. Recurrent hematochezia requires endoscopic investigation even in patients younger than standard screening age. See Table 1.

Table 1.

Colorectal Cancer Staging

Stage	Primary tumor1	Regional lymph nodes2	Distant metastasis3
I	T1/T2	N0	M0
II	T3/T4	N0	M0
III	Any T	N1	M0
IV	Any T	Any N	M1

¹Primary tumor

T1: tumor invades lamina propria or submucosa;

T2: tumor invades muscularis propria;

T3: tumor invades through muscularis propria into the subserosa;

T4: tumor perforates the vascular peritoneum or directly invades other organs, including mesentery, abdominal wall, and pancreas.

²Regional lymph nodes

N0: no regional lymph nodes metastasis;

N1: regional lymph nodes metastasis.

³Distant metastasis

M0: no distant metastasis;

M1: distant metastasis.

Colon Cancer

Colon cancer affects approximately 107,000 new patients in the United States each year and is the third leading cause of cancer death. Despite significant improvements in prevention and treatment, 30,000 deaths are estimated to have been due to colon cancer.⁶ Most patients will present with localized disease amenable to curative surgical resection, but approximately 20% of patients still present with distant metastasis.⁵

The cause of colorectal cancer is multifactorial. Risk factors include diet, smoking, alcohol, and genetic factors. Ulcerative colitis, Crohn’s disease, familial adenomatous polyposis (FAP), hereditary non-polyposis colorectal cancer (HNPCC aka Lynch Syndrome) are common associated disease states.²¹

The evaluation of colon carcinoma includes colonoscopy; CT of the chest, abdomen, and pelvis with IV contrast; and labs including CBC and CEA.⁹ The evaluation serves as the initial staging and preoperative planning. Genetic consultation in young patients and in patients with significant family history is important.

The initial treatment for colon carcinoma is segmental colon resection which includes the draining lymph nodes. Patients are happy to learn that a colostomy should not be needed for an elective resection. In complicated, urgent settings (such as advanced colonic obstruction or perforation), a colostomy may be required. A minimally invasive approach, including laparoscopic or robotic technology, is considered standard of care, which minimizes complications in well-selected patients.⁶ Extended resections may be required based on tumor location and in cases of FAP and HNPCC. Pathologic evaluation of the surgical specimen will confirm final stage and determine follow-up and further care (Figure 1).

Figure 1.

Colon Cancer.

Postoperatively the patient should be evaluated by an oncologist. In select stage II patients and stage III patients, chemotherapy may be recommended. Radiation is rarely indicated in the treatment of colon cancer.⁷ Close postoperative surveillance with colonoscopy, labs and imaging is recommended to detect possible recurrence earlier than when it becomes symptomatic and less likely responsive to additional treatment.⁸

Many treatment options exist for Stage IV disease, occasionally including surgical treatment with curative intent. Long-term survival can be achieved for some patients with favorable tumor biology. A true multidisciplinary approach is required to prioritize goals and coordinate care among colorectal surgeons, hepatobiliary surgeons, medical and radiation oncologists, radiologists and pathologists.¹⁰

Rectal Cancer

Rectal cancer differs from colon cancer “only” in its anatomic location and is generally defined as adenocarcinoma in the distal 15 cm of the large intestine. However, this can complicate treatment significantly where careful consideration is needed for issues such as bowel function and control, involvement of adjacent organs like genitourinary structures, need for intestinal stoma (temporary or permanent), and pre and postoperative therapies such as radiation, among others. Rectal cancer is the disease around which many board-certified colon and rectal surgeons focus their expertise.

Fortunately, routine colorectal screening is quite effective in detecting polyps prior to malignant transformation or identifying cancers at an earlier stage. As a result, annual incidence has steadily decreased except in patients under 50, where it is increasing for unknown reasons. We have seen patients in their early 20s with no family history, risk factor or genetic mutation present with advanced disease. Additionally, rectal cancers are more likely to cause symptoms earlier, perhaps making early detection more likely compared to colon cancers in the right colon, for instance. Many can be detected on simple digital rectal exam. Rectal bleeding can be attributed to hemorrhoids only after a thorough investigation (Figure 2).²⁰

Figure 2.

Rectal Cancer.

Diagnosis of rectal cancer is confirmed by colonoscopy with biopsies of the concerning lesion/ tumor. All rectal cancers require staging. CT of the chest, abdomen. and pelvis with IV contrast assesses for metastatic disease and possibly local invasion into nearby pelvic structures. MRI or trans-rectal ultrasound help determine the local stage (how deep into the wall of the rectum the tumor grows or suggestion of adjacent lymph node spread). The CEA is sometimes elevated but can also be normal even in advanced disease.¹¹ If abnormal, it can be monitored over time to help detect possible recurrences prior to symptoms.

Similar to many other malignancies, the treatment of rectal cancer involves complete resection with negative margins and adequate lymph node resection. The two most common operations for rectal cancer are the low anterior resection (LAR) and abdominoperineal resection (APR, which necessarily includes a permanent colostomy.¹²) Minimally invasive surgery, either laparoscopy or robotic-assisted approaches have become standard of care among colon and rectal surgeons and help minimize complications.¹⁴ Most colorectal surgeons offer sphincter preserving (ostomy avoiding) operations even in very low cancers, depending on tumor and patient factors. It is in cases with a very distal rectal cancer, at the level of the anal sphincters, where APR with permanent colostomy is expected. “Open” surgery still has a role in re-operative scenarios or other complicated pelvic situations. Recently, minimally invasive trans-anal approaches have grown in popularity for favorable early cancers or large polyps. Sometimes potentially complicated conventional rectal resection can be avoided.

Stage 2 and 3 diseases might benefit from preoperative chemo-radiation or stand-alone chemotherapy depending on location of tumor, patient factors and tumor factors. Stage 4 disease with spread to liver or lung or peritoneum is typically treated with systemic chemotherapy.¹³ Other options such as liver directed embolization/chemotherapy/radiation are sometimes appropriate for certain metastatic tumors. Rectal cancer is also truly a multi-disciplinary cancer and colorectal surgeons should be involved in every case.

Long-term prognosis is directly related to stage of disease at the time of diagnosis. The most effective treatment remains prevention. Though a typical initial treatment plan can take up to a year, patients who present with Stage 2 and 3 diseases who undergo preoperative chemo-radiation, followed by operative resection, then adjuvant chemotherapy can many times achieve long-term disease free survival.

Anal Cancer

Anal cancer is defined as a malignant tumor originating from squamous cells of the perianal region (tumors within 5 cm of the anus) or anal canal (tumors incompletely visualized on simple inspection up into the distal rectum). Pathogenesis involves previous, occult Human Papilloma Virus infection in most cases. Approximately 1% of patients with HPV develop visible lesions such as condyloma. Fewer develop dysplastic lesions, which can then progress to invasive cancer. It is important to recognize that anoreceptive intercourse is not prerequisite for anal HPV/condyloma/dysplasia/ malignancy as much personal and interpersonal grief may exist when this point is not clarified (Figure 3).

Figure 3.

Anal Cancer

Fortunately, the incidence of anal cancer is around 5,000 cases annually. Virtually all tumors are found on simple visual and/or digital rectal exams. Many patients present for evaluation of their painful and “hemorrhoid” but their symptom onset is usually more insidious.¹⁵ Biopsies, often obtained easily during office exam, confirm the diagnosis by histological exam. As with many cancers, staging exams are important and a CT chest, abdomen, and pelvis with IV contrast is standard. Size of tumor and degree of local invasion to adjacent structures is suggested during exam but can also be evaluated by trans-rectal ultrasound or contrasted pelvic MRI.¹⁶

Perianal tumors are generally treated with wide-local excision assuming a negative margin can be obtained without significant sphincter compromise. Larger tumors are more difficult to resect completely and are more likely to have lymph node spread. Chemo-radiation is recommended with very good results. Salvage radical operation (abdominoperineal resection with permanent colostomy) is reserved for those with persistent tumor after chemo-radiation and has less than ideal oncologic results when needed, usually indicating aggressive tumor biology.¹⁷

Anal canal tumors are rarely amenable to wide excision with negative margins due primarily to sphincter preservation concerns. Chemo-radiation is the mainstay of treatment. Chemotherapy includes 5-fluorouracil and mitomycin-C or cisplatin.¹⁸ Results are excellent but radiation effects including incontinence and recto-vaginal fistula can occur. Radical surgery is again reserved for disease persistence and is associated with aggressive disease and a poor prognosis.

Patients treated with local excision or chemo-radiation require close office follow-up for five years including anoscopy every three to six months and periodic imaging. Recurrent post-treatment pain or bleeding that persists mandates evaluation.¹⁹

Conclusion

The United States has seen progress with colorectal cancer with both falling incidence and mortality rates. Factoring into this decline, the significance of early detection and removal of precancerous lesions through screening must be underscored. Screening participation is still suboptimal, among underserved populations. Improving screening rates among underserved populations can reduce the colorectal cancer burden in the United States.