Gardner’s syndrome is an autosomal dominant syndrome of adenomatous polyposis of the colon that is associated with osteomas and skin lesions. The osteomas often precede any other symptoms, including those due to colonic polyposis, and may thus serve as a marker of the latter.
Early Evaluation for Gardner's Syndrome
The association of colonic polyps with colonic cancer in almost 100% of patients with Gardner’s syndrome makes it important to screen patients with osteomas for the syndrome, and thus potentially save their lives. Asking for a family history is the first step; however, even in its absence, a detailed assessment is highly recommended in trying to establish this condition in an asymptomatic patient. This is especially important since about a quarter of these patients have no family history of the disease—the mutation apparently having arisen de novo.
The consideration of this diagnosis means that the gastric mucosa, the thyroid, retinal epithelium, skull, and teeth, as well as the skin, need to be assessed for epidermoid cysts, desmoid tumors, congenital hypertrophy of the retinal pigment epithelium, odontomes, impacted teeth, and colonic polyps. The classical site for osteoma formation is the mandible, especially at the angle of the jaw, but these tumors may also form on the skull, the paranasal sinuses, and long bones. A CT scan may help show their location and size.
Polyps are most often found to blanket the entire colonic surface but may sometimes occur in the gastric and small intestinal mucosa. They are usually first seen after puberty but become symptomatic at about age 40, on average. Colonic adenocarcinoma is the inevitable outcome by this age in all patients with Gardner syndrome.
Detecting Other Tumors
Screening for papillary carcinoma of the thyroid, adenomas, and adenocarcinomas of the adrenal glands, hepatocellular carcinomas, osteosarcoma, and chondrosarcoma, and for other thyroid and liver tumors is also an important part of the initial evaluation.
Prevention of Colon Cancer
Because all patients develop colonic cancer before 40 years of age, a prophylactic colectomy is necessary. Various surgical options for preventing colon cancer are available, incuding:
- Total proctocolectomy with a permanent terminal ileostomy
- RPC with IPAA, which is more exacting and requires a longer recovery,but avoids the need for a stoma at the price of lifelong monitoring because of the possibility that some mucosa is left
- Subtotal colectomy and IRA (if the rectum has less than 20 polyps at the time of surgery)
A restorative proctocolectomy with ileal pouch anal anastomosis (RPC/IPAA) along with mucosectomy is recommended because the whole of the mucosa of the large intestine is resected to prevent polyp formation while still conserving intestinal function and enabling sexual fulfilment. By avoiding the need for a colostomy, the patient is able to obviate a lot of psychological and physical distress. An ileostomy is put in place temporarily to allow the rectal-colonic anastomosis to heal properly.
When gastric polyps are found in association with Gardner’s syndrome, the rate and speed of carcinogenesis in such cases is lower than for colorectal polyposis. As such, a more conservative approach, such as snare polypectomy, may yield good results.
Surgical Treatment of other Components of Gardner's Syndrome
Cutaneous cysts of various types are treated as they would be in normal patients. Osteomas which cause disfigurement or functional interference may be resected. Desmoid tumors recur in eight of ten cases following resection, and hence this should be performed only if the patient has symptoms. Various drugs have been tried, from the NSAID category, selective estrogen receptor modulators, and even cytotoxic drugs, in situations where the tumor was spreading fast or could not be resected. Radiation therapy has also been attempted. Mesenteric desmoids are extremely difficult to manage by surgery because of the diffuse nature of the growth and its interference with neighboring vessels and organs.
Pharmacotherapy and prevention
Drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) may be of help in preventing the progression of colorectal polyps to carcinoma in familial adenomatous polyposis of which Gardner’s syndrome is one form. They have been shown to reduce the size and number of polyps for the duration of administration, but this is not invariable, with some patients showing the emergence of new tumors or the malignant transformation of existing polyps at the same time.
Newer drugs in this category include the COX-2 inhibitors because of the finding that COX-2 receptors are present in colonic mucosa undergoing cancerous changes but not in the normal colonic mucosa. The result of clinical trials showed that polyp size was decreased, but the effect on malignancy rates has not been determined.
Some claims have been made for the use of traditional Chinese medicine with surgical polypectomy of gastric polyps, suggesting a beneficial effect in terms of their disappearance over a short period of time. The characterization and testing of the components of traditional Chinese medicine remains a vital but missing link in making use of this suggestion in treatment recommendations. It is known that these contain an array of organic acids such as oxalic, tartaric, malic, and lactic acid, along with palmitic acid, uracil, and erythritol derivatives.
Other herbal alternatives such as green tea extract and ascorbic acid have not been proven to be effective in this regard.
All patients with Gardner’s syndrome must receive scheduled regular monitoring of the small intestine and colon as well as the liver and thyroid gland. It is indicated when:
- The patient shows no mutation but has a positive family history of familial adenomatous polyposis. It is typical to carry out an annual flexible sigmoidoscopy from about 13 years until 30 years and then every 3-5 years until the age of 60 years.
- The patient has a demonstrated mutation linked to the APC (adenomatous polyposis coli) gene but the patient is not willing to have a surgical resolution. In such cases a flexible sigmoidoscope is used to carry out an endoscopy with colonoscopy every 6 months from the age of 10, and surgery at any time before the age of 25. The ideal age for surgery is between 16 and 20. If the number of polyps is large, a sooner time for surgery is better.
- The patient is known to have FAP and has had a colectomy with an ileorectal anastomosis, following which is an annual rectoscopy should be carried out. If an IPAA has been performed, an annual proctoscopy is sufficient. All patients with FAP require surveillance of the stomach and small intestine, using a 3-yearly upper GI endoscopy. If multiple polyps are found, an annual endoscopy is indicated.
Thyroid examination and ultrasound must be carried out yearly, and liver monitoring using ultrasound and AFP (alfa-fetoprotein) measurements.
- Aletaha, M., & Fateh-Moghadam, H. (2012). Gardner Syndrome. Journal of Ophthalmic & Vision Research, 7(3), 257–260.
- Gu, G.-L., Wang, S.-L., Wei, X.-M., & Bai, L. (2008). Diagnosis and treatment of Gardner syndrome with gastric polyposis: A case report and review of the literature. World Journal of Gastroenterology : WJG, 14(13), 2121–2123. http://doi.org/10.3748/wjg.14.2121.
- Charifa A. & Zhang X. (2018). Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482342/.