Cancer Treatment Today » Rectal Cancer

Staging rectal cancer with MRI

M Levin, MD — Mon, 24 Jun 2013 12:06:59 +0000

With the advent of powerful gradient coil systems and high-resolution surface coils, magnetic resonance imaging (MRI) has come into tis own in being able to assess the relationship of a rectal tumor to surrounding organs and tissues. MRI is currently the only imaging modality that is highly accurate in predicting whether or not it is likely that a tumor can be resected without leaving cells behind and, therefore, provides important information for planning effective surgery versus chemotehrapy and radiation, especially in patients with advanced rectal cancer. It enables selection of surgery versus chemotherapy and radiation as treatment for localized rectal cancer.

MRI is recommended in selected cases by the European Guideline. One notable difference between this NICE guideline and the American NCCN guidelines is the use of ultrasound versus magnetic resonance imaging (MRI) for rectal cancer staging. In the US ultrasound is used more frequently for staging it and has advantages for discerning early and small cancers. Nevertheless, staging with MRI should still be considered medically appropriate even in the USA.

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Gemzar for colon and rectal cancer

M Levin, MD — Fri, 09 Nov 2012 19:17:56 +0000

Gemzar( gemcitabine) has been tested for colon and recatl cancer. A 1992 study found that Gemcitabine did not demonstrate activity against advanced colorectal adenocarcinoma. ON teh other hand,a much later study found that Gemcitabine has a modest activity in heavily pre-treated colorectal cancer patients and may be an option in good performance status patients. There are a number of reports and ongoing studies of gemcitabine in combination for colorectal cancer. A recent study, Gemcitabine in Treating Patients With Advanced Colorectal Cancer, NCT00007943, was completed in 2009 but not published as of 2012.

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Posttreatment surveillance after hepatic metastases resection for colorectal cancer

M Levin, MD — Fri, 24 Aug 2012 19:54:24 +0000

Since the appearance of effective new drugs for colorectal cancer and more aggressive surgical approaches to resecting isolated metastases, many patients who had metastatic cancer are now free of disease for an extended period of time. There are few guidelines on how to follow such patients it is fairly new situation and there are no mature studies. For high risk non-metastatic colon cancer, NCCN guidelines recommend annual CT of chest, abdomen and pelvis. Post-surgery surveillance is similarly warranted following resection of isolated colorectal cancer metastases because a minority of the recurrent patients can be treated with metastatectomy from the liver and lung, and some of them will enjoy long-term survival and even cure. The liver is the only site of recurrence in approximately 35 to 40 percent. Five-year survival rates up to 43 percent are reported following repeat liver resection for a second recurrence, with acceptable morbidity and perioperative mortality. Clearly, these patients need to be followed so as to intervene early after new metastases appear.

The impact of CT-based follow-up for the detection of resectable disease recurrence was addressed in a review of 705 patients who underwent resection of isolated colorectal cancer liver metastases at a single institution over a 14-year period. All were followed with a similar surveillance protocol, which included outpatient clinical examinations at 3, 6, 12, 18, and 24 months, and annually thereafter, with measurement of CEA and CA 19-9 levels at each visit. In addition, all patients had CT of the thorax, abdomen and pelvis every three months for the first two years, at six monthly intervals for three more years, then annually from year six to ten.

Of the 444 patients with a recurrence diagnosed on a surveillance CT, 404 were detected within two years. The site of recurrent disease was liver only in 36 percent, outside of the liver only in 38 percent, and both in the liver and in other organs in 26 percent. The authors did not report how many recurrences were detected by serum tumor markers versus CT scans.

In total, recurrent disease was treated surgically in 124 patients. At every time point (within one year of original surgery, one to two years, beyond two years), those patients treated by liver and/or lung resection had significantly better median survival than did those who received palliative chemotherapy alone. The mean number of scans performed per resectable recurrence was 35.3, and the cost per life-year gained was £2883, a value that compares favorably to other cost-effectiveness ratios that are considered acceptable in the US and elsewhere. UPTODate recommends the following surveillance strategy for patients with stage IV disease who are rendered surgically NED (no evidence of disease):

CEA every three months for two years, then every six months for three to five years

CT of the chest/abdomen and pelvis every three to six months for two years, then every 6 to 12 months up to a total of five years
Colonoscopy in one year; if no advanced adenoma repeat in three years, then every five years; if advanced adenoma is found, repeat in one year

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FAP and AFAP testing: Genetic colon cancer

M Levin, MD — Fri, 24 Aug 2012 13:48:34 +0000

A small proportion of colon and rectal cancers arise in individuals who have genetic mutations. Familial Adenomatous Polyposis(FAP) and AFAP are autosomal dominant disorders with 50% risk of inheritance and about 75–80% of individuals with these conditions have an affected parent. Autosomal dominant inheritance means that an offspring of an affected individual has a 50% risk of inheriting the altered APC gene.
Adenomas develop in approximately half of all patients with FAP by age 15, and in 95% by age 35. Without intervention, most individuals with FAP will develop colon or rectal cancer by the fourth decade of life. Thus, screening and intervention for at-risk persons is critical and typically begins at puberty (National Comprehensive Cancer Network® [NCCN®], 2012). AFAP is an attenuated variety of FAP. Evidence in the published, peer-reviewed scientific literature indicates that genetic testing for mutations in the APC gene is appropriate for a specific subset of individuals who have been identified as at high-risk for FAP or AFAP. Among the specialty organizations that have recognized the role of FAP and AFAP genetic testing are the American Gastroenterological Association (AGA), American College of Medical Genetics (ACMG), NCCN and National Cancer Institute (NCI). It is generally accepted that genetic testing for FAP and AFAP is appropriate for the following purposes:
• to confirm the diagnosis of FAP and AFAP in an affected patient
• to provide predictive testing for at-risk relatives of AFAP and FAP-affected patients with known APC gene mutation.
MYH-Associated Polyposis (MAP), also known as MUTYH-associated polyposis, is a recently described syndrome that is related to FAP and that is also characterized by adenomatous polyps. It is, however, an autosomal-recessive syndrome, in which half of the affected individuals are carriers of the disease but are not affected, unless they receive one gene from each parent.

American College of Medical Genetics (ACMG) and the American Society of Human Genetics (ASHG) and American Gastroenterological Association (AGA) also offer guidelines. For genetic counseling and testing for adenomatous polyposis syndromes, including FAP, and AFAP, the guidelines include the following (NCCN, 2012):
• FAP Inclusion criteria include:
Presence of over 100 polyps, or fewer polyps at younger ages, especially in family known to have FAP
Autosomal dominant inheritance
Possible associated additional findings, including:
o Congenital hypertrophy of retinal pigment epithelium (CHRPE)
o Osteomas, supernumerary teeth, odontomas
o Desmoids, epidermoid cysts
o Duodenal and other small bowel adenomas
o Gastric fundic(body) gland polyps
increased risk of medulobastoma, papillary carcinoma of the thyroid (<2%) or hepatobalstoma (usually ?age 5 years)
Pancreatic cancers (<1%)
Gastric cancers (<1%)
• AFAP inclusion criteria include:
Fewer than 100 adenomas (range 0 – >1000) (average of 30 polyps)
Frequent right-sided distribution of polyps
Adenomas and cancers at age older than classic FAP (i.e., mean cancer age greater than 50)
Upper GI findings and thyroid cancer risk is similar to classic FAP
?Other extraintestinal manifestations, including CHRPE and desmoids are rare
• If personal history is positive, then refer to genetic screening
• If family mutation is known, then refer at-risk family members to genetic screening
For genetic counseling and testing for MAP, the guidelines include the following (NCCN, 2012):
• MAP inclusion criteria include:

Polyposis or colon cancers consistent with autosomal recessive (i.e., parents unaffected, siblings affected)
Fewer than 100 adenomas (range 0–100s and uncommonly >1000)
Adenomas and colorectal cancer at age older than classical FAP (median age >50)
Duodenal adenomas are uncommon
Attenuated polyposis with negative APC gene mutation

• If personal history is positive, then refer to genetic screening
• Testing for APC gene mutations usually precedes testing for MYH mutations, except in families in which only siblings are affected
• Recommend genetic counseling and testing for germ line MYH mutations for siblings of affected patients
• If family mutation is known, then refer at-risk family members to genetic screening

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