Of the many methods doctors use to help determine the stage of colorectal cancer, endorectal ultrasounds are typically regarded as being an accurate testing method, especially when the disease is still fairly localized. Often, the course of treatment that a doctor recommends depends heavily on the results of tests like endorectal ultrasounds since they can detect the extent of a tumor’s invasion as well as if the lymph nodes have been affected.

Unfortunately, serious errors sometimes occur when determining the stage of colon and rectal cancer. For instance, if your doctor suspects the cancer is in its earliest stages, but it is actually much more advanced, he or she may recommend treatment which isn’t aggressive enough and ends up being ineffective. Likewise, if the cancer is interpreted to be very advanced, but actually isn’t, your doctor may recommend a course of treatment which is unnecessarily aggressive.

According to the National Cancer Institute, an endorectal ultrasound is a test where a probe is inserted into the rectum. The tube emits high-energy sound waves which resonate off of internal tissues and organs, much like a medical form of sonar. The echoes from the sound waves form a picture called a sonogram. The doctor inspects the sonogram to examine the tumor’s size and depth, as well as to check for the presence of other tumors or growths in the rectum and colon.

There are many ways an inaccurate staging of colorectal cancer can be made by your doctor when an endorectal ultrasound is used. One way is by under- or overestimating the depth of a tumor. Also, it’s possible doctors can misread whether the lymph nodes have been affected by the spread of the cancer. Differences in interpretation aren’t uncommon in staging colorectal cancer, and can lead to an inaccurate diagnosis. Doctors may simply go by the appearance of a lymph node, such as its relative size, to determine if lymph node involvement has occurred.  Imflammation around a tumor can often cause doctors to overestimate the severity of the tumor’s depth.

Many of these errors can be attributed to a test operator who is simply too inexperienced to accurately stage colon and rectal cancers. A practitioner’s inexperience with staging colon and rectal cancers may result in the tendency to want to avoid understaging for fear of undertreating the patient. However, staging colorectal cancer too high can be every bit as detrimental to the patient as understaging. Though endorectal ultrasounds are generally accurate methods of testing, doctors can make pivotal mistakes when relying too heavily upon the results alone when determining stage, and consequently recommending treatment.