When a rectal cancer patient is dxd, a variety of tests are done on them to give them a CLINICAL staging - tests such as the endorectal ultrasound or sometimes a rectal MRI. Tests like these, that specifically target one area, are not generally given to, for example, colon cancer patients. When you think about it it is quite simple. A colon cancer patient is dxd, has the required tests (CEA, CT or PET, etc) and generally has surgery within a few weeks of dx. The pathology report will indicate what stage the patient is, unless obviously the CT or PET has indicated a dx of stage IV.
When a rectal cancer patient is dxd (and its obviously rectal cancer), the rectal ultrasound is done to determine the depth of the tumor and to ascertain whether or not any pelvic nodes appear to be affected. If it appears that the patient is, for example, a stage I, the accepted protocol would call for some form of surgical resection (excision, LAR or APR) and a pathology report will be obtained that will either (a) confirm the dx of a stage I or refute it. Keep in mind that rectal cancer patients, just like colon cancer patients also have a CT or PET to rule out metastatic disease. The difficulty arises when the patient is clinically staged a stage II or above. Then, since the studies have shown that neoadjuvant chemoradiation does have a significant effect on local recurrence and generally the patient undergoes neoadjuvant chemoradiation. The problem, as Gaelen stated, comes when the treatments do their work- specifically (a) shrinking the tumor and/or (b) sterilizing the pelvic nodal field. Keep in mind that the treatments don't have to be 100% effective (meaning no cancer cells are left) to skew the results of the surgical pathology report. By 'skewing' the results I simply mean that IF the surgical report was used for staging purposes, it would most probably NOT be correct which is why a CLINICAL dx is given before any treatment begins. Too many rectal cancer patients erroneously believe that the surgical pathology report is their actual diagnosis and either (a) often want to 'restage' themselves based on that report and/or (b) don't feel any adjuvant treatment is necessary when the pathology report comes back differently than the clinical dx.
Remember that local recurrences for the rectal cancer patient are much different than a local recurrence for the colon cancer patient. They tend to be more difficult to treat and they tend to also mean that distant spread is a much more likely possibility. The pelvic area is rich in blood vessels and lymph system is quite extensive in this area as well.
Grace, you have to also understand that regardless of what type of cancer a patient has, there is no guarantee with cancer that the staging the patient receives is 100% accurate. Simply put, there could be cancer cells circulating in a patient's body that are too small to be picked up by the CT or PET scan which is precisely why adjuvant chemotherapy for stage II and higher is generally recommended to kill off any of those cells. Cancer is based on statistics from historical data and from studies that indicate which treatments are the best, etc. You should, however, feel confident that all the presurgical testing done does give the doctor a darn good idea of what your staging is and he/she will coordinate your care accordingly. The best thing you or any cancer patient can do is to go through the treatments but then make sure you have your followups (doctor visits, blood draws, CT or PET, etc) to keep on top of what is going on in your body.
Dx 6/22/2006 IIA rectal cancer
6 wks rad/Xeloda -finished 9/06
1st attempt transanal excision 11/06
11/17/06 XELOX 1 cycle
5 months Xeloda only Dec '06 - April '07
10+ blood clots, 1 DVT 1/07
transanal excision 4/20/07 path-NO CANCER CELLS!
NED now and forever!
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