© 2005 Oxford University Press
CORRESPONDENCE |
RESPONSE: Re: Colon Cancer Survival Rates With the New American Joint Committee on Cancer Sixth Edition Staging
Affiliation of authors: Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA
Correspondence to: Jessica B. O'Connell, MD, Department of Surgery, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, 72-215 CHS, Los Angeles, CA 90095 (e-mail: jbocjboc{at}hotmail.com).
In our recent article (1) that reported the 5-year survival rates for colon cancer by use of the newly updated American Joint Committee on Cancer (AJCC) sixth edition staging system, we were surprised to find that colon cancer survival was worse for T4N0M0 (stage IIB) than for T1-2N1M0 (stage IIIA) disease. This finding initiated some discussion as to whether or not we should revert back to the fifth edition staging system (2)—with the above editorial providing some background and additional information regarding current issues pertaining to staging systems development. Our sentiment, and response to the editorial and correspondence by Edge et al., is that the sixth edition staging system clearly allows for increased stratification of the disease much more than the prior fifth edition. The gaps in survival curves between stages II and III of the fifth edition were probably too large and thus justify the increased number of substages in the sixth edition. It is really because of the increased detail provided by the sixth edition that we were able to identify the survival differences between the more advanced stage II patients and the early stage III patients. Such detail is also good because it will likely allow us to develop increasingly focused clinical trials. As an example, we have received much feedback from our study saying that the stage IIB survival rate is lower because of the lack of adjuvant therapy. As such, this cohort may need to be studied in a trial to validate this observation.
Although we agree that we should not revert to the fifth edition, we also agree with Edge et al. that there are several issues to address currently regarding the staging of colorectal cancer. The use of molecular markers or a panel of items has shown promise in studies (3) and may be an important addition in the future to staging systems. Also, the inclusion of some sort of comorbidity risk adjustment is an important issue to address—for the study of receipt of therapy, quality of care, and also survival outcomes. Finally, the issue of staging rectal cancers has become increasingly complex with the advent of neoadjuvant therapy, and the staging system for rectal cancer needs to have thoughtful improvements made. Although our original study addressed only colon cancer, we attempted to perform this same analysis with rectal cancer. We came upon several issues that made the analysis difficult to perform—most notably the lack of reliable pretreatment clinical-staging information. In the cancer registry, we have the pathological stage after surgical resection. However, this stage may not be the most appropriate for prognosticating outcomes, as poignantly exemplified by the number of cases with a complete response (4). In any case, if we are to use cancer registry data to help study survival rates for rectal cancer patients, more data variables will probably be needed.
In summary, and as concluded in the above editorial by Burke, continuous scrutiny and thoughtful revision of the colorectal cancer staging system are needed.
REFERENCES
(1) O'Connell JB, Maggard MA, Ko CY. Colon cancer survival rates with the new American Joint Committee on Cancer sixth edition staging. J Natl Cancer Inst 2004;96:1420–5.
(2) Burke HT. Outcome prediction and the future of the TNM staging system. J Natl Cancer Inst 2004;96:1408–9.
(3) Agrawal D, Chen T, Irby R, Quackenbush J, Chambers AF, Szabo M, Cantor A, Coppola D, Yeatman TJ. Osteopontin identified as lead marker of colon cancer progression, using pooled sample expression profiling. J Natl Cancer Inst 2002;94:513–21.
(4) Pucciarelli S, Toppan P, Friso ML, Russo V, Pasetto L, Urso E, et al. Complete pathologic response following preoperative chemoradiation therapy for middle to lower rectal cancer is not a prognostic factor for a better outcome. Dis Colon Rectum 2004;47:1798–807.[CrossRef][Medline]
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J Natl Cancer Inst 2005 97: 463-464.
J Natl Cancer Inst 2005 97: 464-465.
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