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Although not as common as basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC) can metastasize and exhibit more aggressive growth patterns than BCC. As a result, many experts have called for an improved staging system for cSCC to determine prognosis of tumors.
Baltimore - Although not as common as basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC) can metastasize and exhibit more aggressive growth patterns than BCC. As a result, many experts have called for an improved staging system for cSCC to determine prognosis of tumors.
There are many specialties interested in improving staging for cSCC. According to Nanette J. Liégeois, M.D., Ph.D., oncology and plastic surgery departments, Johns Hopkins University School of Medicine, Baltimore, the American Joint Committee on Cancer (AJCC) should be applauded for its effort in taking the next step and providing a template whereby future revisions can be made.
The cSCC AJCC chapter, led by Dr. Liégeois, features seven board-certified specialties.
Staging system concept
The concept of a cancer staging system was developed more than half a century ago by French physician Pierre Denoix from the International Union against Cancer. Dr. Denoix provided the TNM (tumor, nodes, metastasis) template that has guided staging systems to date, classifying cancers according to very strict clinical and pathologic definitions. Though the system has many weaknesses, it has provided the gold standard upon which all cancers are staged.
The movement of the AJCC to establish the first cSCC staging system represents a landmark event in the field of cutaneous oncology, Dr. Liégeois says. She led the development of this first staging system under the auspice of Arthur Sober, M.D., and Charles Balch, M.D. She says the staging system is currently being used at Johns Hopkins to understand the prognosis of patients, and further improvements to the staging system are planned. The staging system "provides international unity and serves as a template to foster collaboration," she says.
According to Dr. Liégeois, the need to develop an independent staging system for cSCC is manifold. First, the immunosuppressed and elderly population are particularly at risk for poor prognosis disease. Also, cancer treatments are evolving, and finally, nonmelanoma skin cancer (NMSC) remains one of the most costly cancers for Medicare.
Dr. Liégeois says she sees numerous high-risk skin cancer patients while collaborating with plastic surgeons and oncologists at Johns Hopkins.
"We are seeing increasing numbers of advanced SCC cases. This presses the issue that we need to understand the determinants of poor prognosis disease," Dr. Liégeois says. "Some studies suggest that a third of all skin cancer deaths are from nonmelanoma skin cancers, of which the largest offender is cSCC. Right now, the best thing for our patients is to provide multidisciplinary care."
Previous staging literature on NMSC included everything from BCC to Merkel cell carcinoma (MCC). According to Dr. Liégeois, BCC and MCC have no similarities in clinical presentation or prognosis. Therefore, a staging system that encompasses such diverse disease entities does not suitably provide clinicians with helpful prognostic parameters. Similarly, cSCC tends to have unique biologic behavior compared with other NMSC tumors, such as BCC.
Staging nodal burden
According to Dr. Liégeois, there has been recent scientific data suggesting that the amount of lymph node burden needs to be considered when staging cSCC tumors. Therefore, Dr. Liégeois put forth a new staging system in which nodal disease is staged in multiple ways: N0, N1, N2 and N3. This significantly differs from the older classification, in which nodal disease was staged as either present or absent (N1 versus N0, respectively).
Ophthalmologic plastic surgeons have developed their own staging system for NMSC of the eyelid. In contrast to Dr. Liégeois' cSCC staging system, ophthalmologists are basing their staging system according to anatomic-based sites. Dr. Liégeois notes that cSCC often extends beyond the eyelid and does not respect cosmetic anatomic boundaries.
Nonmelanoma skin cancers are sunlight-induced tumors in which the epidermis is completely contiguous. According to Dr. Liégeois, cSCC should be staged according to evidence-based medicine and not according to anatomic sites, because the biology of the disease does not respect the anatomic subunits.
"It seems that the staging of tumors in accord with evidence-based medicine will be preferable to anatomic-based methodology," Dr. Liégeois says. "I hope that this discrepancy does not introduce unnecessary confusion for registrars. Moreover, it is time that all specialties agree to an SCC staging system that will clearly benefit patients, and such a system must be evidence-based. I believe we can make a difference."