Analyses of clinical and pathological correlations in oral carcinoma, such as positive margins, nodal status, extracapsular spread, degree of invasion and overall staging congruence are important in order to implement the most appropriate treatment pathways [5–7]. In our multi-institutional analysis of patients in Alberta, clinical and pathological staging was congruent in 21.9% of early stage patients upstaged and 7.9% of patients downstaged. Previous studies have shown the level of pathological upstaging in HNSCC patients with clinical N0 necks to be 34–44% [2, 3], and an estimated 20–30% of OCSCC harbour occult regional metastases . This is clinically relevant in the context of recommendations by the American Joint Committee on Cancer, which state an elective neck dissection (END) may be performed where the risk of nodal metastasis is greater than 20% . A recent study also demonstrates that nodal disease is a strong independent predictor of outcome in OCSCC . Taken together, although the level of upstaging in our study was relatively low, this lends support to perform END for OCSCC patients with clinically N0 necks.
Possible causes for staging discrepancy includes delay between clinical diagnosis and pathologic analysis resulting in upstaging, pathologic interpretation of specimen and lack of accuracy of clinical staging tools. Physical examination measures such as measurement of tumor and node size and manual palpation are relatively inaccurate and may be subjectively different based on surgeon experience. The lower limit of node palpation has been shown to be 0.5 cm in superficial areas and 1 cm in deeper regions . The use of CT scanning does significantly improve the accuracy of staging, however, it does not detect micrometastasis and may have limited utility in differentiating nodal disease from submandibular gland in the submandibular region [3, 11]. Therefore microscopic deposits and extracapsular spread may not be clinically identified and can only be definitively assessed by neck dissection with pathological assessment. Given the current limitation in clinical staging even in combination with advanced imaging technology, initial surgical intervention for all patients with OCSSC may be warranted . Some patients with early stage disease only treated with radiation will not have the benefit of appropriate staging to initiate multimodality treatments known to improve survival in advanced stage OCSCC .
To our knowledge, the influence of clinical and pathological staging disparity on survival in OCSSC has not been reported. Our data suggests OCSSC patients pathologically upstaged or downstaged do not have a significantly altered disease-specific survival (Figure 2). It is important to note that all patients in this study had surgery as part of their treatment pathway, which is necessary to enable appropriate staging. In the 21.9% of patients with early stage disease, upstaging may have enabled for appropriate adjuvant treatment. In 7.9% of advanced stage patients, downstaging may have prevented unnecessary adjuvant treatment if initially treated surgically. Taken together, further study to determine the role of stage discrepancy on the alteration of treatment pathways way be warranted.
In contrast to other studies, although our data demonstrates staging discrepancy, we have found that this level of discrepancy does not significantly alter survival. One possibility for this result is a lower level of staging discrepancy in our cohort in comparison to other reports. In addition, most staging differences resulted in upstaging from early to advanced stage disease. In these cases, patients should have received appropriate post-operative radiation or chemoradiation and would therefore not be undertreated.
This study demonstrates levels of stage discrepancy in a cohort of patients predominantly treated with surgery as the primary treatment modality for OCSCC. This is in contrast with numerous practices in other institutions where chemoradiation is a first line treatment for OCSCC. In a subset of patients, primary surgical excision may provide more appropriate treatment if pathological upstaging or downstaging occurs from further analysis of the pathological specimen. For instance, when a patient is upstaged from early stage disease following surgery, chemoradiation may be added to the treatment protocol. Conversely, a patient being downstaged following surgery may have their therapy de-escalated. To further address these possibilities, a prospective analysis of patient outcomes following upstaging or downstaging should be performed.
Our study has a number of limitations. This is a retrospective analysis of patients staged by a variety of head and neck surgeons in various tertiary care centers, with specimen interpreted by different pathologists. This heterogeneity however enables a more realistic representation of overall staging differences. In terms of our survival analysis, one of the subgroups analysed, namely downstaged patients, was relatively small. This may therefore under represent a potentially significant difference in a larger sample size.