Pathologic Complete Response of Primary Tumor Following Preoperative Chemoradiotherapy for Locally Advanced Rectal Cancer: Long-term Outcomes and Prognostic Significance of Pathologic Nodal Status (KROG 09–01)
We read with great interest the article by Yeo et al.1 They have defined that a positive lymphatic basin confers a poorer oncological outcome after neoadjuvant chemoradiation followed by adjuvant chemotherapy. Of critical importance, however, is that the 5-year actuarial risk of relapse showed that the vast majority of these were distant metastases (12.9%), whereas only the minority (3.5%) of patients underwent a local recurrence. These data, however, pertain to the entirety of their group and unfortunately they do not specifically state comparative local control data between patients who were node positive and node negative. A by-proxy estimate of the impact of nodal disease on local control can, however, be achieved by comparing the data from this study with that of a previously published study of 566 patients downstaged to pT0 N0 after chemoradiation.2 Here 1.6% of patients underwent a local recurrence despite all patients being node negative. By simple subtraction of these 2 data sets, it could be inferred that nodal positivity had less than 2% influences on local recurrence in patients whose tumors had achieved pT0 status. This, in our opinion, is the key point in the current climate where local excision of tumors downstaged to pT0 is gaining momentum.
Considering that lymph node involvement is generally accepted to be in the region of only 5% to 10%1,3,4 when pT0 status has been achieved and that up to 30% of patients may undergo complete pathological response after CRT, we believe that studies like this one by Yeo et al should herald a “Damascus Moment” for the surgical community as a whole. Specifically, tumors downstaged to pT0 are extremely unlikely to locally recur, as the vast majority of them contain no tumor in either the rectal wall or the lymph nodes. Of those that do contain involved nodes, the main impact of this is that they are likely to develop a distal recurrence, which would, of course, not be influenced by radical surgery to the local tumor site. It is, therefore, our opinion that all patients should undergo endoscopic examination and local excision of the tumor after CRT. Assuming both clear margins and pT0 status have been obtained, local excision alone should provide oncological equivalence to radical surgery. Such an approach would avoid the current endemic of performing radical surgery on an empirical basis based on pretreatment clinical stage and thus probably grossly overtreating patients who have been essentially cured from rectal cancer. We therefore feel that the results of this study in combination with other published data fuel the need for a study of local excision alone as a primary treatment modality for pT0 status.