Discussants: G. Melton-Meaux (Minneapolis, MN)
The authors addressed an important and controversial topic in colorectal surgerywith colorectal cancer. They used publicly available SEER data over 11 years and examined both cancer-specific and OS with early colorectal cancer, looking at these outcomes after both local excision and radical resection.
As treatment paradigms shift in colorectal cancer, there is a trend toward trying to have less invasive therapies, to try to lessen morbidity while trying to maintain overall surgical outcomes, including CSS and OS. They found, again, equivalent outcomes with carcinoma in situ but worse outcomes with stage I with just local resection.
I have 3 questions for the authors.
First, did they observe any changes in the use of local excision versus resection over the time period of the study? Were there differences in survival over time? Can you speculate on the reasons for what you observed?
Second, were you able to capture patients who first underwent local excision and later underwent a salvage procedure—namely, a radical resection? And what were the outcomes associated with this?
Final question, I found it really surprising the number of younger patients in your cohort who underwent local excision. Can you comment on this specifically?
I congratulate the authors on this work, which addresses an important and controversial area in the treatment of colorectal cancer.
Response From A. Bhangu (London, UK)
First, for the time issue, over time there was a significant improvement in survival for major resection. An increasing trend to improved survival for local excision was seen but has not yet achieved significance. It may be that improvements in screening, selection, and adjuvant therapy account for this.
Over time, there was a slight but significant reduction in the use of local excision, which is perhaps counterintuitive, as it is a new technology, but with stable rates of major resection. It is unclear why, but transanal and endoscopic techniques are highly specialized,which may restrict their use to certain centers and perhaps even to certain individuals.
Second, for the issue of salvage, we restricted patients in the local excision group to those with zero or 1 lymph node, so this group is unlikely to include patients who were salvaged. However, it is reasonable to speculate that they may well be in the major resection group.
The risks of salvage surgery, including early versus late timing, were really beyond the scope of this study. A linked study to Medicare data would probably be able to answer this question; however, we did not seek this data because it would have excluded patients under the age of 65, who are perhaps the most important group for the current study.
Finally, we were also surprised by the proportion of younger patients. It is not exactly clear why. If we were to speculate, I would say that it may be an issue of clinician equipoise. Some surgeons and endoscopists are true believers in this technology, and they may be applying it to a wide scope of patients.