Colorectal cancer (CRC) is very common among western countries. Surgical resection was the frequent option to offer the best oncological outcomes. However, surgery can have negative impact in quality of life. For instance, a rectal cancer located at 5 cm or less from the anal merge was usually submitted to abdominoperineal resection with a huge negative impact in patient’s life. Additionally, every CRC surgeries can have severe and life-threatening complications. Aiming at preserving the rectum and its function and to give rectal cancer patients’ a good quality of life, new different strategies are changing the surgeons’ role in cancer treatment.
Advances in oncology have been changing the need for surgery and decreasing the need for aggressive surgical procedures. Endoscopic resections have also contributed to promote less aggressive treatments, but doctors must not forget that even endoscopic ressections can cause life-threatening complications (e.g. perforation). Not all CRC need to be surgically resected. What? Yes, and I am not talking about chemotherapy nor radiotherapy. I am talking about surveillance alone.
Today, endoscopic resection of a T1 CRC may be accepted as oncological treatment based on histopathological features associated with a low risk of lymph-node metastasis. Selecting cases for endoscopic resection will increase the number of good specimens for an accurate histopathological analysis, and will decrease the need of unnecessary surgery (because of inaccurate histopathological analysis). Other situation is a cancer incidentally diagnosed after a polypectomy. The specimen should be resected in one piece, with well-defined margins, and the highest quality and quantity of submucosal tissue. Only a good endoscopic resection will maximize the chance of a "curative" resection.
In the case of endoscopic resection of a T1 CRC, the histological analysis will define the endoscopic resection as “curative” (low risk of lymph-node metastasis) or “non-curative”. That is why the quality of the resection is so important. Dr. Klaus Metter et al. from the Klinik fur Gastroenterologie in EichertstraBe, Germany, presented the following features as criteria for “curative” endoscopic resection (T1 CRC):
En-bloc complete resection with horizontal and vertical free margins
No lymphatic or blood vessels infiltration
Low or moderate histological grade (G1/G2)
Infiltration depth in the submucosa < 1000um
Low-grade tumor budding
According to Dr. Klaus et al. the most important factors of a “non-curative” resection and association with lymph-node metastasis are lympho-vascular invasion, poor grading, and high tumor cell budding. On the other hand, infiltration into the submucosa > 1000 um without any other feature is associated with a relative low risk of lymph-node metastasis. However, the authors state that only 11-15% of patients submitted to surgical resection following a “non-curative” resection have positive lymph-node metastasis. Because of this, different authors have tried to find better ways to predict the presence of lymph-node metastasis after “non-curative" endoscopic resection. Some include female gender and distal tumor location.
In conclusion, Dr. Klaus Metter et al state that endoscopic resection of a T1 CRC with features of “curative” resection (meaning low-risk of lymph-node metastasis) is a good oncological treatment. For maximizing this treatment option an accurate histological analysis is paramount, for which a high-quality endoscopic resection is mandatory. It is important to have good horizontal and vertical margins with minimal thermal artifacts (but a good hemostasis is important).
The Japanese Society for Cancer of the Colon and Rectum published in 2016 the following guidelines (figure) to guide the treatment decision following an endoscopic resection of a T1 CRC.
This idea of surveillance for T1 CRC following a “curative” endoscopic resection may not be well accepted by many. Knowing that it is based on the idea of low-risk of lymph-node metastases may not be enough, I think. T1 is an invasive tumor. The spread may also be within the colon and rectum wall, as well as through blood vessels. Histological analysis may fail. Some questions need a solid answer:
Would a radical surgical resection improve oncological outcomes? Some authors report no recurrence, no lymph-node metastasis, and no cancer-related deaths after “curative” endoscopic resection (median of 3.5 years follow-up).
Will postoperative consequences and potential complications of a radical resection be acceptable in a low risk cancer? Probably not.
Will patients accept surveillance instead of radical resection? Some authors reported that several patients submitted to “curative” endoscopic resection were concerned about lymph-node metastasis and proceeded to surgical resection.
Will colorectal screening programs decrease the number of radical resections for CRC? Finding early CRC will decrease aggressive surgeries, I think.
Will surgeons’ lose experience in CRC surgery? Probably. If so, will medical community keep reducing even more the number of surgeons’ they think should be doing CRC surgeries? Hmmm... As a consequence, will the accessibility of patients with advanced CRC to radical surgical treatment be reduced in the future?
Everybody seek less invasive procedures and try to avoid surgery. Not operating is always the best way of not having complications. This is good for patients and for surgeons. But is this good for cancer treatment? The future will tell, but for now this is good news for CRC patients.
Bibliography:
Dr. Carlos Eduardo Costa Almeida
General Surgeon
Comments