After surgical resection of gastric cancer, it is possible to hear the surgeon determine the surgical determination as R0, R1, or R2. Patients are inevitably confused as to what this means. In fact, the R classification is a way to determine whether there is residual tumor at the surgical site after surgery (not applicable to endoscopic treatment) and is informative for the development of subsequent treatment plans.
What is R0, R1, and R2?
The surgeon evaluates the status of the resected tumor margin during surgery and the pathologist evaluates the resected specimen postoperatively, whereby a judgment is made about the R classification.
- R0 was defined as no evidence of residual tumor. After complete resection of the tumor by the surgeon, the pathologist looks at the edges of the resected specimen under the microscope and finds no residual tumor, indicating that the entire lesion was completely removed and no tumor remains in vivo.
- R1 was defined as the presence of tumor residue at the cut edge of the resected specimen on pathologic examination despite the absence of tumor residue in the naked eye.
- R2 is defined as the presence of tumor residue at the cut edge of the resected specimen that is detectable to the naked eye.
- R2
R0 surgery is often referred to as radical surgery, and neither R1 nor R2 can be considered radical resection of the tumor.
R How does the postoperative treatment differ by classification?
For those who have achieved R0 resection, there is a difference in treatment.
For patients who achieve R0 resection, the tumor is radically resected, and the surgeon will generally decide on a postoperative adjuvant treatment strategy based on the tumor stage, either standard postoperative treatment or follow-up only.
- For patients with early gastric cancer without lymph node metastasis (N0), follow-up is generally recommended.
- For patients with a pathological diagnosis of T2 and no lymph node metastasis (N0), physicians generally recommend continued follow-up and observation. However, adjuvant chemotherapy or radiotherapy is usually recommended if there are high-risk factors (e.g., high tumor grade, vascular thrombosis or infiltrating nerve, younger than 50 years, no D2 radical surgery).
- For patients with lymph node metastases in T3 to T4 or whatever the T stage, adjuvant therapy, including adjuvant chemotherapy or radiotherapy, is usually recommended.
R1 or R2 resection still has tumor remnants because the surgery did not achieve radical cure. Therefore, for this group of patients, regardless of postoperative T-stage and N-stage, physicians generally recommend adjuvant radiotherapy or multidisciplinary discussion (MDT) to decide the next treatment plan according to their condition, if their physical condition allows. (Contributed by Pengliang Wang, Department of Gastrointestinal Oncology, The First Hospital of China Medical University)