The Surgeon and Adjuvant Therapy for Stage II Colon Cancer
One of the more controversial issues in oncology is the role of postoperative adjuvant chemotherapy for stage II colon cancer. There are approximately 26,000 patients who are diagnosed with stage II colon cancer each year. The source of this controversy is the relatively high survival rates following surgical resection. Overall survival rate is 80% for stage II colon cancer, and it is difficult to demonstrate a clinical benefit with postoperative adjuvant therapy when the risk of recurrence is relatively low. When the risk of recurrence is low, a great number of patients have to be treated in order to achieve a small statistical benefit. Surgeons are aware of the favorable results of operative therapy for stage II colon cancer and recommending postoperative adjuvant therapy to patients can be confusing.
Identifying stage II patients who have a high risk for recurrence and who then could benefit from postoperative systemic adjuvant therapy would be a major advance. E5202 is a multi-institutional trial which has been endorsed by ACOSOG to answer the question of postoperative adjuvant therapy in high-risk stage II colon cancer patients (http://www.med.wright.edu/dcop/schemas/E5202.pdf). Eligibility criteria include T3/4N0M0 colon cancer and ≥8 lymph nodes in the resected specimen. Patients who present with obstruction or perforation are excluded. Initially patients are divided into high- and low-risk recurrence groups based on laboratory assessment of the primary tumor. High risk is defined as microsatellite stability and loss of heterozygosity at 18q. Patients with stage II tumors that exhibit microsatellite stability or low-frequency instability have a significantly worse prognosis than those patients whose primary colon cancers have high microsatellite instability.1 Allelic loss of chromosome 18q in the primary tumor decreases the survival of stage II patients.2 High-risk patients will be randomized into two groups: Group A will postoperatively receive 5FU, Leucovorin and oxaliplatin and Group B will receive 5FU, Leucovorin and oxaliplatin plus bevacizumab. Low-risk patients will not receive postoperative therapy and will be followed as Group C. It is estimated that 40% of all stage II colon cancers will be in the high-risk category (Groups A and B). Therefore, a sample size of 3,438 patients with stage II colon cancer is needed to complete this study.
In order for this study to accrue patients timely and to answer this important question of postoperative systemic adjuvant chemotherapy in high-risk patients, surgeons are needed to screen eligible stage II colon cancer patients for this trial. Surgeons have played a key role in postoperative adjuvant therapy trials by referring patients to medical oncologists who enroll the patients and receive the credit. The uniqueness of E5202 is that surgeons will receive credit for identifying patients with stage II disease and for explaining the importance of the trial to their patients. A simple one-page form was developed so that the data center can track the credits. This form with instructions can be found at http://www.acosog.org. E5202 needs surgeons who understand the trial design and patient eligibility criteria and who can explain the trial to their patients. While there is currently no reimbursement for the credit, it is possible that if ACOSOG can demonstrate that surgeons made a significant, measurable contribution to this trial, reimbursement for this trial and future adjuvant trials is possible. ACOSOG needs your participation in E5202 by screening patients for stage II and supporting the treatment described in the protocol. This is also an opportunity to demonstrate that surgeons play an important role in the success of large phase III postoperative adjuvant trials.