Adjuvant Treatment for Node-Negative Rectal Adenocarcinoma After TME

Critical Staging Information Needed

• The quality of the TME specimen, including the mesorectal plane, intramesorectal plane, or muscularis propria plane, is crucial for determining the treatment plan 1, 2, 3
• A clear circumferential resection margin (CRM) status, with a margin of more than 1mm, is necessary for optimal outcomes 4
• The presence of adverse features, such as lymphovascular invasion, perineural invasion, tumor perforation, should be assessed 4

Treatment Algorithm Based on Pathologic Stage

• For upper rectal cancer (>12 cm from anal verge), treatment should follow colon cancer guidelines, with adjuvant chemotherapy recommended for stage III and considered for high-risk stage II 5, 4, 6
• Postoperative chemoradiotherapy is recommended for mid/low rectal cancer (≤12 cm from anal verge) with pT3N0 if preoperative radiotherapy was not given 4

Specific Chemotherapy Regimens

• The FOLFOX regimen, consisting of oxaliplatin, leucovorin, and 5-FU, is a recommended adjuvant chemotherapy option, although the evidence for its use is not strong 7
• The CAPOX regimen, consisting of oxaliplatin and capecitabine, is an alternative adjuvant chemotherapy option 7

Common Pitfalls to Avoid

• At least 12 lymph nodes must be examined to accurately stage as N0, as fewer than 12 nodes examined may represent understaging 5, 4, 6
• Poor quality TME (muscularis propria plane) significantly increases recurrence risk regardless of adjuvant therapy 1, 2, 3
• A positive CRM (<1mm) is an indication for postoperative chemoradiotherapy if preoperative RT was not given 4