[Rectal cancer and adjuvant chemotherapy: which conclusions?]

Area of Science:

• Oncology
• Gastroenterology
• Surgical Oncology

Context:

• Rectal adenocarcinoma constitutes a third of colorectal cancers, with 12,000 annual cases in France.
• Unlike colon cancer, the benefits of adjuvant chemotherapy for rectal cancer remain under investigation.
• Preoperative chemoradiotherapy is standard for mid/lower rectal cancers, improving local control but not survival outcomes.

Purpose:

• To evaluate the efficacy of adjuvant chemotherapy in rectal cancer patients.
• To analyze the impact of fluoropyrimidine-based chemotherapy on metastatic relapse and survival.
• To inform treatment guidelines for stage II and III rectal adenocarcinoma.

Summary:

• Historical data and meta-analyses suggest adjuvant fluoropyrimidine chemotherapy decreases metastatic relapse risk in stage II/III rectal cancer post-surgery, similar to colon cancer.
• EORTC trial 22921 showed increased progression-free survival (though not statistically significant) with 5-fluorouracil and leucovorin, despite low treatment completion rates.
• Current French recommendations favor discussing fluoropyrimidine chemotherapy for stage III rectal cancer and generally not for stage II, pending multidisciplinary review.

Impact:

• Adjuvant chemotherapy decisions for rectal cancer require multidisciplinary team meetings.
• While combinations like FOLFOX4/6 or XELOX are considered for stage III (expert opinion), their benefit in complete responders or node-negative cases is unproven.
• Ongoing trials are assessing fluoropyrimidine/oxaliplatin combinations and neoadjuvant chemotherapy for rectal cancer.