Outcomes of persistent lymph node involvement after neoadjuvant therapy for stage III rectal cancer.

INTRODUCTION: Lymph node involvement is a well-known predictor of recurrent rectal cancer in patient who did not undergo neoadjuvant therapy patients. The role of persistent lymph node disease after neoadjuvant treatment, however, is debatable. This study compares outcomes of patients with clinical, stage III rectal cancer who had nodal disease on surgical pathology after neoadjuvant treatment to patients with negative nodes.

METHODS: We reviewed retrospectively a consecutive cohort of all clinical, American Joint Committee on Cancer stage III rectal cancer patients who received neoadjuvant chemoradiotherapy and had an R0 resection at the Massachusetts General Hospital between 2004 and 2015.

RESULTS: A total of 166 patients met the inclusion criteria, of whom 53 had persistent nodal disease on pathologic examination. This group had a greater rate of local and distant disease recurrence and a shorter median recurrent disease-free survival than patients with a complete nodal response. In multivariable analyses for disease recurrence, disease free survival was greater for patients without positive results in lymph nodes on pathologic examination.

CONCLUSION: Persistent nodal involvement after neoadjuvant therapy is associated with an increased risk of distant metastases and a shorter disease-free survival. Identifying patients with treatment-resistant lymph nodes preoperatively and adjusting neoadjuvant treatment might result in better outcomes.