[Do metachronous colorectal adenomas show proximal shift?].

Area of Science:

• Gastroenterology
• Oncology
• Colorectal Surgery

Context:

• Colorectal cancer (CRC) management involves resecting tumors and synchronous lesions.
• Post-resection surveillance aims to detect new or recurrent adenomas.
• Understanding adenoma behavior after CRC treatment is crucial for optimizing follow-up strategies.

Purpose:

• To investigate the potential for a proximal shift in the location of metachronous adenomas after colorectal cancer resection.
• To compare the localization of metachronous adenomas with synchronous lesions.
• To analyze the influence of patient sex, tumor size, and number of synchronous lesions on adenoma localization.

Summary:

• A review of 382 patients with resected CRC and complete colonoscopies revealed a high incidence of synchronous (54.5%) and metachronous adenomas (42.4% after median 48 months follow-up).
• Metachronous adenomas demonstrated a significant proximal shift in localization compared to synchronous lesions (39.5% vs. 21.2%, p=0.0001).
• This proximal shift was consistent across successive generations of metachronous adenomas and independent of sex, tumor size, or initial lesion count.

Impact:

• Identifies a specific spatial behavior of metachronous adenomas post-CRC resection.
• Highlights the need for comprehensive colonoscopic surveillance throughout the postoperative period.
• Informs clinical practice regarding the importance of thorough examination of the entire colon in CRC survivors.