PAST

The circumferential resection margin (CRM) is one of the most important prognostic indicators in rectal cancer.1 Preoperative magnetic resonance imaging and evaluation of the CRM can identify those patients at high risk for local recurrence.2 Current guidelines recommend neoadjuvant treatment in all patients with American Joint Committee on Cancer (AJCC) stage II and III rectal cancer. However, local recurrence rates are similar with and without neoadjuvant treatment before surgery if only high-risk patients are selected for treatment.3,4

The importance of variable mesorectum thickness in local recurrence has not been investigated to date. We hypothesized that ventrally located tumors are more prone to local recurrence than dorsally located tumors because of the varying thickness of the mesorectum. To test this hypothesis, we retrospectively analyzed all patients who underwent radical rectal resection for mid- and low-rectal cancer in our department between October 2001 and December 2013.

PRESENT

Our results show that ventral tumor location is an independent risk factor for local recurrence. Tumor location also affected how much patients benefited from neoadjuvant therapy—irradiation reduced local recurrence rates in patients with ventrally located tumors, but not in patients with dorsally located tumors.5

FUTURE

Tumor location is easy to define during preoperative diagnostics. Therefore, based on our results, we propose that tumor location should be considered in future studies on rectal cancer.