Is the 1-cm Rule of Distal Bowel Resection Margin in Rectal Cancer Based on Clinical Evidence? A Systematic Review

Abstract

Background. Distal intramural spread is present within 1 cm from visible tumor in a substantial proportion of patients. Therefore, C1 cm of distal bowel clearance is recommended as minimally acceptable. However, clinical results are contradictory in answering the question of whether this rule is valid. The aim of this review was to evaluate whether in patients undergoing anterior resection, a distal bowel gross margin of \1 cm jeopardizes oncologic safety. Methods. A systematic review of the literature identified 17 studies showing results in relation to margins of approximately \1 cm (948 patients) versus [1 cm (4626 patients); five studies in relation to a margin of B5 mm (173 patients) versus [5 mm (1277 patients), and five studies showing results in a margin of B2 mm (73 patients). In most studies, pre-or postoperative radiation was provided. Results. A multifactorial process was identified resulting in selection of favorable tumors for anterior resection with the short bowel margin and unfavorable tumors for abdominoperineal resection or for anterior resection with the long margin. In total, the local recurrence rate was 1.0% higher in the \1-cm margin group compared to the [1-cm margin group (95% confidence interval [CI] -0.6 to 2.7; P = 0.175). The corresponding figures for B5 mm cutoff point were 1.7% (95% CI -1.9 to 5.3; P = 0.375). The pooled local recurrence rate in patients having B2 mm margin was 2.7% (95% CI 0 to 6.4). Conclusions. In the selected group of patients, \1 cm margin did not jeopardize oncologic safety.

Altering the therapeutic paradigm towards a distal bowel margin of < 1 cm in patients with low‐lying rectal cancer: a systematic review and commentary

“…The results of our review of low-lying tumours in irradiated patients are in line with the results of two recent systematic reviews that included all patients regardless of tumour location within the rectum [4,5]. One of these reviews, reported by our group, identified 17 studies including 5903 patients [4]. Regardless of cutoff point (1 cm, 5 mm or 2 mm) or whether radiotherapy was delivered or not the meta-analysis showed that the differences in the local recurrence rate between the small margin groups and the large margin groups was not statistically significant.…”

“…The results of our review of low-lying tumours in irradiated patients are in line with the results of two recent systematic reviews that included all patients regardless of tumour location within the rectum [4,5]. One of these reviews, reported by our group, identified 17 studies including 5903 patients [4].…”

The influence of the distal resection margin length on local recurrence and long- term survival in patients with rectal cancer after chemoradiotherapy and sphincter- preserving rectal resection

“…The cut of values for the subgroups were set theoretically, based on previously published reports 23 - 28 . We observed 4 (14.8%) deaths due to rectal cancer in Group I, 6 (19.4%) in Group II and 12 (23.5%) in Group III.…”

“…All the specimens were histopathologically tested for all the resection margins, including the circumferential resection margin; if any of the margins were positive, patients were excluded from the study (R1 resection). One of the most comprehensive systematic reviews of the literature was published by Bujko et al 23 . In this review authors identified 17 studies showing results in relation to margins < 1 cm versus > 1 cm, five studies in relation to a margin ≤ 5 mm versus ≥ 5 mm and five studies showing results in a margin of ≤ 2 mm.…”

Importance of surgical margins in rectal cancer

“…In another retrospective study of 218 rectal cancer patients, Hong et al [25] compared groups of patients with DRM length of >2 cm, 1-2 cm, and <1 cm and did not find any statistically significant difference in overall survival or local recurrence rates. Bujko et al [26] performed a systematic review of literature and a pooled analysis of studies comparing recurrence rates for DRMs of 10, 5, and 2 mm and demonstrated that the local recurrence rates were 1% more with margin of <1 cm, 1.7% more with margin of 5 mm, and 2.7% with margin of 2 mm, and concluded that a DRM of <1 cm did not compromise oncologic safety. Although interpreting the above data, one should keep in mind that most studies measuring DRM length use a variety of specimen processing techniques including fixed [13,20,21] versus unfixed [4,8] and pinned [13] versus unpinned [4,8,21] specimens.…”