Predictive factors in locally advanced rectal cancer treated with preoperative hyperfractionated and accelerated radiotherapy.

This study examines the prognostic significance of pathologic
factors in patients with primary locally advanced rectal cancer treated
prospectively with preoperative radiotherapy. From 1992 to 1998, 104
patients with rectal cancer of grades T3 or T4 and any N underwent
preoperative radiotherapy followed by surgical resection. Survival
curves were estimated according to the Kaplan-Meier method. Correlation
of outcome with clinicopathologic variables (pathologic tumor
and lymph node staging, histology, radial resection margin
[RRM], clearance, vessel involvement, and tumor regression grade
[TRG], quantitated in 5 grades) was evaluated using the Cox proportional
hazards model. None of the patients achieved a histologically
confirmed complete pathologic response, but 79% of the patients
showed partial tumor regression (TRG2–4) and 21% did not show
any tumor regression (TRG5). Among the tumors, 22% were of a
mucinous type. The RRM was free of tumor in 76% of the surgical
specimens. The median clearance was 2 mm. Vascular invasion was
present in 37 cases (36%). In the univariate analysis, lymph node
metastases, absence of tumor regression, positive RRM, and vascular
invasion were correlated with adverse overall survival and diseasefree
survival; absence of tumor regression, positive RRM, and clearance
<2 mm were correlated with local recurrences; and advanced
pT stage was correlated only with disease-free survival. However, in
the multivariate analysis, only lymph node metastases and RRM were
independent prognostic factors for overall survival and disease-free
survival, and clearance <2 mm was an independent prognostic factor
for local control. Pathologic parameters remain strong determinants
of local recurrence and survival in locally advanced rectal cancer,
treated preoperatively with hyperfractionated and accelerated radiotherapy.
We show that patients with advanced pT, positive lymph
nodes, vascular invasion, positive RRM, clearance <2 mm, or absence
of tumor regression are known to have poor clinical outcome.
HUM PATHOL 34:541-548. © 2003 Elsevier Inc. All rights reserved.

Abbreviations: , computed tomography; DFS, disease-free survival;
HART, hyperfractionated accelerated radiotherapy; OS, overall
survival; RRM, radial resection margin; TRG, tumor regression
grade.