To assess the frequency and magnitude of changes in lower
rectal cancer resulting from preoperative therapy and its
impact on sphincter-saving surgery. Preoperative therapy can
increase the rate of preserving surgery by shrinking the
tumor and enhancing its distance from the anal sphincter.
However, reliable data concerning these modifications are
not yet available in published reports.
Methods and Materials
A total of 98 cases of locally
advanced cancer of the lower rectum (90 Stage uT3-T4N0-N+
and 8 uT2N+M0) that had undergone preoperative therapy were
studied by endorectal ultrasonography.
The maximal size of
the tumor and its distance from the anal sphincter were
measured in millimeters before and after preoperative
therapy. Surgery was performed 6–8 weeks after
therapy, and the histopathologic margins were compared with
the endorectal ultrasound data.
Results
Of the 90 cases,
82.5% showed tumor
downsizing, varying from one-third to two-thirds or more of
the original tumor mass. The distance between the tumor and
the anal sphincter increased in 60.2% of cases. The median
increase was 0.73 cm (range, 0.2–2.5). Downsizing was
not always associated with an increase in distance.
Preserving surgery was performed in 60.6% of cases. It was
possible in nearly 30% of patients in whom the cancer had
reached the anal sphincter before the preoperative therapy.
The distal margin was tumor free in these cases.
Conclusion
The results of our study have
shown that in very low rectal cancer, preoperative therapy
causes tumor downsizing in >80% of cases and in more than
one-half enhances the distance between the tumor and anal
sphincter. These modifications affect the primary surgical
options, facilitating or making sphincter-saving surgery
possible.