Radiation therapy for pelvic recurrent colorectal or gynecological cancer: is whole pelvic irradiation necessary?

Background: Preoperative whole pelvic radiation therapy (RT) is used commonly for rectal cancer and is the standard field postoperatively in gynecological cancer. However, the ideal field (local vs. whole pelvis) has not been determined for local recurrence of these cancers.

Methods: We retrospectively reviewed the data for 52 patients who developed local tumor recurrence of rectal or gynecological cancer treated from 2013 to 2021. The initial treatment for all patients was total excision of the primary tumors without radiation therapy. Radiation therapy targets were surgical stumps, perianastomosis sites, and pelvic lymph nodes, classified according to the pelvic nodal volume atlas for radiation therapy. Patients were divided into the local recurrent tumor only radiation therapy group and the whole pelvis radiation therapy group. Whole pelvis radiation therapy included the common iliac lymph nodes or prophylactic lymph nodes below the L5/S1 junction. We recorded second recurrence after RT and the affected site(s) in each group. We also compared disease-specific survival using uni- and multivariate analyses.

Results: We found no significant differences between the groups regarding second recurrence or regarding the site(s) of recurrence. We also found no significant differences in disease-specific survival between the two RT groups. However, patients who did not receive chemotherapy after the initial surgery and before RT had significantly longer survival (P=0.015).

Conclusions: In patients with locally recurrent rectal or gynecological cancer, we found no significant difference in second recurrence or survival between the local tumor only RT field and the whole pelvic RT field.