Pelvic sidewall involvement in recurrent rectal cancer

The lateral pelvic sidewall is an area not routinely dissected during standard operative procedures in surgery for rectal cancer in Western countries. This study analyzed data to evaluate the pattern of recurrence in rectal cancer with special emphasis on lateral tumor extension in a recently treated patient population.

In a multicenter retrospective study 123 patients were evaluated by our own CT-based three-dimensional datafile system and an extensive questionnaire. Patients had histological confirmation, clear bone destruction, a positive PET scan, and at least three minor criteria: progressive soft tissue mass, invasion of adjacent organs on follow-up CT or MRI, rising tumor markers, and typical appearance in cross-sectional imaging. Clinical or serological signs of inflammation were exclusion criteria. Initially 54% of the evaluated patients were N0, and the others were distributed evenly between N1 and N2; initial T stage was T1 in 2%, T2 in 24%, T3 in 60%, and T4 in 13%.

. Recurrent tumors were situated mainly in the posterior part of the bony pelvis. The pelvic side wall was a rare site of recurrence and involved in fewer than 5%. When abdominoperineal resection was compared to low anterior resection as primary operation, there was a significant difference in extension of recurrent tumors in the inferior parts of the pelvis; no significant differences were found in superior or lateral parts of the pelvis.

Because most tumor recurrences arise in the central pelvis, extending surgery to include dissecting the iliac vessels would probably offer only a moderate benefit, which must be balanced against potential side effects.