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Rates of pathologic complete response and sphincter-sparing surgery after neoadjuvant radiochemotherapy with or without regional pelvic hyperthermia for locally advanced rectal cancer.

622 Background: Regional pelvic hyperthermia is frequently added to neoadjuvant radiochemotherapy for locally advanced rectal cancer. The present retrospective study is the first to evaluate the impact of hyperthermia on rates of complete pathologic response and sphincter-sparing surgery in the context of a standard up-to-date neoadjuvant radiochemotherapy scheme.


METHODS
Between 2007 and 2010, 85 consecutive patients with locally advanced cancer (cT3, cT4, cN+) of the middle and lower rectum received neoadjuvant radiochemotherapy at our institution. 45 of 85 patients ("RCT group") received standard treatment consisting of radiotherapy to the pelvis with 5040 cGy in 28 fractions of 180 cGy and 5-fluorouracil as a continuous infusion with 1000 mg/m² over 120 hours during the first and fifth week of treatment. 40 of 85 patients ("HRCT group") received the same treatment with at least four treatments of weekly regional hyperthermia. Target temperature was 40.5°C for at least 60 minutes. Total mesorectal excision was routinely performed.


RESULTS
No significant difference in the distribution of age, gender, clinical stage and tumor grade was observed between both groups. Complete pathologic response was seen in 6.7% of patients in the RCT group and 22% of patients in the HRCT group (p=0.034). Overall rates of sphincter-sparing surgery were 64% in the RCT group and 65% in HRCT. However for deep seated tumors located within 4 cm of the anal verge (based on initial staging), sphincter sparing surgery was achieved in only 11.1% of patients in the RCT group but 35.7% of patients in the HRCT group (p = 0.19).


CONCLUSIONS
The addition of regional hyperthermia to neoadjuvant radiochemotherapy significantly increases the rate of complete pathologic response, with a tendency towards higher rates of sphincter-sparing surgery for deep seated tumors.