Early response of total neoadjuvant therapy with regional deep hyperthermia for low-lying locally advanced rectal...

Total neoadjuvant therapy (TNT) combined with regional deep hyperthermia (HT) for the treatment of patients with low-lying locally advanced rectal cancer (LARC) is a promising strategy to optimize patient outcomes. However, its feasibility in a real-world setting requires evaluation, particularly regarding sphincter preservation rates and the effects on tumor response, downstaging, and treatment.

Patients with low-lying LARC who underwent TNT, including chemoradiation with regional deep HT twice weekly during chemoradiation, were evaluated with regard to sphincter preservation, downstaging, and clinical (cCR) or pathological (pCR) complete response rates. Data were obtained between 2018 and 2023.

A total of 49 patients with LARC at local UICC stages II (25%), III (67%), and IV (8%) were included in the analysis. The combination of TNT and deep HT demonstrated encouraging complete remission (CR) rates, with cCR or pCR achieved in 39% of patients and significant tumor downstaging in 76% of cases. A watch-and-wait concept was applied in nine cCR cases (18%). In total, 40 (82%) patients underwent surgical resection. Sphincter preservation was achieved in 31% of the patients, corresponding to a total sphincter preservation rate of 49%. Generally, TNT in combination with HT was well tolerated with an acceptable toxicity profile.

Combining TNT with regional deep HT for low-lying LARC is a promising treatment strategy that improves tumor response rates, complete remission rates, and tumor downstaging while maintaining acceptable toxicity profiles. Further prospective randomized studies are warranted to confirm these findings and establish the role of HT in neoadjuvant protocols.