Potentiation of the Abscopal Effect by Modulated Electro-Hyperthermia in Locally Advanced Cervical Cancer Patients

Carrie Anne Minnaar; Jeffrey Allan Kotzen; Olusegun Akinwale Ayeni; Mboyo-Di-Tamba Vangu; Ans Baeyens

doi:10.3389/fonc.2020.00376

Potentiation of the Abscopal Effect by Modulated Electro-Hyperthermia in Locally Advanced Cervical Cancer Patients

Front Oncol. 2020 Mar 24:10:376. doi: 10.3389/fonc.2020.00376. eCollection 2020.

Authors

Carrie Anne Minnaar¹, Jeffrey Allan Kotzen², Olusegun Akinwale Ayeni³, Mboyo-Di-Tamba Vangu³, Ans Baeyens^{1

4}

Affiliations

¹ Radiobiology, Department of Radiation Sciences, University of the Witwatersrand, Johannesburg, South Africa.
² Radiation Oncology, Wits Donald Gordon Medical Centre, Johannesburg, South Africa.
³ Nuclear Medicine, Department of Radiation Sciences, University of the Witwatersrand, Johannesburg, South Africa.
⁴ Radiobiology, Department of Human Structure and Repair, Ghent University, Ghent, Belgium.

Abstract

Background: A Phase III randomized controlled trial investigating the addition of modulated electro-hyperthermia (mEHT) to chemoradiotherapy for locally advanced cervical cancer patients is being conducted in South Africa (Human Research Ethics Committee approval: M1704133; ClincialTrials.gov ID: NCT03332069). Two hundred and ten participants were randomized and 202 participants were eligible for six month local disease control evaluation. Screening ¹⁸F-FDG PET/CT scans were conducted and repeated at six months post-treatment. Significant improvement in local control was reported in the mEHT group and complete metabolic resolution (CMR) of extra-pelvic disease was noted in some participants. We report on an analysis of the participants with CMR of disease inside and outside the radiation field. Method: Participants were included in this analysis if nodes outside the treatment field (FDG-uptake SUV>2.5) were visualized on pre-treatment scans and if participants were evaluated by ¹⁸F-FDG PET/CT scans at six months post-treatment. Results: One hundred and eight participants (mEHT: HIV-positive n = 25, HIV-negative n = 29; Control Group: HIV-positive n = 26, HIV-negative n = 28) were eligible for analysis. There was a higher CMR of all disease inside and outside the radiation field in the mEHT Group: n = 13 [24.1%] than the control group: n = 3 [5.6%] (Chi squared, Fisher's exact: p = 0.013) with no significant difference in the extra-pelvic response to treatment between the HIV-positive and -negative participants of each group. Conclusion: The CMR of disease outside the radiation field at six months post-treatment provides evidence of an abscopal effect which was significantly associated with the addition of mEHT to treatment protocols. This finding is important as the combined synergistic use of radiotherapy with mEHT could broaden the scope of radiotherapy to include systemic disease.

Keywords: abscopal effect; cervical cancer; immunomodulation; modulated electro-hyperthermia; radiotherapy.