Pathological complete Response with Immunotherapy and Brachytherapy to 15 Metastatic Liver Lesions in a Single Patient

Abstract

Materials & methods: High dose rate interstitial brachytherapy (HDR-IBT) treatment plan for 15 metastatic liver lesions in a patient with pancreatic cancer was retrieved and analyzed for liver dose parameters and diaphragm dose. Serial ¹⁸F-FDG PET-CT scans were reviewed for disease response assessment and left liver lobe volume. Serial laboratory records were analyzed for liver parameters. Results: Left liver lobe volume increased from 241 cm³ pre-HDR-IBT to estimated 600 cm³ after seven sessions of HDR-IBT. Metabolic complete response (CR) and subsequently pathological CR was confirmed in the right hepatotectomy specimen for all the 15 PET-CT avid lesions treated with HDR-IBT. Maximum diaphragm dose in a single fraction was 82 Gy. The liver parameters were stable and patient did not develop radiation induced liver disease. Discussion: This is the largest reported series of HDR-IBT to liver lesions in a single patient. This first ever reported combined treatment of immunotherapy (IT) and HDR-IBT had likely rendered this patient disease free both at local the liver and systemically. Metabolic CR by PET-CT can be seen as early as 46 days after HDR-IBT. Diaphragm can tolerate very high doses of radiation and repeated treatment. Conclusion: In this patient HDR-IBT for multiple liver lesions with IT is well tolerated. PET-CT can be used for response assessment of HDR-IBT liver. Synergistic effect of IT with HDR-IBT and it’s role as bridging for liver resection has clinical potential and should be further studied in prospective trials.

Keywords:

• brachytherapy and immunotherapy
• diaphragm radiation tolerance
• HDRIBT liver
• liver brachytherapy
• Pet-CT for brachytherapy response

Acknowledgments

Authors would like to acknowledge Liver Malignancy Research Group, Advanced Medical & Dental Institute, Universiti Sains Malaysia for article processing fee funding.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

Informed consent was obtained from the patient described in this manuscript and has institutional human ethics approval for CT-guided interstitial liver brachytherapy analysis in Universiti Sains Malaysia (JEPeM USM Code: USM/JEPeM/20050263).