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Review
. 2025 Jun 14;17(6):e86007.
doi: 10.7759/cureus.86007. eCollection 2025 Jun.

Risk of Perihippocampal Recurrence After Hippocampal Avoidance in Prophylactic Cranial Irradiation: A Literature Review

Georgios Giakoumettis  1   2 , Areti Gkantaifi  3 , Dimitrios Giakoumettis  4 , Konstantinos Kouskouras  5 , Anastasios Siountas  1   2 , Panagiotis Bamidis  1   2 , Emmanouil Papanastasiou  1   2
Affiliations
Review

Risk of Perihippocampal Recurrence After Hippocampal Avoidance in Prophylactic Cranial Irradiation: A Literature Review

Georgios Giakoumettis et al. Cureus. .

Abstract

A standard practice in the treatment of patients with small-cell lung cancer (SCLC) is prophylactic cranial irradiation (PCI) to reduce the chance of brain metastases. However, whole brain radiation therapy (WBRT) has been associated with concerns about neurocognitive decline. This has led to the development of WBRT techniques with the simultaneous avoidance of the hippocampus (HA). This article reviews the existing literature on the incidence of hippocampal failure after HA PCI in patients with SCLC. The effort to protect the hippocampus aims to reduce side effects at a cognitive level, but, as reported in various studies, the results regarding safety and effectiveness are ambiguous. Some indicate a higher risk of recurrence in the hippocampal and perihippocampal regions, particularly in non-oligometastatic patients. Despite any concerns, many trials have shown that HA in PCI significantly reduces cognitive decline without compromising overall survival or control of brain metastases. The mixed results noted between studies indicate the necessity of clinical trials to elucidate the benefits and risks of PCI with simultaneous hippocampal protection in patients suffering from SCLC.

Keywords: failure; hippocampal avoidance; pci; prophylactic cranial irradiation; radiotherapy; small-cell lung cancer.

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Conflict of interest statement

Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram.
See this image and copyright information in PMC

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