Artikel
Quantification of PpIX-fluorescence of cerebral breast cancer metastases
Quantifizierung der PpIX-Fluoreszenz zerebraler Brustkrebs-Metastasen
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Veröffentlicht: | 4. Juni 2021 |
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Objective: Introduction of the 5-ALA technique is one major advance in neuro-oncological surgery. Protoporphyrin IX (PpIX)-fluorescence was observed in about half of cerebral metastases. For now, no study found a correlation between the dichotomized PpIX-fluorescence of breast cancer metastases and neither the receptor status nor the histological subtype of breast cancer metastases. Aim of the present pilot study was to quantify PpIX-induced fluorescence of breast cancer metastases and correlate this with the hormone receptor status.
Methods: 5-ALA induced fluorescence intensity was quantified in 26 patients suffering from cerebral breast cancer metastases. A systematic spectrometric evaluation of tumor specimen and the resultant PpIX-induced fluorescence was performed using a spectrometer connected by optic fiber to a handheld probe. The difference between maximum PpIX-fluorescence at 635 nm and baseline fluorescence was considered as PpIX fluorescence intensity of the metastasis. In addition, results were correlated with receptor status (PD-L1, estrogen receptor, progesteron receptor, HER-2/neu) and histopathological examinations.
Results: All 26 patients had breast cancer with cerebral metastases. The mean age was 49 year (32 – 81 years). All patients were female. All 26 cerebral breast cancer metastases were considered as ALA fluorescent by the surgeon. A PpIX fluorescence over 1.1x106 AU was observed as “ALA-positive” by the surgeon. The mean PpIX fluorescence of analyzed cerebral breast cancer metastases was 3.4x106 AU (2.1x106 – 6.5x106 AU). After quantification we observed no significant difference in the levels of 5- ALA fluorescence in cerebral breast cancer metastases with different hormone receptor status.
Conclusion: Firstly, PpIX fluorescence over 1.1x106 AU was observed as “ALA-positive” by the surgeon. Secondly, all cerebral breast cancer metastases were tested as “ALA-positive” by the spectrometer. Thirdly, quantification of 5-ALA fluorescence showed no significant difference between cerebral breast cancer metastases with different hormone receptor status in our cohort.