Brain Metastases as a First Site of Recurrence in Patients Receiving Chemotherapy with Controlled Systemic Cancer: a Critical but Under-Recognized Clinical Scenario
Purpose of review
As the treatment of many malignancies has improved, brain metastases (BM) have been observed as a site of the first recurrence in patients with controlled systemic cancers. This suggests that while the administered chemotherapy is effective against systemic cancer, drug concentrations in the central nervous system (CNS) are likely too low to be effective. These findings are in accord with data suggesting that more than 98% of FDA-approved drugs on the market today are unable to cross the blood-brain barrier (BBB).
This retrospective literature review was conducted to estimate the proportion of patients with non-small lung cancer, breast cancer, and melanoma who develop BM as their initial site of recurrence while their systemic cancers are well controlled. Of 267 studies screened, 12 studies fit criteria for inclusion. These 12 studies reported on 923 patients. According to compiled data across these studies, 16% of patients on chemotherapy with stable or responding systemic cancer developed isolated BM as their initial site of relapse.
These findings strongly suggest that while chemotherapy controlled systemic cancer, drug concentrations within the CNS were low enough to allow disease progression. Ultimately, reducing the incidence of BM in these patients will require novel therapeutic approaches that facilitate drug entry through an intact BBB early in their treatment.
KeywordsBrain metastasis Non-small cell lung cancer Breast cancer Melanoma Blood-brain barrier
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflicts of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
References and Recommended Reading
Papers of particular interest, published recently, have been highlighted as: • Of importance
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