Erratum to: The role of stereotactic radiosurgery in the management of patients with newly diagnosed brain metastases: a systematic review and evidence-based clinical practice guideline

Radiosurgery and stereotactic irradiation of multiple and contiguous brain metastases: A practical proposal of dose prescription methods and a literature review

PURPOSE

In literature, there are no guidelines on how to prescribe dose in the case of radiosurgery (SRS) or stereotactic irradiation of multiple and adjacent BM. Aim of this work is to furnish practical proposals of dosimetric methods for multiple neighboring BM, and to make a literature review about the SRS treatment of multiple BM, comparing radiotherapy techniques on the basis of different dosimetric parameters.

MATERIALS AND METHODS

A theoretical proposal of dosimetric approaches to prescribe dose in case of multiple contiguous BM is done. A literature review between 2010 and 2020 was performed on MEDLINE and Cochrane databases according to the PRISMA methodology, with the following keywords dose prescription, radiosurgery, multiple BM. Papers not reporting dosimetric solutions to irradiate multiple BM were excluded.

RESULTS

Only one article in the literature reports a practical modality of dose prescription for multiple adjacent BM. Thus, we proposed other five practical solutions to prescribe radiation dose in case of two or more neighboring BM, describing advantages and drawbacks of each method in terms of different dosimetric parameters. The literature review about dosimetric solutions to irradiate multiple BM led to 56 titles; 14 articles met the chosen criteria and we reported their results in terms of dosimetric indexes and low doses to the normal brain tissue.

CONCLUSIONS

The six dosimetric approaches here described can be used by physicians for multiple contiguous BM, depending on the clinical situation. These methods may be applied in clinical studies to better evaluate their usefulness in practice.

Non-small cell lung cancer histological subtype has prognostic impact in patients with brain metastases

In patients with brain metastases from non-small cell lung cancer, the prognostic impact of primary tumour histology, a feature with increasing implications for choice of systemic therapy, is not well defined. Therefore, a multi-institutional analysis was performed: retrospective uni- and multivariate analyses in 209 patients treated with different approaches including surgery and radiosurgery. While squamous cell and large cell carcinoma patients had comparable survival, those with adenocarcinoma survived significantly longer. In multivariate models, adenocarcinoma histology was confirmed as independent prognostic factor, which complements both recursive partitioning analysis (RPA) classes and diagnosis-specific graded prognostic assessment (GPA). When evaluated together with primary tumour control, extracranial metastases, number of brain metastases, age and performance status as individual covariates rather than RPA or GPA score, adenocarcinoma histology again emerged as significant prognostic factor. A significant but small survival advantage for patients with adenocarcinoma was evident already in the time period before drugs such as pemetrexed and epidermal growth factor receptor tyrosine kinase inhibitors were available. However, the gap has widened in recently treated patients. Comparable to patients without brain metastases, primary tumour histology should be taken into account when assessing patients' prognosis and recommending treatment strategy.