Multimodality treatment of oligometastatic non-small cell lung cancer: review of literature

Oligometastasis represents a sub-group of systemic cancer diseases characterized by a limited (1 to 5) number of metastatic or recurrent lesions; when the disease presents in this particular state of progression the possibility to associate a local therapy to systemic treatment can lead to a favourable evolution with long-term survival and even cure. We have reviewed the literature in order to clarify the different trends of treatment in oligometastatic non-small cell lung cancer (NSCLC), particularly referring to single brain or isolated adrenal gland metastasis. The cornerstone of treatment of oligometastatic disease is still represented by systemic therapy (chemotherapy and/or immunotherapy). Local aggressive therapy (surgery and/or radiotherapy) is mandatory to eradicate all known sites of disease (primary tumor and metastases). If technically possible and in fitting patients, surgical resection represents the gold standard in the “local” treatment of isolated metastasis. Radiotherapy is considered as a noninvasive alternative to the reference of surgery in not-fitting patients. Five-year survival ranges between 10% and 30% for brain metastases and between 11% and 34% in isolated adrenal gland metastases. Mediastinal node involvement of primary lung cancer, number of metastases and number of metastatic sites are the prominent predictors of survival in brain oligometastatic disease. Synchronous or metachronous character, side of adrenal metastasis with respect to primary lung cancer and N0/N1 versus N2 lung cancer stage are the principal prognostic factors in adrenal oligometastatic disease. Oligometastatic disease seems to be a less aggressive and slowly-growing cancer, characterized by a different biological and immunological environment, with a more indolent evolution; in this subgroup of patients, if primary tumour is controlled, in the absence of disseminated metastatic disease and in fitting population, an aggressive local approach seems to be not only efficacy, but even mandatory. However it has to be integrated in the setting of a multidisciplinary approach including surgery, chemotherapy, radiotherapy, and targeted therapies.