Osteoblastic Progression during EGFR Tyrosine Kinase Inhibitor Therapy in Mutated Non-small Cell Lung Cancer: A Potential Blunder

Abstract

The correct clinico-radiologic interpretation of osteoblastic reaction is crucial to avoid waste of therapeutic lines when TKI treatment has not yet exhausted its potential effectiveness. Clinical implications of ambiguous radiologic findings as described in this study deserve further discussion.

A Flare for the Unexpected: Bone Flare as Response to Tyrosine Kinase Inhibitor Treatment in a Lung Cancer Patient

“…It is caused by increased osteoblastic activity, representing healing of the bone metastases. As a result it can be considered as a sign of therapeutic efficacy [4]. It is impossible to differentiate between disease progression and osteoblastic flaring on CT scan or bone scintigraphy.…”

Osteoblastic Changes During Non-Small Cell Lung Cancer (NSCLC) Treatment: How to Distinguish between Objective Response and Progressive Disease

“…In EGFR-addicted NSCLC population treated with targeted therapy, osteoblastic reaction reached prevalence higher than 20% [18]. Patients with osteosclerotic changes during EGFR TKI therapy showed good objective response both in primary and other metastatic sites [18,19]. Finally, these morphological changes after EGFR TKI could be significantly related to an improved survival (p<0.01) ( Table 2) [20].…”

“…Bersanelli et al [18] 10/43 (23) ADC (39) Others (4) Erlotinib (12) Gefitinib (5) PR (7) SD (2) PD (1) 4.3-17.4 CT Pluquet et al [19] 17/36 (36) ADC (32) Others (4) Erlotinib (12) Gefitinib (5) PR/SD (12) PD (5) NR CT In our opinion this phenomenon represents an underestimated condition of bone metastases response, particularly in highly chemosensitive tumors and in oncogene-addicted ones. In clinical practice, a misinterpretation of these morphological or functional bone changes could lead to erroneously discontinue an effective treatment and finally have a negative impact on patients' clinical outcome.…”

“…Osteoblastic reactions have also been reported during epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment. In EGFR-addicted NSCLC population treated with targeted therapy, osteoblastic reaction reached prevalence higher than 20% [18]. Patients with osteosclerotic changes during EGFR TKI therapy showed good objective response both in primary and other metastatic sites [18,19].…”

Pitfalls in Oncology: Osteoblastic Response Mimicking Bone Progression during Ceritinib Treatment in ALK -Rearranged NSCLC

“…2 However, "osteoblastic responses" (the appearance of either new osteoblastic lesions or a sclerotic component within preexisting lytic lesions) have been described, particularly in epidermal growth factor receptor gene (EGFR)-addicted NSCLC. 3,4…”