Osteoblastic reaction in non-small cell lung carcinoma and its association to epidermal growth factor receptor tyrosine kinase inhibitors response and prolonged survival

Could MRONJ Be Related to Osimertinib Monotherapy in Lung Cancer Patients after Denosumab Suspension?

BACKGROUND

Medication-related osteonecrosis of the jaws is the most frequent complication in patients treated or in therapy with antiresorptive/antiangiogenetic drugs. The list of medications possibly related to MRONJ onset is constantly growing; we aimed to report on a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (Osimertinib) as possibly responsible for bilateral maxillary necrosis onset in the herein-described case.

METHODS

In June 2023, an oncologic patient with two different maxillary bone exposures was referred to our attention. His medical history revealed a two-year Denosumab regimen along with Osimertinib, the latter not suspended before teeth extractions. The clinicians performed a sequestrum removal and bone debridement after three cycles of antibiotic therapy.

RESULTS

Histologic examinations confirmed the clinical diagnosis of MRONJ excluding a metastatic occurrence, while complete mucosal healing was achieved after 15 days.

CONCLUSIONS

The patient suspended Denosumab for more than six months before teeth extraction for MRONJ prevention; hence, failure to discontinue Osimertinib led us to consider it a possible etiological factor. From a literature analysis, only one case has already been published reporting a possible Osimertinib-related occurrence of MRONJ in lung cancer patients. Our case is a further report that could be intended as an alert both for oncologists and dentists to share decisions about the oral management of such patients together, also informing them about this possible risk. Also, this report could trigger in the scientific community the necessity to evaluate further guidelines for similar doubtful cases in which the drug interaction, the mono-suspension, and the possible removable prosthesis-related additional trauma should be considered causes or con-causes.

Osteoblastic bone reaction in non-small cell lung cancer harboring epidermal growth factor receptor mutation treated with osimertinib

BACKGROUND

Osteoblastic bone reaction (OBR) refers to an increase in bone density at the site of bone metastasis or the appearance of new sclerotic bone lesions after anticancer treatment. OBR can be misunderstood as disease progression. In this study, we aimed to investigate the prevalence and details of OBR and its association with clinical outcomes in patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) treated with osimertinib.

METHODS

This was a single-center, retrospective cohort study. We reviewed patients who were diagnosed with EGFR-mutant NSCLC with bone metastasis and received osimertinib as a first-line treatment between February 2018 and October 2022. The OBR was evaluated by comparing baseline computed tomography (CT) scans with the first CT scan after treatment initiation.

RESULTS

A total of 45 patients were included in this study. Thirty-seven patients (82%) developed OBR. OBR developed in 94% (n = 16) of patients with sclerotic bone lesions (n = 17) at baseline. Similarly, OBR developed in lytic and mixed bone lesions in 76% and 82% of patients with lytic and mixed lesions, respectively. Progression-free survival (PFS) did not differ significantly between patients with (OBR group) and without OBR (non-OBR group) (median PFS, 24 months vs. 17 months; hazard ratio (HR), 0.62; 95% CI, 0.24-1.6; p = 0.31). In univariate analysis, the OBR group showed a trend toward longer skeletal-related events-free survival (SRE-FS) than the non-OBR group (median SRE-FS, 26 months vs. 12 months; HR, 0.53; 95% CI, 0.21-1.33; p = 0.16). Multivariate analysis showed OBR was a significant independent predictor of SRE-FS (HR, 0.35; 95% CI, 0.13-0.92; p = 0.034).

CONCLUSIONS

OBR developed in most patients with NSCLC and bone metastasis who received osimertinib treatment. The increased incidence of OBR in patients with EGFR-mutant NSCLC with bone metastasis treated with osimertinib should not be confused with disease progression, and treatment decisions should be made carefully.

Bone-specific response according to MDA criteria predicts immunotherapy efficacy among advanced non-small cell lung cancer (NSCLC) patients

PURPOSE

The presence of bone metastasis at baseline has been associated with dismal prognosis under immunotherapy in advanced non-small cell lung cancer (NSCLC). Response Evaluation Criteria in Solid Tumors (RECIST) criteria may be limited for bone-specific response evaluation. Whether their assessment through MD Anderson (MDA) criteria predict immunotherapy efficacy is unknown.

MATERIALS AND METHODS

We conducted a single-center retrospective study to assess the use of MDA criteria in evaluating bone metastasis in NSCLC treated with immunotherapy. Radiological imaging were reviewed to classify bone lesions as osteolytic, osteoblastic, or mixed. Bone response to treatment data was classified according to MDA criteria.

RESULTS

222 patients received single-agent immunotherapy. The presence of bone metastasis increased the risk of death both in the univariate (HR: 1.46, 95% CI, 1.05-2.03, p = 0.024) and in the multivariate model (HR: 1.61, 95% CI, 1.10-2.36, p = 0.015). According to MDA criteria, 57.3% of patients had progressive disease as best response, 29.5% stable disease, 11.4% partial response and 1.6% complete response. Bone-specific objective response was associated with a significantly increased median overall survival (11.3 vs. 3.1 months, p = 0.027) and longer median progression-free survival (6 vs. 2.1 months, p = 0.056). The median time to bone failure (TBF) was 2.4 months (IQR, 1.67-3.0). In 25.7% of cases, TBF was shorter than progression-free survival according to RECIST 1.1 criteria. TBF was positively correlated with overall survival (HR = 0.73, p = 0.00019).

CONCLUSIONS

MDA criteria represent a reliable tool in assessing bone-specific response, offering a more accurate evaluation with the aim to earlier predict survival outcomes or treatment failure compared to RECIST criteria for advanced NSCLC patients receiving immunotherapy.

Prolonged durability of extensive contiguous spinal metastasis stabilization in non-small cell lung cancer patients receiving targeted therapy: two case reports and a literature review

Contiguous spinal metastasis poses a challenge for spine surgeons. In patients with a short remaining life expectancy, surgery may be discouraged. However, in select cases, surgery may be inevitable to eliminate pain and improve the patient’s quality of life. Additionally, with advancements in systemic cancer therapy, the efficacy and duration of tumor control have improved significantly. Consequently, a patient’s life expectancy may be difficult to estimate with existing prognostic scores. Because patients may achieve prolonged survival, spinal metastasis surgery could greatly benefit a patient’s quality of life. In this report, we present the details of two patients with non-small lung cancer with contiguous spinal metastasis who underwent spinal surgery for their metastatic disease. After surgery and targeted therapy with epidermal growth factor tyrosine kinase inhibitors (EGFR TKI), the patients attained substantial healing of their previously lytic spines and achieved prolonged survival of up to 42 months. With modern systemic therapy for lung cancer, the treatment of spinal metastatic disease can achieve decent outcomes, even in poor surgical candidates.

Bone Tropism in Cancer Metastases

Bone is a frequent site of metastases in many cancers. Both bone properties and the tumor-intrinsic traits are associated with the metastatic propensity to bone (i.e., the bone tropism). Whereas an increasing body of mechanistic studies expanded our understanding on bone tropism, they also revealed complexity across the bone lesions originated from different cancer types. In this review, we will discuss the physical, chemical, and biological properties of bone microenvironment, identify potential players in every stage of bone metastases, and introduce some of the known mechanisms regulating the bone colonization. Our objectives are to integrate the knowledge established in different biological contexts and highlight the determinants of bone tropism.

A Flare for the Unexpected: Bone Flare as Response to Tyrosine Kinase Inhibitor Treatment in a Lung Cancer Patient: New osteoblastic bone lesions in a lung cancer patient may represent bone flare and should not be misdiagnosed as disease progression

We report the case of a 72-year-old female never-smoker with stage IV endothelial growth factor receptor (EGFR) mutated lung adenocarcinoma. This patient was started on first line tyrosine kinase inhibitor (TKI) and seemingly developed new bone metastases under this treatment. As there was a remarkable discrepancy between the partial response seen in the primary tumor and non-osseous metastatic locations, the possibility of a bone flare phenomenon was considered. In this case report, we demonstrate that new bony lesions are not always synonymous with disease progression.

Analysis of Progression Patterns and Failure Sites of Patients With Metastatic Lung Adenocarcinoma With EGFR Mutations Receiving First-line Treatment of Tyrosine Kinase Inhibitors

BACKGROUND

Reliable prediction of progression patterns and failure sites for patients with stage IV lung adenocarcinoma is valuable for physicians to deliver personalized tyrosine kinase inhibitor (TKI) treatment.

PATIENTS AND METHODS

We retrospectively enrolled 266 patients who had stage IV lung adenocarcinoma and received first-line TKI treatment from 2013 to 2017 in Shanghai Chest Hospital. The clinical characteristics at initial diagnosis, progression patterns, and failure sites were analyzed with the attempt to identify some predictive factors for progression patterns and failure sites.

RESULTS

Among all patients, 62.4% developed systemic progression, and 37.6% developed oligoprogression. Both cohorts had a median progression-free survival (PFS) of 9 months. The percentage of patients who developed original and distant failure was 39.1% and 60.9%, respectively. Patients with oligometastasis at initial diagnosis were more prone to develop oligoprogression (odds ratio [OR], 4.370; 95% confidence interval [CI], 1.881-10.151; P = .001), whereas pulmonary metastasis was negatively correlated with oligoprogression (OR, 0.567; 95% CI, 0.330-0.974; P = .04). Both oligometastasis diagnosis (OR, 2.959; 95% CI, 1.347-6.500; P = .007) and the maximum diameter of the primary lung lesion (threshold 3.25 cm: OR, 3.646; 95% CI, 2.041-6.515; P = .0001) were strong predictive factors for original failures. Osseous metastasis at initial diagnosis might be an indication for distant failure (OR, 0.536; 95% CI, 0.316-0.909; P = .021).

CONCLUSION

Over one-half of patients with stage IV lung adenocarcinoma receiving first-line TKI treatment developed systemic progression and distant failure. Metastasis patterns at initial diagnosis was the most important predictive factor for progression patterns and failure sites. The maximum diameter of the primary lung lesion and evidence of osseous metastasis were also found to be significant indicative factors for failure sites.

Factors associated with improvement in symptoms and quality of life for first-line EGFR-tyrosine kinase inhibitor treatment in patients with EGFR-mutated non-small-cell lung cancer - A multicenter prospective SMILE study

Introduction: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are a standard first-line treatment for advanced EGFR-mutated NSCLC patients. Factors associated with symptoms and quality of life (QOL) improvements have not been investigated.

Methods: We conducted a multicenter, prospective study to evaluate improvements in QOL and symptoms in NSCLC patients treated with first-line EGFR-TKIs. QOL was assessed using the instrument of Functional Assessment of Cancer Therapy-Lung questionnaire (FACT-L) and Treatment Outcome Index (TOI). Assessment of symptoms was evaluated using the Lung cancer subscale (LCS).

Results: Eligible subjects included 280 patients for endpoint analyses. The mean FACT-L score increased by 4.0 ± 15.56 at Week 2 (p<0.001), 5.1 ± 18.48 at Week 4 (p<0.001), and 4.2 ± 20.27 at Week 12 (p=0.001). Similarly, a 2.3 ± 11.65 (p<0.001), 3.2 ± 13.59 (p<0.001), and 2.4 ± 14.34 (p=0.009) increase in mean TOI score were observed at Weeks 2, 4 and 12, respectively. For LCS, it was slightly increased by 1.7 ± 4.61, 2.0 ± 5.50, and 2.0 ± 5.36 at Weeks 2, 4, and 12 (all p<0.001), respectively. Subgroup analyses showed patients who were ex-smokers or with at least 3 metastatic sites were associated with symptoms improvement. Patients who were ex-smokers, with at least 3 metastatic sites, a PS of 1, or treated with gefitinib were associated with QOL improvement.

Conclusions: In EGFR -mutated NSCLC patients who were treated with first-line EGFR-TKIs, these ex-smokers or with 3 or more metastatic sites were associated with improvements in symptoms and QOL.

Osteoblastic bone response mimicking bone progression during treatment with pembrolizumab in advanced cutaneous melanoma

Pembrolizumab is an immune checkpoint inhibitor approved for the treatment of patients with unresectable or metastatic melanoma. Appearance of bone metastases, either osteolytic or osteoblastic, during treatment qualifies as disease progression. We report the case of a 64-year-old White woman with a metastatic melanoma undergoing second-line treatment with pembrolizumab. At first evaluation, after 3 months of therapy, computed tomography scans showed the onset of osteosclerotic lesions and a significant reduction in all the previously identified metastases; on the contrary, a fluorine-18-fluorodeoxyglucose PET showed the normalization of fluorine-18-fluorodeoxyglucose uptake in all the baseline lesions, including bone metastases. Osteoblastic response, consisting of occurrence of new osteoblastic lesions on computed tomography imaging, as a consequence of an osteoblastic reaction of previously undetectable bone metastases, has been reported in some cancers that receive treatments such as chemotherapy, hormonal or targeted therapy. However, it had never been reported in patients with melanoma treated with immunotherapy. An apparent worsening of bone imaging on standard computed tomography scan in patients under checkpoint inhibitor should not lead to modification of treatment strategy, because misinterpretation as disease progression may lead to the premature cessation of a beneficial treatment and finally have a negative effect on patients' clinical outcome.

Epidermal growth factor receptor is associated with the onset of skeletal related events in non-small cell lung cancer

Background

Bone metastasis and skeletal related events (SREs) are common in non-small cell lung cancer (NSCLC). Patients with mutant epidermal growth factor receptor (EGFR) could benefit from tyrosine kinase inhibitors (TKIs). However, it is unclear whether SRE is influenced by EGFR status. We aimed to evaluate the correlation of EGFR status and TKIs with the incidence of SREs.

Methods

We conducted a retrospective study of stage IV NSCLC patients with bone metastasis. Incidence rate of SREs was collected and was compared using chi-square test. Logistic-regression analysis was used to identify the risk factors predicting the incidence of SREs.

Results

410 eligible patients were enrolled in the study. 49.0% were detected with EGFR mutation. 49.8% of patients received EGFR-TKIs therapy prior to the onset of SREs. 42.7% experienced at least one SRE. Patients who were treated with TKIs held lower incidence of SREs than patients who were not treated with TKIs (23.5% vs 61.7%, p<0.001). Multivariate analysis showed that poor performance status (OR 5.550, 95%CI 2.290-13.450; p<0.001) and mutant EGFR (OR 3.050, 95%CI 1.608-5.787, p=0.001) were independent risk factors predicting the onset of SREs, while the usage of TKIs (OR 0.102, 95%CI 0.054-0.193, p<0.001) was a protective factor of SREs in NSCLC patients with bone metastasis.

Conclusions

This study indicates that the incidence of SREs is common in both patients with and without EGFR mutation. Poor performance ability and mutant EGFR imply higher risks of SREs, while the usage of TKIs may be a protective factor of SREs.

Efficacy of Second-line Tyrosine Kinase Inhibitors in the Treatment of Metastatic Advanced Non-small-cell Lung Cancer Harboring Exon 19 and 21 EGFR Mutations

Background: Although superior clinical benefits of first-line epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in the treatment of advanced non-small-cell lung cancer (NSCLC) had been reported with different sensitivity, the sensitivity of second-line TKIs in NSCLC patients with different EFGR mutations was unknown. The purpose of this study is to investigate the clinical outcome of second-line EGFR-TKIs in the treatment of NSCLC patients according to different EGFR genotypes.

Methods: The treatment outcomes of 166 NSCLC patients with different EGFR mutations treated by second-line TKIs were retrospectively reviewed. The efficacy was evaluated with Pearson chi-square or Fisher's exact tests, Log-rank test and Cox proportional hazards model.

Results: The disease control rate (DCR) and objective response rate (ORR) of enrolled NSCLC patients were 77.7% and 11.4%, respectively. The exon 19 deletion group had a significantly longer median progression-free survival (PFS) (6.7 vs. 4.5 months, P=0.002) and overall survival (OS) (13.7 vs. 11.7 months, P=0.02) compared with the exon 19 L858R mutation group for NSCLC patients, as well for patients with brain metastasis [PFS: (6.7 vs. 3.9 months, p<0.001), OS: (13.7 vs. 7.9 months, p=0.006)]. No significant difference on PFS and OS was observed between exon 19 deletion and L858R mutation group for patients with bone metastasis. EGFR genotype and ECOG PS were independent predictors of PFS. Never smoking, exon 19 deletion, EGOC PS (0-1) and no brain metastasis were correlated with longer OS. No significant difference on side effect between exon 19 and 21 mutation group was observed.

Conclusions: NSCLC patients harboring exon 19 deletion achieved better PFS and OS than those with L858R mutation, indicating that EGFR mutation is a significant prognostic factor for advanced NSCLC patients with and without brain metastasis receiving second-line EGFR-TKIs treatment.

Osteoblastic progression during EGFR tyrosine kinase inhibitor therapy in mutated non-small cell lung cancer: a potential blunder

AIMS AND BACKGROUND

Bone flare reaction as a sign of response to antineoplastic treatment has been redefined, including the onset of new osteoblastic lesions. If misunderstood as skeletal progression, this finding could lead to erroneous therapy discontinuation, changing the disease clinical course. We aim to describe this clinical phenomenon in patients with advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) gene-activating mutations treated with tyrosine kinase inhibitor (TKI).

METHODS

We retrospectively reviewed the computed tomography scans of 43 EGFR-mutated patients with NSCLC treated with EGFR-TKI, analyzing the bone response in terms of increase in the quantity and/or density of lesions, and assessing objective tumor response to treatment.

RESULTS

Osteoblastic reaction was detected in 10 cases (23%), showing different patterns: dimensional or density increase of known osteosclerotic metastases (pattern A, n = 4); response of previously lytic lesions (pattern B, n = 2); onset of new osteosclerotic lesions (pattern C, n = 4). Seven patients had partial response to TKI treatment, with response rate of 70%, vs 50% of patients with bone metastases without this reaction. No difference in terms of median overall survival or progression-free survival emerged between patients with or without osteoblastic reaction.

CONCLUSIONS

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.

[Limitations of active therapeutic and palliative care in chronic respiratory disease]

The issue of intensive and palliative care in patients with chronic disease frequently arises. This review aims to describe the prognostic factors of chronic respiratory diseases in stable and in acute situations in order to improve the management of these complex situations. The various laws on patients' rights provide a legal framework and define the concept of unreasonable obstinacy. For patients with chronic obstructive pulmonary disease, the most robust decision factors are good knowledge of the respiratory disease, the comorbidities, the history of previous exacerbations and patient preferences. In the case of idiopathic pulmonary fibrosis, it is necessary to know if there is a prospect of transplantation and to assess the reversibility of the respiratory distress. In the case of amyotrophic lateral sclerosis, treatment decisions depend on the presence of advance directives about the use of intubation and tracheostomy. For lung cancer patients, general condition, cancer history and the tumor treatment plan are important factors. A multidisciplinary discussion that takes into account the patient's medical history, wishes and the current state of knowledge permits the taking of a coherent decision.

Bone metastases in lung cancer. Potential novel approaches to therapy

The skeleton is a common site of metastases in lung cancer, an event associated with significant morbidities and poor outcomes. Current antiresorptive therapies provide limited benefit, and novel strategies of prevention and treatment are urgently needed. This review summarizes the latest advances and new perspectives on emerging experimental and clinical approaches to block this deleterious process. Progress propelled by preclinical models has led to a deeper understanding on the complex interplay of tumor cells in the osseous milieu, unveiling potential new targets for drug development. Improvements in early diagnosis through the use of sophisticated imaging techniques with bone serum biomarkers are also discussed in the context of identifying patients at risk and monitoring disease progression during the course of treatment.

Personalized chemotherapy of lung cancer: What the radiologist should know

Lung cancer is the leading cause of deaths due to cancer in France. More than half of lung cancers are discovered at an advanced-stage. New anticancer treatment strategies (i.e., the so-called personalized or targeted therapy) have recently been introduced and validated for non-small-cell lung cancer (NSCLC), in addition to or in association with standard chemotherapy. Personalized therapy includes tyrosine kinase inhibitors (TKIs), antiangiogenic treatments and immunotherapy. Because these treatments may be responsible for atypical thoracic adverse effects and responses as compared to standard chemotherapy, RECIST 1.1 criteria may be inadequate to evaluate the responses to these agents. The goal of this article was to review personalized treatment strategies for NSCLC, to consider the therapy-specific responses and thoracic complications induced by these new therapeutic agents and finally to discuss future directions for the personalized assessment of tumor response.

Bone and brain metastasis in lung cancer: recent advances in therapeutic strategies

Bone and brain metastases are a very common secondary localization of disease in patients with lung cancer. The prognosis of these patients is still poor with a median survival of less than 1 year. Current therapeutic approaches include palliative radiotherapy and systemic therapy with chemotherapy and targeted agents. For bone metastasis, zoledronic acid is the most commonly used bisphosphonate to prevent, reduce the incidence and delay the onset of skeletal-related events (SREs). Recently, denosumab, a fully human monoclonal antibody directed against the receptor activator of nuclear factor κB (RANK) ligand inhibiting the maturation of pre-osteoclasts into osteoclasts, showed increased time to SREs and overall survival compared with zoledronic acid. The treatment of brain metastasis is still controversial. Available standard therapeutic options, such as whole brain radiation therapy and systemic chemotherapy, provide a slight improvement in local control, overall survival and symptom relief. More recently, novel target agents such as the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) erlotinib, gefitinib and afatinib have shown activity in patients with brain metastasis. Inter alia, in patients harboring EGFR mutations, the administration of EGFR TKIs is followed by a response rate of 70-80%, and a longer progression-free and overall survival than those obtained with standard chemotherapeutic regimens. This review is focused on the evidence for therapeutic strategies in bone and brain metastases due to lung cancer.

High prevalence of osteoblastic bone reaction in computed tomography scans of an European Organisation for Research and Treatment of Cancer prospective randomised phase II trial in extensive stage small cell lung cancer

BACKGROUND

Osteoblastic bone reaction is an important phenomenon defined by an increase in apparent bone density of previously known bone metastasis or development of new osteoblastic lesions in the presence of response in other tumour sites. Osteoblastic bone reaction in lung cancer has only been described in a few reports and mostly in patients with pre-existing bone metastasis.

METHODS

In this report we present the data of an independent, blinded and preplanned radiological review of the occurrence of osteoblastic lesions in patients with extensive stage small cell lung cancer (SCLC). The computed tomography (CT) scans of the chest and upper abdomen of 71/88 patients who had an investigator reported complete response (CR), partial response (PR) or stable disease (SD) were retrospectively analysed for the development of osteoblastic lesions. Furthermore, baseline exams were reviewed for the presence and location of bone metastasis and local radiological reports were reviewed for any knowledge of bone metastasis.

RESULTS

There were 14 patients with osteoblastic bone lesions in the reviewed follow-up CT scans. Three patients had known bone metastases at baseline, and 11 patients had no history or findings of bone metastases on the baseline scan. During the course of the disease, 13 out of 14 patients developed new osteoblastic lesions, while all responded in other sites. The prevalence of osteoblastic bone reaction in our study was 19.7%.

CONCLUSION

In this study osteoblastic bone reaction was observed in a larger number of patients without previously documented bone metastases, indicating a high prevalence of occult bone metastases in SCLC. If bone metastases are not documented at diagnosis, then osteoblastic bone reaction may cause confusion in a responding patient.

Optimizing response to gefitinib in the treatment of non-small-cell lung cancer

The epidermal growth factor receptor (EGFR) is expressed in the majority of non-small-cell lung cancer (NSCLC). However, only a restricted subgroup of NSCLC patients respond to treatment with the EGFR tyrosine kinase inhibitor (EGFR TKI) gefitinib. Clinical trials have demonstrated that patients carrying activating mutations of the EGFR significantly benefit from treatment with gefitinib. In particular, mutations of the EGFR TK domain have been shown to increase the sensitivity of the EGFR to exogenous growth factors and, at the same time, to EGFR TKIs such as gefitinib. EGFR mutations are more frequent in patients with particular clinical and pathological features such as female sex, nonsmoker status, adenocarcinoma histology, and East Asian ethnicity. A close correlation was found between EGFR mutations and response to gefitinib in NSCLC patients. More importantly, randomized Phase III studies have shown the superiority of gefitinib compared with chemotherapy in EGFR mutant patients in the first-line setting. In addition, gefitinib showed a good toxicity profile with an incidence of adverse events that was significantly lower compared with chemotherapy. Therefore, gefitinib is a major breakthrough for the management of EGFR mutant NSCLC patients and represents the first step toward personalized treatment of NSCLC.