Role of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in the Treatment of Bronchoalveolar Carcinoma

A correlation between EGFR gene mutation status and bronchioloalveolar carcinoma features in Japanese patients with adenocarcinoma

BACKGROUND

The presence of epidermal growth factor receptor (EGFR) mutations in gefitinib-naive lung cancer patients has been reported to be higher in females, in non-smokers, in Japanese, and in adenocarcinoma patients, especially in bronchioloalveolar carcinoma (BAC). To further investigate the prevalence of EGFR mutations in relation to pathological factors, we evaluated EGFR mutations in series of Japanese adenocarcinoma patients who had never been treated with gefitinib.

METHODS

In the previous studies, we examined mutation status in the tyrosine kinase domain of EGFR, exon18 through exon21, in 112 primary lung adenocarcinoma samples. Using these data, adenocarcinomas were histologically classified according to the presence or absence of bronchioloalveolar components.

RESULTS

Among 112 patients, 48 had adenocarcinoma with BAC components. Those with adenocarcinomas with BAC components had higher frequency of EGFR mutation (28/48, 58%) than those with non-BAC adenocarcinoma (24/64, 37%, P = 0.036). Male patients had the same trend; 12/23 (52%) male patients with adenocarcinoma with BAC components and 10/47 (21%) of those with non-BAC adenocarcinoma had EGFR mutation (P = 0.0135) but there was no correlation between the EGFR mutation status and with/without BAC components in 42 female patients (P = 0.30). Among 11 male non-smokers, patients with adenocarcinoma with BAC components had a tendency to have EGFR mutation more frequently than those with non-BAC adenocarcinoma (P = 0.061). In clear contrast, the frequency of EGFR mutation did not differ significantly between male smoker patients with adenocarcinoma with BAC components and those with non-BAC. Among patients with adenocarcinoma with BAC components, those with adenocarcinoma with EGFR gene mutation had a significantly better 5 year survival than those with adenocarcinoma with wild-type (85.7 versus 46.0%, P = 0.0017).

CONCLUSIONS

Adenocarcinomas with BAC components in male non-smokers seem to predict the presence of EGFR mutation. Half of female adenocarcinoma patients with EGFR mutation exhibit adenocarcinomas with non-BAC suggesting a different behavior from those in males. The prognosis of patients with adenocarcinoma with BAC components with EGFR gene mutation is predicted to be better than that of patients with adenocarcinoma with BAC components with wild-type EGFR gene.

Skin rash and bronchoalveolar histology correlates with clinical benefit in patients treated with gefitinib as a therapy for previously treated advanced or metastatic non-small cell lung cancer

BACKGROUND

Only 15% of patients with non-small cell lung cancer (NSCLC) treated with oral epidermal growth factor tyrosine kinase inhibitor gefitinib, as a second-line therapy have objective responses. Fifty percent will have improvement of lung cancer related symptoms. It will be critical to identify patients who will benefit clinically from this therapy even when there is no objective response seen on imaging studies. We have performed a retrospective analysis of 76 patients who received gefitinib as a therapy for previously treated metastatic NSCLC at the University of Minnesota Comprehensive Cancer Center in order to describe characteristics of patients who will likely derive benefits from gefitinib therapy.

METHODS

All patients treated with gefitinib therapy at the University of Minnesota from September 2001 to January 2004 were entered into the study. The Log-rank Test and Cox proportional hazards regression were used to assess the effect of the number of previous therapy lines, histology subtype, performance status, gender, stage of disease at initial diagnosis, and presence of skin rash on time to disease progression and overall survival (OS). Fisher's Exact Test and multiple logistic regressions were used to assess the effect of these covariates on disease response.

RESULTS

Seventy-six patients entered the study, with a median age of 60 years (range 37-82). There were 37 female and 39 male patients; 47 patients had adenocarcinoma, 22 had squamous and 7 had other NSCLC histologies. Six patients had no prior therapy, 23 had one, 32 had two, 8 had three, and 7 had four prior therapies for lung cancer. Fifty-six were current smokers. Median time to disease progression was 3 months (95% CI: 3.0, 6.0). There was no difference in time to disease progression whether patients had one or more prior therapies. Patients with brain metastases (26 patients) benefited from gefitinib therapy at least equally well as those without brain metastatic disease. Patients with adenocarcinoma histology with bronchoalveolar features had superior median time to progression versus other lung cancer histology (14 months versus 3 months, p=0.076), which translated into survival advantage in this group >24 months (95% CI: 0.76, 24+) versus 6.6 months (p=0.0096). Patients with EGFR positive tumors had median survival of 10.2 months (95% CI: 1.45, 16.94) versus 3.7 months (95% CI: 2.66, 4.74) with EGFR negative tumors. Patients who developed any degree of skin rash had prolonged time to disease progression with median of 6 months (95% CI: 2.56, 15.5) versus patients without skin rash median 3 months (95% CI: 1.43, 2.83) (p=0.023). This last factor was the best predictor of improved time to disease progression in multiple regression analysis (p=0.0405).

CONCLUSION

A subgroup of patients with NSCLC will benefit from gefitinib therapy. Objective responses will likely be seen in half the patients with mutation of internal domain of EGFR; however, a larger group of patients will also enjoy prolonged disease stabilization and clinical benefit. We suggest that adenocarcinoma with bronchoalveolar features and the presence of skin rash may be used as predictors of gefitinib benefit.