Circulating Tumor DNA (ctDNA) as a Prognostic Tool in Patients With Advanced Lung Adenocarcinoma

Lung cancer is the leading cause of cancer death in the U.S. and throughout the world. Lung cancers are broadly divided histologically into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). About 25% of patients with NSCLC have stage I or II disease. The primary treatment modality is surgical resection,2 and 5-year survival rates are 65% for stage I and 41% for stage II disease. However, more than 70% of patients with NSCLC present with stage III or IV disease. Patients with stage III disease are most commonly treated with chemoradiation, and 5-year survival rate is 26%. Chemotherapy and targeted therapy are often used for stage IV disease, which has a 5-year survival rate of 4%. Tyrosine kinase inhibitor (TKI) is a targeted therapy against specific molecules in critical cell-signaling pathways involved in lung carcinogenesis. The currently available FDA approved TKIs for advanced NSCLC include afatinib, gefitinib, and erlotinib that inhibit epidermal growth factor receptor (EGFR) signaling 6 and crizotinib that inhibits anaplastic lymphoma kinase (ALK) signaling. However, only tumors that carry the corresponding oncogenic mutations (e.g., sensitizing EGFR mutations) would respond well to these TKIs. Meta-analyses of clinical trials evaluating the efficacy of gefitinib and erlotinib have demonstrated that NSCLC patients who are EGFR mutation-positive have a lower risk of disease progression when treated with an EGFR-TKI as compared to those treated with chemotherapy (HR = 0.43, 95% confidence interval, CI=0.38-0.49). EGFR-TKI, however, confers no benefits to patients who are EGFR wildtype (HR = 1.06, 95% CI=0.94-1.19). A phase III trial of crizotinib has also demonstrated the superiority of crizotinib to standard chemotherapy in ALK-positive NSCLC patients (HR = 0.49; 95% CI=0.37-0.64). In Hong Kong, as in other parts of Asia like in China and in Taiwan, other than the majority of lung cancer patients being smokers, there is also a prominence of non-smokers in lung cancer. Compared with Caucasians, there is also a relatively higher incidence of EGFR mutation in lung adenocarcinomas. The prevalence of EGFR mutation in Asian population with lung adenocarcinomas can reach up to 60% compared to at most 30% in the Caucasian population. These EGFR mutant tumors will demonstrate better response to the drug EGFR-TKI, boosting up the response rate to almost 70% compared to 30% with conventional chemotherapy for lung cancer. Even with this remarkable response, however, EGFR-TKI will eventually fail in EGFR mutant lung cancer. There is an imminent need to look for newer therapeutic targets or agents that can overcome this acquired resistance to anti-cancer drugs and to explore alternative molecular signaling pathways that could interact or enhance EGFR signaling pathways to modulate the therapeutic response in lung cancer.

Sex

All

Minimum age

18 Years

Maximum age

80 Years

Inclusion Criteria:

* Patients are eligible if they (1) are diagnosed with primary adenocarcinoma, (2) have no concurrent cancers, (3) are going to receive TKI or chemo as first-line therapy, and (4) are willing to sign informed consent and enrolled in the study before treatment starts.

Exclusion Criteria:

* Patients have other concurrent cancers
* Patients who are not eligible receive TKI or chemo as first-line therapy
* Patients who are not willing or able to sign informed consent
* Histology other than adenocarcinoma

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