Evaluation of Clinical Utility of a Circulating Tumor Cells (CTCs) and CTC clusters-based test (‘TruCheck’) for early detection of malignant Lung Lesions in heavy smokers

According to American Cancer Society, Lung cancer (both small cell and non-small cell) is the second most common cancer in both men and women (not counting skin cancer) in United States. In men, prostate cancer is more common, while in women breast cancer is more common. The American Cancer Society’s estimates for lung cancer in the United States for 2021 are: About 235,760 new cases of lung cancer (119,100 in men and 116,660 in women) and about 131,880 deaths from lung cancer (69,410 in men and 62,470 in women). Lung cancer mainly occurs in older people. Most people diagnosed with lung cancer are 65 or older; a very small number of people diagnosed are younger than 45. The average age of people when diagnosed is about 70. Lung cancer is by far the leading cause of cancer death among both men and women, making up almost 25% of all cancer deaths. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined. According to Cancer Statistics, 2020: Report from National Cancer Registry Programme, India, Lung is one of the common 5 leading cancer sites including breast, mouth, cervix uteri, and tongue. Lung cancer was the leading site in metropolitan cities. The majority of the patients with cancer were diagnosed at the locally advanced stage for breast (57.0%), cervix uteri (60.0%), head and neck (66.6%), and stomach (50.8%), whereas in lung cancer, distant metastasis was predominant among males (44.0%) and females (47.6%). Lung cancer has showed a significant increase in females. One in 68 males in India will develop lung cancer during their lifetime (0-74 years of age). In India, lung cancer can be attributed to tobacco use and air pollution, which are the leading risk factors. A hospital-based study from northern India showed that 90% of patients with lung cancer were diagnosed at an advanced stage of the disease, and there was a delay in diagnostic evaluation and treatment. Screening examinations are tests performed to find disease before symptoms begin. The goal of screening is to detect disease at its earliest and most treatable stage. In lung cancer, treatment based on surgical removal in the early stages of the disease results in better survival. Early-stage lung cancer is usually asymptomatic and most patients presenting with symptoms are diagnosed at advanced stages with poor treatment outcome. Early detection is the most effective way to improve survival of lung cancer patients. The most important risk factor for lung cancer is smoking, which results in approximately 85% of all U.S. lung cancer cases. Other risk factors include specific occupational exposures, radon exposure, family history, and history of pulmonary fibrosis or chronic obstructive lung disease. Although the prevalence of smoking has decreased, approximately 37% of U.S. adults are current or former smokers. Lung cancer has a poor prognosis, and nearly 90% of persons with lung cancer die of the disease. However, early-stage non–small cell lung cancer (NSCLC) has a better prognosis and can be treated with surgical resection. Chest radiography and sputum cytologic evaluation have not shown adequate sensitivity or specificity as screening tests. Screening by low-dose computed tomography (LDCT) has demonstrated high rates of early-stage lung cancer detection in a high-risk population. This has led to incorporation of LDCT in various screening guidelines for high-risk individuals and LDCT is currently the only recommended screening test for lung cancer. The U.S. Preventive Services Task Force expanded screening eligibility to recommend annual screening with low-dose CT in adults ages 50-80 who have a 20 pack-year smoking history and who currently smoke or have quit smoking within the past 15 years. This is a "B" recommendation according to The United States Preventive Services Task Force (USPSTF) criteria. The task force also recommended that screening be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery. American Cancer Society Lung Cancer Screening Guideline recommends annual screening in current or former smokers aged 55â€74 years in good health with at least a 30â€packâ€year history of smoking (adults who currently smoke or have quit within the past 15 years; and have at least a 30 packâ€year smoking history). The harms associated with LDCT screening include false-negative and false-positive results, incidental findings, overdiagnosis, and radiation exposure. False-positive LDCT results occur in a substantial proportion of screened persons; 95% of all positive results do not lead to a diagnosis of cancer. In a high-quality screening program, further imaging can resolve most false-positive results; however, some patients may require invasive procedures. A modeling study performed for the USPSTF estimated that 10% to 12% of screen-detected cancer cases are over diagnosed—that is, they would not have been detected in the patient’s lifetime without screening. Radiation harms, including cancer resulting from cumulative exposure to radiation, vary depending on the age at the start of screening; the number of scans received; and the person’s exposure to other sources of radiation, particularly other medical imaging.

TruCheck is a blood-based liquid biopsy developed by Datar Cancer Genetics and is proposed for screening of cancer. TruCheck employs a label free, size independent, non- mechanical approach to allow enrichment of viable apoptosis-resistant circulating tumor cells and their clusters. TruCheck is relevant for detection of cancer on the basis that Circulating tumor cell clusters are ubiquitous in the blood of individuals with cancer and are uncommon in patients with benign conditions or other healthy individuals. First study conducted in 16,134 participants showed presence of C-ETACs in 90% of cancer patients as against in 3% of healthy cohort. Total 5509 cancer and 10625 asymptomatic individuals were included. The detection rates across organ systems ranged between 83% and 94.4%. In a subsequent study, with total of 30,060 individuals, there were 9416 with diagnosed cancer. When profiled with TruCheck, concordance was observed in 92%. In individuals with suspicion of cancer who were yet to undergo tissue biopsy, concordance rate of 92.6% was observed among 6025 individuals diagnosed with cancer on tissue biopsy. Among the 700 individuals with benign diagnosis on tissue sample, on organ specific marker staining only 0.71% showed false positive TruCheck results. One-year follow-up data of the asymptomatic cohort showed that C-ETAC positive individuals have a 230-fold higher 1-year cancer risk as compared to individuals where C- ETAC were undetectable. This approach has been evaluated to discern primary lung malignancy from metastatic deposit based on Immunocytochemistry (ICC) profiling of Circulating Tumor Cells (CTCs) from peripheral blood. Evaluation of conditioned peripheral blood had sensitivity of 84% in detecting lung cancers, specificity of 96% in predicting patients negative for lung cancer with overall accuracy of 96%. Circulating tumor cell clusters originate from tumor proper and are not a result of cell aggregation in peripheral blood. They are ubiquitous in cancer and uncommon in benign tumors and healthy individuals. C-ETACs can be profiled by ICC for organ specific markers. Thus, the C-ETAC based lung cancer screening strategy may offer a viable non- invasive approach. TruCheck has been granted CE-IVD status and is presently offered as a single-site laboratory developed test at DCG’s CAP and CLIA accredited facility in Nasik, India. The following technical parameters need to be met to be an accredited site for CTLS:

·         Multidetector helical scanner with ≥4 detector rows

·         Entire chest imaging

·         Image thickness of ≤2.5 mm

·         Volume computed tomography dose index (CTDIvol) ≤3 mGy (for “standardâ€-sized patients [i.e., 5 feet 7 inches and 154 pounds])

·         Dose modulation, either manual or automatic, according to patient size

The LDCT will be interpreted as per NCCN Lung cancer screening guideline version 1.202. Evaluation of positive nodules will be performed as per existing standard recommendations. Interpretation of Findings at CT or Chest Radiographic Screening

·  Negative or minor abnormality: not suspicious for lung cancer

No findings or minor findings not suspicious for lung cancer, such as morphologically benign nodules or noncalcified nodules, 4 mm.

·  Clinically important abnormality: not suspicious for lung cancer

Important findings not suspicious for lung cancer but requiring some form of clinical follow-up.

·  Positive: suspicious for lung cancer

Findings suspicious for lung cancer, such as noncalcified nodule 4 mm, lung consolidation or obstructive atelectasis, nodule enlargement, and nodules with suspicious changes in attenuation.

This is a prospective observational study to evaluate performance of TruCheck as a lung cancer screening tool in high-risk individuals. The study will be conducted at only one investigative site. Recruitment will stop when approximately 1500 subjects are screened. 1500 volunteers will be screened to enroll a total of 1000 participants. (Cohort A: 900 and Cohort B: 100). The study duration per subject will be up to 790 days, with up to 60 days from study eligibility screening to the LDCT screening and remaining 2 years for follow-up. The study investigator or his authorized representative will identify individuals eligible for the study, based on the inclusion/exclusion criteria enlisted in this protocol. After providing all necessary information related to study and after the written informed consent given by the eligible participant, 15 ml blood will be drawn as per study protocol. After the blood draw, high-risk participants will undergo LDCT as per standard protocol (within 60 days of screening visit). Participants with - Positive: suspicious for lung cancer – findings on the LDCT will be advised to go for further procedure as per the standard positive LDCT management practice. Once the requisite procedure such as FNAC or biopsy has been performed, histopathological/immunohistochemistry results will be entered in the Case Record form for analysis. Clinical data/outcomes including LDCT results will be shared with sponsor every 15 days for the samples for which Trucheck results have been submitted to the PI. On the completion of the cohorts, data will be analyzed to evaluate the study objectives.

Primary Objective

·    Evaluation of sensitivity of Circulating tumor cells (CTC) and CTC clusters-based TruCheck test for detection of malignant Lung Lesions in heavy smokers.

Secondary Objective

·    To performance of LDCT as a lung cancer screening tool for heavy smokers in Indian population

·    To determine whether TruCheck can offer non-inferior alternative to LDCT for lung cancer screening of high-risk individuals.

·   To determine performance of TruCheck as a blood-based solution in comparison to histopathological examination of physical biopsy or FNAC performed in individuals with high-  risk findings on LDCT

·    To explore additional CTC or cell free nucleic acid-based biomarkers for screening and diagnosis of lung cancer.