Speaker Biography

Jingmei Jiang

Chinese Academy of Medical Sciences, Beijing

Title: Benefits and harms of low-dose CT screening in China: a decision analysis

Jingmei Jiang
Biography:

Abstract:

Background: This study aimed to evaluate population outcomes with low-dose CT (LDCT) screening for lung cancer in urban areas of China.

 

Methods: A decision tree model with three scenarios (low-dose CT screening, chest X-ray screening, and no screening) was developed to compare screening results in a simulated Chinese urban cohort (100,000 smokers aged 45-80 years). Data of participant characteristics were obtained from national registries and epidemiological surveys for estimating lung cancer prevalence. The selection of other tree variables such as sensitivities and specificities of LDCT and chest X-ray screening were based on literature research (mainly in China). Base case and sensitivity analyses were performed to compare mortality, false positive findings, and quality-adjusted life years (QALY) in the three scenarios.

Results: In base case analysis, there were 448, 541, and 591 lung cancer deaths in the low-dose CT, chest X-ray, and no screening scenarios, respectively (17.2% reduction in low-dose CT screening over chest X-ray screening and 24.2% over no screening). LDCT screening resulted in slightly more QALYs: 147 years over chest X-ray screening and 250 years over no screening. However, in sensitive analysis, improvement in mortality was subtle or negative with LDCT (16 absolute, 5.4% relative reduction compared with no screening, −11 absolute, −4.1% reduction compared with chest X-ray) in worst case, and the gain of QALY in low-dose CT screening over no screening would diminish if screening was performed among populations with a low prevalence of lung cancer below 436 per 100,000. Besides, the costs of LDCT screening were 9387 false diagnoses (3.76 times over chest X-ray) and 7 deaths due to false diagnosis (3.50 times over chest X-ray).

 

Conclusions: Our findings favor conducting LDCT screening in urban China in terms of mortality outcome. However, approaches to reducing false diagnoses and optimizing other screening conditions are highly needed to maximize benefits and minimize harms associated with this screening device.

Yuyan Wang

Peking Union Medical College, China

Title: Benefits and harms of low-dose CT screening in China: A decision analysis

Yuyan Wang
Biography:

Abstract:

During tumor progression, transformed cells accumulate mutations and gain malignancy. By now, it is unclear how easily this
process can be undertaken and if it can be considered the main bottleneck in tumorigenesis. To measure the probability of
glioma progression, we used a well-characterized murine model of gliomagenesis, induced by overexpressing PDGF-B in embryonic
Neural Progenitor Cells (NPC), mimicking a possible first hit of tumorigenesis. In order to univocally tag each PDGF-transduced cell,
we added a degenerated barcode sequence to the PDGF-B transducing vector and we produced high complexity libraries of barcoded
retroviruses that had been injected in mouse embryos. After the development of gliomas, tumor masses were analyzed by NGS and
compared to embryonic brains few days post infection. By using in-house developed software, we successfully retrieved barcodes
from tumor masses and reconstructed the clonal composition of several independent tumors in different progression stages. Our
data shows that even though low grade, partially progressed tumor masses are clonally heterogeneous and composed by about one
thousand independent clones each, they are the result of a strong selection because the number of oncogene-transduced cells is more
than 10 times higher. Still, high grade and fully progressed gliomas are characterized by a very low clonal complexity and often are
composed by a single clone, suggesting another great bottleneck in glioma progression divides these two stages. More strikingly, fully
progressed tumors derived from in vivo transplant the same pool of thousands different transduced NPCs are composed by the same
clones, suggesting that a predetermined cell state is required to gain malignancy.