Abstract 4689
Background
Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for early prediction of relapse across different tumor types. In patients with colorectal cancer (CRC), multiple studies have analyzed ctDNA to monitor tumor burden using fixed gene panels and droplet digital PCR. Here, we use a highly sensitive and specific, bespoke, whole exome-based NGS approach (Signatera™) for ctDNA monitoring.
Methods
A cohort of 33 patients with stage III CRC who underwent surgery and were treated with at least 4 months of adjuvant chemotherapy was analyzed. Mutational profiles derived from primary tumor tissue and germline DNA whole exome were used to design assays targeting tumor-specific somatic variants. The bespoke assays were used for ctDNA detection in plasma samples. Relapse-free survival (RFS) was calculated for patients stratified by ctDNA status.
Results
Plasma samples (n = 44; average volume=1.8mL) from patients (N = 33) were analysed for the presence of ctDNA. Of the five ctDNA-positive patients, clinical follow-up was available for three patients, all of whom relapsed (100%; 3/3); three of 27 ctDNA-negative patients (11%) also clinically relapsed. Molecular relapse through ctDNA analysis was detected up to 668 days ahead of radiological imaging with an average lead time of 305 days. The majority of relapses in ctDNA-positive patients (67%; 2/3) occurred within a year of follow-up, while no relapses were observed in ctDNA-negative patients during the one-year time frame. All plasma samples (n = 34) from 24 non-relapsing patients were ctDNA negative, corresponding to a specificity of 100%. The presence of ctDNA was associated with a markedly reduced RFS compared to ctDNA-negative patients (HR: 5.6; 95% CI: 0.6-52.1; p < 0.01).
Conclusions
The study results indicate that ctDNA status is associated with high relapse risk in patients with CRC and can serve as a predictor of patient outcome. Despite low plasma volumes (<5mL) and lack of longitudinal samples for analysis, ctDNA was detected in 50% of relapse cases.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Natera, Inc. and NSABP Foundation.
Funding
Natera, Inc., Bayer, NSABP Foundation.
Disclosure
H. Sethi: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. T.J. George: Research grant / Funding (institution): Merck; Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): BMS; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Lilly; Research grant / Funding (institution): Incyte; Research grant / Funding (institution): Seattle Genetics; Research grant / Funding (institution): Pharmacyclics. S. Shchegrova: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. A.S. Tin: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. A. Olson: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. D. Renner: Full / Part-time employment: Natera, Inc. E. Kalashnikova: Full / Part-time employment: Natera, Inc. M. Louie: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. R. Salari: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. B. Zimmermann: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. A. Aleshin: Shareholder / Stockholder / Stock options, Full / Part-time employment, I am an employee of Natera and own stock/options to stock.: Natera, Inc. All other authors have declared no conflicts of interest.
Resources from the same session
2888 - Development and validation a nomogram based on pathological microscopic features to predict survival in nasopharyngeal carcinoma and guide treatment decision
Presenter: Kuiyuan Liu
Session: Poster Display session 3
Resources:
Abstract
3607 - Deep learning in nasopharyngeal carcinoma: a retrospective cohort study of 3D convolutional neural networks on magnetic resonance imaging
Presenter: Meng Yun Qiang
Session: Poster Display session 3
Resources:
Abstract
5848 - Combined androgen blockade in patients with advanced androgen receptor–positive salivary gland carcinoma: Exploratory biomarker analyses
Presenter: Chihiro Fushimi
Session: Poster Display session 3
Resources:
Abstract
4484 - Classification of esthesioneuroblastoma (ENB) based on chromosome (chr) arm gain and loss (CNA) in the setting of a hypomutated genomic landscape
Presenter: Russell Madison
Session: Poster Display session 3
Resources:
Abstract
5753 - Trastuzumab plus docetaxel in patients with advanced HER2–positive salivary duct carcinoma: Exploratory biomarker analyses
Presenter: Hideaki Takahashi
Session: Poster Display session 3
Resources:
Abstract
3373 - Development and characterization of salivary gland cancer organoid cultures
Presenter: Wim Boxtel
Session: Poster Display session 3
Resources:
Abstract
3118 - A parent-of-origin effect of the RB1 mutations in retinoblastoma with low penetrance and variable expressivity
Presenter: Ekaterina Alekseeva
Session: Poster Display session 3
Resources:
Abstract
4512 - The humanistic burden reported by patients diagnosed with Recurrent/Metastatic Squamous Cell Carcinoma of the Head and Neck (R/M SCCHN) in Europe
Presenter: Prianka Singh
Session: Poster Display session 3
Resources:
Abstract
3961 - Concurrent Chemotherapy and External Radiation Therapy: An Open Label Non-Inferiority Phase III Randomized Controlled Trial of Weekly versus Three Weekly Cisplatin and Radical Radiotherapy in Locally Advanced Head and Neck Squamous Cell Carcinoma: CONCERT trial
Presenter: ATUL SHARMA
Session: Poster Display session 3
Resources:
Abstract
3973 - A randomized phase II study on the OPTimization of IMmunotherapy in squamous carcinoma of the head and neck (SCCHN) – OPTIM (AIO-KHT-0117)
Presenter: Viktor Grünwald
Session: Poster Display session 3
Resources:
Abstract