Comprehensive serial biobanking in advanced NSCLC: feasibility, challenges and perspectives.

BACKGROUND: Availability of tumor material at baseline and disease progression is increasingly important for patient management in non-small-cell lung cancer (NSCLC), especially for the application of targeted therapies like tyrosine kinase inhibitors and for immune checkpoint inhibitor treatment. Here we report the experience of prospective biomaterial acquisition in advanced NSCLC from a pilot project. METHODS: Main objective was the longitudinal collection of high-quality, cryoconserved biopsies in addition to formalin-fixed paraffin-embedded (FFPE) biopsies required for routine diagnostics, along with blood samples and detailed clinical annotation using standardized questionnaires. RESULTS: Over five years, 205 patients were enrolled for the project, yielding 387 cryoconserved biopsies and 1,098 serum, plasma and buffy-coat samples. The feasibility of obtaining the cryoconserved biopsies in addition to the FFPE biopsies was 89% for newly diagnosed cases, but dropped down to 56% and 47% at first and second disease progression, respectively. While forceps biopsy was the preferred procedure for tissue acquisition, the highest tissue amounts were received using the cryobiopsy method. Biopsies had a median tumor cellularity of 34% and yielded in median 13.6 µg DNA and 12 µg RNA (median RIN =8). During the five-year project, a maximum of 38 follow-up blood samples per patient were assembled in up to four therapy lines. CONCLUSIONS: Despite the poor condition and limited prognosis of most NSCLC patients, this serial biomaterial acquisition including routine collection of cryoconserved biopsies is feasible to support individualized management. The standardized collection of high-quality material has enabled and enriched several translational research studies that can advance therapeutic options.

Mutation analysis of circulating plasma DNA to determine response to EGFR tyrosine kinase inhibitor therapy of lung adenocarcinoma patients.

Long-lasting success in lung cancer therapy using tyrosine kinase inhibitors (TKIs) is rare since the tumors develop resistance due to the occurrence of molecularly altered subclones. The aim of this study was to monitor tumors over time based on the quantity of mutant plasma DNA and to identify early indications for therapy response and tumor progression. Serial plasma samples from lung adenocarcinoma patients treated with TKIs were used to quantify EGFR and KRAS mutations in circulating DNA by digital PCR. Mutant DNA levels were compared with the courses of responses to treatment with TKIs, conventional chemotherapy, radiotherapy, or combinations thereof. Variations in plasma DNA mutation levels over time were found in 15 patients. We categorize three major courses: First, signs of therapy response are associated with a fast clearing of plasma DNA mutations within a few days. Second, periods of stable disease are accompanied by either absence of mutations or fluctuation at low levels. Finally, dramatic increase of mutational load is followed by rapid tumor progression and poor patient survival. In summary, the serial assessment of EGFR mutations in the plasma of NSCLC patients allows conclusions about controlled disease and tumor progression earlier than currently available methods.