Objective To develop an affordable and robust pipeline for selection of patient-specific somatic structural variants (SSVs) being informative about radicality of the primary resection, response to adjuvant therapy, incipient recurrence and response to treatment performed in relation to diagnosis of recurrence. Design We have established efficient procedures for identification of SSVs by next-generation sequencing and subsequent quantification of 3–6 SSVs in plasma. The consequence of intratumour heterogeneity on our approach was assessed. The level of circulating tumour DNA (ctDNA) was quantified in 151 serial plasma samples from six relapsing and five non-relapsing colorectal cancer (CRC) patients by droplet digital PCR, and correlated to clinical findings. Results Up to six personalised assays were designed for each patient. Our approach enabled efficient temporal assessment of disease status, response to surgical and oncological intervention, and early detection of incipient recurrence. Our approach provided 2–15 (mean 10) months' lead time on detection of metastatic recurrence compared to conventional follow-up. The sensitivity and specificity of the SSVs in terms of detecting postsurgery relapse were 100%. Conclusions We show that assessment of ctDNA is a non-invasive, exquisitely specific and highly sensitive approach for monitoring disease load, which has the potential to provide clinically relevant lead times compared with conventional methods. Furthermore, we provide a low-coverage protocol optimised for identifying SSVs with excellent correlation between SSVs identified in tumours and matched metastases. Application of ctDNA analysis has the potential to change clinical practice in the management of CRC.

BRCA1 and BRCA2 gene pathogenic variants account for most hereditary breast cancer and are increasingly used to determine eligibility for PARP inhibitor (PARPi) therapy of BRCA-related cancer. Because issues of BRCA testing in clinical practice now overlap with both preventive and therapeutic management, updated and comprehensive practice guidelines for BRCA genotyping are needed. The integrative recommendations for BRCA testing presented here aim to (1) identify individuals who may benefit from genetic counselling and risk-reducing strategies; (2) update germline and tumour-testing indications for PARPi-approved therapies; (3) provide testing recommendations for personalised management of early and metastatic breast cancer; and (4) address the issues of rapid process and tumour analysis. An international group of experts, including geneticists, medical and surgical oncologists, pathologists, ethicists and patient representatives, was commissioned by the French Society of Predictive and Personalised Medicine (SFMPP). The group followed a methodology based on specific formal guidelines development, including (1) evaluating the likelihood of BRCAm from a combined systematic review of the literature, risk assessment models and expert quotations, and (2) therapeutic values of BRCAm status for PARPi therapy in BRCA-related cancer and for management of early and advanced breast cancer. These international guidelines may help clinicians comprehensively update and standardise BRCA testing practices.

We used a novel method based on allele-specific quantitative polymerase chain reaction (Intplex) for the analysis of circulating cell.free DNA (ccfDNA) to compare total ccfDNA and KRAS- or BRAF-mutated ccfDNA concentrations in blood samples from mice xenografted with the human SW620 colorectal cancer (CRC) cell line and from patients with CRC. Intplex enables single-copy detection of variant alleles down to a sensitivity of ≥0.005 mutant to wild-type ratio. The proportion of mutant allele corresponding to the percentage of tumor-derived ccfDNA was elevated in xenografted mice with KRAS homozygous mutation and varied highly from 0.13% to 68.7% in samples from mutation-positive CRC patients (n = 38). Mutant ccfDNA alleles were quantified in the plasma of every patient at stages II/III and IV with a mean of 8.4% (median, 8.4%) and 21.8% (median, 12.4%), respectively. Twelve of 38 (31.6%) and 5 of 38 (13.2%) samples showed a mutation load higher than 25%and 50%, respectively. This suggests that an important part of ccfDNA may originate from tumor cells. In addition, we observed that tumor-derived (mutant) ccfDNA was more fragmented than ccfDNA from normal tissues. This observation suggests that the form of tumor-derived and normal ccfDNA could differ. Our approach revealed that allelic dilution is much less pronounced than previously stated, considerably facilitating the noninvasive molecular analysis of tumors.

This randomized phase II–III trial sought to evaluate the efficacy and safety of adding bevacizumab (Bev) following induction chemotherapy (CT) in extensive small-cell lung cancer (SCLC). Enrolled SCLC patients received two induction cycles of CT. Responders were randomly assigned 1:1 to receive four additional cycles of CT alone or CT plus Bev (7.5 mg/kg), followed by single-agent Bev until progression or unacceptable toxicity. The primary end point was the percentage of patients for whom disease remained controlled (still in response) at the fourth cycle. In total, 147 patients were enrolled. Partial response was observed in 103 patients, 74 of whom were eligible for Bev and randomly assigned to the CT alone group (n = 37) or the CT plus Bev group (n = 37). Response assessment at the end of the fourth cycle showed that disease control did not differ between the two groups (89.2% versus 91.9% of patients remaining responders in CT alone versus CT plus Bev, respectively; Fisher's exact test: P = 1.00). Progression-free survival (PFS) since randomization did not significantly differ, with a median PFS of 5.5 months [95% confidence interval (CI) 4.9% to 6.0%] versus 5.3 months (95% CI 4.8% to 5.8%) in the CT alone and CT plus Bev groups, respectively [hazard ratio (HR) for CT alone: 1.1; 95% CI 0.7% to 1.7%; unadjusted P = 0.82]. Grade ≥2 hypertension and grade ≥3 thrombotic events were observed in 40% and 11% of patients, respectively, in the CT plus Bev group. Serum vascular endothelial growth factor (VEGF) and soluble VEGF receptor titrations failed to identify predictive biomarkers. Administering 7.5 mg/kg Bev after induction did not improve outcome in extensive SCLC patients.