Table 1.
Summary of cfDNA studies in SCLC.
| Study | Cohort (LD-SCLC/ED-SCLC) | Method | Main Results |
|---|---|---|---|
| Morgensztern D et al., 2016 [70] | 134 patients | NGS (Guardant360) | 132/134 (92.3%) of patients had at least one mutation. The most common mutations were found in TP53 (70%) and RB1 (32%). |
| Fernandez-Cuesta L et al., 2016 [49] | 51 (42/9) patients and 225 healthy controls | NGS (Custom panel) | 25/51 (49%) patients had mutations in TP53. 25/225 (11.1%) controls had mutations in TP53. |
| Ou S.H.I et al., 2017 [74] | 1 NSCLC patients transform to SCLC | NGS (FoundationACT) | An NSCLC with an ALK fusion transforms the histology into SCLC. |
| Almodovar K et al., 2018 [69] | 27 (11/16) patients | NGS (Custom panel of 14 genes) | 23/27 (85%) patients had disease-associated mutations. The most common altered genes were TP53 (70%) and RB1 (52%). Changes in cfDNA levels correlated with response to therapy and relapse. |
| Nong J et al., 2018 [71] | 22 (11/11) patients | NGS (Custom panel of 430 genes) | All patients had at least one mutation. Mutations were mostly found in TP53 (91%) and RB1 (64%). 94% of mutations detected in tumor DNA were also detected in the paired ctDNA sample. High cfDNA levels in SCLC patients were associated with significantly worse PFS and OS. |
| Du M et al., 2018 [72] | 24 (11/13) patients | WGS for CNA and NGS (xGen Pan-Cancer Panel) | 16/24 (66.7%) of patients had CNAs. All patients had any mutation. TP53 and RB1 mutations were found in 4/17 patients (23.5%). A higher mutation risk index was strongly associated with poor PFS and OS. |
| Devarakonda S et al., 2019 [75] | 564 patients | NGS (Guardant360) | 94% of patients had at least one mutation or amplification. The most common mutations were found in TP53 (72.5%) and RB1 (18%). A higher percentage of alterations in APC and AR were observed in samples obtained at relapse. |
| Mohan S et al., 2020 [73] | 69 (39/30) patients and 32 healthy controls | WGS for CNA and NGS (Custom panel of 110 genes) |
58/62 (94%) of patients had at least one mutation. Most of the mutations were found in TP53 (79%) and RB1 (34%). 0/23 (0%) controls had genetic alterations. The presence of CNAs was associated with OS, being a potential prognostic factor and monitoring tool in SCLC patients. |
| Iams W.T et al., 2020 [76] | 23 LD-SCLC patients | NGS (Custom panel of 14 genes) | Detection of ctDNA in patients with LS-SCLC after curative intent therapy predicts disease relapse and death. |
Abbreviations: SCLC: small cell lung cancer; NGS: next-generation sequencing; NSCLC: non-small cell lung cancer; WGS: whole-genome sequencing; CNA: copy number alteration; cfDNA: cell-free DNA; ctDNA: circulating tumor DNA; PFS: progression-free survival; OS: overall survival LD-SCLC: limited disease SCLC.