Weston Park Cancer Centre

Abstract Background: Detection of circulating tumour DNA (ctDNA) in plasma predicts future recurrence in early breast cancer (EBC). Previous studies have relied on tumour-informed approaches with personalised assays. In this study, we performed orthogonal testing on plasma samples collected prospectively in the c-TRAK-TN study to compare a tissue-free assay with digital droplet PCR (ddPCR) for ctDNA analysis. Methods: c-TRAK-TN recruited 161 patients with early triple negative breast cancer (TNBC) deemed clinically high risk of relapse. Patients underwent ctDNA analysis by ddPCR starting within 4 weeks of completion of treatment and continuing every 3 months for up to 2 years. ddPCR tracked 1 or 2 patient specific variants as previously described. We further analysed 1062 timepoints from a total of 159 patients (median 7 per patient, range 1-11) using Guardant Reveal assay, a tissue-free approach that exploits differential methylation patterns in breast cancer compared with normal tissue. Results: Samples were successfully analysed from 95.3% (1012/1062) timepoints from 159 patients with the tissue-free Reveal assay. CtDNA was detected in 34.0% (54/159) of patients in at least 1 timepoint, with a median methylation tumour fraction of 0.266% (range 0.002 to 51.0%). Detection of ctDNA with the tumour agnostic assay strongly associated with future risk of relapse (HR 20.62, p<0.0001; logrank). Of patients who relapsed by 24 months follow up, 89.5% (34/38) of relapses were detected by prior ctDNA analysis. There were 159 patients available for comparison between ddPCR and the tissue-free assay (Reveal), in 1005 timepoints (median 7 per patient, range 1-11). Concordant test results were observed in 950/1005 timepoints with an overall agreement rate of 94.5%. In this cohort, 63.5% (101/159) of patients did not have ctDNA detected by either assay; 26.4% (42/159) had ctDNA detected by both assays and 10.1% (16/159) had discordant results. Of those detected, 44.8% (26/58) were detected by the tissue-free assay first and 6.9% (4/58) by ddPCR (p<0.0001, Fisher exact test). The median time from first detection of ctDNA to relapse for the tissue-free assay was 7.9 months (95% confidence interval (CI): 5.7-10.5 months) compared to ddPCR assay with 5.7 months (95% CI: 2.9-9.7 months) (HR = 0.6, p=0.0574; mixed effects cox model). Conclusion: Detection of ctDNA with a tissue-free assay anticipated relapse with high accuracy, in patients with early TNBC. The tissue-free assay frequently detected ctDNA at an earlier timepoint than ddPCR, trending towards a longer lead time from detection of ctDNA to relapse. Tissue-free approaches might offer simpler workflows for ctDNA analysis than tumour-informed approaches, and further assessment in clinical trials is warranted. Citation Format: N. Cunningham, R. J. Cutts, C. Swift, K. Dunne, M. Dewan, L. Kilburn, K. Goddard, P. Hall, C. Harper-Wynne, T. Hickish, I. Macpherson, A. Okines, A. Wardley, S. Waters, C. Palmieri, M. Winter, J. Bliss, D. Dustin, M. Ellis, I. Garcia- Murillas, N. C. Turner. Tissue-free circulating tumour DNA detection in patients with early triple negative breast cancer from the c-TRAK-TN trial [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr RF3-05.

Uterine placental site trophoblastic tumors (PSTTs) are rare trophoblastic neoplasms, presumed to be of gestational origin. Herein, using a comprehensive morphologic, immunohistochemical, and molecular approach, we describe 5 cases of primary uterine nongestational PSTTs. The median age at presentation was 32 years (range 25 to 45). All tumors were initially expected to be of gestational origin as all were located in the uterus and all patients had a history of pregnancy (5/5, 100%). The median size of the primary uterine tumors was 6.3 cm (range 4.8 to 7.5). Three patients (3/5, 60%) had metastatic disease at presentation or revealed during initial workup (1/5 [20%] patients with lymph node metastasis only and 2/5 [40%] with distant metastases). All tumors showed similar histopathologic and immunohistochemical features to those of gestational PSTTs. The tumor cells expressed hPL in 5/5 (100%) tumors, hCG in 5/5 (100%; focal in all tumors), and GATA3 in 5/5 (100%). However, short tandem repeat (STR) genotyping did not identify any nonpatient alleles in the tumors, indicating a nongestational origin. The median progression-free survival was 18 months (range: 0 to 85) and 2/5 (40%) patients died from disease, highlighting the potential poor prognosis of this nongestational tumor. Thus, in the same way as gestational and nongestational choriocarcinomas are recognized as different entities, nongestational PSTTs could be viewed as a distinct entity from their gestational counterparts, although further investigation and more cases are needed. Furthermore, we propose recommendations for diagnosing and staging of nongestational PSTTs to improve patient stratification and management.

Combination chemotherapy provides significant survival advantage in patients with advanced gastro-oesophageal adenocarcinoma compared with best supportive care. Peri-operative chemotherapy is standard of care for patients with operable disease. We hypothesised that biomarkers of genomic instability and inflammation may have clinical utility in these patients. We initiated open-label, non-randomised biomarker studies in patients with advanced disease due to receive Epirubicin, Cisplatin and Capecitabine (ECX)/Epirubicin, Cisplatin and Fluorouracil (ECF) or Epirubicin, Oxaliplatin and Capecitabine (EOX)/Epirubicin, Oxaliplatin and Fluorouracil (EOF) regimens (advanced study, n = 375), and in patients planned to receive perioperative chemotherapy with the same regimen (peri-operative study, n = 306). Relative telomere length (RTL) in peripheral blood mononuclear cells (PBMCs) and plasma levels of 10 inflammatory cytokines were analysed to determine association with progression-free and overall survival, and response. Blood samples were collected prior to treatment and on each treatment cycle. Both studies comprised biomarker discovery and validation cohorts. Here we report analysis of the discovery cohorts. In advanced disease, high pre-treatment levels of IL8 and IL10 associated with poor Progression Free Survival (PFS) and Overall Survival (OS) in univariate analysis, and IL6 with poor OS. In multivariate analysis, IL6 and IL8 remained associated with OS, and IL8 with PFS. In the perioperative study, cytokine levels were significantly lower and no relationships were observed. There was no association between RTL and any endpoint in either study. Pre-treatment RTL was not prognostic, although IL6/IL8 were negative prognostic factors in advanced disease. Levels of these were lower in patients with localised disease, suggesting an association with disease progression. Further analysis of systemic inflammatory status in gastro-oesophageal adenocarcinoma may be promising for development of future predictive biomarker signatures.

Patients with differentiated thyroid cancer can often be treated with postoperative radioiodine (also called radioiodine ablation) after total thyroidectomy. The IoN trial was designed to assess whether recurrence-free survival was non-inferior after no ablation compared with ablation in patients with low-risk differentiated thyroid cancer. IoN was a multicentre, non-inferiority, phase 3 randomised trial conducted at 33 UK cancer centres. Eligible patients had complete (R0) resection following total thyroidectomy; stage pT1, pT2, pT3 (according to Tumour, Node, Metastasis staging version 7 [TNM7]), or pT3a (according to TNM8) disease; and N0, Nx, or N1a disease. Participants were randomly assigned (1:1) by minimisation, using a central electronic system, to have either 1·1 GBq ablation or no ablation, following thyroidectomy. Stratification factors were centre, age, T stage, and nodal status. Patients had annual neck ultrasound scans and 6-monthly serum thyroglobulin measurements. The primary endpoint was 5-year recurrence-free survival, defined by the absence of locoregional recurrent or persistent structural disease, distant metastases, or death from thyroid cancer. Non-inferiority was assessed with a margin of 5 percentage points. Per-protocol and intention-to-treat (ITT) analyses were done for the primary endpoint, and safety was analysed in the per-protocol population. The trial is registered with ClinicalTrials.gov (NCT01398085), ISRCTN (ISRCTN80416929), and EUDRACT (2011-000144-21), and is still in active follow-up. We recruited 504 patients (including 390 [77%] female patients and 114 [23%] male patients) between June 26, 2012 and March 18, 2020 and randomly assigned 251 to receive no ablation and 253 to receive ablation (ITT population). 249 patients in the no ablation group did not have ablation and 231 in the ablation group had ablation (per-protocol population). Median follow-up was 6·8 years (IQR 5·6-8·6) in the no ablation group and 6·6 years (4·8-8·5) in the ablation group; 17 recurrences (eight in the no ablation group and nine in the ablation group; ITT population) occurred during follow-up. 5-year recurrence-free rates were 97·9% (95% CI 96·1-99·7) in the no ablation group versus 96·3% (93·9-98·7) in the ablation group in the ITT analysis, and 97·9% (96·1-99·7) versus 96·9% (94·7-99·1) in the per-protocol analysis. The 5-year absolute risk difference was 0·5 percentage points (95% CI -2·2 to 3·2, pnon-inferiority=0·033; ITT analysis), showing that non-inferiority was reached. The observed recurrence rate was higher among patients with pT3 or pT3a tumours (four [9%] of 46 patients overall with pT3 or pT3a tumours vs 13 [3%] of 458 with pT1 or pT2 tumours), or N1a tumours (six [13%] of 47 with N1a vs 11 [2%] of 457 with N0 or Nx), but they were similar among those who did not receive ablation. Adverse events were similar between the groups, the most common being fatigue (63 [25%] of 249 in the no ablation group vs 65 [28%] of 231 in the ablation group), lethargy (34 [14%] vs 32 [14%]), and dry mouth (24 [10%] vs 21 [9%]), and there were no treatment-related deaths. The IoN trial shows that ablation (or postoperative radioiodine) can be avoided for patients with pT1, pT2, and N0 or Nx tumours with no adverse features. Many patients with low-risk differentiated thyroid cancer worldwide can safely avoid postoperative radioiodine and its related hospitalisation and side-effects, which in turn results in lower health-care costs. Cancer Research UK.