RB1 circulating-tumor DNA in the blood of Retinoblastoma patients increases in untreated patients.

PURPOSE: Circulating tumor DNA (ctDNA) in plasma has been identified in many cancers, including retinoblastoma at diagnosis. We have previously shown that with treatment (enucleation or ophthalmic artery chemosurgery (OAC)) all ctDNA disappears; and if there is persistent plasma ctDNA after treatment metastases develop. The purpose of this study was to determine how the ctDNA RB1 variant allele frequency (VAF) changes in patients with retinoblastoma who have delayed treatment. METHODS: Circulating tumor DNA RB1 was detected and VAF was measured at diagnosis and again prior to any intervention at some time later ranging from 2 to 28 days. RESULTS: Four patients with five ctDNA RB1 mutations were detected at diagnosis and VAF was increased on re-evaluation of the same RB1 mutations in ctDNA. CONCLUSION: In this small cohort, every patient (4) and every RB1 mutation (5) plasma level VAF% increased when measured at two time periods before treatment was instituted suggesting that growing tumors demonstrate increasing plasma ctDNA.

Circulating Tumor DNA Posttreatment Measurements and Clinical Correlates in Retinoblastoma.

Importance: Plasma measurements of RB1 circulating tumor DNA (ctDNA) after completion of treatment may be associated with the development of metastases in patients with retinoblastoma. Objective: To determine if the absence of previously detectable plasma ctDNA is associated with metastasis-free survival in patients with a minimum of 1 year follow-up after treatment of retinoblastoma. Design, Setting, and Participants: This cohort study was conducted from June 2019 to September 2023. Patients with retinoblastoma who had measurable ctDNA levels at diagnosis and had repeated ctDNA measurements after ocular treatment (enucleation or intra-arterial chemotherapy) with a minimum of 1 year of follow-up (mean [SD], 28.2 [10.3] months) were included in the study. Patients were recruited from a single-center, tertiary cancer hospital. Exposure: Memorial Sloan Kettering's New York State-approved gene test, which interrogates 129 known cancer genes (called ACCESS), was performed on plasma samples before and after ocular treatments. All exons of the RB1 gene are included in the test and listed as ctDNA in this article. Main Outcomes and Measures: Plasma ctDNA level before treatment, after completion of ocular treatment, and development or absence of metastases. Results: A total of 24 patients (mean [SD] age, 20.7 [17.1] months; 15 female [62.5%]) were included in the study. None of the 23 patients who had a measurable ctDNA level and then no detectable ctDNA level after completion of ocular treatment developed metastases with a minimum of 1 year of follow-up. One patient had persistent measurable ctDNA after initial treatment and developed metastases. Conclusion and Relevance: Patients with retinoblastoma who had a measurable ctDNA level at diagnosis did not develop metastases if the plasma ctDNA level became unrecordable after ocular treatment; 1 patient who had persistent measurable ctDNA after treatment did develop metastasis.

Mutant-RB1 circulating tumor DNA in the blood of unilateral retinoblastoma patients: What happens during enucleation surgery: A pilot study.

Cell free DNA (cfDNA) and circulating tumor cell free DNA (ctDNA) from blood (plasma) are increasingly being used in oncology for diagnosis, monitoring response, identifying cancer causing mutations and detecting recurrences. Circulating tumor RB1 DNA (ctDNA) is found in the blood (plasma) of retinoblastoma patients at diagnosis before instituting treatment (naïve). We investigated ctDNA in naïve unilateral patients before enucleation and during enucleation (6 patients/ 8 mutations with specimens collected 5-40 minutes from severing the optic nerve) In our cohort, following transection the optic nerve, ctDNA RB1 VAF was measurably lower than pre-enucleation levels within five minutes, 50% less within 15 minutes and 90% less by 40 minutes.

Retrospective Evaluation of Somatic Alterations in Cell-Free DNA from Blood in Retinoblastoma.

Purpose: Analysis of circulating tumor DNA (ctDNA) in the plasma of patients with retinoblastoma and simulating lesions. Design: Retrospective cross-sectional study of the association of plasma ctDNA from retinoblastoma and simulating lesions with disease course. Participants: Fifty-eight Memorial Sloan Kettering Cancer Center patients with retinoblastoma comprising 68 plasma ctDNA samples and 5 with retinoblastoma-simulating lesions. Methods: The ctDNA analyzed with hybridization capture and next-generation sequencing in blood (plasma) of patients who had retinoblastoma or simulating lesions were evaluated for association with clinical course of the disease. Main Outcome Measures: Presence or absence of molecular aberrations in the RB1 gene and correlations with clinical features. Results: RB1 cell-free DNA (cfDNA) was detected in 16 of 19 patients with newly diagnosed, untreated intraocular retinoblastoma and in 3 of 3 patients with newly diagnosed, untreated metastatic disease. It was also present in 3 patients with recurrent intraocular disease before therapy, but was not present in patients with recurrent disease who received intra-arterial chemotherapy, nor in 21 patients who had undergone enucleation for unilateral disease. In 1 patient who had delayed treatment (insurance reasons) and showed rapid growth of the intraocular tumor, the variant allele frequency increased in 1 month from 0.34% to 2.48%. No RB1 mutations were detected in the cfDNA from plasma of patients with simulating lesions (3 with Coats disease and 1 with persistent fetal vasculature [PFV]). In 2 patients, we identified 2 independent RB1 mutations in plasma. Conclusions: Mutations in RB1 were found in the cfDNA from blood of patients with newly diagnosed, untreated retinoblastoma and in patients who showed disease recurrence in the eye after prior treatment, but not in unilateral retinoblastoma after enucleation Levels of ctDNA increase in patients with progressive disease who did not receive any treatment. High plasma cfDNA levels were detected in patients with newly diagnosed metastatic disease, and these levels decreased after systemic chemotherapy was administered. Further validation is needed for measuring the somatic alterations in cfDNA from blood in retinoblastoma that could provide a promising method of monitoring patients in the future.