Скачать или смотреть JCO PO Article Insights: Circulating Tumor DNA in Germ Cell Tumors

In this JCO Precision Oncology Article Insights episode, host Dr. Jiasen He summaries the article, "Longitudinal Evaluation of Circulating Tumor DNA as a Prognostic Biomarker to Detect Molecular Residual Disease in Germ Cell Tumors," by Hassoun et al.

TRANSCRIPT

Jiasen He: Hello, and welcome to the JCO Precision Oncology Article Insights. I'm your host, Jiasen He, and today, we'll be discussing the JCO Precision Oncology article, "Longitudinal Evaluation of Circulating Tumor DNA as a Prognostic Biomarker to Detect Molecular Residual Disease in Germ Cell Tumors," by Dr. Rebecca Hassoun and colleagues.

Traditionally, treatment response for solid tumors has relied on imaging, which focuses on visible anatomic changes in the tumor. However, imaging does not always reflect molecular or cellular changes and cannot detect microscopic disease, which is clinically important and often linked to relapse. Liquid biopsy, on the other hand, is minimally invasive and can be used for cancer monitoring by analyzing circulating biomarkers in biofluids such as blood.

One type of liquid biopsy is circulating tumor DNA, or ctDNA, which measures small fragments of DNA released by tumor cells into the bloodstream. ctDNA can allow precise monitoring of tumor-specific mutations and be a powerful tool for assessing treatment responses. ctDNA has already been applied in clinical settings for cancers such as non-small cell lung cancer and breast cancer, etcetera. However, there is still limited data on the use of ctDNA for germ cell tumors.

Germ cell tumors are the most common malignancy affecting men aged 15 to 35 years. Accurate risk stratification and disease monitoring is key to risk-adapted therapy, maximizing the chance of cure while minimizing side effects. One unique tool we use currently for diagnosis, staging, and monitoring is serum tumor markers, such as AFP, beta-hCG, and LDH. However, these markers have limitations, including false elevation in certain clinical scenarios, and studies have shown that they can be normal in up to 40 percent of patients with germ cell tumor. This creates an unmet need for other sensitive and specific biomarkers to improve patient care.

In this paper, the authors investigated the use of ctDNA in a cohort of patients with germ cell tumor at various disease time points. They compared ctDNA results with traditional serum tumor markers to evaluate whether ctDNA can predict relapse and survival outcomes. This multi-institutional retrospective study included patients with stage I, II, and III germ cell tumors, primarily testicular cancer, who had at least one ctDNA test result.

ctDNA was evaluated longitudinally at different time points, including pre-orchiectomy, during the molecular residual disease, or MRD, window, defined as 1 to 12 weeks post-orchiectomy but before primary therapy, and during the surveillance window, defined as more than 12 weeks post-orchiectomy or follow retroperitoneal lymph node dissection or post-chemotherapy. ctDNA analysis was performed using a tumor-informed 16 multiplex PCR next-generation sequencing assay.

A total of 324 plasma samples were analyzed from 74 patients in this cohort. The majority had stage I disease, around 40 percent, and nonseminomatous histology, around 70 percent. 15 patients were evaluated in the pre-orchiectomy window, and only one patient tested negative for ctDNA. This patient had stage I disease. The authors further assessed ctDNA positivity in both the MRD window and surveillance window, evaluating its association with event-free survival.

They found that ctDNA outperformed serum tumor markers in both settings. ctDNA positivity was associated with significantly worse event-free survival compared with ctDNA-negative patients. Among the 14 patients with stage II to III disease who had ctDNA assessed in both the MRD window and surveillance window, nine patients consistently had a negative ctDNA or converted from positive to negative over time. In contrast, five patients demonstrated persistent ctDNA positivity, and all of these patients subsequently relapsed.

Among the 38 patients who had both ctDNA and serum tumor marker tests during the MRD window, nine patients showed discordant biomarker results. Of these, 6 patients were ctDNA-negative but serum tumor marker-positive, and one of them experienced recurrence. Three patients were ctDNA-positive but serum tumor marker-negative, and one of these patients also recurred. During the surveillance window, 46 patients had both biomarkers available, and 10 showed discordant results. Three patients were ctDNA-negative but serum tumor marker-positive, and none of them recurred. In contrast, all seven patients who were ctDNA-positive but serum tumor marker-negative experienced recurrence.

This intriguing data strongly support the potential role of ctDNA in patients with stage I, II, and III germ cell tumors. However, as the authors noted, the retrospective...