ctDNA: promise of precision or reflection of inequality?

By Ana Espino | Published on October 24, 2025 | 3 min read


Breast cancer is the most common malignancy among women worldwide. Despite major therapeutic advances, a substantial proportion of patients remain at risk of relapse, particularly those with residual disease after neoadjuvant therapy. Residual disease is a strong prognostic factor for early recurrence, especially in aggressive subtypes such as triple-negative breast cancer (TNBC) and HER2-positive disease. Early detection of residual disease or imminent recurrence is therefore a critical challenge for improving personalized care and overall survival.  

In this context, circulating tumor DNA (ctDNA) has emerged as a promising molecular surveillance tool. It enables the detection of minimal residual disease before any clinical or radiological manifestation, allowing for earlier therapeutic intervention.

However, access to this innovative technology remains deeply unequal, both geographically and socioeconomically. Populations living in rural areas or in low- and middle-income countries (LMICs) are less likely to be enrolled in trials, to be tested, or to receive ctDNA-guided targeted therapies.

This study was designed to analyze inequalities in access, use, and representation of ctDNA in breast cancer care and to propose practical strategies for achieving more equitable precision medicine.  

Is ctDNA really for everyone?

The study highlights several layers of inequality. Biologically, certain populations display distinct genetic profiles, such as frequent TP53 mutations or CCND2 alterations, that may influence ctDNA release or detectability. Structurally, persistent inequities in access to molecular testing due to cost, insurance coverage, and infrastructure continue to hinder ctDNA implementation. Clinically, Black women are less likely to receive targeted therapies even when actionable mutations are identified, and they remain largely underrepresented in ctDNA-based clinical trials, which limits the generalizability of results. Geographically, pilot studies in countries such as Ghana, India, and China demonstrate that ctDNA testing is feasible but faces significant infrastructural and logistical challenges.  

No precision medicine without equity  

Breast cancer remains the leading cause of cancer in women, with relapse risk remaining high, particularly in patients with residual disease after initial treatment. The central challenge lies in detecting these potential recurrences early using sensitive, accessible, and validated tools—without worsening existing inequalities.

This study aimed to evaluate ctDNA’s clinical utility, performance, and limitations in breast oncology while shedding light on the structural and biological disparities affecting its deployment. The findings suggest that while ctDNA represents a major breakthrough, its uneven implementation could widen existing gaps in cancer care if systemic corrective measures are not taken.

Key limitations include the scarcity of robust data from non-white populations or those in low- and middle-income countries, as well as the lack of standardized thresholds and interpretation criteria. The authors emphasize the need for future efforts to design more inclusive clinical trials, decentralize molecular testing platforms to improve accessibility, standardize ctDNA detection thresholds across diverse genetic backgrounds, and integrate ctDNA into a broader, equity-focused framework of precision medicine.  

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