Breast cancer, the most common cancer diagnosed among women, disproportionately affects low- and middle-income countries (LMICs). Based on an ethnographic study conducted in Central Vietnam in 2019, including observation and interviews with 33 women patients, we investigate how women and their families managed the financial burden of breast cancer care. Our findings suggest that in a context where health-related risk protection is poorly organised and out-of-pocket expenses are burdensome, despite the presence of universal health coverage, patients must rely heavily on informal arrangements to finance their treatment. They proactively researched available information and undertook extensive and ramified work to prove their deservingness for some types of assistance, including strategically disclosing their cancer status or using tactics to accelerate the process of applying for state welfare. Affected families must make hard calculations to prioritise the pressing health need of a member diagnosed with cancer and in many circumstances, forfeited the education of their young children. We offer theoretical understanding of ‘patient work’ beyond the routine management of the biological aspects of an illness. In addition, we demonstrate how engaging in those various coping practices can reinforce one's vulnerability to a vicious cycle of illness and poverty and amplify socio-economic inequalities among the affected community and the larger society. We argue this situation, if not tackled urgently and appropriately, can impede the progress towards achieving Sustainable Development Goal 3 (Good Health and Wellbeing) and Goal 10 (Reduced Inequalities) in LMICs amidst the non-communicable disease epidemic.