?Background
The World Health Organization (WHO) emphasizes the importance of continuity of care in cancer care for improving the patient outcomes and the effectiveness of cancer care systems.  However, a significant proportion of cancer patients fail to complete their prescribed course of treatment (Treatment Abandonment (TxA) without any medical reasons. TxA is a critical challenge in low- and middle-income countries as it leads to poor outcomes and wastage of healthcare resources. Understanding the factors contributing to TxA is crucial for designing patient-centered, context-specific interventions that improve adherence and treatment outcomes. This mixed-method study explored the phenomenon of TxA in cancer care.
Objectives
Among newly diagnosed adult patients with common non-haematological cancers;
To identify the factors contributing to TxA
To develop a predictive tool to identify the patients who are at high risk of TxA at the baselineMethods
This was a prospective mixed-methods study conducted at a tertiary cancer care center in India. Newly diagnosed adult patients (N=947) diagnosed with common cancers, including breast, cervix, head and neck, stomach, colo-rectum, ovary and lung malignancies, and initiating curative or palliative intent of treatment with expected survival of >1 year were prospectively enrolled and followed up for 6 months. Baseline sociodemographic, economic, clinical, psychological, cognitive/behavioural, and health-system variables were collected at treatment initiation. Treatment abandonment was defined as discontinuation of prescribed therapy for 4 weeks or more in the absence of medical indication. Predictive models were developed using regression-based approaches (LASSO & Elastic net) to assess the ability of baseline variables to predict abandonment and model performance was assessed using discrimination and calibration. Concurrently, in-depth interviews were conducted with patients and caregivers who discontinued treatment to explore factors influencing abandonment. Quantitative and qualitative findings were integrated to examine dynamic interactions contributing to TxA.
Results
Participants ranged in age from 22 to 88 years, with a median age of 54 years, and 68.8% were female. Of the 947 patients enrolled, 167 (17.6%) abandoned treatment during the first six months of therapy. Although treatment abandonment was more common among elderly patients, those with lower educational attainment, lower socioeconomic status, lack of insurance coverage, higher levels of distress, and advanced disease with palliative intent of therapy, the strength of these associations was modest. Baseline predictive models demonstrated modest discrimination (cvAUC = 0.688); however, calibration was suboptimal, with significant deviation between predicted and observed risks, indicating that baseline variables alone may be insufficient to accurately estimate individual risk of treatment abandonment. Qualitative findings revealed that patients-initiated treatment with the intention to be cured. Abandonment emerged during the treatment process as patients encountered cumulative financial constraints due to unemployment and wage loss, communication gaps, navigation challenges, unaddressed toxicities, and health-system delays, which progressively led to treatment abandonment.
Conclusions/Implications for policy 
TxA is a complex issue, mostly system-driven, not reliably predictable at baseline. Cancer control efforts should prioritise real-time patient support, navigation, and system responsiveness during treatment rather than reliance on baseline risk stratification alone. TxA should be incorporated as a “quality metric” for evaluating continuity of care.