Introduction: 

Circulating tumor cells (CTCs) are increasingly used to assess minimal cellular residual disease (MCRD) in solid tumors. However, no standardized guidance exists for communicating MCRD results to patients, potentially leading to psychological distress and increased apprehension regarding residual disease after treatment, including surgery. We developed RUPIKA—Rapport, Understanding and Education, Preparation for Sample Collection, Inform Results, Kind Closure, and Advise for Follow-up—a structured communication protocol for sharing post-surgery outcomes with patients. We report an apprehension protocol for communicating MCRD outcomes in pre- and post-surgery breast cancer patients.

Method: 

In an ongoing prospective interventional study (CTRI/2025/09/094661 and IEC SJNAHS 113/2025; St. John’s Medical College Hospital, Bengaluru, India), six oncology experts standardized the study using the ABC Content Validity Index (CVI) framework. Pre- and post-surgery, 22 patients with early-stage or in-situ stage I–III breast cancer were enrolled and equally assigned to routine disclosure (control, n=11) or RUPIKA-guided disclosure (intervention, n=11). A 1.5 mL blood sample was analyzed for CTCs (CK⁺/DAPI⁺/CD45⁻) and PD-L1 expression using the CDSCO-India-approved OncoDiscover immunomagnetic CTC platform. The six-step RUPIKA protocol included rapport building, understanding and education, preparation for sample collection, structured communication of CTC results, supportive closure, and follow-up planning. Cancer worry and apprehension were assessed before and after disclosure. The mean patient age was 52±12 years. Twenty-seven percent had early-stage/in-situ disease, with Luminal B representing the predominant molecular subtype. Most participants were from rural backgrounds, and none had prior awareness of MRD.

Results: 

The protocol demonstrated high validity (CVI=0.98). CTCs persisted in a substantial proportion of patients (66.7%) after completion of chemotherapy and surgical intervention, suggesting the presence of MCRD. Before surgery, CTCs were detected in 83.3% of patients. After surgery, CTCs remained detectable in 66.7% of patients, while four patients became CTC-negative. Following surgery, cancer worry increased significantly in the control group (54.73±8.89; P=0.003), whereas it decreased significantly in the RUPIKA group (24.73±6.59; P<0.001). Between-group comparison showed significantly lower post-disclosure cancer worry among patients receiving RUPIKA-guided counselling compared with routine disclosure (t=8.992; P<0.001).

Conclusion: 

This ongoing observational study demonstrates that RUPIKA—the first dedicated CTC-based MRD disclosure protocol—effectively mitigates cancer worry in breast cancer patients. Larger studies across diverse cancer cohorts are warranted.