Introduction : Breast cancer is the most common cancer among women in India and a leading cause of cancer-related mortality, largely due to late-stage diagnosis. Strengthening early detection at the primary care level is critical for improving outcomes and reducing inequities. This case study describes the early detection of breast cancer through nurse-led Clinical Breast Examination (CBE) at a Primary Health Centre (PHC) in Poonamallee, Tamil Nadu, in 2025. A 55-year-old woman attending the PHC for routine follow-up of hypertension and diabetes underwent opportunistic CBE by a staff nurse, which revealed a suspicious axillary lymph node. Prompt referral and further diagnostic evaluation confirmed invasive breast carcinoma, despite initial benign imaging findings. The patient underwent definitive treatment and has completed therapy successfully. This case highlights the strength of the primary health care system in delivering comprehensive, people-centred care, the importance of integrating cancer screening into routine services, empowering nurses, and ensuring effective referral linkages. Strengthening such primary care–based interventions can significantly contribute to early cancer detection and improved survival in resource-constrained settings.