**3. Conclusion**

Cancer, an uncontrolled cell proliferation condition, has become a major health challenge and global killer. The incidence and related treatment facilities are unfortunately determined by the lifestyles and geographic locations of cancer patients. Breast cancer is a common carcinoma that affects the tear-shaped milk glands in women and its classification is been facilitated by the presence or not of certain receptors (HER-2 and HR), which are also to predict the prognosis. Photodynamic therapy is a promising cancer treatment and offers better specific targeting of cancer and limited side-effects, when compared to conventional therapy. Mitochondria, lysosomes and perinuclear areas are reported as the most frequent localization sites for third generations of photosensitizers. The treatment efficiency depends upon the successful light-activation and intersystem conversion into the excited triplet state, only then photosensitizers interact with molecular oxygen to produce reactive oxygen species, toxins responsible for cytodestruction and cell death. If required, Photodynamic can be repeated but the contribution of nanoparticles in combination therapy for cancer and particularly breast cancer, has permitted the successful delivery of therapeutic agents to the targeted tumor site and enhancement of therapeutic effects. When conjugated, they facilitate the delivery of hydrophobic drugs into biological environments, ensure the preservation of the pharmacologic properties of the drugs, and enhance selective targeting to cancer cells through their large surfaces, which can be functionalized with a various kind of components. The use of photodynamic therapy offers controlled conditions with high selectivity to cancer, hence reducing the undesired side-effects seen with conventional treatments. Whether used as main or adjuvant therapy, the aim of combination cancer therapy using photodynamic therapy is to selectively and completely eradicate cancer by targeting and killing both cancer and cancer stem cells.
