**1. Introduction**

The unregulated growth and proliferation of abnormal cells to form solid or liquid tumor in a given part of the body is referred as cancer. Currently, the condition denotes a collection

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

of related diseases with more than 100 types of cancer have been identified and named after the organs or tissues of origin [1]. Carcinoma is a common category that affects the inner and outer surfaces of the body and the subcategories include basal cell, squamous cell, transitional cell and adenocarcinoma. Sarcoma affects the cells in bones and smooth tissues, leukemia and lymphoma that of the blood and lymphocytes, respectively [1]. Due to the nature of the condition, the detection has to be as early as possible, followed by appropriate managerial approach based on the type of cancer to insure the survival of cancer patients. Early detection and treatment have increased the lifespan of patients diagnosed with cancers, and the survival rate is thrice higher than that observed in postponed intervention scenarios [2, 3]. Cancer has become a major health problem and foremost cause of death, claiming more than 8.8 million deaths in 2015, and 8.2 million deaths with 14 million new cases been diagnosed in 2012 [4–6]. The lifestyle plays a decisive role in determining cancer incidence and mortality rates, for example, the consumption of tobacco alone is one of the deadliest causes and accounts for 22% of the global cancer related deaths [5]. In developing countries, about a quarter of the incidence rate is infection-dependent, such as Hepatitis and Human Papilloma Virus (HPV) are known to facilitate carcinogenesis. While more than 90% of proper facilities and services for cancer management are reportedly available in the developed parts of the globe, less than 30% of those are in the low and middle countries. It has been established that the cancer mortality rate is proportionate to the regional dietary behavior and a third of the global cancer related deaths could be avoided as it is associated with obesity, high both tobacco and alcohol consumption, both low vegetable and fruit consumption, and physical inactivity [7, 8].

necessitates the accompaniment of chemotherapy or radiation therapy, or both for improved results [16]. Generally, hormone-blocking agents act as effectors for treatment of luminal (HR+) types and immune-modulators are favored for certain metastatic and late-staged breast

Photodynamic Therapy, a Potential Therapy for Improve Cancer Management

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Photodynamic therapy is an unconventional treatment modality for neoplastic conditions and a promising treatment for recurrent cancers, depending on photochemical reactions and subsequent damage, and leading to cancer cell death [20, 21]. Experimental data from a diverse pool of research reports proved Photodynamic therapy to be a good treatment option for numerous cancers, offering reduced long-term mobility, very limited side-effects, better cancer-specificity over surgery, chemotherapy or radiotherapy [20, 22–23]. The radiotherapy causes loss of oxygen while oxygen is required during the Photodynamic therapy, therefore the two approaches should not be considered for a combined therapy. Furthermore, combination with conventional chemotherapeutic agents should be avoided as it would forfeit the cancer control and selectivity benefits of Photodynamic therapy. A superior targeting and eradication of breast cancer cells was achieved with photodynamic therapy, which is appealing and leaving normal-like cells such as breast epithelium and fibroblast unaffected, thus satisfying a safe usage norms. This emphasizes the edge of photodynamic therapy over other therapeutic methods; limited to none side-effects to patients. Photosensitivity is the usually side-effect observed and involves skin redness, tingling or burning sensation up to 24 hours post Photodynamic therapy, which can only treat tumors where light can reach and [21–25].

Photodynamic therapy was discovered more than a century ago and now is a minimally invasive and clinically approved therapeutic modality for neoplastic conditions. It involves the administration of photochemotherapeutic agents, known as photosensitizers, followed by the irradiation of the agents at a wavelength that matches their absorption properties. When this occurs in the presence of molecular oxygen, a sequence of reactions that lead to the tumor microvasculature damage, cytotoxicity and subsequent tumor cell death (**Figure 1**) [21, 26, 27]. Photosensitizers have evolved over time and are nontoxic, light absorbing dyes, able to undergo photochemical changes and transitions between the ground state and first or higher excited states. The deactivation can happen by heat-release (nonradioactive decay), emission as fluorescence or undergoing intersystem crossing (ISC). Ideal photosensitizers are readily able to be excited by appropriate photons, available in simple chemical formulation, easily synthesized from their precursors, stable and soluble in physiological environments, easily delivered into the body (injection or other means), and excreted from the body upon completion of therapy. They have high singlet oxygen quantum yield with strong absorption in the red region of the visible spectrum (680–800 nm) and high extinction coefficient, and

The third generation of photosensitizers are currently being developed from conjugating previous ones with organic and inorganic polymers, immunologic agents and nanoparticles. The first generation of photosensitizers include the members of Photofrin and hematoporphyrin

**2. Fundamentals of photodynamic therapy**

effective accumulation in tumor tissues and low dark toxicity [28].

cancer [17–19].

When a cancer develops and originates from the lobular or ductal tissues in the breast, it is commonly known as breast cancer, one of the most deadly cancers and the most common womanlike cancers globally [9, 10]. This carcinoma can be either recurrent, metastatic, invasive (or not) and seldom originates in the connective tissues of muscles, fat and blood vessels. A well developed breast is a tear-shaped milk producing gland and breast cancer is classified according to level of differentiation, from well differentiated in normal breast to moderately and poorly differentiated glands in breast cancer. Additionally, the size of the tumor, the possible invasion to lymph nodes in the armpits and metastatic ability help oncologists to stage breast cancer from the small ductal/lobular precancerous stage (stage 0) to medium sized in breast and lymph nodal regions (stage 1–3) and large metastatic phase (stage 4), the latter is usually associated with worse prognosis [10, 11]. Better prediction of prognosis is facilitated by the presence or not of certain receptors and the human epidermal growth factor receptor-2 (HER2) together with hormone receptors (HR, estrogen and progesterone) are usually considered. The luminal A type (HR+/HER2-) of breast cancer has the best prognosis, the luminal B type (HR+/HER2+) and the HER2-enriched type (HR−/HER2+) have moderate prognosis and the worst scenario is observed with the triple negative type (HR−/HER2+) [12–15].

The management approach of any kind of breast cancer mainly depends on the stage and the predicted prognosis; with the more hostile treatments administrated to patients, whose conditions have predicted poor prognosis and elevated probability of recurrence after intervention. Although the occasional and circumscribed effectiveness, surgery remains the main treatment modality for breast cancer, including entire (mastectomy), partial (quadrantectomy) or minute (lumpectomy) removal of the breast. The multidisciplinary approach is often preferred and necessitates the accompaniment of chemotherapy or radiation therapy, or both for improved results [16]. Generally, hormone-blocking agents act as effectors for treatment of luminal (HR+) types and immune-modulators are favored for certain metastatic and late-staged breast cancer [17–19].

Photodynamic therapy is an unconventional treatment modality for neoplastic conditions and a promising treatment for recurrent cancers, depending on photochemical reactions and subsequent damage, and leading to cancer cell death [20, 21]. Experimental data from a diverse pool of research reports proved Photodynamic therapy to be a good treatment option for numerous cancers, offering reduced long-term mobility, very limited side-effects, better cancer-specificity over surgery, chemotherapy or radiotherapy [20, 22–23]. The radiotherapy causes loss of oxygen while oxygen is required during the Photodynamic therapy, therefore the two approaches should not be considered for a combined therapy. Furthermore, combination with conventional chemotherapeutic agents should be avoided as it would forfeit the cancer control and selectivity benefits of Photodynamic therapy. A superior targeting and eradication of breast cancer cells was achieved with photodynamic therapy, which is appealing and leaving normal-like cells such as breast epithelium and fibroblast unaffected, thus satisfying a safe usage norms. This emphasizes the edge of photodynamic therapy over other therapeutic methods; limited to none side-effects to patients. Photosensitivity is the usually side-effect observed and involves skin redness, tingling or burning sensation up to 24 hours post Photodynamic therapy, which can only treat tumors where light can reach and [21–25].
