Radiation dermatitis is one of the most common side effects of radiotherapy approximately occurring in about 95% of patients receiving radiotherapy . Acute injury due to structural tissue damage, generation of free radicals, irreversible double-stranded breaks in nuclear and mitochondrial DNA, and initiation of an inflammatory response in the epidermis and dermis occurs within hours to weeks after radiation exposure. Radiation dermatitis due to pain and discomfort has an adverse impact on the quality of a patient's life.The radiation toxicities such as radiation dermatitis encountered in clinical practice are typically managed with a variety of topical agents such as water-based moisturizing creams or lotions, topical steroids, antiinflammatory emulsions, and wound dressings. Pharmacologic interventions for the prevention and treatment of these toxicity can be used to protect skin against radiation damage.Currently, there is no standard treatment for the prevention of radiation-induced dermatitis with demonstrated effectiveness.The aim of this randomized, double-blind, placebo-controlled study is to evaluate the effectiveness of topical doxepin for the prevention and management of radiation-induced dermatitis during postoperative radiotherapy for breast cancer.

The patients who have undergone breast surgery and require radiotherapy and fulfill the inclusion criteria of the study will be entered the study. All the patients will be treated by 3D conformal radiation therapy using CT -based treatment planning and multi leaf linear accelerators. The patients will be treated by conventional fractionation regimens to a total dose of 5000 cGy (25 fractions of 200 cGy, 5 days per week). Every week the patients will be visited by an experienced radiation oncologist and the skin reaction will be determined and recorded according to RTOG Acute Radiation Morbidity Scoring Criteria which scores from 0 to 4. The patients receive Doxepin cream at the beginning of 5th week of radiotherapy and use it for a whole week. After acquiring written permission, the radiotherapy site will be photographed at the start and ending of the Doxepin

Inclusion Criteria:

• Female with a diagnosis of, breast adenocarcinoma and be referred for post-operative radiotherapy with or without concurrent chemotherapy and with or without mastectomy
• Participants must not be pregnant.
• Participants treated with a total dose of 5000 cGy (25 fractions of 200 cGy, 5 days per week

Exclusion Criteria:

• Patients who are not eligible
• The presence of skin diseases in the radiation area
• Patients have constipation, xerostomia, blurred vision, urinary retention
• Hypersensitivity to doxepin