Radiation Dermatitis in Breast Cancer Patients Undergoing Radiotherapy - An Overview

Introduction

Breast cancer is the most typical female malignancy in the US. Around 250,000 evaluated recent cases are diagnosed, and over 40,000 deaths are registered yearly. Breast cancer is the second highest cause of malignant deaths in American women. Many breast cancer patients accept adjuvant radiation therapy in breast conservation or postmastectomy procedures to reduce locoregional (localized regional) recurrence and overall survival rates. Patients undergoing radiation therapy to the breast or chest wall with or without regional lymph nodes typically receive around six weeks of therapy, with radiation dermatitis expected as the most typical acute side effect.

What Is the Historical Perspective of Radiation Dermatitis?

After radiation was presented as a therapeutic modality in the early 1900s, the outcomes of X-rays on the skin were identified as one of the primary dose-limiting toxicities. Investigators began instantly studying techniques for decreasing radiation-induced skin responses.

Initial radiobiologic findings pioneered by Regaud, Coutard, Reisner, Quimby, and others directed to this fact. If the tumor is delivered in a fractionated method (low doses are given daily to a more increased total cumulative dose), the acute and late consequences of the radiation on the skin and normal tissues are significantly reduced.

Improved knowledge of the restoration mechanisms of normal tissue compared to tumors has explained that fractionated therapy enhances the therapeutic ratio by permitting normal tissue repair while still inducing tumor cell death. Historically, physicians who used radiation for therapeutic objectives utilized the skin on their forearms to estimate the degree of radiation exposure.

The calibration system named erythema dose was utilized to define the reduced radiation dose that created erythema on the exposed skin to compare the radiation dose given per fraction. The evolution of megavoltage X-ray machines in the 1950s was a significant improvement in the field of radiation oncology before radiation techniques utilized orthovoltage units that were understood to deposit maximum radiation dose at the skin surface. In distinction, cobalt-60 radiation units and linear accelerators creating X-ray beams with energies of greater than or equal to 4MV could take benefit of a skin-sparing phenomenon, where high-intensity X-rays lead to reduced doses to the skin. Megavoltage X-rays deposit maximum radiation dose at a specific depth, often millimeters or centimeters below the skin's surface. As radiation beam energy rises, the depth of maximal dose deposition also rises, reducing the dose to the skin.

Despite these historic improvements in understanding radiotherapy and its consequences on normal tissue, radiation dermatitis remains one of the typical side effects of modern radiotherapy.

Radiotherapy is a fundamental part of curative breast cancer therapy, and it has been calculated that 45 % of all breast cancer cases obtain radiotherapy.

• Most patients have radiodermatitis during breast cancer radiotherapy, also explained as skin toxicity. The physical representations of radiodermatitis can vary from faint erythema, which includes redness, warmth, and rash-like appearances.

• Dry desquamation, like dryness, skin itching, and peeling.

• Moist desquamation like moist, oozing, redness, exposure of the dermis, and necrosis.

Following the conclusion of radiotherapy, patients might develop cutaneous fibrosis, which includes transformations in skin texture, skin retraction, telangiectasia, ache, and skin itching radiodermatitis (that also) not only impacts breast skin.

Qualitative analysis and examination articles have indicated that cases may undergo radiodermatitis as:

• Itching.

• Sensitivity.

• Ache.

• Warmth.

• Tingling.

• Tightness, heaviness, and burning that skin ache may be connected with exhaustion.

• Body image disorder, sleep difficulties, and emotional distress.

Certain qualitative data indicate that to comprehend the effect of radiodermatitis on quality of life, it is necessary to evaluate the presence of skin reactions and patients' knowledge of such responses.

What Is the Pathophysiology of Radiation Dermatitis in Breast Cancer?

The two primary skin components are the superficial epidermis and the deeper dermis, each of which has special structures and function and react differently to radiation exposure.

• Anatomy and Function - Skin is the protective barrier of the body. The epidermis comprises four histologic layers: stratum basale, stratum spinosum, stratum granulosum, and stratum corneum.

• The basal keratinocytes of the stratum basale are stem cells that asymmetrically split to produce additional basal stem cells, which systematically determine into the more superficial epidermal layers.

• The keratinocyte maturation and keratinocyte migration to the stratum corneum takes around two weeks and finally develops an anucleated flattened layer of keratin.

• Other cellular kinds within the epidermis contain melanocytes and Langerhans cells. The dermis, present deep in the epidermis and basement membrane, is mainly comprised of a collagen network created by dermal fibroblasts that create the skin with structural integrity.

• The dermis possesses diverse cellular kinds not seen in the epidermis. The vasculature and lymphatics in the dermis supply the dermis and the overlying epidermis with enough nutrients. In addition, nerve endings, sebaceous glands, and hair follicles are present within the dermis.

• Alteration of appropriate skin function can direct to a loss of fluid and electrolyte balance, improved exposure of deeper tissues to dangerous chemicals, carcinogens, and infectious elements, and can alter core body temperature regulation.

• Possible Mechanisms of Injury - High-energy X-rays given during radiotherapy create direct and indirect ionization circumstances that direct to the impairment of cellular macromolecules, significantly in the shape of double-stranded DNA breaks. Through this DNA-damaging mechanism, radiotherapy impacts all cellular kinds within the epidermis and dermis and directs to the clinical syndrome of radiation dermatitis. In the epidermis, radiation-induced DNA damage alters basal keratinocytes' standard proliferation and differentiation. As an outcome, differentiated epidermal keratinocytes are exhausted, and maintenance of this physical barrier is not retained. Radiation effects in the dermis are more complicated. Hair follicles and sebaceous glands are susceptible to relatively lower doses of radiation and leading to the acute consequences of hair loss and skin dryness.

Conclusion

Despite increased awareness and knowledge of the side effects of radiotherapy in breast cancer, radiation dermatitis continues to be among the most typical side effects. To manage cases with radiation dermatitis, they should be conscious of the anticipated appearance and timing of symptoms presentation, the appropriate scoring systems for adequately observing symptom severity over time, and pursue evidence-based therapy approaches when practical.