The aim of the study is to evaluate the effect of Gelronate gel, NaHA based product (medical device for topical application) vs. Aloevera gel, in prevention or minimizing of radiation induced skin reaction in breast cancer patients

Gelronate is gel composed of 1% high molecular weight pharmaceutical grade sodium hyaluronate and preservatives dissolved in pharmaceutical grade purified water. Gelronate supply in an airless pump bottle contain ~30 ml gel. In the study, 120 female patients planned to receive whole breast radiation (with or without lymphatic drainage) in the radiotherapy unit at Sheba Medical Center.

Patients will undergo CT simulation with 3D treatment planning (as routine done) and will receive 42.4 Gy in daily fraction of 2.65 Gy, five times per week to the whole breast according to the standard department protocol, with or without concomitant or subsequent lumpectomy cavity boost. Patients data including demographics, staging, systemic therapy, radiation details, other medications will be recorded the protocol's forms.

The gel will be applied as a thin lotion twice a day, immediately after radiotherapy treatment and once more in the evening/morning. The therapy will continue for 10 days following the end of radiation therapy.

Inclusion Criteria:

• Female patients aged at least 18 years with unilateral breast following lumpectomy +/- chemotherapy
• Planned to receive 42.4 Gy whole breast irradiation +/- boost to tumor bed.
• ECOG performance status 0-2.
• Capable of giving written informed consent.
• No co-morbidities known to affect radiotherapy reactions.
• No co-existing acute or chronic skin disease.
• No evidence of infection or inflammation of breast to be treated.
• Not receiving chemotherapy during radiotherapy course. Biological therapy (e.g. Herceptin) or hormone therapy will be allowed during the study.

Exclusion Criteria:

• Chemotherapy within 4 weeks prior to planned start of radiation or chemotherapy planned during radiation.
• Prior radiotherapy to the chest wall.
• Collagen vascular disease.
• Participation in other clinical study.

Double blind study