This study has patients using two different moisturising creams during radiation therapy after mastectomy. These are Cavilon and sorbolene. It is hypothesised that skin reactions may be reduced by the Cavilon cream compared to sorbolene.

Skin reactions are a common and undesirable result of radiation treatment. Preventative measures are often used although there are few controlled trials. Commonly employed agents for established reactions have included sorbolene (10% Glycerine), silver sulphadiazine, hydrocolloid dressings, topical steroids, salt water or bicarbonate of soda water solution bathing and hydrogen peroxide. One trial found that Cavilon No-Sting Barrier film reduced Grade 3 skin reaction compared to sorbolene, although this film did not contain any moisturising agents.

General Hypothesis: That in a paired double blind randomised study peak and overall skin reactions experienced by post mastectomy breast cancer patients receiving radiotherapy may be reduced by Cavilon Durable Barrier Cream (CDBC) compared to Sorbolene.

Alternative Hypothesis of primary outcome: the frequency of grade 3 or more skin reaction will be reduced from 35% to 25% for skin care using sorbolene or CDBC respectively.

Alternative Hypothesis of secondary outcome: the mean area under the curve (AUC) of total skin reaction will be reduced from 9 to 8 for skin care using sorbolene or CDBC respectively.

Inclusion Criteria:

• Ages 18 or more years
• Post total mastectomy
• Planned dose at least 45 Gy in 25 fractions
• ECOG 0-2
• Able to attend weekly during treatment for review and photo and for up to 6 weeks after radiotherapy
• Patients capable of childbearing using adequate contraception
• Written informed consent

Exclusion Criteria:

• Previous radiotherapy to the chest wall to be treated
• Macroscopic cutaneous involvement by malignancy at time of radiotherapy
• Known allergy to product contents
• Patients who are pregnant or lactating.