Proton therapy and hair loss: what to expect

Proton therapy may cause hair loss in the area where radiation enters, while hair outside the treated field is usually unaffected. The chance and extent depend on the body area, treatment plan, dose, and whether other cancer treatments are given. Hair changes may be temporary or may last longer in the treated patch.

Radiation can affect hair follicles within or close to the treatment field. A scalp treatment may therefore produce a defined area of thinning or hair loss, whereas treatment to another body region does not normally affect scalp hair. Hair may become dry, fragile, or slower to grow before it sheds. Regrowth, when it occurs, can take time and may differ in texture or thickness.

Proton therapy directs protons toward a planned target and can limit radiation beyond that target. It does not remove every possible effect on nearby normal tissue. Review the treatment field with the radiation team so you know which skin and hair areas may be involved.

Use gentle shampoo, avoid tight hairstyles and harsh chemical treatments, and protect exposed scalp skin from sun and cold. Do not apply a new lotion, oil, or hair product to the treatment area unless the radiation team approves it. A soft hat, scarf, or other comfortable covering can protect the scalp; ask whether it is suitable during treatment sessions. Tell the team about itching, tenderness, peeling, or increasing redness so they can recommend appropriate skin care.

Contact your oncology team promptly for moist peeling, open skin, blisters, spreading redness, drainage, fever, or pain that is becoming harder to control. Seek urgent help for trouble breathing, facial swelling, confusion, or sudden weakness. These symptoms need assessment and are not explained by hair loss alone.

Ask which hair-bearing areas are inside the planned field, when changes might begin, what products are safe, and whether other treatments could add to hair loss. You can also ask how the team will monitor scalp skin and whom to contact between appointments.