There are many hair changes attributable to anticancer therapies. In approximately 65% of patients treated with chemotherapy and in up to 100% of areas treated with radiotherapy can lead to hair changes.
These can manifest as hair loss (alopecia), pigment changes, textural changes, and changes in hair cycle.
Chemotherapy induced hair loss typically begins weeks after the first dose of chemotherapy and represents what is called an anagen effluvium, predominantly in areas of increased friction on the scalp. Eyebrows and eyelashes may also be affected. Usually asymptomatic, it can be associated with itch or pain. Two to six months after the chemotherapy has finished, the hair typically begins to regrow, although the hair loss can be persistent.
Radiotherapy will also cause hair loss as a result of acute damage to the hair follicle, causing an anagen effluvium. This hair loss is confined to the the area of radiation and will start 1-3 weeks after the first dose of radiation. Hair regrowth usually begins 2-6 months after the cessation of treatment, although the hair loss can be persistent.
These are the most common presentations of hair loss associated with anticancer treatments, although it can sometimes manifest as scarring alopecias and alopecia areata. For example, if the radiation therapy is aggressive, the hair follicles may permanently damages, causing scarring hair loss.
Some of the pigment changes include depigmentation (loss of pigment) and hyperpigmentation (increased pigment). This most typically affects the scalp but can affect eyelashes, eyebrows, and body hair.
Straight hair may become curly or wavy in 2/3 of patients treated with cytotoxic chemotherapy. Chemotherapy may also cause hair to become finer and more brittle.
Changes in Hair Cycle
Some anticancer therapies can paradoxically cause excessive hair growth, although this will usually only be present when treated with medications that affect hormones such as estrogen or with a special subset of agents called growth factor inhibitors.
Can Hair Changes from anticancer treatments be prevented?
For the most part, the answer is no as there are no medicated agents that have shown sufficient benefit. However, there is some evidence that cooling the scalp may be beneficial for chemotherapy induced hair loss. Scalp cooling systems may be helpful in reducing hair loss from chemotherapy and this is thought to be secondary to reduced blood flow to the hair follicles, decreased hair follicle metabolism, or reduced follicular uptake of the anticancer drug.