The first study to systematically address the problem of persistent hair loss in patients who undergo radiation to the scalp for central nervous system (CNS) or head and neck tumors has found that treatment with topical minoxidil leads to improvement in hair loss.
The study was published online on August 5 in JAMA Dermatology.
Minoxidil has been used for many years to treat age-associated baldness in men, note the authors. It was used off label in this study to treat radiation-associated persistent hair loss; 82% of patients showed at least some improvement.
“Almost in all instances, there is something that can be done to improve persistent hair loss after radiation and give patients a sense of control,” senior author Mario E. Lacouture, MD, told Medscape Medical News. He is director of the Oncodermatology Program at Memorial Sloan Kettering Cancer Center in New York City.
About 60% of people with CNS tumors and 30% with head and neck cancer receive radiation to the head, and 75% to 100% of these patients experience acute hair loss. For many, hair grows back in 2 to 3 months. However, for about 60%, hair loss persists for 6 or more months after completion of radiotherapy, the authors note.
“There are therapies and procedures that may mitigate persistent radiation therapy hair loss that can bring back psychosocial well-being to many of these patients,” Lacouture said. “These approaches are likely underutilized because patients are not being referred to specialists in hair or scalp reconstruction.”
Specialists can be found through the International Society for Hair Restoration Surgery and the American Academy of Dermatology, he added.
The retrospective cohort study included 71 children and adults who developed persistent hair loss after radiotherapy for primary CNS tumors (90%, n = 64) or head and neck sarcoma (10%, n = 7). The median age of the patients was 27 years (range, 4 – 75 years); 72% (n = 51) were female, and 82% (n = 58) were White patients.
These patients had been treated at Memorial Sloan Kettering Cancer Center in New York City or St. Jude Children’s Hospital in Memphis, Tennessee, from January 2011 through January 2019.
The team analyzed standardized clinical photographs of the scalp using the Common Terminology Criteria for Adverse Events version 5.0. Grade 1 alopecia was defined as hair loss of less than 50% of normal that does not require camouflage with hair pieces, scarves, or similar items. Grade 2 alopecia was defined as hair loss greater than 50% of normal that requires camouflage and is associated with negative psychosocial effects.
Over half of patients (56%, 40/70) had grade 1 hair loss. Clinical images were available for 54 patients; for most of these patients, hair loss was attributable to radiation alone (74%, n = 40/54). Evaluation of clinical imaging showed three variants of hair loss: localized (54%, 29/54), diffuse (24%, 13/54), and mixed pattern (22%, 12/54). Data on dermatologic imaging of the scalp (trichoscopy) were available for 28 patients; the main finding was white patches (57%, 16/28).
The median scalp radiation dose was 39.6 Gy (range, 15.1 – 50.0 Gy). The researchers estimate that a dose of 36.1 Gy (95% CI, 33.7 – 39.6 Gy) was sufficient to induce grade 2 hair loss in 50% of patients.
Severity of hair loss appeared to increase with radiation dose. For every 1 unit increase in radiation dose, the odds of grade 2 hair loss increased by 15% (odds ratio [OR], 1.15; 95% CI, 1.04 – 1.28; P < .001). Proton irradiation was associated with even higher odds of severe hair loss (OR, 5.7; 95% CI, 1.05 – 30.8; P < .001). Results remained significant when analyses were controlled for sex, age at time of radiotherapy, and concurrent chemotherapy.
The majority of evaluable patients who were treated with topical minoxidil (5%) twice daily showed a response (82%, 28/34) during a median follow-up of 61 weeks (interquartile range, 21 – 105 weeks).
Among 25 of these patients for whom clinical images were available, 16% (4/25) showed complete response. Two patients improved with hair transplant, and one showed complete response with plastic surgery reconstruction of the hair.
The study had several limitations, including its retrospective design and a lack of complete data for certain variables, such as standardized clinical photographs, trichoscopy images, and radiotherapy treatment plans.
On the basis of these results, the authors are seeking funding for a prospective study of the use of minoxidil for persistent radiation-induced alopecia.
The study was funded in part by the National Institutes of Health/NationalCancer Institute Cancer Center. One or more authors has relationships with pharmaceutical companies, as listed in the original article.
JAMA Dermatol. Published online August 5, 2020. Abstract