White Race Increases Hypothyroidism Risk after Hodgkin Lymphoma Treatment
By Will Boggs, MD
NEW YORK (Reuters Health) - White patients face a higher risk than black patients for becoming hypothyroid after neck irradiation for pediatric Hodgkin's lymphoma, according to a report in the April 1st Journal of Clinical Oncology.
"This article should remind any physician taking care of Hodgkin survivors that hypothyroidism is a common side effect of radiation therapy to the neck and chest, and that a high level of suspicion is warranted especially in white patients," Dr. Monika L. Metzger from St. Jude Children's Research Hospital, Memphis, Tennessee told Reuters Health.
In response to an earlier report suggesting that white race is a risk factor for hypothyroidism in adults who undergo head and neck irradiation, Dr. Metzger and colleagues investigated the possibility further in a study of 461 survivors of pediatric Hodgkin's lymphoma -- 338 whites, 73 blacks.
Hypothyroidism developed in a significantly higher percentage of white patients (47%) than black patients (21%), the authors report, after a median of 2.9 years.
The estimated cumulative incidence of hypothyroidism at 20 years was also significantly higher for white patients (52%) than for black patients (23%), the results indicate, and after adjustment for other risk factors the risk of hypothyroidism was 2.5 times higher in whites than blacks.
Radiation dose also affected the incidence of hypothyroidism, the researchers note. Less than a third (30%) of patients who received 21 Gy or less of radiation to the thyroid would be expected to develop hypothyroidism over the ensuing 20 years, but 61% of patients who received more than 21 Gy would be expected to become hypothyroid.
Combining race and dose, hypothyroidism occurred within 20 years in 65% of white patients who received more than 21 Gy of radiation, compared with only 36% of black patients.
"It appears that the racial differences for hypothyroidism are related to different genetic make up, as several endocrinopathies favor different races," Dr. Metzger said. "Nonetheless, it would be interesting to see whether white and black patients have different tolerance to radiation therapy. This is something we would like to study."
"Every pediatric Hodgkin lymphoma survivor merits regular thyroid function screening after radiation to the neck and chest, regardless of race," Dr. Metzger advised. "Patients who develop signs and symptoms suggestive of hypothyroidism (weight gain, depression, cold intolerance, and fatigue) should be screened at the time of symptom onset, since treatment for hypothyroidism is simple and cheap, and delayed diagnosis can have significant negative impact on quality of life."
NEW YORK (Reuters Health) - White patients face a higher risk than black patients for becoming hypothyroid after neck irradiation for pediatric Hodgkin's lymphoma, according to a report in the April 1st Journal of Clinical Oncology.
"This article should remind any physician taking care of Hodgkin survivors that hypothyroidism is a common side effect of radiation therapy to the neck and chest, and that a high level of suspicion is warranted especially in white patients," Dr. Monika L. Metzger from St. Jude Children's Research Hospital, Memphis, Tennessee told Reuters Health.
In response to an earlier report suggesting that white race is a risk factor for hypothyroidism in adults who undergo head and neck irradiation, Dr. Metzger and colleagues investigated the possibility further in a study of 461 survivors of pediatric Hodgkin's lymphoma -- 338 whites, 73 blacks.
Hypothyroidism developed in a significantly higher percentage of white patients (47%) than black patients (21%), the authors report, after a median of 2.9 years.
The estimated cumulative incidence of hypothyroidism at 20 years was also significantly higher for white patients (52%) than for black patients (23%), the results indicate, and after adjustment for other risk factors the risk of hypothyroidism was 2.5 times higher in whites than blacks.
Radiation dose also affected the incidence of hypothyroidism, the researchers note. Less than a third (30%) of patients who received 21 Gy or less of radiation to the thyroid would be expected to develop hypothyroidism over the ensuing 20 years, but 61% of patients who received more than 21 Gy would be expected to become hypothyroid.
Combining race and dose, hypothyroidism occurred within 20 years in 65% of white patients who received more than 21 Gy of radiation, compared with only 36% of black patients.
"It appears that the racial differences for hypothyroidism are related to different genetic make up, as several endocrinopathies favor different races," Dr. Metzger said. "Nonetheless, it would be interesting to see whether white and black patients have different tolerance to radiation therapy. This is something we would like to study."
"Every pediatric Hodgkin lymphoma survivor merits regular thyroid function screening after radiation to the neck and chest, regardless of race," Dr. Metzger advised. "Patients who develop signs and symptoms suggestive of hypothyroidism (weight gain, depression, cold intolerance, and fatigue) should be screened at the time of symptom onset, since treatment for hypothyroidism is simple and cheap, and delayed diagnosis can have significant negative impact on quality of life."
posted by TM at 11:51 AM
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