Thyroid dysfunction following external irradiation to the neck for Hodgkin's disease in childhood

Risk of thyroid disorders in adult and childhood Hodgkin lymphoma survivors 40 years after treatment

Thyroid abnormalities are well reported following childhood treatment for Hodgkin Lymphoma (HL). Limited information exists for adult patients and after modern treatments. We analyzed risks of thyroid disorders in 237 female participants treated at the Royal Marsden Hospital 1970-2015. Multivariable analyses of risk according to treatment and time-related factors, survival analyses, and Cox regression modeling were undertaken. Overall, 33.8% of patients reported thyroid disorders (hypothyroidism 30.0% and thyroid nodules 6.8%). Cumulative prevalence was 42.9% by 40 years follow-up. Risks were greatest after supradiaphragmatic radiotherapy (RR = 5.0, p < 0.001), and increasing dose (RR = 1.03/Gy, p < 0.001). There was no association with a chemotherapy agent. Risks of thyroid disease were as raised following adult as childhood treatment. There was no trend in risk by decade of supradiaphragmatic radiotherapy treatment. Risks of thyroid disease after supradiaphragmatic radiotherapy are as great after adult as childhood treatment and persist after more recent treatment periods.

Thyroid abnormalities in survivors of childhood cancer

OBJECTIVE

To investigate the late side effects of childhood cancer therapy on the thyroid gland and to determine the risk factors for development of thyroid disorder among childhood cancer survivors.

METHODS

One hundred and twenty relapse-free survivors of childhood cancer (aged 6-30 years) were included in this study. The diagnoses of patients were lymphoma, leukemia, brain tumor, rhabdomyosarcoma and nasopharyngeal carcinoma (NPC). The patients were divided into two groups depending on the treatment: group 1-chemotherapy (ChT) only (n=52) and group 2-combination therapy of ChT + radiotherapy (RT) (head/neck/thorax) (n=68). Thyroid function tests, urinary iodine levels, and thyroid gland ultrasound examinations were evaluated in both groups.

RESULTS

Incidence of thyroid disease was 66% (n=79) in the survivors. The thyroid abnormalities were: hypothyroidism (HT) (n=32, 27%), thyroid nodules (n=27, 22%), thyroid parenchymal heterogeneity (n=40, 33%), autoimmune thyroiditis (n=36, 30%), and thyroid malignancy (n=3, 2%). While the incidence of HT and thyroid nodules in group 2 was significantly higher than in group 1, the incidence of thyroid parenchymal heterogeneity and autoimmune thyroiditis was similar in the two patient groups. HT and thyroid malignancy were seen only in group 2. In multivariate logistic regression analysis, a history of Hodgkin lymphoma (HL), brain tumor and NPC, as well as cervical irradiation and 5000-5999 cGy doses of radiation were found to constitute risk factors for HT. History of HL and 4000-5999 cGy doses of radiation were risk factors for thyroid nodules. Head/neck irradiation and treatment with platinum derivatives were risk factors for autoimmune thyroiditis. In univariate analysis, a history of NPC, cervical + nasopharyngeal irradiation, and treatment with platinum derivatives were risk factors for thyroid parenchymal heterogeneity.

CONCLUSION

Our results indicate that there is especially an increased risk of HT and thyroid nodules in patients treated with combination therapy of ChT with head/neck/thorax RT. Although chemotherapeutic agents per se do not seem to cause HT, longer follow-up is needed to assess whether or not there is an increased risk for autoimmune thyroiditis and thyroid parenchymal heterogeneity after antineoplastic therapy.

Protection against radiation-induced damage of 6-propyl-2-thiouracil (PTU) in thyroid cells

Many epidemiologic studies have shown that the exposure to high external radiation doses increases thyroid neoplastic frequency, especially when given during childhood or adolescence. The use of radioprotective drugs may decrease the damage caused by radiation therapy and therefore could be useful to prevent the development of thyroid tumors. The aim of this study was to investigate the possible application of 6-propyl-2-thiouracil (PTU) as a radioprotector in the thyroid gland. Rat thyroid epithelial cells (FRTL-5) were exposed to different doses of γ irradiation with or without the addition of PTU, methimazole (MMI), reduced glutathione (GSH) and perchlorate (KClO4). Radiation response was analyzed by clonogenic survival assay. Cyclic AMP (cAMP) levels were measured by radioimmunoassay (RIA). Apoptosis was quantified by nuclear cell morphology and caspase 3 activity assays. Intracellular reactive oxygen species (ROS) levels were measured using the fluorescent dye 2',7'-dichlorofluorescein-diacetate. Catalase, superoxide dismutase and glutathione peroxidase activities were also determined. Pretreatment with PTU, MMI and GSH prior to irradiation significantly increased the surviving cell fraction (SF) at 2 Gy (P < 0.05), while no effect was observed with KClO4. An increase in extracellular levels of cAMP was found only in PTU treated cells in a dose and time-dependent manner. Cells incubated with agents that stimulate cAMP (forskolin and dibutyril cAMP) mimicked the effect of PTU on SF. Moreover, pretreatment with the inhibitor of protein kinase A, H-89, abolished the radioprotective effect of PTU. PTU treatment diminished radiation-induced apoptosis and protected cells against radiation-induced ROS elevation and suppression of the antioxidant enzyme's activity. PTU was found to radioprotect normal thyroid cells through cAMP elevation and reduction in both apoptosis and radiation-induced oxidative stress damage.

Thyroid neoplasm after central nervous system irradiation for medulloblastoma in childhood: report of two cases

OBJECTIVE

Surgical excision combined with radio-chemotherapy represents the gold standard of therapy of medulloblastoma. The effectiveness of such a combined treatment has encouraged the use of radiotherapy even in young paediatric patients, in spite of the many adverse effects reported in literature, and, in particular, the increased risk of a second radioinduced malignancy. Irradiation is the well-known risk factor for development of benign and malignant thyroid tumours. Children are more exposed to this risk because of their thyroid gland is more sensitive to carcinogenic effect of ionising radiation.

CASE REPORT

Two children underwent radiotherapy for the treatment of a medulloblastoma when they were 3 and 4 years old, respectively. At the age of 20 and 23, both of them underwent the surgical excision of a papillary thyroid carcinoma, 20 and 17 years after the radiotherapeutic treatment, respectively.

CONCLUSIONS

Radioinduced thyroid tumours are a well-recognised nosographic entities due to the particular sensitivity of this gland to ionising radiations. However, only a few papers on radioinduced thyroid neoplasms after CNS irradiation have been published in the literature. We report on two additional cases of thyroid neoplasms following childhood CNS irradiation for the treatment of a posterior fossa medulloblastoma.

Hyperparathyroidism after neck irradiation for Hodgkin's disease

A 38-year old man developed hypercalcaemia 13 years after treatment with mantle field radiation for Hodgkin's disease. A parathyroid tumour was removed surgically. The histological diagnosis was parathyroid adenoma with marked central fibrosis. Hyperparathyroidism as a possible late complication of radiation therapy of malignant diseases has, to our knowledge, not been described before. Key words: Hodgkin's disease, hyperparathyroidism, irradiation, parathyroid adenoma.

Thyroid-stimulating hormone suppression for protection against hypothyroidism due to craniospinal irradiation for childhood medulloblastoma/primitive neuroectodermal tumor

PURPOSE

Hypothyroidism is one of the earliest endocrine effects of craniospinal irradiation (CSI). The effects of radiation also depend on circulating thyroid-stimulating hormone (TSH), which acts as an indicator of thyrocyte function and is the most sensitive marker of thyroid damage. Hence, our study was launched in 1998 to evaluate the protective effect of TSH suppression during CSI for medulloblastoma/primitive neuroectodermal tumor.

PATIENTS AND METHODS

From Jan 1998 to Feb 2001, a total of 37 euthyroid children scheduled for CSI for medulloblastoma/primitive neuroectodermal tumor underwent thyroid ultrasound and free triiodothyronine (FT3), free thyroxine (FT4), and TSH evaluation at the beginning and end of CSI. From 14 days before and up to the end of CSI, patients were administered l-thyroxine at suppressive doses; every 3 days, TSH suppression was checked to ensure a value <0.3 mum/ml. During follow-up, blood tests and ultrasound were repeated after 1 year; primary hypothyroidism was considered an increased TSH level greater than normal range. CSI was done using a hyperfractionated accelerated technique with total doses ranging from 20.8-39 Gy; models were used to evaluate doses received by the thyroid bed.

RESULTS

Of 37 patients, 25 were alive a median 7 years after CSI. They were well matched for all clinical features, except that eight children underwent adequate TSH suppression during CSI, whereas 17 did not. Hypothyroidism-free survival rates were 70% for the "adequately TSH-suppressed" group and 20% for the "inadequately TSH-suppressed" group (p = 0.02).

CONCLUSIONS

Thyroid-stimulating hormone suppression with l-thyroxine had a protective effect on thyroid function at long-term follow-up. This is the first demonstration that transient endocrine suppression of thyroid activity may protect against radiation-induced functional damage.

Endocrine intervention during irradiation does not prevent damage to the thyroid gland

Radiation to the head-neck region may damage the thyroid gland, leading to hypothyroidism or thyroid carcinoma. Outcomes of radiation protection by lowering plasma thyroid-stimulating hormone (TSH) have thus far been ambiguous. Our aim was to evaluate the radioprotective effect of inhibiting the thyroid gland's activity during x-radiation. For this purpose, of 80 5-week old Wistar rats, 64 received cervical irradiation with 15 Gy (single dose). During irradiation, endocrine intervention was done, using thyroxine (T(4)), T(4) plus iodine, or iodine alone compared to placebo. During the endocrine interventions and follow-up, TSH and T(4) concentrations were measured periodically. Histologic examination of thyroid, pituitary gland, or the hypothalamus and any suspect lymph nodes, lungs, and liver was performed after 6 and 54 weeks. It was found that during the endocrine intervention, plasma levels of TSH were lower in rats given T(4) and higher in rats given iodine. After 6 and 54 weeks, no significant reduction in hypothyroidism or thyroid carcinoma was found between the different groups of rats given any endocrine intervention or no intervention. In conclusion, the administration of T(4), iodine or the combination during x-irradiation does not protect against radiation-induced thyroid damage.

Long-term follow-up of pediatric cancer survivors: education, surveillance, and screening

Cancer and its treatment predispose childhood cancer survivors to chronic or late occurring health problems that may not become clinically significant until many years after therapy. Frequently, long-term survivors of childhood cancer report late cancer-related effects that diminish quality of life and increase the risk of early mortality. Risk-based health care that involves a personalized plan for surveillance, screening, and prevention is recommended to reduce cancer-related morbidity in childhood cancer survivors. To implement optimal risk-based care, the survivor and health care provider must have accurate information about cancer diagnosis, treatment modalities, and potential cancer-related health risks to guide screening and risk-reducing interventions. However, previous studies evaluating health knowledge of childhood cancer survivors demonstrate noteworthy deficits and misperceptions about their cancer diagnosis, treatment, and cancer-related health risks. In addition, because of the relative rarity of childhood cancer, many health care providers lack familiarity with cancer-related health risks and risk-reduction methods relevant for this population. To correct these deficits, the Scottish Intercollegiate Guidelines Network (SIGN) and the Children's Oncology Group (COG) developed clinical practice guidelines to foster appropriate risk-based survivor care. Herein, we discuss the development, benefits, and limitations of the SIGN and COG guidelines and the foundation they provide for standardizing long-term follow-up care of the ever-growing vulnerable population of childhood cancer survivors.

The effect of cervical X-irradiation on activity index of thyrocytes and plasma TSH: a pre-clinical model for radiation-induced thyroid damage

Because radiotherapy in the head and neck region is necessary in the treatment of childhood cancer, possibilities to prevent damage to the thyroid gland must be explored. We developed a model in which radiation-induced effects can be investigated in a way that these effects can be quantified, using thyroid dysmorphology and plasma TSH. Thirty-five Wistar rats, 5 weeks old, were X-irradiated on the cervical region, with a single dose varying from 0 to 20 Gy. After 6 weeks, TSH, T4 and T3 were determined, and thyroid glands were processed for histological examination by two independent pathologists. A histological classification scale was developed, using follicular size, colloid density and cell height of thyrocytes to measure hyperplasia and hypertrophy. By the sum of these scores, a cell-activity index was calculated, which was related to plasma TSH concentration. Numbers of PAS-positive droplets and epithelial desquamation were also counted. Inter-observer reliability was assessed. Good to very good reliability was found for scores of follicular size, colloid density and cell height. Significant increase of cell-activity index was found after 10, 15 and 20 Gy. The plasma TSH concentration was positively correlated to the cell-activity index, increasing with radiation-doses up to 15 Gy. The number of desquamated cells was significantly increased after radiation doses >10 Gy, with moderate reliability. In conclusion, this model using cell-activity index of thyrocytes together with plasma thyrotropin concentrations and desquamation of cells can be used for interpretation and future (pre-clinical) studies of prevention of radiation-induced thyroid damage.

Development of risk-based guidelines for pediatric cancer survivors: the Children's Oncology Group Long-Term Follow-Up Guidelines from the Children's Oncology Group Late Effects Committee and Nursing Discipline

The Children's Oncology Group Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent, and Young Adult Cancers are risk-based, exposure-related clinical practice guidelines intended to promote earlier detection of and intervention for complications that may potentially arise as a result of treatment for pediatric malignancies. Developed through the collaborative efforts of the Children's Oncology Group Late Effects Committee, Nursing Discipline, and Patient Advocacy Committee, these guidelines represent a statement of consensus from a multidisciplinary panel of experts in the late effects of pediatric cancer treatment. The guidelines are both evidence-based (utilizing established associations between therapeutic exposures and late effects to identify high-risk categories) and grounded in the collective clinical experience of experts (matching the magnitude of risk with the intensity of screening recommendations). They are intended for use beginning 2 or more years following the completion of cancer therapy; however, they are not intended to provide guidance for follow-up of the survivor's primary disease. A complementary set of patient education materials ("Health Links") was developed to enhance follow-up care and broaden the application of the guidelines. The information provided in these guidelines is important for health care providers in the fields of pediatrics, oncology, internal medicine, family practice, and gynecology, as well as subspecialists in many fields. Implementation of these guidelines is intended to increase awareness of potential late effects and to standardize and enhance follow-up care provided to survivors of pediatric cancer throughout the lifespan. The Guidelines, and related Health Links, can be downloaded in their entirety at www.survivorshipguidelines.org.

Frequent adverse events after treatment for childhood-onset differentiated thyroid carcinoma: a single institute experience

Since the mortality rate for childhood differentiated thyroid carcinoma is nearly zero, the focus must be to minimise morbidity following treatment. Our aim was to analyse early and late adverse events. Twenty-five of 26 children treated between 1962 and 2002 were evaluated. Median follow-up was 14.2 years (range 0.9-39.4 years). All underwent total thyroidectomy, 15 (60%) with lymph node dissection and 15 (60%) with adjuvant radio-iodide therapy. Mortality was zero. Seven developed recurrent disease, two developed a third recurrence. Twenty-one (84%) had > or =1 adverse event. Eight had permanent hypoparathyroidism (PH), six permanent recurrent nerve paralysis (PRNP) and two Horner's syndrome. Risk factors for PH and PRNP were total thyroidectomy with lymph node dissection (RR: 6.45, P = 0.015) and recurrent nerve tumour encasement (RR: 8.00, P = 0.001), respectively. Other adverse events were fatigue (n = 5), scar problems (n = 4) and chronic myeloid leukaemia (n = 1). These results emphasise the need to improve treatment strategies.

Improved radiation protection of the thyroid gland with thyroxine, methimazole, and potassium iodide during diagnostic and therapeutic use of radiolabeled metaiodobenzylguanidine in children with neuroblastoma

BACKGROUND

During radiolabeled metaiodobenzylguanidine (MIBG) administration in children with neuroblastoma, the thyroid is protected from (123/131)I uptake by potassium iodide. Despite this protection, up to 64% of patients develop thyroid dysfunction. The authors introduce a new method of radiation protection for the thyroid gland.

METHODS

In a prospective cohort study, 34 children with neuroblastoma who received MIBG were given thyroxine, methimazole, and potassium iodide for protection of the thyroid gland. Protection started 1 day before the start of diagnostic 123I-MIBG and was continued until 4 weeks after the last therapeutic 131I-MIBG dose. Follow-up measurements were performed every 3 months after the protection was stopped. Visualization of the thyroid on MIBG images was reviewed by three nuclear medicine physicians. Results were compared with a historic control group of children who had received potassium iodide for thyroid protection during MIBG administration.

RESULTS

After a mean follow-up of 19 months, there were 23 evaluable patients. Thyroid function was normal in 86% of survivors compared with 44% of children in the historic control group (P=0.011; Pearson chi-square test). Scintigraphic visualization of the thyroid diminished substantially after the new protection (21.5% vs. 5.3%, respectively; P=0.000).

CONCLUSIONS

The results of the current study indicate that compared with potassium iodide alone, combined thyroxine, methimazole, and potassium iodide protect the thyroid more effectively against radiation damage from (123/131)I during diagnostic and therapeutic MIBG administration in children with neuroblastoma.

High incidence of thyroid dysfunction despite prophylaxis with potassium iodide during (131)I-meta-iodobenzylguanidine treatment in children with neuroblastoma

BACKGROUND

Treatment modalities like targeted radiotherapy with (131)I-meta-iodobenzylguanidine ((131)I-MIBG) improve survival rates after neuroblastoma (NB). Radiation to the thyroid gland can lead to hypothyroidism and even malignancy. Because hypothyroidism after (131)I-MIBG treatment was reported, the current KI prophylaxis against thyroidal radiation damage was evaluated.

METHODS

The incidence, pathogenesis, and consequences of thyroid dysfunction among 42 NB patients treated with (131)I-MIBG were evaluated retrospectively. Efficacy of KI prophylaxis was established by measuring thyroidal radioiodide uptake. Thyroid damage was expressed as thyrotropin elevation (TE, plasma concentration of thyroid stimulating hormone > or = 4.5 mU/L).

RESULTS

The mean followup was 2.3 years (range, 0.1-8.5). The mean number of treatments with (131)I-MIBG was 3.3. Of 428 scintigrams, uptake of (131)I in the thyroid was visible in 92 (21.0%). Twenty two patients (52.4 %) presented TE after a mean period of 1.4 years (range, 0.1-5.8). Clinical signs of hypothyroidism were not observed. Eight patients received suppletion therapy with thyroxine. Thyrotropin elevation was transient in four patients. Of 25 survivors, with a mean followup of 3.5 years, 16 (64%) developed TE. No correlation was found between TE and thyroid visualization after (131)I-MIBG administration or the number of treatments. No abnormalities were seen by ultrasound imaging of the thyroid.

CONCLUSIONS

Occurrence of thyroid dysfunction after treatment with (131)I-MIBG for NB is high, in spite of KI prophylaxis. Close followup of thyroid function and structure is required in patients treated with (131)I-MIBG. New ways of protecting the thyroid during exposure to radioiodine should be developed.

Response-adapted radiotherapy in the treatment of pediatric Hodgkin's disease: an interim report at 5 years of the German GPOH-HD 95 trial

PURPOSE

A multinational trial on pediatric Hodgkin's disease (HD) with the aim to reduce the risk of long-term toxicity of combined modality treatment by restricting dose and volume of radiation therapy (RT) while maintaining the excellent treatment results of previous German multicenter trials (DAL-HD82-90).

METHODS AND MATERIALS

Patients were treated according to stage of disease (CS) and defined risk factors in three treatment groups (TG) with 2, 4, or 6 cycles of combination chemotherapy. When a complete remission (CR) had been achieved, treatment was terminated without RT independent of initial stage or tumor bulk. Patients with a partial remission (PR) of >75% tumor regression were irradiated with 20 Gy using modified involved fields; in the case of PR <75% RT dose was 30 Gy, residual masses >50 mL received 35 Gy.

RESULTS

From August 1995 to July 2000 a total of 956 patients have been registered, 830 as trial patients, 39% in TG1, 27% in TG2, 34% in TG3. 827 patients were evaluable by June 2001 with a median follow-up of 38 months. Chemotherapy (CTx) resulted in CR in 22%, PR >75% in 62%, PR <75% in 12%. Event-free survival (EFS) for the entire group is 90% (SD 0.01), for TG1 94%, TG2 91%, and TG3 84%; the overall survival is 97% in Kaplan-Meier-analysis. Relapse-free survival (RFS) is superior for patients with RT after PR (93%) than for those without RT after CR (89%); the difference is significant (p = 0.01) for advanced stages, however not in TG1. Seventy-two events were observed by June 2001: 28 progressions during the initial therapy or within the first 3 months, 38 relapses, 3 second malignancies, three fatal accidents or infections; 18 patients have died.

CONCLUSION

Treatment results of the GPOH-HD 95 trial are excellent thus far. The reduction of RT dose and volume in PR has not caused a significant impairment of overall and event-free survival in comparison to the previous German trials; however, failure rates are higher in advanced stages when RT is omitted after achieving a CR. It is too early to tell whether the HD 95 protocol will be successful in reducing late toxicity.

[Hypothyroidism after external radiotherapy. Fifteen cases]

Hypothyroidism frequency is estimated to be between 10 and 45% after radiotherapy alone, and 40 to 67% after radiotherapy associated with thyroidectomy. This hypothyroidism is infraclinical in 60% of the cases. Our study concerned 15 cases of hypothyroidism after external radiotherapy delivered between and 1991 and 1999. An irradiation of the cervical, cerebral and thorax regions was indicated for different types of cancers. Larynx carcinoma epidermoid was the most frequent cancer (seven cases); the radiation treatment used cobalt 60 with conventional fractionation, i.e., 2 Gy per treatment, five treatments a week. In nine cases, the hypothyroidism was discovered during a systematic examination; it was clinically evident in the six remaining cases. Hypothyroidism appeared after an irradiation dose average of 50 Gy (extremes 30-65 Gy). The average duration of the irradiation was about 7 weeks and the hypothyroidism appeared in a mean 22 months. In all cases, the substituting treatment was initiated with a favorable progression. Faced with the risk of hypothyroidism, it is necessary to check patients who have undergone external irradiation of the neck.

Subclinical thyroid disease after radiation therapy detected by radionuclide scanning

PURPOSE

The actuarial risk for developing benign or malignant thyroid disease following radiation therapy (RT) is controversial, but may be as high as 50% at 20 years. An effective screening modality should be specific but not overly sensitive, a limitation of ultrasound. We questioned whether Technetium-99 m pertechnetate ((99m)Tc TcO(4)(-)) scanning could detect clinically significant disease in ostensibly disease-free cancer survivors.

METHODS AND MATERIALS

Eligibility criteria included an interval of at least 5 years after RT to the cervical region, a thyroid gland that was normal to palpation, euthyroid status determined by clinical examination, free T4 and TSH. The 34 patients scanned included 16 children (<18 years old) and 18 adults at the time of RT, 16 females and 18 males. The mean age at RT was 20 years (range, 2.1-50.3 years), and the mean age at (99m)Tc TcO(4)-scanning was 33 years (range, 13.6-58 years), providing a mean interval of 13 years (range, 5.3-26.6 years). The mean RT dose to the thyroid was 36.4 Gy (range, 19.5-52.5). Thyroid scanning was performed with a 5 mCi dose of (99m)Tc TcO(4)(-) obtaining flow, immediate and delayed static, and pinhole collimator images.

RESULTS

Seven patients (21.6%) had abnormal scans, and the percentage was higher among children (25%) and females (25%) compared to adults (16.7%) and males (16.7%), respectively. Two of 34 patients (5.9%) were discovered to have a thyroid cancer; histopathologies were papillary and follicular carcinoma.

CONCLUSION

In this population of clinically normal cancer survivors who had been irradiated to the cervical region, subclinical thyroid disease, of potential clinical significance, was detected by (99m)Tc TcO(4)(-) in about 20%. Children may be more commonly affected. Although the cost effectiveness of screening will require a larger sample number, we propose a surveillance schema for this patient population.

[Late effects of ionizing radiations on the thyroid gland]

The thyroid is the purest endocrine gland in the body and is likely to produce clinically significant abnormalities after external radiotherapy. Functional clinical modifications after direct irradiation exceeding 30 Gy are essentially related to hypothyroidism which may be clinically overt or subclinical with normal serum free thyroxine levels and high thyrotropin concentrations; the risk of hyperthyroidism, silent thyroiditis and Hashimoto's disease is also increased. Secondary hypothyroidism related to irradiation of the hypothalamus and the pituitary gland may arise with doses over 40-50 Gy following treatment for brain and nasopharyngeal tumors--Morphological glandular modifications induced by radiotherapy are responsible for the appearance of benign adenomas, more rarely cystic degenerations and specially well differentiated papillary or follicular carcinomas among children and adults. After irradiation during childhood for benign or malignant tumors, thyroid cancers are more frequent, higher for younger children, and the relative excess risk is increased from 15.6-to 53-fold; tumors can belatedly occur, more than 35 years after initial therapy. Thereby, in order to limit excess morbidity, it is evident that long term supervision with careful clinical and biological evaluations is necessary for patients who previously received neck, upper mediastinum and pituitary radiation therapy.

Thyroid dysfunction after mantle irradiation of Hodgkin's disease patients

Thyroid dysfunction can develop in patients with Hodgkin's disease who are treated with mantle irradiation. During the period 1970-89, the records of 320 patients who received mantle irradiation and who had thyroid function tests (TFT) were retrospectively reviewed. The median age was 30 years (range, 7-69 years). The median mantle and thyroid dose was 36 Gy (range, 30-40 Gy) and 39.8 Gy (range, 32-65 Gy), respectively. Overall thyroid dysfunction was present in 39% of the patients. Clinical hypothyroidism was seen in 10% and biochemical hypothyroidism was noted in 25%. Hyperthyroidism was found in 4% of patients. Thyroid nodules had developed in six patients (2%), of which those in four patients were malignant. Age, sex, histological subtype, stage of disease, dose, lymphangiogram and treatment with chemotherapy were not significant factors in the development of thyroid dysfunction. The narrow dose range prevented adequate analysis of dose effect. The results indicate that the incidence of thyroid abnormalities is high enough to warrant regular TFT assessment with pre-irradiation levels and follow-up testing for life because the development of abnormalities can occur many years later. Thyroid examination should form part of the routine follow-up examination and any abnormality should be promptly investigated.

The influence of lymphangiography on the development of hypothyroidism in patients irradiated for Hodgkin's disease

PURPOSE

There is no consensus in the literature regarding the role of lymphangiography in promoting hypothyroidism in individuals with Hodgkin's disease irradiated with a mantle field. We sought to analyze the onset and rate of developing clinical or chemical hypothyroidism as well as possible factors related to its development in patients who received irradiation to the thyroid gland during treatment of Hodgkin's disease.

METHODS AND MATERIALS

One hundred and forty-two patients with Hodgkin's disease were treated at the Fox Chase Cancer Center between June 1967 and October 1993. All patients were treated with curative intent with radiation therapy using a mantle field. After exclusion of patients without available thyroid function tests, < 200 days of follow-up, or no radiation to the thyroid, 104 patients were eligible for analysis. Follow-up ranged from 7-170 months (median: 43 months). Sixty-seven patients had a lymphangiogram. Seventy-three patients were treated with radiation alone and 31 with radiation plus chemotherapy.

RESULTS

The actuarial 2-, and 5-year rates of biochemical hypothyroidism for all 104 patients were 18 and 37%, respectively. Forty patients developed hypothyroidism: 9 (23%) at < or = 1 year, 18 (45%) at < or = 2 years, and 33 (83%) at < or = 5 years. The actuarial 2-, and 5-year rates of biochemical hypothyroidism for patients who underwent a lymphangiogram were 23 and 42%, respectively, compared to 9 and 28%, respectively, for patients who received mantle irradiation without a lymphangiogram (p = 0.05). The effects of lymphangiogram, total thyroid dose, stage, chemotherapy, dose per fraction, energy, and age were evaluated for all patients by Cox proportional hazards regression analysis. The use of a lymphangiogram (p = 0.05) was the only variable that significantly influenced hypothyroidism.

CONCLUSIONS

This paper demonstrates in a multivariate analysis accounting for other potentially important variables the significant effect of lymphangiography and subsequent radiation therapy on the development of hypothyroidism. This information must be balanced with the fact that lymphangiograms remain a useful aid in assessing lymph node involvement, staging patients, and planning treatment fields.

Sonographic abnormalities of the thyroid gland following radiotherapy in survivors of childhood Hodgkin's disease

The aims of this study were as follows. (1) To demonstrate the spectrum, frequency and changes on follow-up of sonographic abnormalities in the thyroid gland of survivors of Hodgkin's disease who had received radiotherapy to the neck in childhood. (2) To compare the sonographic findings with clinical examination and radionuclide imaging. (3) To investigate the association between the presence or absence of focal sonographic abnormalities with age at radiotherapy, the interval from radiotherapy, the presence of a raised thyroid stimulating hormone (TSH) and the length of time the TSH had been raised. 46 patients were scanned prospectively and rescanned at 6-18 months. The mean age at first sonography was 22.7 years, the median age at radiotherapy was 12.5 years, and the median interval post-radiation was 10.3 years. Sonographic abnormalities were seen in all 46 patients. 45 had diffuse atrophy and 30 had focal sonographic abnormalities. 18 patients developed new focal sonographic abnormalities on follow-up. Focal sonographic abnormalities were more commonly associated with longer duration of a raised TSH. Two patients had thyroid carcinoma. Sonographic abnormalities of the thyroid are common in patients following neck radiotherapy in childhood. Focal abnormalities are usually associated with a longer duration of raised TSH.

Testicular function following the treatment of Hodgkin's disease in childhood

Testicular function was studied in 40 males treated in childhood for Hodgkin's disease at St Bartholomew's Hospital, and the Hospital for Sick Children, London, between 1971-1985. All patients were 16 years or over at evaluation, and off treatment more than 6 years. Basal FSH, LH and testosterone levels were measured. Testicular size was measured using a Prader orchidometer, and all patients were offered a seminal analysis. Twenty-eight patients were treated with chemotherapy, usually ChlVPP. Twenty-one also had radiotherapy, five below the diaphragm. Twelve patients were treated with radiotherapy alone (five below the diaphragm). Twenty-six of 28 patients treated with chemotherapy and three of five patients treated with radiotherapy alone below the diaphragm have elevated basal FSH levels, and 18 of these also have elevated basal LH levels. Median testicular volume is 11 ml (range 5-25 ml). Eleven of 13 patients investigated are azoospermic. All patients have normal testosterone levels, and normal secondary sexual characteristics. There is no biochemical evidence of healing of the damaged germinal epithelium with elevated FSH levels persisting up to 17 years from the end of therapy. These results indicate a high incidence of damage to the germinal epithelium in patients treated with ChlVPP chemotherapy and/or radiotherapy below the diaphragm. Appropriate counselling of these patients with regard to their reproductive capabilities is essential.

Treatment of early stage Hodgkin's disease

Current trends in the treatment of patients with Stages I and II Hodgkin's disease are discussed in this review. Recommendations for staging procedures and the updated staging classification are described. Long-term results with extended field radiation therapy overall and in subgroups of patients are detailed. As follow-up and numbers of patients treated with extended field radiation therapy have accrued, prognostic factors, predictive of outcome, have emerged. The evolution of combined modality treatment with chemotherapy and radiation therapy and, more recently, chemotherapy alone for early stage patients is reviewed. Discussion is made of recent programs in various centers to reduce toxicity while maintaining good results. Long-term potential toxicities are described, and recommendations are made for long-term follow-up monitoring.

Thyroid function after treatment of brain tumors in children

In 134 children who had been treated for a brain tumor not involving the hypothalamic-pituitary axis, thyroid function was assessed up to 24 years after treatment with cranial or craniospinal irradiation. In addition, 78 children received up to 2 years of cytotoxic chemotherapy. Of 85 children who received craniospinal irradiation, 30 (35%) had abnormalities of thyroid function, and 10 (20%) of 49 who received cranial irradiation had such abnormalities. Frank hypothyroidism developed in three children and thyrotoxicosis in one. Thirty-six children had an elevated thyroid-stimulating hormone level in the presence of a normal thyroxine level; in 16 of them the thyroid-stimulating hormone level subsequently returned to normal. Twenty-eight children who were treated between 1960 and 1970 were excluded from the analysis. Of 34 children who received cranial irradiation, five had thyroid dysfunction and 24 of 72 who received craniospinal irradiation had such dysfunction (p = 0.013). Thyroid dysfunction was present in 4 of 35 children who received no chemotherapy and in 25 of 71 who received chemotherapy (p = 0.014). Direct irradiation plus chemotherapy was more damaging than irradiation alone. These data confirm the high incidence of thyroid dysfunction when the thyroid gland is included in the radiation field. However, in a high proportion, the thyroid abnormalities are minor and revert to normal with time; life-long replacement therapy with thyroxine may be unnecessary.

Thyroid diseases after treatment of Hodgkin's disease

BACKGROUND AND METHODS

Thyroid disease, especially hypothyroidism, is common in patients with Hodgkin's disease who have been treated with irradiation. We reviewed the records of 1787 patients (740 women and 1047 men) with Hodgkin's disease who were treated with radiation therapy alone (810 patients), radiation and chemotherapy (920 patients), or chemotherapy alone (57 patients) at Stanford University between 1961 and 1989. Among these patients, 1533 were alive at the last follow-up, and 254 had died of causes other than Hodgkin's disease. (Four other patients were excluded from the analysis because they had undergone thyroidectomy before treatment for Hodgkin's disease. The thyroid was irradiated in 1677 patients. Follow-up averaged 9.9 years.

RESULTS

A total of 573 patients had clinical or biochemical evidence of thyroid disease. Among the 1677 patients whose thyroid was irradiated, the actuarial risk of thyroid disease 20 years after treatment was 52 percent, and it was 67 percent at 26 years. Hypothyroidism was found in 513 patients. A total of 486 patients received thyroxine therapy for elevated serum thyrotropin concentrations and either low free thyroxine (208 patients) or normal free thyroxine values (278 patients); 27 had transient elevations of the serum thyrotropin level that were not treated. Graves' hyperthyroidism developed in 30 patients (2 of whom had not undergone thyroid irradiation), and ophthalmopathy developed in 17 of these patients. Ophthalmopathy developed in four other patients with Graves' disease during a period of hypothyroidism (n = 3) or euthyroidism (n = 1). The risk of Graves' disease was 7.2 to 20.4 times that for normal subjects. Silent thyroiditis with thyrotoxicosis developed in six patients. Forty-four patients were found to have single or multiple thyroid nodules, 26 of whom underwent thyroidectomy. Six of the 44 had papillary or follicular cancers. Among the patients who did not undergo operation, 12 had small functioning nodules, 4 had cysts, and 2 had multinodular goiters. The actuarial risk of thyroid cancer was 1.7 percent. The risk of thyroid cancer was 15.6 times the expected risk.

CONCLUSIONS

High risks of thyroid disease persist more than 25 years after patients have received radiation therapy for Hodgkin's disease, reinforcing the need for continued clinical and biochemical evaluation. Prolonged follow-up confirms an elevated risk of thyroid cancer and Graves' disease as well as hypothyroidism in these patients.

Thyroid iodine content and serum thyroglobulin level following external irradiation to the neck for Hodgkin's disease

Fifty-four clinically euthyroid patients were evaluated 1 up to 17 yr after external irradiation to the neck for Hodgkin's disease. T4 level was decreased in 6%, while basal TSH level was increased in 44%, and TSH response to TRH was increased in 66% of the patients with normal basal TSH level. Thyroid iodine content (TIC), measured in 50 patients, was below 5 mg in 18. The 29 patients with normal basal TSH level had a mean TIC (6.8 +/- 2.7 mg) significantly lower (p less than 0.01) than the control population (14.6 +/- 5 mg). A significant positive correlation was found between log T4 and log TIC (r = 0.55, p less than 0.01). Thyroglobulin (Tg) level was increased in 53% of the patients with no palpable thyroid abnormality. It was not related to TSH level but was related to younger age at irradiation. T4 treatment decreased Tg level to the normal range in 5 of 8 patients. These facts suggest subclinical thyroid abnormalities and patients with elevated Tg levels should be considered at risk for developing a thyroid tumor.

Incidence of hypothyroidism after irradiation of the neck with special reference to lymphoma patients. A retrospective and prospective analysis

Twenty-eight patients were studied prospectively in order to determine the incidence of hypothyroidism after mantle irradiation for malignant lymphoma. This group was compared with a historical group of 65 patients, among them 36 patients with malignant lymphoma. The mean follow-up was 30 months for the prospective group and 46 months for the retrospective group. The mean thyroid dose for irradiated malignant lymphomas in the prospective and the retrospective group was 45 Gy and 43 Gy respectively. For other tumors with neck irradiation (retrospective group) the mean thyroid dose was 53 Gy. There were no cases of clinical hypothyroidism in our study. As for subclinical hypothyroidism which is characterised by elevated TSH, the incidence was 22% in the prospective group and 3% in the retrospective group, i.e. 8/93 patients showed a hypothyroid dysfunction. Three of the 8 patients with subclinical hypothyroidism had undergone lymphangiography before radiotherapy. Due to the elevated iodine pool a lymphangiogram is considered as a risk factor for hypothyroidism as well as for hyperthyroidism, which we observed twice in the prospective group. Evaluation of the thyroid function before lymphangiography and irradiation as well as regular thyroid function studies during the follow-up are recommended in order to detect hypothyroidism in time.

Thyroid function in survivors of cancer

Thyroid function was assessed in three selected groups of children who had survived cancer. Children in group 1 had received radiotherapy to the thyroid area, group 2 had radiotherapy to the thyroid area and adjuvant chemotherapy, and group 3 had chemotherapy with or without radiotherapy away from the thyroid area. There were 75 survivors and 63 (40 boys, 23 girls) were available for study. Eighteen (29%) were found to have thyroid dysfunction, and these included all those who had had lymphangiograms or received a radiation dose greater than 40 Gy to the thyroid area. Only nine of the 18 children were already known to have thyroid dysfunction, and only 15 of 44 children who had had irradiation to the thyroid area had had their thyroid function examined. This study shows that children who have received radiotherapy to the thyroid area should have their thyroid function assessed regularly. Chemotherapy does not appear to be a risk factor but longer follow up of these children is necessary.

Thyroid dysfunction after radiotherapy and chemotherapy of brain tumours

We investigated thyroid function in 119 survivors of treatment for brain tumours not involving the hypothalamo-pituitary region. Cranial irradiation did not effect thyroid function but 11 of 47 children (23%) who had spinal irradiation had raised concentrations of thyroid stimulating hormone. Chemotherapy further increased the incidence of thyroid dysfunction: two of four patients who had cranial irradiation and chemotherapy and 20 of 29 patients (69%) who had spinal irradiation and chemotherapy had increased thyroid stimulating hormone concentrations. Only six patients with raised thyroid stimulating hormone concentrations had low serum thyroxine concentrations. Four children had secondary hypothyroidism. Thyroid function should be monitored in children who have received chemotherapy or radiotherapy. A rise in thyroid stimulating hormone concentrations is the most sensitive indicator of thyroid dysfunction. Children with raised thyroid stimulating hormone concentrations should be treated with thyroxine.

Thyroid dysfunction in Hodgkin's disease

Radiotherapy to the neck and/or polychemotherapy late effects on the thyroid were investigated in 51 patients (34 males and 17 females) with Hodgkin's disease. Except for two untreated, recently diagnosed patients, all were studied after 1 to 105 months (median, 27.5 months) of completion of polychemotherapy. Age ranged from 6.2 to 36.6 years (median, 13.6 years). Patients were divided according to treatment into four groups: (A) patients treated with CVPP (cyclophosphamide, vinblastine, procarbazine, and prednisone); (B) 22 patients treated with CVPP plus radiotherapy (median radiation dose to the thyroid, 3000 cGy); (C) seven patients with ACOP/BVP (adriamycin, cyclophosphamide, vincristine, prednisone, bleomycin, vinblastine, procarbazine); and (D) seven patients treated with different polychemotherapy protocols, four of whom also received radiotherapy. Elevated basal and/or post-TRH, -TSH levels were found in the following: Group A: two of 12 patients (17%); Group B: 11 of 22 (50%); Group C: four of seven (57%); and Group D: two of seven (28%). Positive antimicrosomal thyroid antibody titers (AM Ab) were found in the following: Group A: three of 12 patients (25%); Group B: six of 21 (28%), Group C: two of seven (28%); and Group D: one of six (17%). Of 46 patients studied, 12 (26%) had positive AM Ab; 37 of 46 patients were younger than 20 years of age, 11 (30%) of whom had positive AM Ab versus 4% in the normal population (P less than 0.001). Two recently diagnosed, untreated patients had either high TSH response to TRH or positive AM Ab. In conclusion, higher frequency of thyroid dysfunction was observed in patients receiving radiotherapy (50% versus 27%). Prevalence of positive AM Ab, apparently unrelated to therapy, was higher in young patients than in the normal population. A predisposition to autoimmune thyroid disease seems to be present in these patients, but it is not possible to discern how lymphoma and thyroiditis are interrelated.

Late effects of treatment of cancer in children

Over the past two decades, owing to advances in surgical techniques, chemotherapy, and radiation therapy, there has been dramatic improvement in the survival of children with malignancies. Children cured of cancer will soon form a significant fraction of our adult population. As we follow such survivors, we have become more aware of long-term side effects of treatment. Therapy should not be withheld. Instead, careful follow-up of oncology patients is needed to document the adverse late effects, to identify the etiologic agents, and to alter treatment to give the least toxic therapy without sacrificing the quality or duration of survival.

Thyroid dysfunction and neoplasia in children receiving neck irradiation for cancer

The reported relationship of radiation exposure and thyroid carcinoma stimulated this retrospective study of 298 patients treated at St. Jude Children's Hospital with radiation therapy to the neck for childhood cancer to identify patients who developed subsequent thyroid abnormalities. This series includes 153 patients with Hodgkin's disease, 95 with acute lymphocytic leukemia, 28 with lymphoepithelioma, and 22 with miscellaneous tumors. Inclusion in the study required 5 years of disease-free survival following therapy for their original tumor, which included thyroid irradiation. Follow-up has been 100%. Most patients also received chemotherapy. Seventeen patients were found to have decreased thyroid reserve with normal levels of free triiodothyroxine (T3) or free thyroxin, (T4) and an elevated level of thyroid-stimulating hormone (TSH). In nine patients hypothyroidism developed, with decreased T3 or T4 levels and an elevated level of TSH. One hyperthyroid patient was identified. Two patients had thyroiditis, and seven had thyroid neoplasms: (carcinoma in two, adenoma in two, colloid nodule in one, and undiagnosed nodules in two). This survey has demonstrated an increased incidence of thyroid dysfunction and thyroid neoplasia when compared to the general population. The importance of long-term follow-up for thyroid disease is emphasized in patients who have received thyroid irradiation. The possible role of subclinical hypothyroidism with TSH elevation coupled with radiation damage to the thyroid gland as a model for the development of neoplastic disease is discussed.

Serial thyroid function measurements in children with Hodgkin disease

Thyroid function was measured serially in 28 children with Hodgkin disease diagnosed from 1971 to 1978. The patients' ages ranged from 4 to 16 years at diagnosis, and treatment consisted of chemotherapy only (four patients), radiation alone (15), or radiation plus chemotherapy (nine). None of the four children given chemotherapy only developed thyroid hypofunction, in contrast to 21 (88%) of the 24 children given high doses of radiation (P less than 0.001). Thyroid function in three patients with compensated hypothyroidism and in one child with primary hypothyroidism reverted to normal without thyroid replacement. One child given chemotherapy only and one child given radiation only became transiently hyperthyroid. These results indicate that patients given combined modality therapy for Hodgkin disease are at high risk for thyroid abnormalities. The results of long-term follow-up of thyroid function demonstrate, however, that all such thyroid abnormalities may not necessarily be permanent.

Thyroid dysfunction after radiotherapy in children with Hodgkin's disease

Thyroid function was measured in 119 children, 16 years of age or less, after radiotherapy (XRT) for Hodgkin's disease. Thyroid abnormalities developed in 4 of 24 children (17%) who received 2600 rad or less, and in 74 of 95 children (78%) who received greater than 2600 rad to the cervical area, including the thyroid. The abnormality in all but three (one with hyperthyroidism and two with thyroid nodules) included the development of elevated levels of thyroid stimulating hormone (TSH). Age, sex, and administration of chemotherapy were not significant factors in the development of thyroid dysfunction. All children had lymphangiograms (LAG) and no time relationship was noted between thyroid dysfunction and LAG-XRT interval. The mean interval from radiotherapy to documented thyroid dysfunction was 18 months in the low-dose group and 31 months in the high-dose group, with most patients becoming abnormal within 3 to 5 years. Of interest was a spontaneous return of TSH to within normal limits in 20 children and substantial improvement in another 7. This study confirms the occurrence of dose-related occult hypothyroidism in children following external irradiation of the neck.

Growth and endocrine function after treatment for medulloblastoma

Children with medulloblastoma in Bristol are treated surgically and with craniospinal irradiation, and in some cases chemotherapy. Thirteen medium or long term survivors were investigated to determine their growth and endocrine function. Their rate of growth was considerably reduced through the first year of their illness and after spinal irradiation spinal growth was poor. Nine children developed growth hormone deficiency. They were clinically euthyroid but 7 had raised basal thyroid stimulating hormone values. Gonadal function was abnormal in all but the youngest child. The rate of survival is increasing in children with medulloblastoma but this is associated with appreciable endocrine abnormalities. Some of these problems are present shortly after treatment ends but others may develop later and long term surveillance is therefore essential.

Late effects of treatment of cancer in children

Advances in surgical techniques, in chemotherapy, and in radiation therapy have led to improved survival in children treated for cancer. Children cured of cancer will soon form a significant fraction of our adult population. As we follow such survivors, we have become more aware of long-term side effects of treatment. This is not a reason to withhold therapy. Instead, careful followup of oncology patients is needed to document the late effects, to identify the etiologic agents, and to alter treatment to give the least toxic therapy without sacrificing quality or duration of survival.

Management of Hodgkin's disease in children and adolescents

Between 1970 and 1980, 66 children or adolescents with Hodgkin's disease were treated at the Children's Hospital of Philadelphia. Since 1977, prepubertal patients and postpubertal patients with Stage IIA massive mediastinal disease or Stage IIB-IVB disease were clinically staged and treated with six courses of chemotherapy and 2000 rad involved-field irradiation. Postpubertal patients with Stage IA or IIA disease were staged pathologically and treated with 3600-4400 rad extended-field irradiation. At four years, actuarial survival in 27 patients with Stage IA or IIA disease is 100%; relapse-free survival is 86% in 16 patients treated with combined modality and 70% in 11 patients treated with irradiation. Among 39 patients with Stage IIB-IVB disease, 34 received combined modality; at five years, survival is 86% and relapse-free survival is 60%. In the majority of cases relapses in patients treated with combined modality could be better explained by chemotherapy failure rather than by insufficient radiation. Clinical staging and combined modality therapy may offer advantages for prepubertal patients and those postpubertal patients at high risk of relapse when treated with irradiation alone. The complications of laparotomy and splenectomy are avoided; however, with 2000 rad and limited-field irradiation, hypothyroidism does occur and growth disturbances may appear.

Thyroid dysfunction among long-term survivors of bone marrow transplantation

Thyroid function studies were followed serially in 27 long-term survivors (median 33 months) of bone marrow transplantation. There were 15 men and 12 women (median age 13 1/12 years, range 11/12 to 22 6/12 years). Aplastic anemia (14 patients) and acute nonlymphocytic leukemia (eight patients) were the major reasons for bone marrow transplantation. Pretransplant conditioning consisted of single-dose irradiation combined with high-dose, short-term chemotherapy in 23 patients, while four patients received a bone marrow transplantation without any radiation therapy. Thyroid dysfunction occurred in 10 of 23 (43 percent) irradiated patients; compensated hypothyroidism (elevated thyroid-stimulating hormone levels only) developed in eight subjects, and two patients had primary thyroid failure (elevated thyroid-stimulating hormone levels and low T4 index). The abnormal thyroid studies were detected a median of 13 months after bone marrow transplantation. The four subjects who underwent transplantation without radiation therapy have remained euthyroid (median follow-up two years). The only variable that appeared to correlate with the subsequent development of impaired thyroid function was the type of graft-versus-host disease prophylaxis employed; the irradiated subjects treated with methotrexate alone had a higher incidence of thyroid dysfunction compared to those treated with methotrexate combined with antithymocyte globulin and prednisone (eight of 12 versus two of 11, p less than 0.05). The high incidence and subtle nature of impaired thyroid function following single-dose irradiation for bone marrow transplantation are discussed.

Medulloblastoma in childhood: long-term results of treatment

Thirty-one children under the age of 15 years with verified medulloblastoma were treated at Addenbrookes Hospital from 1940 to 1976. In addition to surgical treatment, all received high dose irradiation to the whole neuraxis. Nine were still alive in 1979, of whom eight were examined. All these patients showed some residual problems, but five were leading active lives and had only minor physical disability. There was evidence of disturbance in growth, with shortening of the spine in relation to the limbs, in all the children. The height centile was lower than expected from parental height in four and one was severely dwarfed. Growth hormone secretion in response to exercise was, however, normal in five of six patients tested. Three children also showed failure of growth of the jaw sufficiently severe to be a cosmetic problem. Frank mental retardation was present in three children. A raised resting TSH level was found in two children, one of whom had a multinodular goiter. Of the three children with severe problems, two had been treated when under two years of age. Long-term follow-up of children who survive medulloblastoma is clearly necessary and consideration should perhaps be given to revision of current treatment regimes in very young children.