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Thyroid Factor

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TSH deficiency

Often subclinical

>30

Basal serum T3 uptake, T4, and TSH TRH stimulation test

L-Thyroxine

ACTH deficiency

Decreased stamina, lethargy, fasting hypoglycemia, dilutional hyponatremia

>30

Basal serum cortisol concentration Adrenal stimulation test (e.g., insulin, ACTH)

Hydrocortisone

Abbreviations: GH, growth hormone; TSH, thyroid-stimulating hormone; ACTH, adrenocorticotropic LH, luteinizing hormone; FSH, follicle-stimulating hormone; GnRH, gonadotropin-releasing hormone; TRH, thyrotropin-releasing hormone. aSee text discussion on use of growth hormone.

Modified from Sklar CA. Neuroendocrine complications of cancer therapy. In: Schwartz CL, Hobbis WL, Constine LS, Ruccione KS, editors. Survivors of Childhood Cancer: Assessment and Management. St. Louis: Mosby, 1994;97-110, with permission.

Abbreviations: GH, growth hormone; TSH, thyroid-stimulating hormone; ACTH, adrenocorticotropic LH, luteinizing hormone; FSH, follicle-stimulating hormone; GnRH, gonadotropin-releasing hormone; TRH, thyrotropin-releasing hormone. aSee text discussion on use of growth hormone.

Modified from Sklar CA. Neuroendocrine complications of cancer therapy. In: Schwartz CL, Hobbis WL, Constine LS, Ruccione KS, editors. Survivors of Childhood Cancer: Assessment and Management. St. Louis: Mosby, 1994;97-110, with permission.

greater adult height versus the potential mitogenic risks, which have not been established.

Luteinizing and Follicle-Stimulating Hormone Deficiency

• Estrogen and progestin therapy in females

• Androgen therapy in males.

Precocious Puberty

• Gonadotropin-releasing hormone (GnRH) analogues to suppress puberty

• GnRH plus GH for patients with coexistent GH deficiency.

Thyroid-Stimulating Hormone Deficiency

• Daily thyroxine therapy.

Adrenocorticotropin Deficiency

• Low-dose hydrocortisone therapy daily

• Stress doses of hydrocortisone during febrile illness or under anesthesia. Hyperprolactinemia

Bromocriptine or related dopamine agonists are used to reduce prolactin levels in young women with amenorrhea and infertility as a result of hyperprolactinemia.

Thyroid Deficiency

Hypothyroidism is the most common sequela following radiotherapy to the neck. Elevated thyroid-stimulating hormone (TSH) levels with normal T3, T 4, indicative of subclinical hypothyroidism, is detected in up to two thirds of patients treated with mantle field (greater than 2600 cGy) in Hodgkin disease. However, in Hodgkin disease treated with low-dose radiotherapy, the incidence of hypothyroidism is 10-28%.

Patients with subclinical hypothyroidism (i.e., elevated levels of TSH with normal thyroxin level) are treated with thyroxine. Patients with a palpable thyroid abnormality should be evaluated with ultrasound and 99mTC scanning. Ultrasound detects the location, number, and density of the nodules, and 99mTC scan detects the functional status of the nodules. Detection of a nodule warrants biopsy. Papillary thyroid carcinoma is treated with total thyroidectomy, radioactive iodine, and TSH suppression with thyroxine.

Ovarian Dysfunction

Radiation

Elevated follicle-stimulating hormone (FSH) and luteinizing hormone (LH) values occur in 95% of patients receiving craniospinal plus abdominal radiation (RT) including ovaries.

Chemotherapy

Prepubertal ovaries are more resistant than postpubertal ovaries to damage by alky-lating agents. Females treated between the ages of 3 and 17 years with 2.8-9.0 g/m2 cyclophosphamide for Burkitt lymphoma have about a 1-year delay in menarche and 94% of these have unimpaired fertility. Females treated with MOPP for Hodgkin disease during their teens retain regular menses compared with females older than 30 years of age who have a high chance of developing amenorrhea after 5-6 cycles of MOPP.

Females treated for malignant germ cell tumors who have an intact ovary and uterus retain fertility. This applies only to patients treated with chemotherapy alone for germ cell tumors. Radiotherapy to the ovaries should be avoided.

Laboratory investigations of primary or secondary amenorrhea consist of:

• Radioimaging studies: bone age, ultrasound of ovaries

• Blood tests: T3, T4, TSH, dehydroepiandrosterone sulfate (DHEAS), testosterone, prolactin, FSH, LH, estradiol.

A complex hormonal regimen (estrogen, Premarin, gonadotropins, growth hormones) may be required to manage amenorrhea.

Pregnancy and Delivery

1. The rate of birth defects is the same as in the general population.

2. The rate of perinatal mortality is higher than in the general population.

3. There is a fourfold increase for low-birth-weight infants in women who received abdominal RT for the treatment of Wilms' tumor during their childhood. These women also are at risk for premature labor and fetal malposition.

Factors responsible for high-risk pregnancy and delivery after RT to the abdomen during childhood:

• Damage to elastic properties of the uterine musculature

• Damage to the vasculature of the uterus.

Testicular Dysfunction

The incidence of impaired fertility is higher in males than in females following cancer treatment. Spermatogenesis is affected more frequently than testosterone production by Leydig cells. Thus, male patients are at significant risk of infertility; however, progression through normal puberty and maintenance of male sexual phe-notype are affected less often.

Prior to beginning therapy that could adversely impact fertility, sexually mature males should be informed and offered the option of preserving sperm prior to treatment. Table 27-11 shows the effects of fractionated testicular irradiation on sper-matogenesis and Leydig cell function.

Cyclophosphamide

Total doses of 300-350 mg/kg cyclophosphamide cause sterility in adults, and in pubertal and prepubertal boys these doses cause oligospermia and azoospermia without effecting normal progression of puberty.

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Pregnancy Guide

Pregnancy Guide

A Beginner's Guide to Healthy Pregnancy. If you suspect, or know, that you are pregnant, we ho pe you have already visited your doctor. Presuming that you have confirmed your suspicions and that this is your first child, or that you wish to take better care of yourself d uring pregnancy than you did during your other pregnancies; you have come to the right place.

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