Medullary cancer of the thyroid

Although rare (10% of thyroid cancers), medullary thyroid cancer is remarkable by the presence of a specific biological marker; elevation of blood calcitonin. It allows its preoperative diagnosis and this extensive surgery which is the only efficient treatment. The possibility of hereditary form (30%) must always be kept in mind; they can now be detected by genetic screening since specific mutations on Ret gene have been recently discovered. Follow up and early treatment of at risk subjects in a family is therefore possible and permits definitive surgical cure.     

131I therapy for pediatric thyroid cancer

Azido-3'-deoxy-thymidine (AZT) is a drug extensively used in the treatment of AIDS. AZT was incubated in vitro either with the pituitary-hypothalamus complex (PHc) or the intact pituitary (PI) of male rats. The PHc is comprised of the hypothalamus and the attached pituitary gland. After a preincubation period, the PHc or PI was incubated for 1 or 2 h with Krebs-Ringer bicarbonate buffer or either of two different concentrations of AZT (1 and 10 microM). In the control incubations, the PHc released less prolactin (PRL) and more follicle-stimulating hormone (FSH) and luteinizing hormone (LH) than the PI, indicating that hypothalamic control of the pituitary was exerted in vitro, presumably by diffusion of releasing and inhibiting hormones from the neurohypophysis to the anterior lobe of the hypophysis. Both concentrations of AZT evoked a significant increase in release of PRL and a decreased release of LH and FSH from the PHc. In the case of LH, the higher concentration of AZT partially suppressed LH release within 1 h. The other effects were not dose-related and were observed after incubating the tissue with AZT for 2 h. However, incubation of the PI with AZT failed to alter anterior pituitary hormone release, illustrating that the site of action of AZT is in the hypothalamus. We hypothesize that AZT blocks DNA synthesis resulting in suppression of synthesis and consequent release of hypothalamic hormones that control release of pituitary hormones in vitro. The results raise the possibility that AZT may alter hypothalamic-pituitary function in vivo.     

Follicular thyroid cancer

Follicular thyroid cancer is the second most common thyroid malignancy after PTC. There are marked geographical variations in the relative proportions of FTC and PTC, most likely related to dietary iodine content. In iodine-deficient areas, the relative rate of FTC tends to be increased. Other risk factors for FTC include age over 50 years and female sex. Genetic factors may also have a role in determining disease susceptibility but remain ill-defined. Histologically, FTC is characterized by follicle formation and the absence of any papillary elements in the tumor. Differential diagnosis from a benign adenoma can be difficult. The degree of vascular invasiveness seems to correlate with tumor aggressiveness, and two histologic subtypes, oxyphilic FTC and insular FTC, may be associated with increased morbidity and mortality. Primary treatment for FTC is complete surgical tumor removal. Extensive bilateral surgery beyond this goal may not confer additional benefit but can facilitate adjuvant treatment and follow-up. Postoperative levothyroxine treatment is almost universally used, and patients deemed at high risk of recurrence may benefit from radioiodine remnant ablation. Treatment of metastatic disease involves operation, radioiodine, and, in selected cases, external beam radiation and chemotherapy. Prognosis for patients with metastatic disease is guarded, but most other patients have good outcomes comparable to that in PTC. For nonoxyphilic FTC, high-risk features other than initial metastases include advanced age, locally extensive disease, and the presence of marked angioinvasion. In oxyphilic FTC, DNA aneuploidy is also important. Follow-up should be most intense during the first 5 years after primary treatment and needs to be tailored to the patient's risk of disease progression. For patients at low risk of recurrence (young, small lesions, minimally invasive tumor), serum thyroglobulin measurements may largely suffice, whereas higher risk patients with elevated serum thyroglobulin levels and patients with significant titers of interfering anti-thyroglobulin autoantibodies may also need to undergo periodic diagnostic radioiodine scanning.     

Surgery of differentiated cancer of the thyroid

A retrospective study on patients with differentiated thyroid carcinoma operated on at the 3rd Department of General Surgery of the University "La Sapienza" of Rome from 1970 to 1996 was performed. In 709 patients total thyroidectomy was performed as the minimal procedure acceptable, while 19 patients had subtotal thyroidectomy out of necessity. A functional ipsilateral or bilateral lymphnectomy of the neck was performed in 256 cases. This wider operation is indicated in the presence of metastatic lymph nodes and on principle in patients older than forty-five years in which at least another risk factor is present. Long term follow-up (12 years) was assured in 302 patients and the survival rate was 92% independently from the histotype (papillary or follicular). The survival rate of a group of 120 patients (80 with papillary and 40 with follicular carcinoma) was analyzed in relation to the risk factors. This group analysis demonstrated a very low mortality rate in patients with low risk index and an increased rate in patients with a high risk index.     

Low-risk differentiated thyroid cancer: the need for selective treatment

By means of an electron microscopic study of the intestine in young rats infected with Cryptosporidium parvum we observed a mass migration of immunocompetent cells of the host (eosinophils, neutrophils and macrophages) into the lumen of intestine. Some lymphocytes were also observed. Immunocompetent cells (except lymphocytes) included inside phagosomes with different endogenic states of C. parvum. Macrophages with typical extracytoplasmic parasitophorous vacuoles formed by C. parvum were also observed in the intestine lumen. Almost all stages of C. parvum could be observed on a surface of such macrophages. However, we did not find in lamina propria of intestine villi any macrophages with parasites. The place of macrophages infection is unknown. We suggest that surviving of C. parvum in macrophages is principally possible.     

Management of the neck in thyroid cancer

The incidence of nodal metastasis in differentiated thyroid cancer ranges between 40% to 75%. Elective neck dissection is generally not advised in patients with differentiated thyroid cancer; however, if clinically apparent nodal disease is noted in the tracheoesophageal groove during surgery, central compartment clearance is advised. If clinically apparent nodal disease is present in the lateral compartment of the neck, modified neck dissection preserving the sternomastoid, accessory nerve, and jugular vein is advised. The "berry picking procedure" is generally not recommended because of the higher incidence of regional recurrence. Due consideration should be given for parathyroidal transplantation if the blood supply to the parathyroids is damaged during central compartment clearance. The incidence of lymph node metastasis is highest in young patients, however, lymph node metastasis has no bearing on long-term survival. There seems to be a higher incidence of regional recurrence in elderly individuals. If patients present with bulky nodal disease, consideration may be given for postoperative radioactive iodine dosimetry and ablation if necessary. Differentiated thyroid cancer represents a unique disease in the human body, where lymph node metastasis has no prognostic implication. Aggressive surgical clearance is advised in patients with medullary thyroid cancer in the central compartment and the jugular chain lymph nodes.     

Radiotherapy in the management of thyroid cancer

Surgery is the definitive and potentially curative treatment for the slow growing well-differentiated papillary and follicular carcinomas. Total (or near-total) thyroidectomy is required, together with excision of adjacent lymph nodes when involved, or a modified block dissection if there is extensive lymphatic involvement. Ablation of residual normal thyroid with radioactive iodine usually follows as this will permit subsequent whole-body I-131 scanning to exclude the presence of residual or metastatic disease. Normally such patients have an excellent prognosis and can be followed simply with serum thyroglobulin estimations. Occasionally therapeutic radioactive iodine is necessary to eradicate metastatic disease. The anaplastic carcinomas grow and metastasise with explosive rapidity. They are typically inoperable at presentation and have no ability to concentrate iodine. Prognosis is appalling with external beam radiotherapy providing only palliation. Medullary carcinoma is different again as it arises from the parafollicular or C-cells. Total thyroidectomy must be undertaken as these tumours may be multifocal; a central compartment neck resection is ideally undertaken at the same time, together with a formal block dissection if lymph node disease is found to be present. External beam radiotherapy is often required. These tumours can be inherited and produce the tumour marker calcitonin. The rarest group of thyroid cancer is the lymphomas. Like the anaplastic carcinomas, they grow very rapidly but, unlike the former, are radio-responsive. The additional use of chemotherapy is necessary when they are of advanced stage or demonstrate poor prognostic factors.     

Thyroiditis and thyroid cancer

We studied a patient with microcephaly, short stature, type B brachydactyly, nail dysplasia, skeletal anomalies, and mental retardation. The mother of the propositus has brachydactyly of thumbs and a similar physiognomy without mental retardation. This appears to be another observation of the Tonoki syndrome, a distinct autosomal dominant or X-linked clinical entity.     

Breast cancer imaging--what are the optimal modalities?

Different soluble dietary fibers known to alter cholesterol metabolism were fed to golden Syrian hamsters, and their specific impact on lipoproteins, biliary bile acid profile, and fecal sterol excretion was evaluated. Semipurified diets containing 20% fat; 0.12% cholesterol; and 8% of psyllium (PSY); high (hePE) and low (lePE) esterified pectin; or high (hvGG) and low (lvGG) viscous guar gum were fed for 5 wk. Compared to control, PSY caused a significant reduction in plasma cholesterol (2.9 +/- 0.5 vs. 5.5 +/- 0.5 mmol/L), whereas hePE, lePE, hvGG, or lvGG had no apparent effect on plasma lipids. Hepatic total and esterified cholesterol were substantially decreased with PSY, pectin and guar gum, whereby PSY produced the most pronounced effect. Distinctive changes existed in the bile acid profile related to the different fibers. In contrast to pectin and guar gum, PSY caused a significant increase in the cholate:chenodeoxycholate and the glycine:taurine conjugation ratio. Pectin and guar gum did not alter daily fecal neutral sterol excretion while PSY caused a 90% increase due to a higher fecal output. Daily fecal bile acid excretion and total fecal bile acid concentration were significantly increased by PSY, whereas hePE, lePE, hvGG, and lvGG revealed no or only minor effects. Taken together, the disparate hypocholesterolemic effects of PSY, pectin, and guar gum on cholesterol and bile acid metabolism in the hamster are possibly related to different physicochemical properties, e.g., viscosity and susceptibility to fermentation, affecting the fiber-mediated action in the intestine.     

Intraluminal involvement of thyroid cancer in the trachea

Conjoined twins are a rare occurrence. We present two cases of conjoined twins diagnosed by ultrasound examination at 8 and 13 weeks' gestation, respectively. These cases demonstrated the possibility of making an accurate diagnosis of conjoined twins and delineating the extent of organ sharing in the first trimester.     

Acute leukemias after treatment with radioiodine for thyroid cancer

Leukemia is an uncommon complication of exposure to radioiodine (131I), used in treatment of thyroid cancer, because low doses are now used. We report two cases of acute myelogenous leukemia developed after the treatment of a thyroid carcinoma with a small dose of 131I.     

Breast cancer. Relationship to thyroid supplements for hypothyroidism

This study was undertaken to determine the relationship between thyroid supplements and breast cancer. The incidence of breast cancer among the patients who received thyroid supplements was 12.13%, while in the control group it was 6.2%. The incidence rate of breast cancer was 10%, 9.42%, and 19.48% among patients who received thyroid supplements for one to five, 5 to 15, and for more than 15 years, respectively. The incidence of breast cancer among nulliparous women who received thyroid supplements was 33%, while in the nulliparous women without thyroid supplements the incidence was only 9.25%. Even in a specific age group, the incidence rate of breast cancer was higher among patients receiving thyroid supplements, when compared to the control patients in the same age group.     

Radio-guided surgery for lymph node recurrences of differentiated thyroid cancer

The objectives of this study were to assess the reliability of radio-iodine (131I) and a gamma probe for radio-guided surgery (RGS) to detect and then radically dissect lymph node recurrences (LNRs) in 10 patients with differentiated thyroid cancer (DTC). The major inclusion criterion was the presence of an iodine-positive LNR after previous total thyroidectomy and at least two ineffective 131I treatments. The protocol was designed as follows. Day 0: all patients were hospitalized and received 3.7 GBq of 131I in the hypothyroid condition. Day 3: presurgery whole-body scan with a therapeutic dose (TxWBS). Day 5: neck surgery using a gamma probe (Navigator GPS, AutoSuture, Italy), recording the absolute counts and the lesion/background (L/B) counts ratio. Day 7: post-surgery TxWBS performed using the remaining radioactivity. The presurgery TxWBS was positive in all patients, and the post-surgery TxWBS showed a negative pattern in 7 of 10 patients, suggesting the efficacy of the surgical procedure in most of the patients. After RGS the mean decrease in the absolute counts and the L/B counts ratio were 77.6% (52.7% minimum, 94.6% maximum) and 77.4% (52.3% minimum, 94.8% maximum), respectively. After operation the surgeon judged the procedure to be decisive in two patients, favorable in six, and irrelevant in two. The final histologic examination showed the presence of 78 lymph node metastases (mean of 8 per patient). There were 33 neoplastic lesions found by both TxWBS and gamma probe evaluations; 41 were shown only by gamma probe, and 4 were negative by both TxWBS and gamma probe evaluations. This protocol permitted us to look for neoplastic foci with high sensitivity and specificity, and we were able to remove lymph node metastases resistant to radioiodine therapy at a single session. The protocol also allowed detection of some additional tumoral foci in sclerotic areas or behind vascular structures that are difficult to identify and were not seen at the presurgery TxWBS evaluation. However, because of the possible false-negative results, complete excision must be undertaken in high risk patients with a local recurrence to eradicate the largest number of lymph nodes, independent of the counts measured by the gamma probe.     

Coexistent thyroid cancer and pregnancy

OBJECTIVE: A study was performed to determine the appropriate time for the initiation of therapy for thyroid carcinoma first diagnosed during pregnancy. DATA SOURCES: Material on thyroid cancer cases was obtained from the New Mexico Tumor Registry, Albuquerque, a computerized population-based registry for the state of New Mexico, and the Indian reservation facilities in New Mexico and Arizona (a Surveillance, Epidemiology, and End Results Registry funded by the National Cancer Institute, Bethesda, Md) for the period 1970 to 1991. STUDY SELECTION: All cases of thyroid cancer, except medullary and anaplastic, in patients aged 18 to 46 years were evaluated. Subgroups were established for (1) all women who were noted to be pregnant at the time of their initial diagnosis and (2) all women with thyroid cancer in the 18- to 46-year-old age group. DATA EXTRACTION: The information was extracted by a certified tumor registrar for age, sex, thyroid cancer, specific type of thyroid cancer, period, race, year of diagnosis, accession date, last date seen, tumor status, treatment, and patient status. DATA SYNTHESIS: There have been no deaths in the pregnant group with a follow-up ranging from 0.5 to 20 years. There was no statistically significant difference in observed survival rates between the pregnant group and 465 women, aged 18 to 46 years, with comparable thyroid cancers or in the death rates of women aged 18 to 67 years in the general population. CONCLUSIONS: Surgical treatment for patients with well-differentiated thyroid cancer diagnosed during pregnancy can be delayed until after parturition.     

The non-surgical treatment of thyroid cancer

The non-surgical treatment of thyroid cancer is outlined. The success of chemotherapy and of radiotherapy is dependent on the number of tumour cells present, and immediate postoperative treatment is therefore often valuable. The role of X-ray therapy, radio-iodine, hormones and chemotherapy is discussed for the different histological types.