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Biomedical subjects

B C Tan

Publications and source records attributed to B C Tan.

33 records · Page 2Linked to original sources
PubMed1982

Thyrotoxicosis and thyroid cancer.

It is generally held that thyroid cancer is uncommonly associated with thyrotoxicosis. We report here nine patients with thyroid cancer amongst 720 patients with thyrotoxicosis. Three patients presented with features of malignancy together with thyrotoxicosis (Group A), one of whom had triiodothyronine (T3)-toxicosis. The remaining six patients were diagnosed following histological examination of tissues removed during subtotal thyroidectomies for hyperthyroidism (Group B). Two patients in Group A had follicular carcinoma; the rest were papillary in type. All the patients were rendered euthyroid initially, followed by ablative therapy for two patients in Group A and four patients in Group B. All but one are alive after one to nine years (mean of 3 . 4 years). The diagnosis of thyroid carcinoma is infrequently considered in the presence of thyrotoxicosis. The association is not clinically apparent in the majority of patients. The optimum management of such occult malignancies in thyrotoxicosis remains to be defined.

Adenocarcinoma↗
PubMed1982

The development of radiation therapy in Singapore--its present status & future prospects.

X-rays were introduced into Singapore soon after their discovery but their use in therapy did not take place until 1914. Radiation therapy was widely used only after 1949 when the first deep X-ray machine was installed. Since then the number of patients given this treatment has progressively increased, keeping pace with the rising cancer incidence. In 1981, 2533 cases were referred for treatment, out of which 1889 were given radiation treatment. The value of radiotherapy in malignant disease has been established both as a palliative as well as a radical method of treatment. Through improved techniques, better therapy equipment, and greater understanding of malignant disease, results of radical radiotherapy have shown progressive improvement. Further advances can be expected with newer techniques which have been put to clinical trials recently. These are planning with CT Scan, conformation radiotherapy, radiation sensitizers and protectors, hyperfractionation, hyperthermia, intraoperative radiotherapy, heavy particle radiotherapy and isotopic immunoglobulin therapy.

Forecasting↗
PubMed1981

Radiation induced cancer: a report of 10 cases.

Ionizing radiations have been shown to be carcinogenic to man as well as experimental animals. Malignancies following therapeutic radiation occur rarely. Over the past 10 years the authors recorded 10 cases of tumours in irradiated tissues. 3 occurred in patients irradiated for nasopharyngeal carcinoma, 3 were irradiated for tuberculosis adenitis, 2 for carcinoma of the cervix, 1 for carcinoma of the breast and 1 for basal cell carcinoma. The latent period for tumour induction following the irradiation varied from 5 years to 31 years. All these cases showed no evidence of recurrence or metastases of the original primary lesion; and the histology of the second primary differed from the first. Evidence of radiation damage was seen in all cases except for 2 patients who were treated for tuberculosis adenitis. The doses received varied from 900r to about, 9000r. Among the tumours produced, there were 3 cases of squamous cell carcinoma of the oral & postcricoid region, 2 cases of papillary carcinoma of the thyroid, 2 cases of adenocarcinoma of the rectum, 1 case of adenocarcinoma of the ethmoid, 1 case of osteosarcoma of the mandible and 1 case of extraskeletal osteosarcoma. The clinical features of these cases are discussed and other cases reported in the literature are reviewed.

Adenocarcinoma↗
PubMed1981

A report of 21 cases of malignant lymphoma treated by radiotherapy.

In 1971, 21 new patients with malignant lymphoma were treated at the Therapeutic Radiology Department, Singapore General Hospital. 17 patients completed their courses of radiotherapy. Of the 17 patients given radical treatment, 5 were of Hodgkin's disease and 12 of Non-Hodgkin's disease. The 5-year survival for the group with Hodgkin's disease is 80% (4/5). The 5-year survival for the group with Non-Hodgkin's disease in 41.6% (5/12).

Adolescent↗
PubMed1981

Thyroid scanning & the significance of the solitary cold nodule.

Since thyroid scanning was introduced in Singapore in 1968 there has been progressive increase in the demand for these scans. 215 patients comprising 153 females and 62 males were scanned in 1976 using 131I. The solitary nodule was the commonest condition referred for scans (60%) and next was the multinodular goitre 919%). Other indications for scan included postthyroidectomy cases, aberrant thyroids, retrosternal goitres, thyrotoxicosis and metastases from thyroid carcinoma. 73 cases of solitary cold nodules were discovered and 43 of these were operated on. 7 of these were found to be malignant, giving an incidence of 16%. The incidence of malignancy in the cold nodule varies in the reported literature. By itself the 131I scan cannot diagnose malignancy but is it a useful supplementary test in addition to the clinical and other investigations.

Adult↗
PubMed1980

Radiotherapy in treatment of nasopharyngeal carcinoma.

Nasopharyngeal Carcinoma is one of the most prevalent malignancies treated by radiotherapy in Singapore. Planning of the radiation fields for this condition is difficult because of the proximity of anatomical structures that are vulnerable to irradiation, such as the eyes, brain stem and cervical cord. However, the treatment results have shown progressive improvement. The treatment technique currently used utilized cobalt as well as caesium teletherapy units. Of the 104 cases treated in 1970 using this technique, the overall absolute 5 years survival rate with no evidence of disease is 30.8%. For Stage I cases, the rate is 62.5%. The prognosis is significantly better for the female than the male and is also related to age.

Adolescent↗
PubMed1978

Distant metastases in nasopharyngeal carcinoma.

Three hundred and fifty-two consecutive cases of nasopharyngeal carcinoma were analysed to determine the pattern of distant metastases. Diagnosis of distant metastases was made wholly on clinical signs and radiography. Ninety-nine patients developed distant metastases, an incidence rate of 28.1%. There did not appear to be any difference in "risk" by age or sex. The predilection of this cancer to develop skeletal metastases is further confirmed. Pulmonary and hepatic involvement were the next commonest. Both extent of primary tumour (T) and cervical lymph node status (N) exerted a significant influence on the probability of metastases developing. Thus significant differences in metastatic rate were observed between T0/T1, T2 and T3/T4 and N0, N1, N2 and N3 groups. 65.6% of metastatic cases had control of local disease (nasopharynx and cervical lymph nodes). When metastases are diagnosed the prognosis is gloomy with a median survival under four months and a fatality rate of 91% within a year of first metastasis.

Adolescent↗