Biomedical subjects

D Choy

Publications and source records attributed to D Choy.

At least 55 records · Page 3Linked to original sources

PubMed1992

Nasopharyngeal carcinoma in situ in nasopharyngeal carcinoma.

AIMS: To assess the presence of carcinoma in situ (CIS) in patients with nasopharyngeal carcinoma (NPC) and to see if the number of biopsy sites facilitates detection of CIS. METHODS: Formalin fixed, paraffin wax embedded biopsy specimens (n = 285) from 187 patients with NPC in 1987 were studied for the presence of CIS as well as for the histological assessment of the subtype of CIS. RESULTS: Fifteen (8.0%) patients had CIS, representing 8.3% of all new patients with NPC and 11.6% of patients with persistent disease or relapse. CIS was undifferentiated or poorly differentiated, no cases of well differentiated squamous cell CIS were identified. There was no significant difference in the incidence of CIS when multiple endoscopic biopsy specimens were taken rather than single forceps biopsy specimens. CONCLUSIONS: CIS can only be identified in a few patients with NPC largely because of late presentation with advanced disease at the time of diagnosis and the focal nature of the dysplastic process. The presence of dysplasia in relapses of NPC suggests that these tumours may be second growths rather than regrowths of a primary tumour.

Carcinoma in Situ↗

PubMed1991

Cranial nerve involvement and base of the skull erosion in nasopharyngeal carcinoma.

In a prospective study of 262 consecutive patients with nasopharyngeal carcinoma (NPC), using computed tomography (CT) as their baseline evaluation, erosion of the base of the skull and intracranial extension into the middle cranial fossa were found in 31.3% and 12.2% of patients, respectively. Thirty-four of these patients had cranial nerve involvement at presentation; 30 of them had involvement of one or more of the third to sixth cranial nerves. Most cases of intracranial extension of tumor were accompanied by erosion of the base of the skull, but the reverse was not true. All patients with cranial nerve palsy involving the third to sixth cranial nerves had associated erosion of the ipsilateral base of the skull. The CT evaluation of patients with cranial nerve involvement who are believed to harbor NPC should include thin cuts of the base of the skull for detection of subtle bone erosion. This may be the only clue to the presence of a small NPC. The prognostic significance of cranial nerve involvement, base of the skull erosion, and intracranial extension of the tumor on the survival of the group of 84 patients who had T4 tumors was evaluated with regression analysis using the Cox model. Only cranial nerve involvement was found to be a significant factor influencing survival.

Cranial Nerve Neoplasms↗

PubMed1991

The efficacy of fiberoptic endoscopic examination and biopsy in the detection of early nasopharyngeal carcinoma.

Fiberoptic endoscopic examination and biopsy of the nasopharynx was done in 130 patients as a prospective study. They all had elevated titers of antibodies against the viral capsid antigen of Epstein-Barr virus but no symptoms or signs of nasopharyngeal carcinoma. Each underwent a biopsy from six fixed sites in the nasopharynx. Of the 780 biopsy specimens taken from seven patients, 11 showed the presence of nasopharyngeal carcinoma. Techniques to improve the yields of such biopsies with fiberoptic endoscopy are discussed. The presence of tumor was unrelated to the macroscopic endoscopic findings. The highest incidence of subclinical tumor is in the pharyngeal recess.

Adult↗

PubMed1991

Chemotherapy for early-stage gastrointestinal lymphoma.

A total of 176 patients with gastrointestinal lymphomas were reviewed. According to a modified staging classification, 51 of them had stage I/II disease and the remaining 125 had stage III/IV disease. In most cases (68%), the histology was intermediate-grade according to the NIH working formulation, and the B-cell immunophenotype was involved in 89% of the 45 cases with a known immunophenotype. The primary site was the stomach in 56% of cases and the bowel in 44%. A significantly higher proportion (P = 0.001) of those with bowel lymphomas had stage III/IV disease (88% vs 57%). The primary gastrointestinal lesion was resected in 122 patients, including all 51 cases of stage I/II disease. In all, 8 stage I/II patients were given radiotherapy alone following surgery and the other 43 underwent chemotherapy; of the latter, 19 received additional radiotherapy following chemotherapy. Chemotherapy was also given to 112 stage III/IV patients, 42 of whom underwent additional radiotherapy. Factors associated with a poorer prognosis included advanced disease, bowel lymphoma and advanced age. Although the complete response (CR) rate according to disease stage was similar, stage I/II patients receiving chemotherapy showed a significantly lower relapse rate, better disease-free survival following CR and improved survival as compared with those receiving radiotherapy alone. However, additional radiotherapy following chemotherapy did not further improve the clinical outcome.

Adolescent↗

PubMed1991

Detection and prevalence of the "f" variant of Epstein-Barr virus in southern China.

The "f" variant of Epstein-Barr virus (EBV) may have an association with the development and/or maintenance of nasopharyngeal carcinoma (NPC) among Southern Chinese. This variant is detected at a higher frequency among individuals with elevated IgA antibody levels against EBV capsid antigen who have no detectable NPC and in NPC patients as compared to healthy individuals or patients who are in remission for NPC for over 3 years. Conversion or replacement of the f variant by the prototype BamHI F virus usually occurs by 3 to 4 years after radiotherapy. By 5 years post-therapy the majority of people in remission for NPC no longer harbor the f variant in their oropharynx. Eradication of this f variant, however, does not appear essential for maintenance of a disease-free state since several patients harboring this variant were in remission for NPC for up to 21 years. The virus strain detected directly in the nasopharynx is not always identical to that seen in the oropharynx. Dual infection was commonly observed in throat washings of NPC patients although the biopsy from tumors harbored unique strains of EBV.

Base Sequence↗

PubMed1991

Chemotherapy versus radiotherapy for stage I-II intermediate grade non-Hodgkin's lymphomas.

The clinical outcome of 149 patients with Stage I-II intermediate grade non-Hodgkin's lymphomas was analysed. There were 77 (52%) males and 72 (48%) females. Their median age was 58 years. Eighty patients (54%) had Stage I disease and 69 (46%) Stage II. Twenty-nine (20%) of them received radiotherapy only, 75 (50%) doxorubicin-containing chemotherapeutic regimens and 45 (30%) other less intensive chemotherapy. Sixty-two patients had additional radiotherapy following chemotherapy. Patients receiving other less intensive chemotherapy were significantly older (P = 0.0001) and those receiving radiotherapy alone had a significantly higher proportion of Stage I disease (P = 0.007). Patients receiving less intensive chemotherapy had a significantly low complete response (CR) rate. Patients receiving radiotherapy alone had a significantly high relapse rate and low disease-free survival following CR. However, there was no significant difference in overall survival regardless of the mode of therapy. This lack of survival advantage might be related to the effective salvage chemotherapy in some of the radiotherapy failures and the occasional chemotherapy-related mortality. Additional radiotherapy following chemotherapy did not appear to give further benefit.

Adolescent↗

PubMed1991

Role of bone scanning in detection of subclinical bone metastasis in nasopharyngeal carcinoma.

One hundred thirty-two new patients with nasopharyngeal carcinoma and no evidence of distant metastases were evaluated for bone metastases with bone scanning. Forty-four patients had abnormal hypercaptation. These abnormal findings were considered related to benign diseases in 39 patients after correlating clinical examinations and skeletal radiographs. The remaining five patients had positive bone scanning which was suggestive of bone metastasis. There were 13 patients who developed symptomatic bone metastases over a follow-up period of 0.2-41 months. In three of these, the bone metastases corresponded to the sites of abnormal hypercaptation in the initial positive bone scanning. In view of the low sensitivity and specificity of bone scanning in this setting, routine bone scanning for staging nasopharyngeal carcinoma is not recommended. But in the research setting, baseline scanning is useful to make subsequent scanning more valuable, and it reduces false-positive results.

Bone Neoplasms↗

PubMed1991

Nasopharyngeal carcinoma: treatment of neck node recurrence by radiotherapy.

The records of 91 nasopharyngeal carcinoma patients who were treated with external radiotherapy for recurrent neck node disease were reviewed. All patients had received prior radiotherapy for cervical nodal disease or prophylactic neck irradiation. The node size (product of the greatest perpendicular diameters) at the time of treatment for nodal relapse ranged from 1cm2 to 35cm2 (median 2.25cm2). The radiation dose ranged from 823 RETs to 1949 RETs (median 1520 RETs). The recurrent node size and radiation dose were found significant prognostic factors for local control. The local tumour control for nodes 4cm2 or smaller was 51% at five years, for nodes greater than 4cm2 was 16% at 18 months (p = 0.01). The overall 5 year survival was 19.7%. Radiation dose greater than 1600 RETs was significantly associated with better survival for patients with recurrent nodes measured 4cm2 or smaller, but higher radiation dose did not improve the survival of patients with recurrent nodes greater than 4cm2. Because of the dilemma of suboptimal control resulting from inadequate radiation dose when compared with surgical treatment, and possible radiation complication from higher dose, surgery should be the treatment of choice for neck node recurrence after primary radiotherapy for nasopharyngeal carcinoma.

Carcinoma↗

PubMed1991

Combined chemotherapy and radiotherapy for lymphomas of Waldeyer's ring.

The management of 47 patients with stage I and II Waldeyer's ring lymphomas was reviewed. Twenty-one of them received radiotherapy only, and the other 26 received combined chemotherapy and radiotherapy. Patients with primary disease in the nasopharynx, high-grade histology or advanced age were associated with poorer survival. Although the complete response rates were similar, the patients receiving combined chemotherapy and radiotherapy had significantly fewer relapses and a better disease-free survival. However, their survivals were similar. The lack of improvement in the overall survival might be due to the effectiveness of salvage chemotherapy in treating some of the radiotherapy failures and the occasional chemotherapy-related mortality.

Adult↗

PubMed1991

Nasopharyngeal carcinoma: role of marrow biopsy at diagnosis.

Twenty-seven new patients with advanced nasopharyngeal carcinoma were evaluated by marrow biopsy at diagnosis. The marrow trephines and blood clots were evaluated by morphology and immunohistochemical studies for cytokeratin and found negative in all cases. The median follow-up of this group of 27 patients was 22 months, and 7 of them had relapsed in the skeletal system. We conclude, in view of its poor sensitivity, that routine use of marrow biopsy for the staging of nasopharyngeal carcinoma is not recommended.

Biopsy↗

PubMed1991

Choroid metastasis from nasopharyngeal carcinoma.

A case of choroid metastasis from nasopharyngeal carcinoma (NPC) is presented. If loss of vision in patients with NPC is not associated with proptosis or weakness of the extra-ocular eye muscles after radiotherapy, investigations to exclude choroid metastasis should be carried out. Choroid metastasis, in contrast to the more common causes of loss of vision in such a situation, radiation retinopathy and optic neuropathy, is amenable to treatment to prevent irreversible blindness and enucleation for intractable glaucoma pain.

Adult↗

PubMed1991

Breast metastasis from nasopharyngeal carcinoma.

The first two cases of breast metastases from anaplastic carcinoma of the nasopharynx are presented. In both cases the breast metastasis was solitary, but there was no delay in confirming their metastatic nature since both lesions manifested after the documentation of disseminated disease. The difference in histology, since 99% of our nasopharyngeal carcinoma patients have anaplastic carcinoma of poorly differentiated carcinoma subtype, makes it easy to differentiate them from primary breast cancer by cytology or histology.

Adult↗

PubMed1990

Nasal lymphoma. A retrospective analysis of 60 cases.

Sixty cases of nasal lymphomas were reviewed. There were 42 men and 18 women. The median age was 49 years. The histologic types were low grade in four cases, intermediate grade in 33, high grade in seven, and unclassifiable in 16. Thirteen cases had features of polymorphic reticulosis. The immunophenotype was available in 18 cases and a majority of 67% of them were T-cell. Forty-one of them (68%) had clinically localized (Stage I and II) disease which often spread locally to neighboring tissues and they presented predominantly with nasal symptoms. Nasal lymphoma appeared to carry a poor prognosis. Although our patients with clinically localized disease had significantly better prognosis than those with advanced disease, the 5-year survival of Stage I and II patients was only 55%. Chemotherapy did not appear to be more effective than radiotherapy alone in preventing relapses but the patient number was too small to allow a firm conclusion to be made. Patients with advanced disease had even poorer prognosis with a 5-year survival of only 17%. Innovative therapy has to be developed for these patients.

Adolescent↗

PubMed1990

Nasopharyngeal carcinoma in young patients.

Seventy-one Chinese patients ranging in age from 9 to 20 years who had histologically verified nasopharyngeal carcinoma were reviewed. The presenting symptoms were often multiple, comprising nasal (77.5%) and ear (73.2%) symptoms, headache (60.6%), and neck swelling (63.4%). The median duration of these symptoms was 2 to 3 months, and 90.1% of the patients were Stage III or IV at presentation. All patients were treated primarily by radiotherapy. Forty-four of the 71 patients died of the disease; the median time to death was 18 months. Nasopharyngeal carcinoma in the young patients in Hong Kong does not appear to be different from that of the adult population in Hong Kong in terms of histology, pattern of relapse, and survival. Compared with the adult patients, however, the current series of young patients presented with more advanced-staged disease. The incidence of nasopharyngeal carcinoma in Hong Kong was compared with Chinese populations in other parts of the world, and the general pattern was comparable. The only postadolescent peak was found in the Chinese population of San Francisco.

Adolescent↗

PubMed1990

Detection of subclinical nasopharyngeal carcinoma by fibreoptic endoscopy and multiple biopsy.

Of 6054 people who had high titres of antibodies against the viral capsid antigen of Epstein-Barr virus but no symptoms or signs of nasopharyngeal carcinoma as assessed by conventional methods, 130 were randomly recruited and examined by fibreoptic endoscopy and biopsy of several sites of the nasopharynx. 7 cases of nasopharyngeal carcinoma were detected. The tumours were largely confined to the pharyngeal recess, which suggests that it is the area of the nasopharynx most prone to the development of the tumour. Tumour was found in both recesses in 1 subject, who also had evidence of transition from severe epithelial dysplasia to carcinoma in a sample from the left roof, which suggests that the disease was multifocal in origin. This study showed that endoscopy and biopsy of several sites of the nasopharynx are more effective than the conventional approach in the detection of subclinical nasopharyngeal carcinoma among seropositive individuals at high risk of the disorder.

Adult↗

PubMed1990

Nasopharyngeal carcinoma. Pattern of tumor regression after radiotherapy.

The primary tumor regression pattern of 50 patients with nasopharyngeal carcinoma was reported. The tumor regression was monitored either by indirect nasopharyngeal mirror examination and biopsy or fiberoptic endoscope and biopsy. Fiberoptic endoscope and biopsy was found to be more accurate in noting residual tumor. It is recommended that booster radiation dose to the residual primary tumors be withheld unless positive biopsy samples persist at 10 or more weeks after radiotherapy.

Biopsy↗

PubMed1990

Split-palate approach for gold grain implantation in nasopharyngeal carcinoma.

Although nasopharyngeal carcinoma is radiosensitive, local failure after external radiotherapy is not uncommon and management of persistent or recurrent disease is a therapeutic challenge. The present review reports the use of brachy-therapy in the form of gold grain (198Au) implants in the treatment of 23 patients with recurrent or persistent primary nasopharyngeal carcinoma. The split-palate approach was employed in the insertion of the gold grains. This approach allows adequate exposure of the nasopharynx and accurate positioning of the implants. Implantation was successful in 21 patients, and local tumor control was achieved in 17 patients (81%) after a median follow-up of 23 months. Palatal fistula developed in 6 patients (26%): 5 healed with conservative management, and 1 had no functional disturbance. There was no operative mortality, and morbidity of the operation was minimal.

Brachytherapy↗

PubMed1990

Efficacy of fine-needle aspiration and sampling of lymph nodes in 1,484 Chinese patients.

A retrospective study of 1,855 fine-needle aspirations of the lymph node (LN) from 1,484 Chinese patients in Queen Mary Hospital over a period of 11.5 yr (January 1, 1976, to June 30, 1987) was reviewed and analyzed. Positive cytologic results diagnosed malignancies in 49.3%. Sensitivity and specificity of cytology reached 95% and 96.5%, respectively. The order of frequency of the metastatic tumors according to primary sites was analyzed. The most common metastatic carcinomas in various groups of LNs were nasopharyngeal carcinoma in the cervical LN, breast carcinoma in the axillary LN, and cervical carcinoma in both the groin and pelvic LNs. Tuberculosis (TB) is an important differential diagnosis; FNAC showed a sensitivity of 76.9% in the detection of TB lymphadenopathy.

Adolescent↗