Biomedical subjects

P T Ang

Publications and source records attributed to P T Ang.

At least 37 records · Page 2Linked to original sources

PubMed1996

Effect of polysaccharide-peptide (PSP), an extract from yun-zhi, on chemotherapy-induced cytopenias.

Polysaccharide-peptide (PSP) is a protein-bound complex carbohydrate derived from mycelia extract of Chinese fungus coriolus versicolor, or better known as Yun-Zhi. It has been shown to inhibit growth of cultured tumour cells, and it prevents cytotoxic-induced bone marrow suppression. An animal study was conducted with 24 Wistar rats to verify the myeloprotective effect of PSP. The rats were divided into two equal groups: group A (given cyclophosphamide [CTX]) and group B (given PSP and CTX). The body weights were similar in both groups of rats. In phase 1, all rats were given intravenous CTX 75 mg/kg. In addition, B rats received PSP 20 mg/day orally from 7 days before CTX to 14 days after CTX. Phase 2 was carried out two weeks after full recovery from CTX-induced cytopenia. The CTX was decreased to 60 mg/kg, and the group B rats received an increased dose of PSP 1.2 g/day for the same 21 days. In both phases, the CTX was well tolerated. Nadir white blood cell count was reached on day 4 and all counts recovered by day 10. There was no difference in absolute neutrophil, lymphocyte and platelet counts between groups A and B. We concluded that oral PSP did not prevent CTX-induced cytopenia in rats.

Adjuvants, Immunologic↗

PubMed1996

Primary mediastinal germ cell tumour.

Testicular germ cell tumour is said to be a model for curable neoplasm. However, the prognosis of primary extragonadal germ cell tumour does not appear to be as promising. Though similar in histology, the biology of primary extragonadal germ cell tumour is different as exemplified by the patients in this review. Eight patients with primary mediastinal germ cell tumours were treated with intensive cisplatin-based chemotherapy. All, except one, had non-seminomatous components. The poor prognosis of mediastinal germ cell tumour is due to a combination of poor treatment results with the cisplatin-based regimen and the development of non-germ cell and haematological malignancies.

Adolescent↗

PubMed1996

A report of infusional 5-fluorouracil and subcutaneous alpha-2A-interferon in the treatment of advanced colorectal carcinoma.

Systemic chemotherapy with 5-fluorouracil (5-FU) has been the mainstay of treatment for patients with metastatic colorectal carcinoma. Administering the drug in a continuous low-dose schedule has produced better result than bolus therapy. Resistance to short-pulse treatment can also be overcome by prolonged exposure. Recent studies suggest the feasibility of biomodulation of 5-FU with recombinant interferon (rIFN alpha-2a) with improved response. Sixteen patients were treated with continuous 5-FU 250 mg/m2 and rIFN alpha-2a 10 x 10(6) u thrice weekly for a maximum of 24 weeks. Five of them had received bolus 5-FU previously. Nine (82%) of the chemonaive group and 1 (20%) previously treated patient had partial response. The median duration of response was 7 months. Grade II to III mucositis were seen in 44% of the patients and 2 patients developed neurological complications. Although the overall response appeared encouraging, the incidence of toxicity was high. In the absence of further phase III studies, rIFN alpha-2a biomodulation of 5-FU cannot be regarded as standard treatment for patients with metastatic colorectal carcinoma.

Adult↗

PubMed1996

Fanconi's anaemia and recurrent squamous cell carcinoma of the oral cavity: a case report.

Fanconi's anaemia is a rare genetic disorder and majority of the patients die of haematologic complications in their second or third decades of life. Others who have mild or no cytopenias survive long enough to develop malignancies. This is a report of a 44-year-old woman who presented with recurrent oral squamous cell carcinoma during her adulthood, without clinical haematological problem. Despite treatment with cis-retinoic acid, she developed a third squamous cell carcinoma 6 months later. In a review of the literature, only in 1 reported case was the patient treated with low-dose retinoids but he developed recurrent anal cancer after 14 months.

Adolescent↗

PubMed1996

Measuring quality of life in different cultures: translation of the Functional Living Index for Cancer (FLIC) into Chinese and Malay in Singapore.

Quality-of-life assessment has become an accepted method of evaluation in clinical medicine. The technique is based on a patient's self-assessment of physical, psychological, and social function, as well as the effects of distressing physical symptoms. The most important aspect of quality-of-life assessment is that it brings into focus a patient-centred view of health outcome, which is broader than the physiologic measures which predominate in Western medicine. Strategies for the development and use of assessment questionnaires have evolved over the past 15 years, and numerous questionnaires have been created. Most originate in Western societies, with English as the most common language of development. Adapting such questionnaires for use in other language and cultural settings is an imprecise practice. Language translation and equivalent cultural meaning must both be addressed. This paper reports on the language translation process and results for the Functional Living Index for Cancer (FLIC) as translated into Chinese and Malay in Singapore. We employed a step-wise process beginning with translation/back translation, followed by structured pilot field trials and population sampling. Taped versions of the questionnaire were devised to meet illiteracy problems in the sample population. Paired comparisons of the Chinese and Malay versions of individual questions with their English counterparts show good correlations and similar means most of the time. Factor analysis on a population sample of 246 (112 Chinese, 35 Malay and 98 English speaking) with cancers of minimal, extensive or palliative extent is convergent with that obtained on a North American population. However, a separate analysis of the Chinese questionnaires showed some differences in factor pattern. Specific language and cultural translation difficulties are discussed. Of note is the predicted significant decrease in total FLIC scores with extent of disease within each of the language preference populations, which provides some evidence for the validity for each language version in the Singapore culture(s). Thus, the FLIC translations into Malay and Chinese in Singapore can be considered for use in local trials, subject to ongoing evaluation.

Activities of Daily Living↗

PubMed1996

Treatment of small cell lung cancer: a single institutional experience.

Forty-three patients with either limited or extensive small cell lung carcinoma were treated with either etoposide and cisplatin (EP) regimen or EP alternating with cyclophosphamide, doxorubicin and vincristine. Patients with limited disease were consolidated with radiotherapy. Responses were 96% (44% complete response) and 71% (6% complete response) in the patients with limited and extensive diseases, respectively. The 2-year disease-free and overall survival in the limited disease patients were 19% and 27%, respectively. None of the patients with extensive disease survived beyond 2 years. Toxicity of the therapy was acceptable. Forty percent developed grade 2 vomiting. Two patients had neutropenic fever of which one was fatal. One of the two-year survivors developed a second malignancy (oesophageal carcinoma). Despite consolidative radiotherapy in all responding patients with limited disease, 73% of the failure included a locoregional component. In the entire group, one-third of the patients developed brain metastases. Hence, more effective drugs and local treatment modalities are needed to improve this result.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

Chemotherapy in non-small cell lung cancer: a review.

Lung cancer, of which non-small cell carcinoma is the most common, has been a significant therapeutic challenge for decades and will remain so for decades to come. Despite its prevalence, progress in the management of non-small cell lung cancer has been relatively slow. This is in part due to the pessimism of most physicians treating this disease, which has resulted in a relatively lackadaisical attitude with regards to clinical trials when compared to other solid tumours like breast or colorectal cancers. Nevertheless, the past decade has seen significant progress, specifically with regards to the management of locally advanced disease. Chemotherapy, though shown to be biologically active in non-small cell lung cancer, is considered an ineffective palliative tool in the setting of metastatic disease due to its toxicities and the "less than encouraging" response rates generated by the cisplatin-based combination regimen which is generally considered to be the most active currently available. The advent of new active agents such as paclitaxel and vinorelbine which are potentially less toxic may change this view. Conversely, the response rate of locally advanced disease to chemotherapy is significantly higher and this has resulted in numerous multimodality trials of neoadjuvant chemotherapy prior to surgery and/or radiation. To date, a number of randomised trials have shown that this approach can result in significant survival benefit for patients with locally advanced disease. An alternative approach makes use of the potential synergism between certain chemotherapeutic agents (such as cisplatin) and radiation when used concurrently. However, data on concurrent chemoradiotherapy in locally advanced disease have been largely based on single-arm studies and are inconclusive. Three randomised trials on concurrent chemoradiotherapy have been shown benefit for the use of combined modality in locally advanced disease. Hence, treatment of locally advanced disease should include chemotherapy as part of the combined modality approach. However, the optimal sequencing of these modalities would require well-designed randomised trials to determine.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

5-Fluorouracil continuous infusion in metastatic colorectal cancer.

5-Fluorouracil (5-FU) remains the most active therapeutic agent in advanced colorectal cancer. This drug has demonstrated differing levels of activity dependent on the schedule of administration in experimental and clinical models. Twenty-six patients were treated with prolonged continuous infusion of 5-FU at 250 mg/m2/day via a portable infusion pump and Hickman's central venous catheter in this study. Twelve patients (46%) experienced a major response (complete response-1, partial response-11). Median duration of response was 5 months. Seventeen patients were chemotherapy-naive on accrual to this study. Ten patients from this group had partial responses (59%) and four were minor responders (24%). Hence 82% of patients who had no prior chemotherapy showed tumour responses to 5-FU continuous infusion. Two of nine patients (22%) with prior chemotherapy achieved major response. Favourable toxicity profile was noted with this regimen. Two patients discontinued therapy due to treatment-related toxicities (severe palmar-plantar erythrodysesthesia and superior vena cava thrombosis secondary to the central venous catheter). Prolonged continuous infusion of 5-FU could well be the standard treatment of advanced colorectal cancer in view of its favourable activity and toxicity profile. The serial serum carcino-embryonic antigen (CEA) trend was shown to correlate well to the objective response; a decline of more than 50% from baseline CEA level correlated with a major response and a rise of more than 50% correlated with progressive disease. Hence the use of serum CEA is suitable for monitoring response to chemotherapy which is advantageous with respect to patient convenience and cost-effectiveness.

Adenocarcinoma↗

PubMed1996

Combination chemotherapy (dacarbazine, carmustine, cisplastin, and tamoxifen) in advanced melanoma.

Melanoma is rare in Singapore with an age-standardised rate (ASR) of 0.4-0.8 per 100,000 per year. Thirteen patients with metastatic or locally advanced melanoma were referred to the Department of Medical Oncology, Singapore General Hospital between Feb 1991 and Nov 1993. Ten patients were given combination chemotherapy comprising carmustine (BCNU), cisplatin, dacarbazine (DTIC) and tamoxifen. The remaining 3 patients either rejected chemotherapy or were too ill to receive chemotherapy. Patient characteristics were as follows: there were 6 males and 4 females; age range 29-75 years; all were Chinese; sites of primary disease: extremities 8, retroorbital 1, vagina 1; sites of metastases: lymph nodes 6, skin 2, pulmonary 3, liver 1. All received the same combination chemotherapy comprising iv BCNU 150 mg/m2 q8wk, iv DTIC 220 mg/m2 x 3 days q4 wk, iv cisplatin 25 mg/m2 x 3 days q4 wk and tab tamoxifen 40 mg daily. There were 6 partial responses and no complete responses, giving a response rate of 60% with a median survival of 11.5 months. Three patients with sites of disease in the vagina, retroorbital region and metastatic liver disease had progressive disease despite chemotherapy and one died of treatment related sepsis. The 6 responders include those with metastases to the skin, nodes and/or lung. Treatment was generally tolerable. Two patients experienced delays of their subsequent cycles of treatment by 1-2 weeks due either to neutropenia and/or thrombocytopenia. This regimen is a fairly active combination against metastatic melanoma, particularly those with metastases to the nodes, skin and the lung. Those with involvement of other sites tend to respond poorly.

Adult↗

PubMed1995

Resolution of superior vena cava obstruction in small cell lung cancer patients treated with chemotherapy.

Small cell lung cancer is a highly chemo-sensitive malignancy. As it often presents with a central lesion, superior vena cava obstruction (SVCO) is not an uncommon manifestation. From January 1990 to December 1993, 161 patients with small cell lung carcinoma were seen at our institution. Twenty (12.4%) of these patients presented with symptoms and signs of SVCO. Initial therapy consisted of radiotherapy in 4 patients and chemotherapy in 16 patients. Of those treated with chemotherapy, patient characteristics included 13 males, median age of 62.5 years (range 51 to 78 years), Eastern Co-operative Oncology Group (ECOG) performance status of 3 to 4 in 7 patients; 1 to 2 in 9 patients, and limited stage disease in 8 patients. The median period of follow-up was 5 months. Nine patients received a combination of cisplatin and etoposide (EP), 5 had cyclophosphamide, doxorubicin and vincristine, 1 had cyclophosphamide, etoposide and vincristine and 1 had monotherapy with oral etoposide. Overall response to chemotherapy was 81% (with 31% complete responses). All responders had resolution of SVCO. Only 3 patients did not respond (1 patient defaulted, 1 patient died of neutropenic sepsis at week one and 1 patient had stable disease). Resolution of SVCO was noted within the first 2 weeks after the first cycle; the earliest being 3 days. The only patient given single-agent oral etoposide responded within 10 days after initiation of treatment. Of the 7 patients with poor performance status (ECOG 3 to 4), 3 died from treatment-related complications. Chemotherapy is highly effective as a primary treatment of small cell lung carcinoma despite presentation with SVCO. However, caution is advised in the use of combination chemotherapy for those presenting with poor performance status. Initial therapy with oral etoposide or radiotherapy should be considered as possible alternatives for these patients.

Aged↗

PubMed1995

Primary cerebral lymphoma--a case report and review of the management.

The brain is an uncommon extranodal site for the development of malignant lymphoma. There is an increased risk among immunocompromised patients. While the overall outcome is poor, innovative approaches with combination chemotherapy and radiotherapy can sometimes produce durable remissions. The treatment of a non-immunocompromised patient with cerebral lymphoma incorporating chemotherapy and radiotherapy is described with a review of the literature.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1995

Extract of astragalus membranaceus and ligustrum lucidum does not prevent cyclophosphamide-induced myelosuppression.

There is increasing evidence that many Chinese medicinal herbs are promising biological response modifiers in cancer treatment. The extract of some Chinese herbs have shown ability in stimulating the bone marrow and improving the peripheral white cell counts in rats. We studied the effect of a dried extract of two commonly used Chinese herbs, Astragalus membranaceus (AM) and Ligustrum lucidum (LL) on cytotoxic-induced myelosuppression. Wistar rats weighing 250-300g each were divided into two groups of 12. Both groups were given cyclophosphamide intravenously at 75 mg/kg on day 1 of the study. Rats in the study group were fed 240 mg of crude extract of AM and LL from day 1 to day 12 of study. The daily absolute neutrophil count (ANC) and the platelet count were monitored. There was no difference between the study and the control group in terms of nadir count, time to nadir and time to recovery for both the ANC and the platelet counts. The duration of neutropenia (ANC < 1.0 x 10(9)/L) was also similar in both groups. Our results showed that the extract of AM and LL does not prevent cyclophosphamide-induced myelosuppression.

Adjuvants, Immunologic↗

PubMed1994

Control of emesis by intravenous granisetron in breast cancer patients treated with 5-FU, epirubicin and cyclophosphamide.

Granisetron, a potent and selective 5-hydroxytryptamine receptor (5-HT3) antagonist was reported to be an effective antiemetic agent both in animal studies and in patients given highly emetogenic chemotherapy. A sample of 43 patients with breast cancer was accrued from September to November 1992 in a phase II study to assess the efficacy of granisetron in patients receiving FEC (5-FU, epirubicin, cyclophosphamide). Each patient received 3 mg intravenous granisetron as a single dose just prior to chemotherapy. Oral metoclopromide was prescribed to each patient as a rescue anti-emetic. The emetic episodes and degree of nausea were evaluated on a daily basis. Good control of emesis (0-2 episodes of vomiting) and nausea (mild or no nausea) was in the range 77%-98% and 77%-93% respectively. There was a complete response (no emetic episodes throughout the 6-day period) in 16 patients (37.2%). Onset of emesis tends to occur on day 1 and tend to subside after day 3; 85% of patients had onset of emesis in the first 2 days after chemotherapy. Control of emesis and nausea tends to improve after day 3, which could be the result of the reduced emetogenicity of the combination FEC with time. Altogether, 77% had good control of acute emesis; control of delayed emesis was better with 84% achieving a major response on day 2 after chemotherapy, which improved to more than 90% after day 4. Granisetron was generally tolerated with headache being the most common side-effect followed by constipation and flushing. This study suggests that granisetron is an effective and well-tolerated anti-emetic agent, which deserves randomised trials to elucidate its efficacy further.

Administration, Oral↗

PubMed1994

A phase II trial of 5-fluorouracil and cisplatinum in recurrent or metastatic nasopharyngeal carcinoma.

BACKGROUND: A phase II clinical trial of the combination of 5-fluorouracil (5-FU) and cisplatinum (CDDP) was conducted in 24 patients (pts) with recurrent or metastatic nasopharyngeal carcinoma. None of the patients had prior chemotherapy and all but 4 had prior radiotherapy. PATIENTS AND METHODS: 5-FU was administered by intravenous (i.v.) infusion at a dose of 1000 mg/m2 daily on days 1 to 5 and i.v. infusion of CDDP at a dose of 100 mg/m2 in divided doses on days 1 to 3 of each 21-day cycle. Pts were examined for response after every two cycles. Of 24 pts accrued, 21 had measurable disease. Three had only bone metastases and were evaluable for toxicity and survival. RESULTS: Thirteen pts had partial response and three achieved complete response, for an overall response rate of 66% (95% confidence interval 59% to 93%). Median time to progression for all patients was 8 months (range 4 to 28+ months) and median survival for all patients was 11 months. Grades 3 to 4 toxicities included granulocytopenia (10 pts). There was no treatment-related mortality. Average relative dose intensity was 0.8. CONCLUSION: This combination is highly effective with acceptable toxicity. The duration of response tended to be brief. Its role in the neoadjuvant and adjuvant setting in patients with poor prognostic features should be further studied.

Adult↗

PubMed1994

Randomised study comparing imipenem/cilastatin to ceftriaxone plus gentamicin in cancer chemotherapy-induced neutropenic fever.

Prompt initiation of empiric antibiotic therapy is the cornerstone in the therapy of chemotherapy-induced neutropenic sepsis in cancer patients. Ceftriaxone plus gentamicin (ceftriaxone/gentamicin) is the most widely used combination of empiric antibiotics in the Department of Medical Oncology, Singapore General Hospital. However, imipenem/cilastatin has been shown to be a practical alternative. To compare the efficacy and cost effectiveness of monotherapy with our usual combination antibiotic therapy, 50 evaluable neutropenic cancer patients admitted for fever were randomised to empiric imipenem/cilastatin or ceftriaxone/gentamicin. Ceftriaxone/gentamicin was started in 24 patients. The initial clinical response rate to ceftriaxone/gentamicin was 62.5% and 84.6% to imipenem/cilastatin (P = 0.075). The average cost of antibiotics per patient started on ceftriaxone/gentamicin including cost of change of antibiotics was S$63 per day of antibiotic use and for imipenem/cilastatin it was S$252 (P < 0.02). In conclusion, although more patients receiving imipenem/cilastatin had an initial clinical response than those receiving ceftriaxone/gentamicin, this difference was not statistically significant. It would appear that imipenem/cilastatin is equivalent to ceftriaxone/gentamicin for the treatment of neutropenic sepsis. However, ceftriaxone/gentamicin was more cost effective.

Antineoplastic Agents↗

PubMed1993

Implantable subcutaneous infusion ports.

Limited vascular access hinders administration of chemotherapy, blood products and antibiotics in cancer patients. Repeated venous cannulation is often psychologically traumatic to patients. The use of a subcutaneous infusion port allows convenient vascular access. Twenty-two cancer patients had ports implanted for venous access (17 patients) and administration of regional chemotherapy (5 patients). The period of indwelling ranged from 70 to 470 days (median 270 days). Two patients (9%) had wound dehiscence that required port revision. Despite this, the wound did not heal in 1 patient and the port had to be removed. Other complications included venous thrombosis (5%) and subcutaneous haematoma (5%). There was no catheter-related bacteraemia. The subcutaneous infusion port provides a suitable vascular access in cancer patients.

Adolescent↗

PubMed1993

MACOP-B in advanced non-Hodgkin's lymphoma.

Between May 1986 and March 1991, 38 patients with previously untreated advanced intermediate and high-grade non-Hodgkin's lymphoma were treated with methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B): 73% of the patients had stages III and IV disease, 55% had "B" symptoms, and 55% had bulky disease (nodal masses > 10 cm). Histologic subtypes included diffuse large-cell and immunoblastic lymphoma. In 96% of patients clinical response was achieved (69% complete response and 27% partial response). Acturial disease-free survival and overall survival were 55% and 60%, respectively, at 2 years. Treatment-related mortality was 16%: 3 patients died from neutropenic sepsis and 3 (hepatitis B carriers) from fulminant hepatitis at the time of steroid withdrawal. The incidence of nonfatal neutropenic fever was 24% and mucocutaneous toxicity was common. The poorer overall results may be attributed to more advanced disease. Caution is advised in the use of MACOP-B among hepatitis B carriers.

Adolescent↗

PubMed1993

Use of oral and intravenous ondansetron in patients treated with cisplatin.

Ondansetron, a selective 5-HT3 antagonist, has been shown to be effective in preventing chemotherapy-induced nausea and vomiting. From July and August 1991, 25 patients were accrued in a phase II study to assess the efficacy of ondansetron in patients receiving cisplatin-containing chemotherapy. Patients received intravenous cisplatin 100 mg/m2, given either as a 24-hour infusion on day 1 or in divided doses as eight-hour infusions daily on days 1 to 3. Each patient received 24 mg of ondansetron per day for six days. Intravenous dexamethasone 24 mg was given daily on the days of cisplatin infusion. The emetic episodes and degree of nausea were evaluated daily. "Good" control of emesis (0-2 episodes of vomiting) and nausea (mild or no nausea) ranged from 64-100% and 88-100% respectively. Failure in emesis control occurred most frequently on days 3 and 4. Ondansetron was generally well tolerated with only minimal side-effects. One patient developed unexplained encephalopathy which resolved completely. Our results suggest that ondansetron is an effective anti-emetic agent with minimal toxicities. Randomised studies comparing ondansetron against "standard" anti-emetics should be conducted.

Administration, Oral↗