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Biomedical subjects

I F Tannock

Publications and source records attributed to I F Tannock.

At least 19 recordsLinked to original sources
PubMed2006

Side effects associated with the use of dexamethasone for prophylaxis of delayed emesis after moderately emetogenic chemotherapy.

The role of dexamethasone to reduce delayed emesis following highly emetogenic chemotherapy is proven, but there is less evidence of benefit after mild-moderately emetogenic regimens. Here, we develop and evaluate a Dexamethasone Symptom Questionnaire (DSQ) to assess the side effects of dexamethasone in the week after patients receive moderately emetogenic chemotherapy. The DSQ was first optimised with the aid of a focus group. Sixty patients receiving oral dexamethasone for prophylaxis of delayed emesis after moderately emetogenic chemotherapy for cancer completed and then evaluated the DSQ. Patients reported that the DSQ was clearly worded and addressed items important to them. Patients receiving dexamethasone reported moderate-severe problems with insomnia (45%), indigestion/epigastric discomfort (27%), agitation (27%), increased appetite (19%), weight gain (16%) and acne (15%) in the week following chemotherapy. The side effects of dexamethasone may outweigh its benefits when used with moderately emetogenic chemotherapy. A randomised, double-blind crossover trial is underway to determine the effect of dexamethasone on nausea and vomiting, and the impact of side effects of dexamethasone and of nausea and vomiting on quality of life.

Acne Vulgaris↗
PubMed2006

Inhibition of endosomal sequestration of basic anticancer drugs: influence on cytotoxicity and tissue penetration.

The basic drugs doxorubicin and mitoxantrone are known to be concentrated in acidic endosomes of cells. Here, we address the hypotheses that raising endosomal pH with the modifying agents chloroquine, omeprazole or bafilomycin A might decrease sequestration of anticancer drugs in endosomes, thereby increasing their cytotoxicity and availability for tissue penetration. Chloroquine, omeprazole and bafilomycin A showed concentration-dependent effects to raise endosomal pH, and to inhibit sequestration of doxorubicin in endosomes. Chloroquine and omeprazole but not bafilomycin A decreased the net uptake of doxorubicin into cells, but there was no significant effect on uptake of mitoxantrone. Omeprazole and bafilomycin A increased the cytotoxicity of the anticancer drugs for cultured cells, as measured in a clonogenic assay, whereas chloroquine had minimal effects on cytotoxicity despite reduced uptake of doxorubicin. Omeprazole but not chloroquine or bafilomycin A increased the penetration of anticancer drugs through multicellular layers of tumour tissue. We conclude that modifiers of endosomal pH might increase therapeutic effectiveness of basic drugs by increasing their toxicity and/or tissue penetration in solid tumours.

Animals↗
PubMed2006

Impact of androgen deprivation therapy on physical and cognitive function, as well as quality of life of patients with nonmetastatic prostate cancer.

PURPOSE: Many patients with prostate cancer receive androgen deprivation therapy for long periods. We compared physical and cognitive function, and quality of life in a cross-sectional study of 57 patients receiving androgen deprivation therapy for nonmetastatic prostate cancer and 51 healthy age matched controls. MATERIALS AND METHODS: Physical and daily function were measured by the 6-minute walk test, grip strength, the timed up and go test, and activities of daily living measures. Cognitive function was evaluated by the High Sensitivity Cognitive Screen and by a self-report prototype Functional Assessment of Cancer Therapy cognitive function subscale. Quality of life was assessed by the Functional Assessment of Cancer Therapy-General with the subscale for fatigue and by the Patient-Oriented Prostate Utility Scale. RESULTS: Androgen deprivation therapy was given for a median of 1.8 years (range 0.4 to 7.4). Patients had lower median hemoglobin than controls (134 vs 148 gm/l, p <0.0001). Performance on physical tests was similar in the 2 groups. Moderate or severe cognitive impairment by the High Sensitivity Cognitive Screen was similar for patients (23%) and controls (35%, p = 0.2). Self-reported cognitive dysfunction was also similar. Scores for the Functional Assessment of Cancer Therapy-General were similar but the Patient Oriented Prostate Utility Scale summary score was worse for patients (median 71 vs 86, p <0.001). More patients reported severe fatigue (Functional Assessment of Cancer Therapy-Fatigue score less than 35, p = 0.03). Low energy, poor bladder control and loss of sexual function were reported in 36%, 47% and 95% of patients, and in 16%, 34% and 33% of controls, respectively. CONCLUSIONS: Patients treated with androgen deprivation therapy experience more symptoms and have worse fatigue than controls, but this study did not detect any effect on physical or cognitive function.

Aged↗
PubMed2004

Is there a role for chemotherapy in prostate cancer?

There is evidence from randomised-controlled trials that patients with symptomatic hormone-refractory prostate cancer may experience palliative benefit from chemotherapy with mitoxantrone and prednisone. This treatment is well tolerated, even by elderly patients, although the cumulative dose of mitoxantrone is limited by cardiotoxicity. Treatment with docetaxel or paclitaxel, with or without estramustine, appears to convey higher rates of prostate-specific antigen response in phase II trials, but is more toxic. Large phase III trials comparing docetaxel with mitoxantrone have completed accrual. There is no role for chemotherapy in earlier stages of disease except in the context of a well-designed clinical trial.

Antineoplastic Agents↗
PubMed2004

Quality of cancer care.

Quality of cancer care is difficult to define and to evaluate. Here we consider three components represented by the questions: (i) Is the right question treatment being given? (ii) Is it being done well? and (iii) Is the patient being treated as well as the disease? Determining the right treatment requires a hierarchy of evidence from clinical trials, and high quality clinical trials to determine and supplement that evidence. Evidence-based guidelines are then useful in increasing compliance with evidence-based treatment. Quality of delivery of treatment is dependent on volume of practice: patients with rare or complex diseases should be referred to cancer centres. Treatment of the whole patient requires attention to communication, and to the management of symptoms such as pain and fatigue. Cancer care must be of high quality and delivered with compassion.

Evidence-Based Medicine↗
PubMed2003

Randomized, double-blind, controlled trial of mitoxantrone/prednisone and clodronate versus mitoxantrone/prednisone and placebo in patients with hormone-refractory prostate cancer and pain.

PURPOSE: To compare the incidence of palliative response in patients with hormone-resistant prostate cancer (HRPC) treated with mitoxantrone and prednisone (MP) plus clodronate with that of patients treated with MP plus placebo. MATERIALS AND METHODS: Men with HRPC, bone metastases, and bone pain were randomly assigned to receive clodronate 1,500 mg administered intravenously (IV) or placebo every 3 weeks, in combination with mitoxantrone 12 mg/m2 IV every 3 weeks and prednisone 5 mg orally bid. Patients completed the present pain intensity (PPI) index and Prostate Cancer-Specific Quality-of-Life Instrument at each treatment visit and used a diary to record analgesic use on a daily basis. The primary end point was a reduction to zero or of two points in the PPI or a decrease of 50% in analgesic intake, without increase in either. RESULTS: The study accrued 209 eligible patients over 44 months. One hundred sixty patients (77%) had mild PPI scores (1 or 2), and 49 (24%) had moderate PPI scores (3 or 4). The primary end point of palliative response was achieved in 46 (46%) of 104 patients on the clodronate arm and in 41 (39%) of 105 patients on the placebo arm (P =.54). The median duration of response, symptomatic disease progression-free survival, overall survival, and overall quality of life were similar between the arms. Subgroup analysis suggested possible benefit in patients with more severe pain. CONCLUSION: MP provides useful palliation in symptomatic men with HRPC. Clodronate does not increase the rate of palliative response or overall quality of life. Clodronate may be beneficial to patients who have moderate pain, but this requires further confirmation.

Aged↗
PubMed2003

Quality of life and understanding of disease status among cancer patients of different ethnic origin.

Patients managed in European or North American cancer centres have a variety of ethnic backgrounds and primary languages. To gain insight into the impact of ethnic origin, we have investigated understanding of disease status and quality of life (QoL) for 202 patients. Patients completed questionnaires in their first language (52 English, 50 Chinese, 50 Italian, 50 Spanish or Portuguese), including the Functional Assessment of Cancer Therapy - General (FACT-G) QoL instrument, questions about disease status, expectations of cure and the language and/or type of interpretation used at initial consultation. Physicians also evaluated their status of disease and expectation of cure, and performance status was estimated by a trained health professional. The initial consultation was usually provided in English (except for 32% of Chinese-speaking patients); interpretation was provided by a family member for 34% of patients with limited English proficiency (LEP) and by a bilingual member of staff for 21%. Patients underestimated their extent of disease and overestimated their probability of cure (P=0.001 and <0.0001, respectively). Estimates of probability of cure by the English speakers were closer to those of their physicians than the other groups (P=0.02). English-speaking patients reported better and Italian-speaking patients poorer overall QoL (P<0.001 for Italian vs other groups). Performance status was correlated with QoL and most closely related with the extent of disease. Understanding of cultural differences is important for optimal management of patients with cancer.

Activities of Daily Living↗
PubMed2003

Assessment of tumor cell repopulation after chemotherapy for advanced ovarian cancer: pilot study.

BACKGROUND: Repopulation of clonogenic tumor cells appears to increase during fractionated radiation treatment and is recognized as an important factor affecting local control. Given the longer intervals between cycles and longer total duration of treatment, the impact of repopulation is likely to be greater after chemotherapy. METHODS: We assessed tumor cell repopulation with the proliferative marker Ki-67 in 21 patients with ovarian carcinoma who received initial chemotherapy. Paraffin slides were evaluated from the diagnostic biopsy and from tumor obtained at debulking surgery after chemotherapy. Immunohistochemistry using the MIB-1 antibody was performed on the paired samples and analyzed with a digital imaging device linked to a color camera mounted on a transmitted-light microscope. The ratio of Ki-67 positive to all nuclei was used as a proliferative index and compared for pre- and postchemotherapy specimens. RESULTS: All patients received platinum-based chemotherapy and most showed a response to treatment. The median duration between last chemotherapy and debulking surgery was 33 days (range, 22-50 days). Four (19%) of 21 patients showed an increased proliferative index after chemotherapy, and the remainder showed a decrease (n = 12) or no significant change (n = 5). CONCLUSIONS: Our results did not suggest an increase in proliferation of tumor cells after this type of chemotherapy in the majority of patients with ovarian cancer.

Antineoplastic Agents↗
PubMed2002

Cytostatic potential of novel agents that inhibit the regulation of intracellular pH.

Cells within the acidic extracellular environment of solid tumours maintain their intracellular pH (pHi) through the activity of membrane-based ion exchange mechanisms including the Na(+)/H(+) antiport and the Na(+)-dependent Cl(-)/HCO(3)(-) exchanger. Inhibition of these regulatory mechanisms has been proposed as an approach to tumour therapy. Previously available inhibitors of these exchangers were toxic (e.g. 4,4-diisothiocyanstilbene-2,2-disulphonic acid), and/or non-specific (e.g. 5-N-ethyl-N-isopropyl amiloride). Using two human (MCF7, MDA-MB231) and one murine (EMT6) breast cancer cell lines, we evaluated the influence of two new agents, cariporide (an inhibitor of the Na(+)/H(+) antiport) and S3705 (an inhibitor of the Na(+)-dependent Cl(-)/HCO(3)(-) exchanger) on the regulation of intracellular pH (pHi). The cytotoxicity of the two agents was assessed by using clonogenic assays. Our results suggest that cariporide has similar efficacy and potency to 5-N-ethyl-N-isopropyl amiloride for inhibition of Na(+)/H(+) exchange while S3705 is more potent and efficient than 4,4-diisothiocyanstilbene-2,2-disulphonic acid in inhibiting Na+-dependent Cl(-)/HCO3(-) exchange. The agents inhibited the growth of tumour cells when they were incubated at low pHe (7.0-6.8), but were non-toxic to cells grown at doses that inhibited the regulation of pHi. Our results indicate that cariporide and S3705 are selective cytostatic agents under in vitro conditions that reflect the slightly acidic microenvironment found in solid tumours.

Adenocarcinoma↗
PubMed2002

A Phase II trial of docetaxel and cisplatin in patients with recurrent or metastatic nasopharyngeal carcinoma.

UNLABELLED: A Phase II study was conducted to determine the efficacy and toxicity of the combination of docetaxel and cisplatin, in patients with recurrent or metastatic nasopharyngeal carcinoma (NPC). Nine patients (median age 39 years) with NPC were enrolled, none had prior chemotherapy for their recurrent or metastatic disease. Docetaxel was administered as a 1-h intravenous infusion at a dose of 75 mg/m(2) on day 1; cisplatin was administered at a dose of 75 mg/m(2) on day 1, immediately after docetaxel. Treatment was repeated every 3 weeks. The primary endpoint was objective response rate and the secondary endpoints were duration of response, time to progression, and overall survival. A total of 45 chemotherapy cycles were administered. In an intention-to-treat analysis two patients (22%, 95% confidence interval (CI): 3-60%) achieved a partial response. The median duration of response was 4.1 months, the median time to progression 8.4 months and the overall survival at 1 year from start of treatment was 76%. Grade 3-4 neutropenia was observed in all (100%) patients over 93% of the treatment cycles, and in three cases this was complicated by fever. Other toxicities were mild. CONCLUSIONS: The combination of docetaxel and cisplatin has manageable toxicity but little efficacy as first-line treatment in patients with recurrent or metastatic NPC. In view of the low response rate, accrual was terminated and the trial was aborted.

Adult↗
PubMed2001

Analysis of the prognostic effects of inclusion in a clinical trial and of myelosuppression on survival after adjuvant chemotherapy for breast carcinoma.

BACKGROUND: Treatment-related factors that might influence survival after adjuvant treatment for breast carcinoma include treatment as part of a clinical trial, toxicity of treatment, the regimen and schedule used, and dose intensity. METHODS: The authors reviewed the records of 680 patients with breast carcinoma who received adjuvant treatment with cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) at Princess Margaret Hospital between 1980-1990. They analyzed the effects on survival of inclusion in a clinical trial (n = 160) and of experiencing Grade 3/4 myelosuppression (according to National Cancer Institute Common Toxicity Criteria) (n = 227, with available data for 584 patients). In an exploratory analysis, the authors examined the effects of the CMF regimen ("classic" CMF [n = 417] vs. intravenous CMF [n = 243]) and of relative dose intensity. Each of these factors was tested in a Cox proportional hazards model with the known prognostic factors of N classification, T classification, estrogen receptor (ER) and progesterone receptor (PR) status, and use of adjuvant hormonal therapy to determine whether they provided additional prognostic information. RESULTS: In univariate analysis, inclusion in a clinical trial was associated with better survival (P = 0.02) with a nonsignificant trend when corrected for other prognostic factors in a multivariate analysis (hazard ratio [HR] = 0.77; 95% confidence interval [CI], 0.56-1.04). There was a similar trend for patients experiencing myelosuppression (HR = 0.77; 95% CI, 0.59-1.00). In exploratory analysis the use of classic CMF, with higher absolute dose intensity, also was associated with a trend toward improved survival (HR = 0.79; 95% CI, 0.63-1.00). CONCLUSIONS: The results of the current study suffer from the inherent problems of retrospective analysis, but, similar to findings for other disease sites, they suggest that patients included in clinical trials have better outcome. Classic CMF should be used when this regimen is selected for adjuvant treatment, and dose adjustment resulting in moderate myelosuppression should be explored in future clinical trials.

Adult↗
PubMed2001

The translational research chain: is it delivering the goods?

PURPOSE: To address whether the translational research chain has influenced clinical practice in radiation oncology. METHODS AND MATERIALS: Merits and limitations of the various steps of the translational chain, i.e., in vitro studies, animal experiments, biomathematical modeling, Phase I and II trials, and randomized Phase III trials are briefly reviewed. The process and value of translational research in radiation oncology are addressed using dose fractionation and the time factor in tumors as examples. RESULTS: The examples show that translational research may indeed change clinical practice in radiation oncology. However, it takes several decades and considerable efforts to define and test new strategies. The "translational process" is by no means unidirectional but a continuing multiway dialog among basic scientists, applied scientists, clinical scientists, and clinical oncologists. CONCLUSION: Translational research works in radiation oncology, and it is difficult to conceive a better alternative for future improvement of therapy. The slow speed of the translational process indicates that there is a need for improving the various steps of the translational network and the interaction as a whole. Massive investments in one part of the network are likely to be at least partly wasted unless the other links are strengthened as well.

Animals↗
PubMed2001

Collaborative clinical trials: quality or quantity?

PURPOSE: To review the merits of using the limited available resources--patients, money, clinical scientists, and ideas--in various types of clinical trial. CONCLUSIONS: Two types of trial represent a poor use of resources: (a) nonrandomized trials that provide no insight into biologic mechanisms and are not precursors to testing new strategies in comparison with standard treatment in randomized trials; and (b) small randomized trials that are difficult to interpret because of a high rate of false-positive and false-negative trials. Very large trials that can detect small differences in survival for patients with common tumors are appropriate, but a similar design to detect transient improvements due to palliative therapy represent a poor use of resources. Larger gains in therapeutic index will require the recognition of tumor heterogeneity and the conduct of small trials that are based on biologic hypotheses, and which provide mechanistic information in patients; two examples are provided. Ultimately, strategies that may be individualized among a group of patients with histologically similar tumors will need to be evaluated against the current standard (and homogeneous) treatment.

Antineoplastic Agents↗
PubMed2001

Evidence against apoptosis as a major mechanism for reproductive cell death following treatment of cell lines with anti-cancer drugs.

An increase in apoptotic cells may be observed after treatment with chemotherapy, and many authors have assumed that anti-cancer drugs kill cells by inducing apoptosis. The most relevant endpoint of cell death following treatment of tumour cells is loss of reproductive ability as measured by a colony-forming assay, since cells with limited reproductive potential cannot regenerate a tumour. We have therefore investigated the relationship between apoptosis and reproductive cell death following in vitro treatment of mammalian cell lines with anti-cancer drugs. Markers of apoptosis (DNA ladders, TUNEL assay) were evaluated at various times after treatment of Chinese Hamster Ovary (CHO) cells, human bladder cancer MGH-U1 cells, and a murine T-lymphocytic cell line (CTLL-2) with several anti-cancer drugs. These markers were found infrequently, despite the use of doses that cause loss of colony-forming ability, except in CTLL-2 cells. We also transfected and expressed the human pro-apoptotic gene bax and the anti-apoptotic gene bcl-2 in MGH-U1 cells and compared cell survival after drug treatment with that of control cells transfected with the vector alone. Expression of these genes had at most small effects to influence cell survival. We conclude that apoptotic mechanisms had at most a minor role in leading to reproductive death of MGH-U1 and CHO cells after chemotherapy. When apoptosis is observed following treatment with anti-cancer drugs it may be a secondary event which occurs in lethally-damaged cells, leading to their lysis, rather than a primary event that leads to loss of reproductive integrity.

Animals↗
PubMed2001

Factors that influence the penetration of methotrexate through solid tissue.

Limited penetration of anticancer drugs through tumour tissue is an important factor that may limit therapeutic effects against solid tumours. Here we report studies of the penetration of radiolabelled methotrexate through multicellular layers (MCL) of murine EMT-6 and human MCF-7 cells grown on semiporous teflon membranes. The penetration of methotrexate was only about 25% of that through the teflon membrane alone after 6 hr. This was true for all methotrexate concentrations examined from 10 microM to 3 mM. The presence of folic acid at concentrations above 0.1 mM and of acidic conditions decreased the uptake of methotrexate into single cells and enhanced tissue penetration. Hypoxic conditions and the presence of folinic acid (leucovorin) had no effect on penetration or uptake of methotrexate. Our data provide evidence that tissue penetration of methotrexate is through the extracellular space, that its distribution in solid tissue may be limited and that it may be possible to improve its tissue penetration.

Animals↗
PubMed2001

Retreatment of patients with the same chemotherapy: implications for clinical mechanisms of drug resistance.

BACKGROUND: Patients who relapse after adjutant chemotherapy, or after attaining remission following treatment of advanced disease, are sometimes retreated with the same type of chemotherapy. The objective of the current review of published reports was to assess the probability of response to retreatment, and to examine evidence for transient rather than stable forms of clinical drug resistance. METHODS: A Medline review of published clinical series where patients were retreated with the same chemotherapy that they had received previously. RESULTS: We located 15 reports of patients with advanced disease who were retreated with the same chemotherapy following complete remission and subsequent relapse, and three reports where patients received the same chemotherapy that was given previously as adjuvant treatment for breast cancer. For patients with advanced disease the median time off-treatment was 48 weeks; response rates to retreatment using appropriate criteria were in the range of 18%-100% (median 51%), with a substantial proportion of second complete responses. For patients retreated after adjuvant chemotherapy for breast cancer the median interval between treatments was 84 weeks and the response rates were in the range of 40%-51%. CONCLUSIONS: With the caveat that this type of review is subject to publication bias, retreatment of patients who relapse after complete response to initial therapy, or after adjuvant therapy, is associated with a substantial probability of response. Together with evidence that more prolonged or intensive initial therapy rarely leads to more frequent or more prolonged responses, the current review suggests that some patients may develop transient resistance to chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗