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Biomedical subjects

G Poston

Publications and source records attributed to G Poston.

6 recordsLinked to original sources
PubMed1996

p53 protein overexpression and response to biomodulated 5-fluorouracil chemotherapy in patients with advanced colorectal cancer.

Biomodulated 5-flourouracil (5-FU) chemotherapy may limit disease progression in up to 50% of patients with metastatic or unresectable carcinoma of the colorectum. However, treatment is expensive and may be toxic. Thus any predictors of response may be clinically and economically valuable. The p53 gene is mutated in more than 50% of colorectal tumours, usually resulting in p53 overexpression. It may regulate cell cycle progression and cellular response to DNA damage. The principal anticancer activity of 5-FU is due to its ability to induce DNA damage. Fifty-nine patients received bolus intravenous 5-FU/folinic acid over 3 months. Response was assessed by CAT scan (WHO criteria). p53 protein overexpression was determined immunohistochemically from paraffin sections of the original primary tumour and resected metastases. Tumour over expression of p53 protein was associated with a lower rate of response and a higher rate of deterioration both radiologically (P < 0.03) and clinically (P < 0.05, chi 2 test for trend), but did not predict survival from start of treatment. Response was unrelated to age, sex, tumour grade, site of disease or chemotherapy schedule. Tumour p53 protein overexpression alone cannot be used to select advanced colorectal cancer patients for chemotherapy but may be useful in association with other markers of tumour biology.

Adult↗
PubMedDate not supplied

Cryosurgery for colorectal liver metastases.

Destructive therapy for liver tumors has been available for some time and a number of options have been used. These include alcohol injection, heating therapy with laser and, more recently, radiofrequency ablation and cryosurgery. The principle of cryosurgery is to destroy tissue by freezing and causing expansion of intracellular water. The effect of this treatment is to cause disruption of the cell membrane as the ice expands, thereby killing the cells and, secondly, releasing intracellular antigen into the circulation to promote an immune response. Lastly, there is a "frostbite" effect with thrombophlebitis of vessels feeding the tumor because of the freezing. A number of trials have evaluated destructive therapy, but none have shown definite benefit over chemotherapy alone. This review examines the data as it currently stands.

Colorectal Neoplasms↗
PubMedDate not supplied

The argument for liver resection in colorectal liver metastases.

The first liver resection for colorectal metastasis was performed by Cattell in 1940. Unfortunately, there has never been a randomized control trial for liver resection against other treatment modalities (best supportive care, palliative chemotherapy, etc). Since this operation is now well established in the surgical repertoire, it would now be ethically difficult to undertake such a trial.

Colorectal Neoplasms↗