Percutaneous Biopsy May Replace Surgery

Tumour biopsy with classic surgical
methods may soon be history
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Inserting biopsy needles through the skin appears to be a safe and reliable alternative to surgery for obtaining diagnostic samples of a suspected solid tumour in children, according to results of a study by investigators at St. Jude Children's Research Hospital. The technique, called percutaneous core-needle biopsy, provides samples of tissue suitable for accurate initial diagnosis of a solid tumour, the researchers say.

The St. Jude team first analysed clinical data obtained from 202 percutaneous core-needle biopsies of solid tumours over 5.5 years (1997 to 2003) in order to determine how many of the individual biopsy samples lead to the correct identification of a cancer.

Attempts to diagnose initial cancer for each of the 103 patients produced 62 "true positive" diagnoses out of 64 results that had been judged to be positive for cancer. This meant the sensitivity of this procedure for making initial diagnoses was 97%, according to the report. The technique also correctly identified all 39 patients who were later found to be negative following laboratory examination of tissues removed surgically - or by clinical follow-up - a specificity of 100%. These "false tumours" were caused by inflammatory or infectious processes rather than cancer, the researchers say. In addition, examination of biopsy samples obtained percutaneously led to the incorrect diagnosis of "no cancer" in only two thyroid carcinoma cases, for an accuracy of 98%.

The researchers also determined the ability of percutaneous biopsy to correctly identify cancer in 99 patients who were suspected of having a recurrence of a previously treated cancer. The results showed that percutaneous biopsy was less reliable than for initial diagnosis. Specifically, the sensitivity was 83%; specificity was 100%; and accuracy was 88%.; Source: St. Jude Children's Research Hospital