Abstract
Purpose:
Tumor cell seeding has been reported with the use of 25-31 gauge needles during fine-needle aspiration biopsy of intraocular tumors. The purpose of this study was to evaluate the safety profile of small, 34-gauge needles for the diagnosis of uveal melanoma and retinoblastoma.
Methods:
Polymer beads 1, 10, and 20 microns in diameter were aspirated using 26, 30, and 34-gauge needles, and bead count was recorded for each group (n=10). All needles were used to aspirate WERI-Rb and Mel-270 cells in culture, and DNA was detected using spectrophotometry (n=1). To evaluate differences in in vitro growth, needles were used to aspirate and deposit WERI-Rb and Mel-270 cells onto culture plates (n=3). Cell counts were performed after initial aspiration and every two days for a total of ten days. Linear regression analyses were performed to compare growth among the aspirates. Aspirates were embedded in paraffin and cellular morphology was examined microscopically. The extent of intercellular adhesion within cells was quantified by counting clusters in high-power microscopic fields.
Results:
All needles aspirated similar amounts of beads, except the 34-gauge needle of 4-mm length, which aspirated significantly fewer 20-micron beads. All aspirates contained DNA. For WERI-Rb, there was a direct relationship between gauge size and cells aspirated. This difference was amplified over 10 days, as 34-gauge aspirates demonstrated significantly less growth [beta = 0.194, t(49)= p< 0.0001]. For Mel-270, there was no difference in cells initially aspirated or in 10-day growth [beta = 0.145; t(49) = -1.194; p = 0.238]. Aspirates from each group demonstrated intact cellular morphology, although fewer numbers of cells were observed in the 34-gauge groups. Compared to Mel-270 cells, WERI-Rb cells occurred in clusters more often [29% vs. 17% of total cells per hpf] and their weighted diameter was higher [mean ± SD = 24.6 ± 16.0 vs. 18.2 ± 9.1; two sample t-test, p<0.01].
Conclusions:
34-gauge needles can obtain DNA for analysis of tumor aspirates. Their use may decrease the spread and metastatic growth of retinoblastoma cells owing to cellular clustering, whose effect may be further amplified in eye tissue, where cells are more tightly bound than in cell culture.
Keywords: 744 tumors •
589 melanoma •
703 retinoblastoma