Prospective evaluation of fiducial marker placement quality and toxicity in liver CyberKnife stereotactic body radiotherapy.

Background: Evaluate morbidities and "quality" of fiducial marker placement in primary liver tumours (hepatocellular carcinoma [HCC]) for CyberKnife.

Materials and methods: Thirty-six HCC with portal vein thrombosis(PVT) were evaluated for "quality" of fiducial placement, placement time, pain score, complications, recovery time and factors influencing placement.

Results: One hundred eight fiducials were placed in 36 patients. Fiducial placement radiation oncologist score was "good" in 24(67%), "fair" in 4(11%), and "poor" in 3(8%) patients. Concordance with radiologist score in "poor", "fair", and "good" score was 2/2(100%), 4/5(80%), and 24/27(89%), respectively(p=0.001). Child-Pugh score(p=0.080), performance status(PS) (p=0.014) and accrued during "learning curve"(p=0.013) affected placement score. Mean placement time(p=0.055), recovery time(p=0.025) was longer and higher major complications(p=0.009) with poor PS. Liver segment involved(p=0.484) and the Barcelona Clinic Liver Cancer(BCLC) stage did not influence placement score. "Good" placement score was 30% in first cohort whereas 93% in last cohort(p=0.023). Time for placement was 42.2 and 14.3 minutes, respectively(p=0.069). Post-fiducial pain score 0-1 in 26 patients(72%) and pain score 3-4 was in 2(6%). Five patients (14%) admitted in "day-care"(2 mild pneumothorax, 3 pain). Mortality in 1 patient(3%) admitted for hemothorax.

Conclusion: Fiducial placement is safe and in experienced hands, "quality" of placement is "good" in majority. Major complications and admission after fiducial placement are rare. Complications, fiducial placement time, recovery time is more during the "learning curve". Poor Child-Pugh score, extensive liver involvement, poor PS have higher probability of complications.