Early reports of intralesional curettage for GCTs of bone noted recurrence rates ranging greater than 50 percent.4–7
As recurrence can make joint-preserving strategies much more difficult, such frequent recurrence is to be avoided if possible.
A number of different techniques () and chemical agents have been used as adjuvants to intralesional curettage of benign aggressive bone tumors such as GCT. These have included the use of a high speed burr, painting or irrigating with phenol,3,6,10–16
cryotherapy with liquid nitrogen,17–19
irrigation with hydrogen peroxide,20
irrigation with aqueous zinc chloride,21
thermal cautery with a carbon dioxide laser,22
defect filling with poly-methylmethacrylate (for its heating properties),3,11,12,23–26
and the use of defect-filling agents that elute methotrexate27
Recurrence rates reported after curettage of giant cell tumors of bone
Most surgeons agree that aggressive curettage through a sufficiently wide cortical window for visibility is of paramount importance. Typically, a high-speed burr is used to extend the intralesional margins after removal of the gross tumor. Some authors argue that these more aggressive excision techniques are sufficient to achieve an acceptably low frequency of recurrence, ranging from 0 to 19 percent.29–33
These authors argue that benefits attributed to chemical adjuvants may stem from their association with more recent curettage and burr techniques.
Of chemical techniques, adjuvant phenolization and cryotherapy have surfaced as the most popular. Phenol, which has been shown to be cytotoxic to GCT cells in vitro,34
has been associated with favorable results ranging from six to 18 percent recurrence rates in recent series.10,11,14,15
While some data exist to confirm low systemic toxicity from the use of phenol as a local adjuvant,35
it is a caustic substance and must be handled carefully with respect to the patient's adjacent tissues and operating suite personnel. Cryotherapy with liquid nitrogen also results in reportedly low recurrence rates, but has associated risks of fracture and skin necrosis.17,18
We are unaware of any previous reports of the use of ethanol irrigation as an adjuvant to intralesional curettage for GCT of bone. High concentration ethanol is readily available in most surgical suites and relatively safe to use. The cytotoxicity from ethanol does not likely extend deeply into surrounding bone, but its adverse effects on adjacent tissues are also minimal.
Overall, the recurrence rate after the use of adjuvant ethanol is not widely different from the use of other adjuvants for GCT of bone. This series does reiterate the argument for the use of a high-speed burr, regardless of the chemical adjuvant selected. While numbers were too small to reach statistical significance, of the 12 primary intralesional curettages that utilized a high-speed burr and adjuvant ethanol, only one led to lesion recurrence. Only one of the 12 patients was followed for less than two years.
A number of factors must be considered in comparing different series of GCT patients for rates of recurrence. While histologic grading (other than malignancy) is not predictive of recurrence in GCT of bone,36
Campanacci staging is considered to be important, as stage 3 lesions, or those that have breached the cortex and involved the adjacent soft tissues, have a higher recurrence rate in series that distinguish them from lower stage lesions.31
Unfortunately, not all series distinguish them. Many others have skewed numbers due to the institutional practice of treating most stage 3 GCTs with wide resection rather than intralesional curettage. Our series had more recurrences after stage 3 primary lesions (three of 10) than after stage 2 lesions (two of 11), but the difference did not reach statistical significance.
Others have noted preoperative fractures as a major risk for recurrence.37
Three patients in the study group had preoperative fractures with significant displacement but none had a recurrence of their tumor.
Location can also play a role in prognosis, with the distal radius being a location notorious for more rampant soft tissue involvement and frequent recurrence.12,19,30,38,39
Only one of the four distal radius GCTs in this series recurred. However, notably, it was the only recurrence after use of a high-speed burr and adjuvant ethanol.
Treatment of recurrent lesions with repeat intralesional curettage is debated by some practitioners who believe that GCT recurrence merits wide excision. Rates of re-recurrence after repeat intralesional curettage range between 30 and 40 percent among the varied techniques reported.5,17,19,31,40
The three re-recurrences of 12 repeat intralesional curettages represent a respectable local control rate with the use of ethanol as an adjuvant. The contribution of the use of acrylic cement as the filling material more frequently in these repeat surgeries is difficult to isolate given the small numbers.
In conclusion, we feel that high concentration ethanol is an effective and safe adjuvant for the treatment of GCT when used in conjunction with aggressive curettage including high-speed burring. Whether any chemical adjuvant is necessary after performance of an appropriately aggressive curettage can probably only be answered definitively with a prospective, randomized comparison including many centers. Until such evidence becomes available, we feel that the use of ethanol is a safe compromise between higher-toxicity adjuvants and no adjuvant at all.