(P 340) PREDICTORS OF LATE RECURRENCE AFTER SARCOMA SURGICAL RESECTION

Objective: The vast majority of sarcoma recurrences occur within the first 2 years after diagnosis and treatment. Only 10% of recurrences take place greater than five years after diagnosis. After this time, surveillance is often de-escalated. We aimed to identify patient and tumor risk factors associated with sarcoma recurrence five years or later after surgical resection.

Methods: A retrospective analysis of a prospectively maintained single-institution database was utilized. Adult who underwent surgical resection of a sarcoma, were on regular, standardized surveillance, and subsequently had a recurrence were included in the study. Patient and tumor characteristics were compared between recurrences that took place prior to and after five years from surgery. Local and distant recurrences were both included.

Results: The study population included 1290 patients; all had a sarcoma recurrence after surgical resection. Of these, 1059 (82%) experienced a recurrence within 5 years of surgery (early recurrence), while 231 (18%) recurred greater than 5 years later (late recurrence). There were no differences between the early and late recurrence groups with respect to sex, smoking history, race, or margin status. Late recurrence was significantly more likely to occur in patients younger than age 55 (p < 0.001) and those with well-differentiated tumors (p < 0.001, 9.2% early recurrence versus 26% late recurrence). Early recurrences were significantly more likely to occur distantly when compared to late recurrences, which were more likely to be local recurrences (p=0.011). On multivariable logistic regression adjusting for histologic subtype, older age (greater than 55) was associated with decreased likelihood of late recurrence (OR .49, p<.05) compared to younger age. Those with pathologic stage IV disease were less likely to have late recurrence than those with stage I (OR 0.4, p=0.02). Those with poorly differentiated tumors were less likely to have late recurrence than those with well-differentiated disease (OR 0.47, p<.001).

Conclusion: Late as opposed to early recurrence of sarcoma after surgical resection is perhaps more common than widely believed. Patients who recurred more than 5 years after surgical resection were more likely to be younger and have well-differentiated tumors. Late recurrences also were more likely to occur locally rather than distantly. These data speak to the importance of long term surveillance and management of sarcoma patients beyond the traditional five years of follow up.