Long-Term Outcomes of Sacral and Sacrococcygeal Chordomas: A 30-Year Single-Center Experience Comparing Three Treatment Modalities.

Abstract

Sacral and sacrococcygeal chordomas present surgical and clinical challenges distinct from those of chordomas in the mobile spine. Over the last 30 years, three primary treatment modalities have emerged: wide surgical resection alone, surgical resection with radiotherapy (RT), and increasingly definitive RT. However, no studies have directly compared outcomes among the three treatment methods. To compare local recurrence (LR), overall survival (OS), perioperative outcomes, and complications among patients with primary solitary sacral or sacrococcygeal chordomas treated with wide surgical resection alone, surgical resection with RT, or definitive RT. Retrospective cohort study Patient Sample. One hundred thirteen patients with sacral or sacrococcygeal chordoma who were treated at a single institution between January 1994 and February 2024. Primary outcome measures were LR and OS. Secondary outcome measures were 30-day and long-term complications. Differences in LR and OS among treatment groups were analyzed using multivariable Cox proportional hazard models weighted by inverse probability of treatment weights. Rates of 30-day complications were compared using chi-squared tests; incidence of complications at any time following treatment was modeled using a negative-binomial regression model. Median follow-up was 7.6 years (interquartile range, 2.7-11). Fifty-five patients (49%) underwent wide surgical resection alone, 40 (35%) underwent wide surgical resection with neoadjuvant or postoperative adjuvant RT, and 18 (16%) received definitive RT. Negative margins were achieved in 83 patients (87%) undergoing surgery. OS varied significantly across treatment modalities and was shorter among patients who underwent surgical resection alone (hazard ratio [HR], 2.01; 95% confidence interval [CI], 0.96-4.20) or definitive RT (HR, 3.73; 95% CI, 1.15-12.1) compared to patients who underwent surgery with RT. Local recurrence was seen in 31 patients and did not differ across treatments in multivariable analysis (p=0.3); the HRs for surgery with RT and definitive RT were 0.48 (95% CI, 0.17-1.31) and 1.01 (95% CI, 0.25-4.12), respectively, relative to surgery alone. Among patients who received RT, a higher biologically effective dose was associated with a lower risk of LR (HR, 0.92; 95% CI, 0.86-0.98; p=.01). Complication rates at 30 days differed among the surgery plus RT (85%), surgery alone (55%), and definitive RT (5.6%) groups (p<.001), but total complication rates at final follow-up did not vary significantly across groups. Wide surgical resection has been the recommended treatment for solitary primary sacral and sacrococcygeal chordoma. The addition of an RT regimen may improve LR and survival. Although definitive RT demonstrated short-term outcomes comparable to those of surgery alone, longer follow-up is required to determine the durability of response and the late-toxicity profile. Therefore, definitive RT should be considered selectively rather than as a replacement for surgery.