Sarcoma after 5 years of progression-free survival: lessons from the French sarcoma group

Assessing the Safety and Utility of Wound VAC Temporization of the Sarcoma or Benign Aggressive Tumor Bed Until Final Margins Are Achieved

BACKGROUND

Local recurrence of microinvasive sarcoma or benign aggressive pathologies can be limb- and life-threatening. Although frozen pathology is reliable, tumor microinvasion can be subtle or missed, having an impact on surgical margins and postoperative radiation planning. The authors' service has begun to temporize the tumor bed after primary tumor excision with a wound vacuum-assisted closure (VAC) pending formal margin analysis, with coverage performed in the setting of final negative margins.

METHODS

This retrospective analysis included all patients managed at a tertiary referral cancer center with VAC temporization after soft tissue sarcoma or benign aggressive tumor excision from 1 January 2000 to 1 January 2019 and at least 2 years of oncologic follow-up evaluation. The primary outcome was local recurrence. The secondary outcomes were distant recurrence, unplanned return to the operating room for wound/infectious indications, thromboembolic events, and tumor-related deaths.

RESULTS

For 62 patients, VAC temporization was performed. The mean age of the patients was 62.2 ± 22.3 years (median 66.5 years; 95% confidence interval [CI] 61.7-72.5 years), and the mean age-adjusted Charlson Comorbidity Index was 5.3 ± 1.9. The most common tumor histology was myxofibrosarcoma (51.6%, 32/62). The mean volume was 124.8 ± 324.1 cm³, and 35.5% (22/62) of the cases were subfascial. Local recurrences occurred for 8.1% (5/62) of the patients. Three of these five patients had planned positive margins, and 17.7% (11/62) of the patients had an unplanned return to the operating room. No demographic or tumor factors were associated with unplanned surgery.

CONCLUSIONS

The findings showed that VAC-temporized management of microinvasive sarcoma and benign aggressive pathologies yields favorable local recurrence and unplanned operating room rates suggestive of oncologic and technical safety. These findings will need validation in a future randomized controlled trial.

Late Local Recurrence and Metastasis in Soft Tissue Sarcoma of the Extremities and Trunk Wall: Better Outcome After Treatment of Late Events Compared with Early

Background

Approximately 80% of soft tissue sarcoma (STS) recurrences, local and metastatic disease, are diagnosed within the first 3 years after primary diagnosis and treatment. Recurrences, however, can present after a longer period of remission. Our goal was to identify factors that may predict the risk of late recurrence.

Methods

We identified 677 patients with STS of the extremities and trunk wall from a population-based sarcoma register. Of these, 377 patients were alive and event-free at 3 years and were included for analysis of possible risk factors for late recurrence.

Results

Fifty-five of 377 (15%) patients developed late recurrence: 23 local recurrence, 21 metastasis, and 11 both manifestations. With R0 wide surgical margin as reference, R0 marginal (hazard ratio [HR] 2.6; p = 0.02) and R1 (HR 5.0; p = 0.005) margins were risk factors for late local recurrence. Malignancy grade (HR 8.3; p = 0.04) and R0 marginal surgical margin (HR 2.3; p = 0.04) were risk factors for late metastasis. We could not find a statistically significant correlation of late recurrence with many of the generally known risk factors for local recurrence and metastasis in STS. Outcome after treatment of late recurrences was better compared with outcome after treatment of early events.

Conclusions

Late recurrences, albeit relatively rare, do occur. Outcome after treatment was good compared with outcome after early events. Long surveillance of all patients with high-grade STS, especially if R0 wide surgical margin is not achieved in the primary treatment, appear to be well justified.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-021-09942-8.

A product-limit estimator of the conditional survival function when cure status is partially known

We introduce a nonparametric estimator of the conditional survival function in the mixture cure model for right-censored data when cure status is partially known. The estimator is developed for the setting of a single continuous covariate but it can be extended to multiple covariates. It extends the estimator of Beran, which ignores cure status information. We obtain an almost sure representation, from which the strong consistency and asymptotic normality of the estimator are derived. Asymptotic expressions of the bias and variance demonstrate a reduction in the variance with respect to Beran's estimator. A simulation study shows that, if the bandwidth parameter is suitably chosen, our estimator performs better than others for an ample range of covariate values. A bootstrap bandwidth selector is proposed. Finally, the proposed estimator is applied to a real dataset studying survival of sarcoma patients.