Do Patients Treated With an Unplanned Resection for Small Superficial Soft Tissue Sarcomas Have Worse Long-term Survival Than Those Initially Treated With an Oncologic Resection?

Background: Histologic grade, size, and depth are well-known prognostic factors in soft tissue sarcomas (STS). Small (< 5 cm) and superficial STS generally have an excellent prognosis when treated with appropriate surgery. However, they are often misdiagnosed and mistreated. We reported that in midterm follow-up (5 to 7 years), patients with unplanned resections of tumors with positive margins who immediately underwent a reoperation with margin-widening re-resection and postoperative radiotherapy had survival comparable to that of patients who were initially treated correctly. In that article, we included STS larger than 5 cm, deep STS, and individuals with local recurrence. However, we wanted to evaluate the impact of unplanned resection on the survival of patients who had STS with the best prognosis, small and superficial STS, with two groups that were as homogeneous as possible.

Question/purpose: Do patients with small and superficial STS who underwent an unplanned resection have worse prognosis in the long term than those who were initially treated correctly?

Methods: We exclusively evaluated patients with small (< 5 cm) and superficial (to the deep fascia) STS. We systematically excluded deep STS. Among this subset, we identified 93 patients with superficial STS. We excluded patients with local relapse, metastatic disease, superficial STS of the head or neck, those with insufficient clinical or dosimetric information, and patients with follow-up of less than 2 years. Furthermore, our focus on investigating the most benign and homogeneous STS prompted us to exclude patients with superficial tumors greater than or equal to 5 cm. This selection was driven by the presumed better prognosis associated with smaller tumors, inevitably leading to a smaller pool of patients for direct comparison with patients who had unplanned resections. The initial expectation was to observe similar survival outcomes between cohorts. Between 1990 and 2019, a total of 17 patients underwent surgical treatment at our private, medium-size center. Of those, 29% (5 patients) were lost to follow-up before 2 years without meeting a study endpoint (relapse, metastasis or revision, reoperation, or death), leaving a total of 71% (12 patients) of the original group who had either follow-up of at least 2 years or who met a study endpoint before that minimum surveillance duration. They were treated with surgery alone. During that same period, another 51 patients were referred to us after undergoing an unplanned resection of a lesion that subsequently was determined to be a soft tissue malignancy. Of those, 18% (9 patients) were lost to follow-up before 2 years without meeting a study endpoint, leaving 82% (42 patients) of the original group who had either follow-up of at least 2 years or who met a study endpoint before that minimum surveillance duration. They were treated with re-excision and postoperative radiotherapy. Patients with unplanned resections had an older mean age (51± 5 versus 44 ± 7 years; p = 0.1) and a higher proportion of female patients (58% versus 38%; p = 0.07), but the groups did not differ in terms of largest diameter, histologic type, or tumor location. However, patients with planned resections had a higher proportion of high-grade STS (75% versus 55%; p = 0.07). No metastases were present in either group at diagnosis. We performed a univariate analysis of the groups. We could not perform a multivariate analysis because of the small sample. We compared the groups in terms of local recurrence and all-cause mortality using the Kaplan-Meier survivorship estimator.

Results: According to the Kaplan-Meier survivorship estimator, survivorship free from local recurrence at a mean of 20 years of follow-up was better in the planned resection group than in the unplanned resection group (92% [95% CI 63% to 100%] versus 69% [95% CI 54% to 81%]; p = 0.04). Furthermore, overall survivorship at 5 years was higher in the planned resection group than in the unplanned resection group (100% [95% CI 72% to 100%] versus 70% [95% CI 54% to 81%]; p = 0.04). Similarly, the planned resection group exhibited superior survivorship at 20 years of follow-up (100% [95% CI 72% to 100%] versus 62% [95% CI 47% to 75%]; p = 0.01). Metastatic disease was absent in the planned resection group, while it occurred in 12 patients in the unplanned resection group (28% [95% CI 17% to 44%]).

Conclusion: Unplanned resection for patients with small and superficial STS was associated with a decrease in overall survival in the long term, despite the use of postoperative radiotherapy. An unplanned resection may be an important prognostic factor. Nevertheless, larger and prospective studies are needed to validate our findings. Although small and superficial lumps are usually benign, nonsarcoma surgeons should be aware that some masses may be malignant, and if in doubt, MR imaging, a biopsy before excision, or consultation with or referral to a sarcoma center should be considered before removing the mass.

Level Of Evidence: Level III, therapeutic study.