Soft tissue sarcoma diagnosed subsequent to lymphoma is associated with prior radiotherapy and decreased survival

Cancer survivors are at increased risk for second malignancies, and vigilance is thus required. The authors sought to determine whether there was an association among lymphoma, sarcoma, and the associated treatments for these diseases.

From the authors' prospective soft tissue sarcoma (STS) database of 8240 patients, they identified 112 patients with STS and lymphoma treated from 1982 to 2009 who had complete follow-up data. They examined the importance of the initial diagnosis in patients with both STS and lymphoma, in addition to determining the role of radiation therapy, a known inducer of sarcoma.

Review of their sarcoma, gastric, urology, breast, and gynecology databases revealed that lymphoma (95%) or leukemia (5%) occurred in 1.6% of STS patients in comparison to 0.5% of patients in the other databases (P < .01; odds ratio, 3.1; 95% confidence interval, 2.6-3.8). Patients diagnosed with STS only were more likely to die of disease at 10 years compared with those with STS and lymphoma (P = .006), but this difference was not significant when patients presenting with recurrence or metastases were excluded. Among patients with lymphoma and STS, lymphoma was the first diagnosis in 71% of patients. Median survival after STS diagnosis was shorter when lymphoma was the initial diagnosis (67 vs 170 months, P = .002), and these patients were more likely to have radiation-associated STS (44% vs 3%, P < .001).

There was a 3-fold higher incidence of lymphoma in STS patients compared with other solid tumors. The poor prognosis of those diagnosed with both STS and lymphoma was most likely a consequence of prior irradiation.