Rhabdomyosarcoma diagnosed in the first year of life: Localized, metastatic, and relapsed disease. Outcome data from five trials and one registry of the Cooperative Weichteilsarkom Studiengruppe (CWS).

BACKGROUND

Rhabdomyosarcoma (RMS) diagnosed during the first year of life is reported to have poor outcome. Little is known about treatment and outcome data of relapsed disease (RD).

METHODS

Characteristics, treatment, and outcome of 155 patients ≤ 12 months registered within the Cooperative Weichteilsarkom Studiengruppe (CWS) between 1981 and 2016 were evaluated.

RESULTS

Localized disease (LD) was diagnosed in 144 patients and metastatic disease (MD) in 11. The histological diagnosis was alveolar (RMA) (n = 38, 23/25 examined patients PAX7/3:FOXO1-positive), embryonal (RME) (n = 100), botryoid (n = 10), anaplastic (n = 1), and spindle-cell RMS (n = 6). Multimodal treatment including conventional (age-adjusted) chemotherapy (CHT) (n = 150), resection (n = 137), and radiotherapy (RT) (n = 37) was administered. Complete remission was achieved in 129 of 144 patients with LD. RD occurred in 51 infants at a median age of 1.7 years (range, 0.3-8.8). Sixty-three percent of patients with RMA suffered RD, in contrast to 28% of patients with RME. Relapse treatment consisted of conventional CHT (n = 48), resection (n = 28), and RT (n = 21). The pattern of relapse and best resection were significant prognostic factors for patients with RD (P = 0.000 and P = 0.002). Late effects occurred as secondary malignancies in 6%, long-term toxicity in 21%, and resection-related impairment in 33% of the 105 surviving patients. The 5-year event-free survival and overall survival for infants with initial LD were 51% and 69%, 14% and 14% for patients with initial MD and 39% and 41% for relapsed patients, respectively.

CONCLUSION

Multimodal treatment including microscopically complete resection is strongly recommended to achieve a good prognosis in LD and RD of infants with RMS.