Immunity Against Tetanus and Diphtheria After Childhood Sarcoma Treatment

An important topic in cancer survivorship is loss of immunity to vaccine-preventable diseases (v. d. Hardt K et al., Vaccine 2000; 18: 2999–3004). Most studies have examined patients after hematological malignancies. Data on patients after treatment for solid tumors are rare.

The Late Effects Surveillance System (LESS) is a trinational multicentre study that prospectively registers sequelae of cancer therapy (Langer T et al., Klin Padiatr 2005; 217: 176–181).

Subject of this report are antibody levels (AL) against diphtheria (D) and tetanus (T), as surrogates for vaccine-preventable diseases, after sarcoma treatment in childhood. The measurements were carried out at the local hospitals conducting follow-up after end of treatment. Ten hospitals of the LESS-network contributed data. AL against D/T <0.1 IU/ml were not considered protective.

Fourty-seven patients (31 male, 16 female) were included (10 osteosarcomas, 12 Ewing sarcomas, 25 soft tissue sarcomas). Median age at diagnosis was 9.6 (interquartile range (IQR): 4.4–14.7) years.

A median of 7.2 (IQR 3.7–12.2) months after end of treatment the median D AL was 0.25 IU/ml and the median T AL was 0.7 IU/ml. In 13/47 (27.6%; 95% CI 16–43%) patients there were no protective AL (<0.1 IU/ml) against D and/or T. A further two patients had unclear D AL (<0.15 IU/ml); when classifying these values also as abnormal then 32% (15/47; 95% CI 19–47%) of patients would have had no protective AL. D and T AL were positively correlated (r=0.39; p=0.007). In multivariable analyses, the schedule of antineoplastic treatment, tumor type and time from end of treatment had no significant effect on AL. For D, girls had significantly lower AL (48% (95% CI 27–86%) than boys, p=0.015), and there was a tendency of younger patients having lower AL (5% (95% CI 0–10%) decrease per year younger, p=0.058). Younger patients also had significantly lower AL against T (9% (95% CI 2–17%) decrease per year younger, p=0.009) whereas there was no statistical significant sex difference (p=0.61).

Over 25% of examined patients were affected by lack of immunity, showing that also patients after sarcoma develop secondary immunodeficiency. Younger children are at increased risk, as previously described for other sequelae (Stöhr W et al., Pediatr Blood Cancer 2007; 48: 447–452).