Heterotopic calcification as a late radiation effect: report of 15 cases.

The LENT-SOMA scoring system for reporting late tissue effects following therapeutic radiation does not include heterotopic calcification as an end-point. Here we report on 15 long-term radiotherapy survivors with significant heterotopic calcifications. In all cases heterotopic calcification was linked to other radiation sequelae, e.g. ulceration, bone necrosis, nerve damage and fibrosis. The median time interval between radiotherapy and the occurrence of heterotopic calcification was 19 years (range 2-31 years). All patients received doses in excess of 40 Gy; overlap of adjacent fields played a role in some cases. It appears that heterotopic calcification can be regarded as end-stage damage following high dose radiotherapy. Heterotopic calcification in conjunction with local tissue breakdown is highly suggestive of previous radiation treatment.