Disease progression or pseudoprogression after concomitant radiochemotherapy treatment: pitfalls in neurooncology

Abstract

Although radionecrosis has been exhaustively described in depth in the neurooncological literature, its diagnosis is still a challenging issue because its radiological pattern is frequently indistinguishable from that of tumor recurrence. This review discusses the causes of radionecrosis and the potential effect of adjuvant chemotherapy concomitant with radiotherapy on its rate and onset. The potential pitfalls in clinical studies attempting to make a differential diagnosis between radionecrosis and disease progression are also discussed.

Fig. 1

Clinical course of pseudoprogression in a 65-year-old patient with glioblastoma multiforme. (A) Presurgical MRI scan. (B) Postsurgical MRI scan. (C) MRI scan performed 1 month after combined temozolomide (TMZ)/radiotherapy; adjuvant TMZ was continued. (D) Four months later, during administration of maintenance TMZ. (E) Eight months later, during administration of maintenance TMZ.

Fig. 2

MR spectroscopic imaging 10 months after temozolomide plus radiotherapy. Choline:creatine and N-acetylaspartate:choline ratios were 1.3 and 0.92, respectively, suggesting a residual non-neoplastic lesion.

Fig. 3

Open questions in detection and interpretation of suspect lesions after combined radiotherapy/temozolomide (RT/TMZ) and potential implication in treatments. Abbreviations: MRS, MR spectroscopy; PD, progressive disease.