. 2015 Aug;22(4):e273–e281. doi: 10.3747/co.22.2436

TABLE I.

Determining first progression, depending on time from initial chemoradiotherapy¹⁰

Timing of progressive disease from completion of chemoradiotherapy	Definition
<12 Weeks after	Progression can be defined using diagnostic imaging only if new enhancement occurs outside the radiation field (beyond the high-dose region or the 80% isodose line) or if unequivocal evidence of viable tumour is obtained on histopathologic sampling (for example, >70% tumour cell nuclei in solid tumour areas, high or progressive increase in the MIB1 proliferation index compared with prior biopsy, or evidence for histologic progression or increased anaplasia in tumour). Given the difficulty of differentiating true progression from pseudoprogression, clinical decline alone—in the absence of radiographic or histologic confirmation of progression—will not be sufficient for definition of progressive disease in the first 12 weeks after completion of concurrent chemoradiotherapy.
≥12 Weeks after	A new contrast-enhancing lesion outside of the radiation field on declining, stable, or increasing doses of corticosteroids. Increase by 25% or more in the sum of the products of the perpendicular diameters from the first post-radiotherapy imaging (or subsequent imaging showing a smaller tumour size) to the imaging at 12 weeks or later on stable or increasing doses of corticosteroids. Clinical deterioration not attributable to concurrent medication or comorbid conditions is sufficient to declare progression on current treatment, but not for entry onto a clinical trial for recurrence. For patients receiving antiangiogenic therapy, a significant increase in a T2 or FLAIR (fluid-attenuated inversion recovery) non-enhancing lesion can also be considered progressive disease. The increased T2 or FLAIR must have occurred compared with baseline imaging or the best response after initiation of therapy, with the patient on stable or increasing doses of corticosteroids, and must not be a result of comorbid events (for example, effects of radiation therapy, demyelination, ischemic injury, infection, seizures, postoperative changes, or other treatment effects).

Timing of progressive disease from completion of chemoradiotherapy

Definition

<12 Weeks after

Progression can be defined using diagnostic imaging only if new enhancement occurs outside the radiation field (beyond the high-dose region or the 80% isodose line) or if unequivocal evidence of viable tumour is obtained on histopathologic sampling (for example, >70% tumour cell nuclei in solid tumour areas, high or progressive increase in the MIB1 proliferation index compared with prior biopsy, or evidence for histologic progression or increased anaplasia in tumour). Given the difficulty of differentiating true progression from pseudoprogression, clinical decline alone—in the absence of radiographic or histologic confirmation of progression—will not be sufficient for definition of progressive disease in the first 12 weeks after completion of concurrent chemoradiotherapy.

≥12 Weeks after

A new contrast-enhancing lesion outside of the radiation field on declining, stable, or increasing doses of corticosteroids.
Increase by 25% or more in the sum of the products of the perpendicular diameters from the first post-radiotherapy imaging (or subsequent imaging showing a smaller tumour size) to the imaging at 12 weeks or later on stable or increasing doses of corticosteroids.
Clinical deterioration not attributable to concurrent medication or comorbid conditions is sufficient to declare progression on current treatment, but not for entry onto a clinical trial for recurrence.
For patients receiving antiangiogenic therapy, a significant increase in a T2 or FLAIR (fluid-attenuated inversion recovery) non-enhancing lesion can also be considered progressive disease. The increased T2 or FLAIR must have occurred compared with baseline imaging or the best response after initiation of therapy, with the patient on stable or increasing doses of corticosteroids, and must not be a result of comorbid events (for example, effects of radiation therapy, demyelination, ischemic injury, infection, seizures, postoperative changes, or other treatment effects).