RANO criteria for glioblastoma

Response assessment in neuro-oncology criteria (RANO), published in 2010 , are used to assess response to first-line treatment of glioblastoma (as well as lower grade astrocytoma ) and have largely superseded the older Macdonald criteria (which only dealt with glioblastoma multiforme) .

For a general discussion see glioma treatment response assessment in clinical trials.

The RANO criteria, roughly similar to other systems (cf. RECIST), divides response into four types of response based on imaging (MRI) and clinical features :

To address the challenges of emerging novel immunotherapy for high-grade glioma immunotherapy response assessment for neuro-oncology (iRANO) criteria have been developed in 2015 and are discussed separately .

Measurement

The RANO criteria were, at least in part, developed to address the issues faced when measuring some lesions on Macdonald criteria, particularly:

• lesions with central necrosis
• T2W component

As such lesions are defined as "measurable" and "non-measurable" .

Measurable lesions

A measurable lesion is measured as follows:

• either CT or MRI
• contrast-enhancing
• clearly-defined margins
• visible on two or more axial slices
  • preferably <5 mm thick with 0 mm skip (i.e. no interslice gap)
• maximal diameter and second perpendicular measurement
  • at least 10 mm in size (if slice thickness <5 mm) 
  • 2 times slice thickness (if slice thickness >5 mm)
  • From ref 1: "In the event there are interslice gaps, this also needs to be considered in determining the size of measurable lesions at baseline." - [needs clarification]
• do not measure any cystic cavity

Non-measurable lesions

Non-measurable lesions are generally those that do not meet the criteria above. Additionally, and worthy of specific mention, is a cystic/necrotic tumor, or one with a surgical cavity. In such cases only a solid peripheral nodular component should be measured, provided it fulfills the above 'measurable' criteria.

Again, it is not difficult to think of numerous examples where defining a 'nodule' is difficult. It is therefore crucial that the baseline scan is available as well as the axes of initial measurement in assessing response.

The measurements are obtained from axial postcontrast T1W images. The maximal diameter is obtained, and then the second diameter is obtained at right angles to the first. The product of these measurements is then used for the purpose of comparison .

Criteria

Complete response

• imaging features
  • disappearance of all enhancing disease (measurable and non-measurable)
  • sustained for at least 4 weeks
  • stable or improved non-enhancing FLAIR/T2W lesions
  • no new lesions
• clinical features
  • no corticosteroids (physiological replacement doses allowed)
  • clinically stable or improved

Partial response

• imaging features
  • 50% or more decrease of all measurable enhancing lesions
  • sustained for at least 4 weeks
  • no progression of non-measurable disease
  • stable or improved non-enhancing FLAIR/T2W lesions
  • no new lesions
• clinical features
  • stable or reduced corticosteroids (compared to baseline) 
  • clinically stable or improved

Stable disease

• imaging features
  • does not qualify for complete response, partial response or progression
  • stable non-enhancing FLAIR/T2W lesions
• clinical features
  • stable or reduced corticosteroids (compared to baseline) 
  • clinically stable

Progression

• imaging features
  • 25% or more increase in enhancing lesions despite stable or increasing steroid dose
  • increase (significant) in non-enhancing FLAIR/T2W lesions, not attributable to other non-tumor causes
  • any new lesions
• clinical features
  • clinical deterioration (not attributable to other non-tumor causes and not due to steroid decrease)