CTCAE v6.0 and v5.0 Lookup.

The Common Terminology Criteria for Adverse Events (CTCAE) are maintained by the Cancer Therapy Evaluation Program (CTEP) in the National Cancer Institute’s Division of Cancer Treatment and Diagnosis[3]. NCI describes CTCAE as a descriptive terminology for adverse event reporting, with a grading (severity) scale for every term[2].

In NCI’s wording, an adverse event is “any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medical treatment or procedure that may or may not be considered related to the medical treatment or procedure”[2].

Each v6.0 term is a MedDRA 28.0 Lowest Level Term, and the terms are grouped by MedDRA primary system organ class (SOC)[2]. MedDRA itself does not rank severity, which is the job CTCAE adds[4].

NCI’s Common Toxicity Criteria date from 1982[3]. Trotti and colleagues described version 3.0 as the first comprehensive, multimodality grading system for the acute and late effects of cancer treatment[5]. Version 5.0 followed on 27 November 2017 with MedDRA 20.1[6], and version 6.0 in July 2025 with MedDRA 28.0[2][7]. NCI says no further changes to v6.0 are planned and expects v7.0 between 2027 and 2030[1].

A grade describes the severity of an adverse event. NCI writes a specific description for each grade of each term, based on a general scale[2]. The CTCAE v6.0 Quick Reference gives these general definitions[7]:

NCI separates the conditions with semicolons. We show each condition on its own line. The v6.0 Excel workbook keeps the older v5.0 wording for grades 2 and 3[2].

Three reading rules come from NCI. A semicolon inside a grade description means “or”, so one condition is enough[7]. A participant does not need every element of a description, and when they show elements of more than one grade, the highest grade is assigned[3]. A dash means the grade is not available for that term, because not every grade fits every event, and grade 5 (death) does not apply to some terms[7].

Activities of daily living

Grades 2 and 3 often turn on activities of daily living (ADL). In the v6.0 Quick Reference, instrumental ADL “refers to preparing meals, shopping for groceries or clothes, using the telephone, managing money, etc.” and self-care ADL “refers to bathing, dressing and undressing, feeding self, using the toilet, taking medications”[7]. The v5.0 list ended with “and not bedridden”, which v6.0 drops[7][6]. For children, v6.0 grades the impact on “age-appropriate normal daily activity”: mild or moderate for grade 2 and severe for grade 3[7].

A grade records severity only. NCI states that reporting and grading an event documents that it occurred and how severe it was, and does not imply that the treatment caused it[3].

Attribution is a separate judgement by the clinical team. NCI uses five levels: unrelated, unlikely, possible, probable and definite. The treating clinician can assign it at the clinical evaluation, and investigators can also assign it later during aggregate review[3].

Seriousness is a third, separate idea. The ICH E2A guideline states that serious and severe are not synonymous. Severity describes intensity, while seriousness is based on outcome or action criteria, such as death, a threat to life, inpatient hospitalisation or persistent disability, and it guides regulatory reporting obligations. ICH’s own example of a severe event that may be of relatively minor medical significance is a severe headache[9].

This lookup returns NCI’s severity criteria only. It does not judge causality or seriousness, which your protocol and safety plan define.

Version 6.0 moved from MedDRA 20.1 to 28.0 and grew from 837 to 850 terms[2][8]. Counting NCI’s own labels in the v6.0 workbook, 60 terms were added, 47 retired and 790 carried over, and 450 of those 790 changed in some way (WeGuide count)[2].

• Retired terms point somewhere. NCI’s mapping sends Platelet count decreased to Thrombocytopenia, Lymphocyte count decreased to Lymphopenia, Proteinuria to Urinary protein increased, and the ankle, hip, spinal and wrist fracture terms to Fracture[2]. Some retired terms are now reported under Other, specify, for example Conduction disorder.
• New terms with no v5.0 predecessor include Immune effector cell-associated neurotoxicity syndrome, Secondary hemophagocytic lymphohistiocytosis, Graft versus host disease and Thrombotic microangiopathy[2].
• More guidance in the text. Navigational notes now appear on 203 terms, up from 74, and many grade descriptions add wording for children[2][8].
• Four terms changed class: Cyanosis, Growth accelerated, Aphonia and Retinoic acid syndrome[2]. Fifteen carried over terms changed which grades exist. Tumor lysis syndrome, for example, went from grades 3 to 5 to grades 1 to 5 (WeGuide count)[2][8].
• Some thresholds moved under a Clarification label. For Neutrophil count decreased, the v5.0 grade 2 range is now grade 1, the v5.0 grade 3 range is now grade 2, and grade 4 now starts below 100/mm3, yet NCI labels the change Clarification[2][8]. The same count can get a lower grade, or no grade, under v6.0.

Comparing the numbers in NCI’s mapping rows, 52 v5.0 terms have changed numbers somewhere. Of these, 34 carried over to v6.0, and each of them has at least one changed threshold that NCI labels Clarification (WeGuide analysis). The lookup flags these terms.

NCI’s implementation FAQ, dated 9 September 2025, says v6.0 “is ready for immediate use for any study except NCI CTEP or DCP NCORP studies” and asks teams with questions to contact their study sponsor[1].

Ongoing NCI CTEP and DCP studies that report in v5.0 continue in v5.0 for the life of the study, and NCI does not require them to convert existing data[1]. NCI has published a mapping of every v5.0 term and grade combination to v6.0, which is the source of the change view in this tool[1][2].

Timing for new NCI studies is less clear. The FAQ ties the v6.0 requirement to a release of NCI’s Rave data system that it tentatively scheduled for July 2026, and it says the timeline may move[1]. A DCTD page updated in July 2026 gives a target of 1 January 2026 for newly opened studies[10]. The two statements conflict and we found no later NCI notice, so confirm the date with your sponsor or CTEP before you plan around it.

Outside NCI’s network, the protocol names the version. If a study will pool adverse events graded in both versions, agree how to map them before the analysis plan is final.

• Clinician grading varies. CTCAE is the standard for investigator reporting of symptomatic adverse events[11]. Two clinicians rating seven symptoms in the same patients reached intraclass correlations of 0.46 to 0.71[12], and two reviewers coding radiotherapy notes reached a kappa of 0.68[13].
• Clinicians miss symptoms. Physician reporting of eight chemotherapy symptoms had 47% sensitivity and 68% specificity against patient answers on the EORTC QLQ-C30[14].
• Patients can report their own symptoms. Because clinician reporting underdetects symptomatic events, NCI commissioned PRO-CTCAE as a patient reported companion to CTCAE. Its developers judged 78 CTCAE terms suitable for self report and wrote 124 items[11], and a study of 975 adults found favourable validity, reliability and responsiveness[15]. Across 28 studies, agreement between CTCAE and patient ratings was moderate at best[16]. Our comparison of eCOA and ePRO explains how electronic patient reports fit into a trial.
• Skin grading is debated. Dermatologists have questioned how v6.0 grades cutaneous toxic effects and proposed an updated framework[17].
• The files change. NCI issued seven errata to v6.0, dated 20 January 2026, and this lookup includes them[2]. Check the official files for anything newer.
• This is a reference, not a grader. The lookup shows NCI’s criteria. It does not grade an event, assign attribution or decide what to report.

Criteria from the Common Terminology Criteria for Adverse Events (CTCAE) v6.0 and v5.0, originally published by the National Cancer Institute. Data from the NCI Excel files for v6.0 (MedDRA 28.0, including errata to 20 January 2026) and v5.0 (MedDRA 20.1), checked on 20 October 2026.

Term names, grade descriptions, definitions, navigational notes and change labels are NCI’s own wording. WeGuide only adjusts spacing and line breaks. Counts and flags marked “WeGuide analysis” are ours. NCI allows its text to be reused with credit to NCI as the source[18].

WeGuide built this lookup from public NCI files. It is not produced, reviewed or endorsed by the National Cancer Institute, and no endorsement by NCI should be inferred.

“CTCAE incorporates elements of the MedDRA terminology. For further details on MedDRA refer to the MedDRA MSSO Web site (https://www.meddra.org/).” This tool does not show MedDRA codes.

NCI also runs its own Online CTCAE Dictionary Tool, which needs a login[3]. If you build symptom questionnaires for a cancer study, our cancer and palliative care instruments and the guide to eCOA in clinical trials are good next reads, and the WeGuide Form Builder turns them into scheduled diaries.