Geriatric Oncology Toxicity Calculators
Compare G8, CARG, CARG-BC, CRASH, and Charlson tools for older adults being considered for chemotherapy.
Original CRASH 2012 source lock
The Original CRASH Chemotherapy Toxicity Score (2012) is limited to adults age 70 or older before a new cytotoxic chemotherapy regimen. MAX2 must already be established for the exact regimen; the calculator does not infer it from a regimen name.
CRASH returns separate hematologic, non-hematologic, and combined source groups. Historical derivation and validation incidences are cohort observations, not individualized probabilities. The score does not prescribe dose, growth-factor use, monitoring, regimen selection, or any other treatment action.
Quick Navigation
1. Why This Cluster Matters
Older adults with cancer vary widely in physiologic reserve, cognition, mobility, nutrition, social support, renal function, and treatment goals. Chronologic age and ECOG performance status alone often miss vulnerabilities that affect chemotherapy tolerance. ASCO and geriatric oncology guidance therefore emphasize structured geriatric assessment and validated tools to identify risks that routine oncology assessment may not capture.1, 2
OncoToolkit now groups several complementary geriatric oncology calculators: G8, CARG, CARG-BC, CRASH, and Charlson. They answer related but different questions. The safest use is to define the clinical question first, then choose the tool that matches the patient population and decision point.
Clinical caution
These scores support risk communication and care planning. They do not decide whether chemotherapy is "allowed," and they should not replace geriatric assessment, oncology judgment, pharmacy review, or patient priorities.
2. Quick Links
- G8 Geriatric Screening
- CARG Chemotherapy Toxicity
- CARG-BC Breast Chemotherapy Toxicity
- Original CRASH Chemotherapy Toxicity Score (2012)
- Charlson Comorbidity Index
- Supportive Care Calculator Hub
3. Tool Comparison
| Tool | Best Use | Output | Notes |
|---|---|---|---|
| G8 | Screening for geriatric vulnerability before cancer treatment | Normal vs abnormal screen | Fast triage tool; abnormal results support fuller geriatric assessment.3 |
| CARG | Older adults starting chemotherapy across cancer types | Grade 3-5 toxicity risk group | Practical, widely used, and easier to collect than CRASH in many clinics.4 |
| CARG-BC | Adults 65 or older with stage I-III breast cancer receiving neoadjuvant/adjuvant chemotherapy | Breast-specific grade 3-5 toxicity risk | Prefer over general CARG for this specific population when inputs are available.5 |
| CRASH | Adults age 70 or older before a new cytotoxic regimen, with exact-regimen MAX2 and all raw factors available | Separate hematologic, non-hematologic, and combined source groups | MAX2 must be externally established for the exact regimen and is never guessed from a regimen name.6 |
| Charlson | Comorbidity burden and mortality-risk context | Weighted comorbidity score | Not a chemotherapy toxicity score by itself. |
Risk Bands to Keep Straight
| Calculator | Low | Intermediate | High |
|---|---|---|---|
| CARG | 0-5 points, about 30% toxicity | 6-9 points, about 52% toxicity | 10-19 points, about 79%-83% toxicity |
| CARG-BC | 0-5 points; 27% observed validation-cohort incidence | 6-11 points; 45% observed validation-cohort incidence | 12-24 points; 76% observed validation-cohort incidence |
| CRASH | 0-3 combined score | 4-6 intermediate-low; 7-9 intermediate-high | >9 combined score |
For CARG-BC, these percentages are observed group-level incidences of grade 3-5 toxicity, not individualized patient probabilities. The development-cohort incidences were 19%, 54%, and 87% for the low, intermediate, and high groups, respectively.5
4. Practical Workflow
- Start with the treatment question. Is the visit about vulnerability screening, chemotherapy toxicity prediction, breast-specific adjuvant therapy, or comorbidity context?
- Screen for vulnerabilities early. Use G8 when the first question is whether a patient needs a fuller geriatric assessment.
- Estimate toxicity before finalizing chemotherapy. Use CARG for broad chemotherapy toxicity discussion, or CARG-BC for older adults with early-stage breast cancer receiving neoadjuvant or adjuvant chemotherapy.
- Use CRASH only with exact source inputs. The Original CRASH 2012 score requires an externally established exact-regimen MAX2 plus raw DBP, IADL, LDH/ULN, ECOG, MMSE, and MNA values.
- Add comorbidity context. Use the Charlson Comorbidity Index to describe comorbidity burden, while remembering it is not a direct chemotherapy toxicity model.
- Keep interpretation separate from management. These tools describe different source-specific screening or toxicity groups; no score by itself determines treatment, dosing, prophylaxis, or monitoring.
5. Clinical Scenarios
New metastatic colorectal cancer consultation, age 78
Use G8 to identify vulnerabilities, then CARG to estimate grade 3-5 chemotherapy toxicity before choosing intensity. Add renal function, neuropathy risk, DPYD/DPD context when relevant, and goals-of-care discussion.
Stage II breast cancer, age 72, considering adjuvant chemotherapy
Use CARG-BC when required inputs are available because it was developed for older adults with stage I-III breast cancer receiving neoadjuvant or adjuvant chemotherapy. Pair toxicity risk with recurrence benefit tools and patient priorities.
Complex regimen review before tumor board
CRASH is interpretable only when MAX2 has already been established for the exact regimen and raw DBP, IADL, LDH/ULN, ECOG, MMSE, and MNA are complete. If MAX2 is unavailable, the calculator withholds all three scores.
6. FAQ
Which geriatric oncology toxicity calculator should I use?
Use CARG for general older-adult chemotherapy toxicity, CARG-BC for older adults with early-stage breast cancer receiving chemotherapy, CRASH when its regimen and geriatric inputs are reliable, and G8 when the question is screening for vulnerability.
Do these tools replace comprehensive geriatric assessment?
No. They help prioritize risk discussion and interventions, but comprehensive assessment remains important for function, cognition, nutrition, falls, mood, polypharmacy, social support, and goals.
Can a high-risk score be used to deny chemotherapy?
No. A high-risk score should trigger a careful conversation about benefit, alternatives, dose intensity, supportive-care interventions, and patient priorities. It should not be used as a stand-alone exclusion rule.
Choose the Right Geriatric Oncology Tool
Screen vulnerability, estimate toxicity, and document supportive-care needs before chemotherapy starts.
Open Supportive Care CalculatorsReferences
- Mohile SG, et al. Practical Assessment and Management of Vulnerabilities in Older Patients Receiving Chemotherapy: ASCO Guideline for Geriatric Oncology. PMC
- Practical Assessment and Management of Vulnerabilities in Older Patients Receiving Systemic Cancer Therapy: ASCO Guideline Update. ASCO
- Bellera CA, et al. Screening older cancer patients: first evaluation of the G-8 geriatric screening tool. Ann Oncol. 2012. PubMed
- Hurria A, Togawa K, Mohile SG, et al. Predicting chemotherapy toxicity in older adults with cancer. J Clin Oncol. 2011. PMC
- Magnuson A, et al. Development and Validation of a Risk Tool for Predicting Severe Toxicity in Older Adults Receiving Chemotherapy for Early-Stage Breast Cancer. J Clin Oncol. 2021. PMC
- Extermann M, et al. Predicting the risk of chemotherapy toxicity in older patients: the Chemotherapy Risk Assessment Scale for High-Age Patients (CRASH) score. Cancer. 2012. PubMed
- Prospective comparison of the value of CRASH and CARG toxicity scores in older adults. PMC