CARG-TT Calculator (Cancer and Aging Research Group Chemotherapy Toxicity Tool)

CARG-TT items

The Cancer and Aging Research Group Chemotherapy Toxicity Tool estimates the risk of severe (grade 3 or greater) chemotherapy-related side effects in older cancer patients (age >65).

This risk predictive model was developed using data from a multi-centre prospective study of 500 cancer patients aged 65 or older, due to undergo chemotherapy.

The 11 risk predictors and the points assigned are presented below:

The model is recommended by the ASCO guidelines for geriatric oncology along with the CRASH score.

Scoring the CARG-TT

CARG-TT scores are obtained by summing the individual scores from the 11 items and range from 0 to 23, where the higher the score, the greater the risk of toxicity side-effects. Three risk categories were established, identifying patients at low, medium and high risk of toxicity.

The table below summarizes the three risk categories and the associated toxicity risk for each score:

About the original study and validations

Hurria et al. initially assessed (sociodemographic variables, tumor/treatment variables, laboratory test results, and geriatric assessment variables) then followed a cohort of 500 oncologic patients aged 65 and older through the chemotherapy course to capture grade 3 – 5 severe side effects.

A predictive model was then developed that consisted of geriatric assessment variables, laboratory test values, and patient, tumor, and treatment characteristics which were shown to independently predict the risk of toxicity.

The median risk score was 7 and the risk stratification schema then identified the low, intermediate and high risk patients.

The CARG-TT was further validated on an independent cohort of 250 cancer patients. The patient’s risk of chemotherapy toxicity was assessed via the predictive model before the start of the chemotherapy regimen.

Chemotherapy side effects were captured with reference to the most severe grades: 3 – 5. The model was validated by calculating the area under the receiver-operating characteristic curve, which was 0.65 (95% CI, 0.58 to 0.71), with similar values to that from the development cohort (0.72; 95% CI, 0.68 to 0.77; P = .09).

When compared to the CRASH predictive model, both scores exhibited similar predictive performance for toxicity in elderly cancer patients.

Another study by Mariano et al. showed that a brief geriatric assessment tool can be effectively utilized in a broad community oncology practice. The tool influenced the oncologist's supportive care plans for a substantial number of older patients receiving cytotoxic chemotherapy.

CARG-TT versus CARG-BC

The CARG-BC was developed based on the CARG-TT to specifically predict risk of severe chemotherapy toxicity side-effects in older patients with early stage breast cancer.

The CARG-BC accounts for specific disease and treatment variables that are relevant for older patients with early-stage breast cancer may provide more accurate risk estimates.

It consists of 8 risk predictors and similarly to the CARG-TT the model provides a risk category and toxicity risk percentage for each of the scores.

References

Original reference

Hurria A, Togawa K, Mohile SG, Owusu C, Klepin HD, Gross CP, Lichtman SM, Gajra A, Bhatia S, Katheria V, Klapper S, Hansen K, Ramani R, Lachs M, Wong FL, Tew WP. Predicting chemotherapy toxicity in older adults with cancer: a prospective multicenter study. J Clin Oncol. 2011; 29(25):3457-65.

Validation

Hurria A, Mohile S, Gajra A, Klepin H, Muss H, Chapman A, Feng T, Smith D, Sun CL, De Glas N, Cohen HJ, Katheria V, Doan C, Zavala L, Levi A, Akiba C, Tew WP. Validation of a Prediction Tool for Chemotherapy Toxicity in Older Adults With Cancer. J Clin Oncol. 2016;34(20):2366-71.

Other references

Ortland I, Mendel Ott M, Kowar M, Sippel C, Jaehde U, Jacobs AH, Ko YD. Comparing the performance of the CARG and the CRASH score for predicting toxicity in older patients with cancer. J Geriatr Oncol. 2020; 11(6):997-1005.

Mariano C, Jamal R, Bains P, Hejazi S, Chao L, Wan J, Ho J. Utility of a chemotherapy toxicity prediction tool for older patients in a community setting. Curr Oncol. 2019; 26(4):234-239.