Pre-emptive skin treatments to prevent skin toxicity caused by anti-EGFR antibody: the real-world evidence in Japan

Validation of algorithms to identify colorectal cancer patients from administrative claims data of a Japanese hospital

BACKGROUND

Administrative claims data are a valuable source for clinical studies; however, the use of validated algorithms to identify patients is essential to minimize bias. We evaluated the validity of diagnostic coding algorithms for identifying patients with colorectal cancer from a hospital's administrative claims data.

METHODS

This validation study used administrative claims data from a Japanese university hospital between April 2017 and March 2019. We developed diagnostic coding algorithms, basically based on the International Classification of Disease (ICD) 10th codes of C18-20 and Japanese disease codes, to identify patients with colorectal cancer. For random samples of patients identified using our algorithms, case ascertainment was performed using chart review as the gold standard. The positive predictive value (PPV) was calculated to evaluate the accuracy of the algorithms.

RESULTS

Of 249 random samples of patients identified as having colorectal cancer by our coding algorithms, 215 were confirmed cases, yielding a PPV of 86.3% (95% confidence interval [CI], 81.5-90.1%). When the diagnostic codes were restricted to site-specific (right colon, left colon, transverse colon, or rectum) cancer codes, 94 of the 100 random samples were true cases of colorectal cancer. Consequently, the PPV increased to 94.0% (95% CI, 87.2-97.4%).

CONCLUSION

Our diagnostic coding algorithms based on ICD-10 codes and Japanese disease codes were highly accurate in detecting patients with colorectal cancer from this hospital's claims data. The exclusive use of site-specific cancer codes further improved the PPV from 86.3 to 94.0%, suggesting their desirability in identifying these patients more precisely.

Cost-effectiveness of preemptive skin treatment to prevent skin-toxicity caused by panitumumab in third-line therapy for KRAS wild type metastatic colorectal cancer in Japan

Background

Clinical management of skin-toxicity associated with the use of anti-Epidermal Growth Factor Receptor (EGFR) antibodies to treat colorectal cancer maintains quality of life of patients with colorectal cancer. Results of clinical trials have recommended the efficacy of prophylactic treatment, but the cost-effectiveness is unclear. This study examined the cost-effectiveness of preventive skin care for skin-toxicity caused by panitumumab in third-line therapy for KRAS wild type metastatic colorectal cancer from the perspective of the Japanese healthcare payer.

Methods

The data source was J-STEPP trial, which compared preemptive skin treatment with reactive treatment in third-line panitumumab therapy for KRAS wild type metastatic colorectal cancer in Japan. The costs and effectiveness of preemptive treatment was compared with reactive treatment in a 3-year time horizon using a 4-state partitioned survival analysis. The health outcome was quality-adjusted life-years (QALYs). The costs were 2020 revisions to the drug prices. The robustness of the model was verified by one-way sensitivity analysis and a probabilistic sensitivity analysis (PSA). A 2% annual discount was applied to the expenses and QALYs. Willingness-to-pay (WTP) threshold of 5 million JPY was used.

Results

Preemptive treatment had incremental effects of 0.0029 QALYs, incremental costs of 5300 JPY (48.6 USD), and incremental cost-effectiveness ratios (ICER) of 1,843,395 JPY (16,912 USD) per QALY. The variability of preemptive and reactive treatment costs for skin-toxicity and the disutility of skin-toxicity had a large impact on ICER. From PSA, the cost-effectiveness rate of preemptive treatment was 75.0%.

Conclusions

The cost to effectiveness of preemptive treatment to prevent skin-toxicity caused by panitumumab in third-line therapy for KRAS wild type mCRC is not high.

Molecular Profiling of EGFR Status to Identify Skin Toxicity in Colorectal Cancer: A Clinicopathological Review

Colorectal cancer (CRC) represents an important health problem, being the third most common type of cancer. In Romania, the CRC incidence has doubled over the years. Both environmental factors and genetic susceptibility are very important for the pathogenesis of CRC. The epidermal growth factor receptor (EGFR) plays an extremely important role in CRC tumorigenesis. Overexpression or dysregulation of EGFR pathway molecules are frequently associated with tumor aggressiveness and patient response to treatment. Based on these considerations, EGFR became one of the first targets of molecular therapies used in CRC. At present, cetuximab and panitumumab are considered to be essential in the treatment of patients with metastatic colorectal cancer expressing the KRAS wild-type gene and EGFR. The main adverse effect for both cetuximab and panitumumab is skin toxicity, present in approximately 80% of patients. The risk of secondary infections, in particular of bacterial infections, is also increased. Cases of staphylococcal infection associated with skin peeling, cellulite, erysipelas, and even Staphylococcus sepsis, were reported. For a long time cutaneous toxicity has been a positive predictor in the efficacy of anti-EGFR treatment, but compliance with treatment and the quality of life of patients with metastatic CRC decreases in the presence of these skin reactions. That is why we emphasize the necessity and importance of using a modern method (molecular analysis of gene polymorphisms possibly supplemented by targeted confocal laser endomicroscopy) to identify a molecular diagnosis, in order to foresee and prevent the appearance of skin reactions and to manage skin toxicity.