Why is chemotherapy dose important?

This is an automatically translated article.

This article was written by doctors of Internal Oncology Department, Vinmec Times City International General Hospital.
Chemotherapy is one of the weapons to treat many cancers. The dose of chemical drugs is calculated based on the weight and height of each patient through the skin area. Each drug, each regimen when recommended in clinical practice guidelines with drug doses has been carefully considered and calculated through clinical trials.

1. The significance of chemotherapy dose in cancer treatment

For certain types of cancer, such as breast cancer, adjuvant chemotherapy significantly improves survival. In these cases, it is very important to use the full dose according to the regimen.
Meta-analyses of the Early Breast Cancer Trial Group (EBCTCG) showed that cyclophosphamide/methotrexate/fluorouracil [CMF] chemotherapy regimens reduce the risk of death by 20% to 25%. The effect was further increased when anthracyclines and taxanes were added.
Some meta-analyses have shown a benefit of a dense regimen, however some question the similarity of the arms compared, e.g. low taxane doses (paclitaxel every 3 weeks). times) are potentially confounding factors. A further limitation in the conclusion was the reduction in the dose of chemotherapy (mg/m2) and cycle delay, suggesting an effect on survival.
In a published study, Bonadonna and colleagues showed superior survival for women receiving ≥85% of the optimal (total cumulative) dose of CMF compared with those receiving <85% of the dose. .
This finding was also observed in a retrospective study of breast cancer in stage I-III women who received 3 cycles of FEC followed by docetaxel (D) chemotherapy for 3 cycles. (FEC-D) from 2007 to 2014 in Alberta, Canada. With the patient receiving the drug with 2 dose levels <85% and >85% of the standard dose.
Results on 1,302 patients, only 202 patients used < 85% of the dose, the remaining 1100 used > 85% of the dose, this number has an outstanding 5-year survival time. In addition, early dose reduction (reduction from the first episodes) continues to adversely affect treatment results, reducing survival time.
Canadian researchers say survival rates are significantly better for breast cancer patients who receive full-dose adjuvant chemotherapy, especially in the first three cycles, than for women who receive full-dose adjuvant chemotherapy. dose reduction.

2. Early chemotherapy dose reduction significantly affects survival

Zachary Veitch, Department of Oncology, University of Calgary, Tom Baker Cancer Center, Alberta, Canada, commented: "What surprised us the most was that early reductions in chemotherapy had a significant impact on survival. compared with late dose reduction.
"This became even more apparent when patients were divided based on chemotherapy dose reductions," he added.
"Often, the first cycle of chemotherapy can be difficult for patients and oncologists as it requires maintaining the initial dose intensity while controlling side effects and comorbidities. ", Dr. Veitch commented.
John Ward, from the Huntsman Cancer Institute at the University of Utah, Salt Lake City, who was a member of the expert panel that drafted the Comprehensive Oncology clinical practice guidelines for Breast Cancer, commented. : Treatment in early breast cancer leads to improved survival. When chemotherapy is part of adjuvant treatment, it is important to take the full prescribed dose. This study is of great practical value.
In many cases, reduce the dose to minimize side effects caused by or from other comorbidities, such as kidney disease or diabetes. "Balanced side effects with effectiveness has always been a challenge," commented Ward.
At the Internal Oncology Department of Vinmec Times City Hospital, doctors always adhere to the recommended dose. To do this, it is necessary to evaluate the patient and a comprehensive, meticulous care regimen. Anticipate possible chemotherapy side effects and devise measures to prevent and reduce side effects as much as possible. This will help the patient complete the course of treatment with the best results.

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Reference source: Medical news today