When it comes to postoperative adjuvant chemotherapy, patients and their families have the question, “How can you tell if chemotherapy is working when the lesions are gone?”
Regular imaging
Unlike advanced gastric cancer, where the size of the tumor is observed and the effect of chemotherapy is determined through imaging, the effect of adjuvant chemotherapy cannot be visualized after surgery for gastric cancer because the lesions have been removed. However, there is still a risk of tumor recurrence/metastasis after surgery. Once recurrence/metastasis occurs, it means adjuvant chemotherapy has failed and the doctor will re-evaluate the disease and change the treatment plan.
For this reason, physicians usually order imaging, such as CT of the whole abdomen and lungs, and possibly magnetic resonance imaging (MRI) or positron emission computed tomography (PET-CT), every 3 months. Monitoring recurrence/metastasis by imaging is an important aspect of assessing the effectiveness of postoperative adjuvant chemotherapy.
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Observation of tumor marker changes
Tumor markers such as carcino-embryonic antigen (CEA) and glycoconjugate antigen 19-9 (CA19-9) are also valuable in determining the efficacy of treatment during and after adjuvant chemotherapy. It has been shown that patients with recurrence/metastasis after adjuvant chemotherapy have higher levels of tumor markers than those without recurrence/metastasis. The level and positive expression of tumor markers may be related to the efficacy of treatment. If tumor markers do not change or continue to be positive after chemotherapy, this may indicate that the current treatment is not successful and that the patient’s disease has progressed or is at risk of recurrence.
Long-term survival metrics are significant
In fact, for postoperative adjuvant chemotherapy, there is still a lack of metrics to evaluate near-term outcomes. Therefore, long-term indicators such as survival are particularly significant in assessing outcomes. The distant indicators that need to be monitored are:
- Disease-free survival (DFS) that is, the time from surgical removal of the tumor to tumor recurrence/metastasis;
- Overall survival (OS) is the time from the start of treatment to death from any cause, and is the “gold standard” for evaluating the efficacy of antineoplastic drugs;
- Median survival (mOS) indicates that half of patients can survive beyond this time. This metric reflects patient outcomes, with longer median survival indicating better outcomes and shorter outcomes being worse.
In summary, in addition to the “hard” indicators of tumor recurrence and metastasis and survival, the evaluation of the efficacy of postoperative adjuvant chemotherapy should also focus on the “soft” indicators of quality of life and toxic side effects, namely The “soft” and “hard” indicators, such as quality of life and toxic side effects, should be taken into consideration. (Diao Yanwen, Department of Medical Oncology, The First Affiliated Hospital of China Medical University, contributed)