The purpose of preoperative neoadjuvant chemotherapy is to downstage the tumor, shrink the mass, and kill invisible metastatic cells early enough to improve the likelihood of achieving radical resection with subsequent surgery and reduce the risk of recurrence. Many patients receiving neoadjuvant chemotherapy are very concerned about the changes in their condition and often ask, “How many cycles do I have to do?” “When can I have surgery?” “How effective is this chemotherapy? This article takes a look at the “start and finish” of neoadjuvant chemotherapy and the assessment of its efficacy.
When to start?
When do you start?
When to start?
Patients with gastric cancer who have been systematically and expertly evaluated by their physicians as needing and being ready for preoperative neoadjuvant chemotherapy should begin chemotherapy immediately. The earlier chemotherapy is started, the less likely the patient is to develop drug resistance.
How to evaluate the efficacy?
Patients receiving neoadjuvant chemotherapy are generally evaluated every 2 cycles or 2 months, and imaging such as CT and magnetic resonance imaging (MRI) are commonly used for evaluation. Positron emission computed tomography (PET-CT) may also be performed for patients with suspected systemic multiple or abdominal metastases. This is usually supplemented by a serum tumor marker test, which is usually taken once a month, several times in a row, to observe trends. It is important to note that the fact that a tumor marker is not outside the standard range does not mean that the disease is not present, but only that it is not significant for the time being for tumor assessment.
What is the role of MRI in gastric cancer diagnosis and treatment?
What do these tumor markers mean for gastric cancer diagnosis?
Indicators for evaluating the efficacy include changes in the size of primary lesions in the stomach, changes in the degree of infiltration, whether surrounding lymph nodes are reduced or disappeared, whether there are changes in gastric cancer metastases, and whether new lesions or new metastases appear. The evaluation criteria were mainly based on the RECIST efficacy evaluation criteria:
For target lesions
- Complete remission (CR): all target lesions are gone;
- Partial remission (PR): visible shrinkage of lesions compared to before treatment initiation;
- Progressive disease (PD): increased or visible enlargement of lesions compared with the pre-treatment period;
- Stable disease (SD): given between PR and PD.
For non-target lesions (metastases, etc.)
- Complete remission (CR): all non-target lesions are gone and tumor marker levels return to normal;
- Incomplete remission/stable (IR/SD): non-target lesions still exist and tumor marker levels remain abnormal;
- Progression of lesions (PD): new lesions appear or existing lesions increase in size and progress.
With the development of liquid biopsy (circulating tumor cells, circulating tumor cell DNA detection) technology, the detection of tumors and metastases is changing rapidly. It is believed that more effective real-time detection will be available in the future.
When does it end?
When does it end?
The results of the neoadjuvant chemotherapy efficacy evaluation, combined with the patient’s physical condition and other factors, will be used to consider whether surgery is appropriate. If surgery is deemed appropriate, neoadjuvant chemotherapy is discontinued. If surgery is deemed unsuitable, some patients may need to continue neoadjuvant chemotherapy and follow the physician’s advice after the next efficacy evaluation; patients whose treatment regimen is ineffective and whose disease has progressed will need to change regimens or be converted to palliative care. If the patient is intolerant during chemotherapy for reasons such as side effects, the physician will promptly evaluate the efficacy and physical status and will recommend surgery if the evaluation deems it operable, or will usually switch to palliative care if the treatment is deemed ineffective or unacceptable.
In conclusion, the effectiveness of chemotherapy and the duration of treatment vary from person to person. The endpoints of preoperative neoadjuvant chemotherapy are not programmed and fixed and depend on the patient’s tolerance to chemotherapy, cancer sensitivity, etc. (Contributed by Xin Wang, Department of Gastrointestinal Oncology, The First Hospital of China Medical University)