When it comes to chemotherapy, patients and their families often wonder why the chemotherapy regimen is different for the same stomach cancer. Indeed, oncologic chemotherapy is a very complex process, and physicians need to consider multiple factors to make decisions.
How would a doctor determine the timing of postoperative adjuvant chemotherapy?
Patients with gastric cancer can receive adjuvant chemotherapy once they have recovered their physical status after surgery, and adjuvant chemotherapy is usually started within 1 month after surgery, usually no longer than 3 months after surgery is recommended.
The duration of postoperative adjuvant chemotherapy is usually 6 months to 1 year, depending on the chemotherapy regimen. For patients who have received neoadjuvant chemotherapy preoperatively, physicians will adjust the timing of postoperative chemotherapy depending on the number of preoperative cycles, and generally recommend that patients receive chemotherapy for 6 months in the perioperative period (before and after surgery).
What factors need to be considered in determining postoperative adjuvant chemotherapy regimens?
The mechanism of gastric cancer is extremely complex, and physicians determine the treatment plan based on the pathologic diagnosis, clinical staging, and molecular pathologic staging of gastric cancer. They also perform a systematic physical examination and medical history to understand organ function and routine laboratory test results to clarify the patient’s physical status, tolerance to treatment, and potential treatment risks. During the consultation, the physician will evaluate several factors to develop the best individualized treatment plan for the patient:
- Patient characteristics, including age, physical status, organ function, and co-morbidities;
- Tumor characteristics, including depth of tumor infiltration, lymph node metastasis, pathological type, etc.;
- Patients who have undergone chemotherapy preoperatively and have not completed the planned cycle are usually required to continue to complete perioperative chemotherapy postoperatively;
- Other factors, such as toxic side effects of chemotherapy drugs, patients’ requirements for quality of life, socioeconomic factors, etc.
What options are available for postoperative adjuvant chemotherapy?
Commonly used regimens
Commonly used regimens
The most common postoperative adjuvant chemotherapy regimens for gastric cancer in China and most recommended by many authoritative international gastric cancer guidelines are the XELOX regimen and the single-agent tegeo (S-1) regimen.
- XELOX
- XELOX regimen [i.e., Oxaliplatin + Capecitabine] 2018 National Comprehensive Cancer Network (NCCN) The gastric cancer guidelines include the XELOX regimen as the only Class 1 recommended (highest of the recommended classes) regimen for postoperative adjuvant chemotherapy for gastric cancer. The XELOX regimen (21 days/cycle) can be considered for patients who are recovering well from surgery, with 8 cycles recommended. The major side effects of this regimen are myelosuppression, neurotoxicity due to oxaliplatin, and hand-foot syndrome due to capecitabine, in addition to possible nausea and vomiting, and hepatic and renal impairment.
- Tegeo Tegeo is a combination of tegafur, a derivative of fluorouracil and two modulators, Gimestat and Oteracil Patassium, for oral use It is also part of the postoperative adjuvant chemotherapy regimen for gastric cancer, which typically lasts for 1 year (8 cycles). For patients with stage II gastric cancer with a low risk of recurrence, either tegeo or XELOX alone is an option, while for patients with a high risk of recurrence in stage IIIb and above, physicians usually consider a two-drug regimen of platinum in combination with fluorouracil. Studies have confirmed that tegeo has a better safety profile than fluorouracil-based chemotherapy agents such as 5-fluorouracil (5-FU) or capecitabine, so tegeo may be safer and better tolerated than the XELOX regimen when patients are less fit.
Other regimens
In addition to the above regimens, the following regimens are also possible postoperative adjuvant chemotherapy regimens for gastric cancer currently chosen by our physicians:
- SOX regimen (i.e., oxaliplatin + tegeo) The SOX regimen is also one of the common adjuvant chemotherapy regimens for gastric cancer used by doctors in China, usually 21 days/cycle, with 6 to 8 weeks of treatment generally recommended. The initial reason for doctors to use this regimen was probably because of the better efficacy of tegeo alone and to try to avoid the hand-to-hand reactions of capecitabine. Our physicians have studied the efficacy and safety of adjuvant chemotherapy with tegeo alone and combined with oxaliplatin in patients with progressive gastric cancer after D2 radical surgery, and the results showed that both adjuvant chemotherapy regimens prolonged postoperative tumor-free survival and overall survival, with the combination being more effective, but also increasing the incidence of toxic side effects. Similarly, small sample studies in China have shown that the SOX regimen is no less effective than the XELOX regimen.
- FLOFOX regimen [i.e., oxaliplatin + calcium folinate + fluorouracil] The FOLFOX regimen is also one of the postoperative adjuvant chemotherapy regimens for gastric cancer patients in China. Although current studies have shown that both XELOX and FOLFOX prolong survival and reduce the risk of recurrence and metastasis for postoperative patients with gastric cancer. However, 5-fluorouracil requires a deep intravenous line for infusion, whereas capecitabine is an oral fluorouracil-based antitumor agent that is easy to use. Thus, the XELOX regimen is more widely used and more acceptable to patients than the FOLFOX regimen.
- XP regimen [i.e., cisplatin (Cisplatin) + capecitabine] The XP regimen is one of the classic regimens of postoperative adjuvant chemotherapy for gastric cancer, again at 21 days/cycle, with a recommended duration of treatment typically of 6 to 8 cycles. The side-effect profile of cisplatin differs from oxaliplatin, mainly in terms of nephrotoxicity, gastrointestinal symptoms such as nausea and vomiting, and ototoxicity.
Patients with gastric cancer have a wide range of conditions and a variety of chemotherapy regimens, and doctors will combine all factors to help patients make appropriate treatment decisions. (Contributed by Yanwen Diao, Department of Medical Oncology, First Affiliated Hospital of China Medical University)