With the three-pronged approach, all the metastases of advanced gastric cancer disappeared

Gastric cancer is a malignant tumor with relatively high incidence and mortality in China, and about 50% of patients are diagnosed in an advanced stage
.
For patients with advanced gastric cancer, chemotherapy is the main treatment measure, but the prognosis is often poor
.

Due to the rise of immunotherapy, PD-1 inhibitors have achieved good results
in the treatment of gastric cancer.
Recently published clinical trials have reported the therapeutic effect of PD-1 inhibitors, nivolumab has accumulated a large amount of data in the treatment of gastric cancer, and patients with advanced gastric cancer can benefit
from PD-1 inhibitor treatment.

Studies have found that patients with advanced gastric cancer who are treated with chemotherapy combined with PD-1 inhibitors only prolong survival time and do not achieve complete remission
.
To achieve this treatment expectation, radiotherapy is also needed, and radiotherapy-induced distal effects may help achieve this goal
.

What are the radiation-induced distal effects?

In oncology, the distal effect of radiotherapy refers to the shrinkage of tumor lesions that have not received radiation therapy in addition to those that have received radiation
.
This means that local tumor treatment also has a therapeutic effect
on distant tumors.

Radiotherapy-induced distal effects have been reported in many types of tumors, and with the widespread use of PD-1 inhibitors, the incidence of radiotherapy distal effects is increasing
.

Although radiation therapy can produce immunogenicity, radiation from radiation therapy also has an immunosuppressive effect
.
Whether PD-1 inhibitors can promote the distant effect of radiotherapy is a comprehensive compromise result
.

Because radiation therapy can cause serious adverse effects, radiation therapy
is generally not considered for gastric cancer.
However, if the primary tumor is bleeding, radiation therapy is an option
.
In the past few decades, several studies have focused on the use of palliative radiotherapy in the treatment of tumor bleeding, with good efficacy
.

In the following case, the stomach cancer patient was unable to undergo surgery and had to undergo radiation therapy
due to bleeding.
As a result, radiotherapy and chemotherapy and PD-1 inhibitors have achieved a synergistic effect, all visible tumor foci have disappeared, and complete remission has been achieved.

The combination of therapeutic measures works synergistically and the lesions disappear completely

In December 2020, a 62-year-old man was admitted to hospital with vague abdominal discomfort and has experienced progressive wasting
over the past six months.
Moderate anaemia on physical examination and positive occult blood test for stool
.

CT imaging performed showed thickening of the stomach wall, pathological lymph nodes
.
By gastroendoscopy, it was determined that it was a moderately low grade gastric adenocarcinoma, and the tumor metastasized to the left lung
.
This advanced stomach cancer cannot be treated with surgery
.

The patient was first treated with oxaliplatin, folinic acid, and the PD-1 inhibitor nivolumab, and after the first treatment cycle, hemoglobin was slightly low, fecal occult blood test was still positive, and the patient was diagnosed with gastric bleeding
.

Patients refuse palliative surgical resection and do not receive endoscopic treatment
.
Finally, palliative radiation therapy
was performed with the informed consent of the patient.
The approximate volume of the tumor lesion was determined by abdominal CT, and radiation therapy
with a total dose of 25 Gy was performed.

After the patient completed the scheduled radiotherapy, a significant improvement
in the condition was observed during subsequent chemotherapy and immunotherapy.
Within one month of radiotherapy, the patient's haemoglobin was markedly elevated
.
Before the third and fifth courses of chemotherapy, chest CT examination showed significant reduction of metastatic nodules in the left lung
.

Figure 1.
Imaging examination shows the process of disappearance of tumor lesions

In July 2021, the patient completed 6 courses of chemotherapy, and the overall treatment regimen was well tolerated
.
CT examination showed a decrease in the thickness of the stomach wall, a decrease in lymph node metastasis, and complete remission
of lung lesions.
Throughout chemotherapy, the patient continues immunotherapy, and hemoglobin remains in the normal range
during follow-up.

In January 2022, follow-up CT imaging showed that the gastric lesions were stable and the lung metastases were still in a state
of complete remission.

Revelation and discussion

There is emerging evidence that low- or moderate-dose (2-6 Gy) radiation therapy is not sufficient to kill cancer cells or stimulate an immune response
.
Traditional fractionated radiotherapy is given at low to moderate doses, and this treatment is even thought to cause local immunosuppression
.

It has been reported that patients with recurrent gastric cancer after distant lymph nodes and brain metastases, using whole-brain radiotherapy (15 times 30 Gy), additional stereotactic body radiotherapy (15 times 30 Gy), and also received multi-line chemotherapy in combination with PD-1 inhibitors, and then brain tumor foci and lymph node shrinkage were observed, and finally all brain and abdominal lesions disappeared
.

Experts in this literature study said that the use of palliative radiotherapy is still helpful if there is gastric bleeding during chemotherapy combined with immunotherapy
.
However, whether radiotherapy can cause a distal effect and achieve the above therapeutic effect cannot give an absolute answer
.
The optimal timing and fractionation of the dose for the distal effect caused by radiotherapy is not well understood
.

Figure 2: A case report of gastric cancer showing distal effects by radiotherapy

In the cancer APP, a foreign medical exchange group, Beijing, Shanghai, Guangzhou and other places have been newly created, and patients who want to know more about radiotherapy, chemotherapy and immune combination therapy can pay attention to the cancer APP, join the corresponding group, and exchange treatment experience
with patients with similar conditions.

Cancer, accompany you to every step of the fight against cancer!

References:

Zengtao Bao, et al.
, An abscopal effect in a gastric cancer patient treated with combined chemoimmunotherapy and palliative radiotherapy, Immunotherapy (2022)

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