If gastric cancer is the end point of disease progression, there is by no means one path to reach that end point. In addition to the main line (major symptoms) that we know about such as epigastric pain, loss of appetite, wasting, weakness, nausea, vomiting, dysphagia, upper gastrointestinal bleeding, etc., there are other paths (concomitant symptoms) that are medically referred to as the concomitant cancer syndrome.
The concomitant cancer syndrome of gastric cancer is a series of clinical manifestations that occur during the development of gastric cancer and for a period of time after treatment that are not directly related to the lesion itself and the metastases, and is a specific clinical manifestation due to the production of certain specific hormones and physiologically active products directly or indirectly by gastric cancer cells. The syndrome is a group of diseases that may occur in all organ systems of the body, and this article will introduce them one by one according to the site of onset.
Dermal lesions
- Herpes zoster: It is often seen in older and frail patients with gastric cancer, so it should be taken more seriously in those who are older. Herpes zoster may be a precursor sign of gastric cancer.
- Dermatomyositis: The incidence of malignancy in patients with dermatomyositis is 5 to 7 times higher than in the general population. One study showed that 71 of 157 cases (45.2%) of dermatomyositis had gastric cancer. Therefore, patients with dermatomyositis, especially those aged 40 years or older, should be alert for the development of gastric cancer.
- Echinoderma nigricans: It is commonly seen in patients with adenocarcinoma of the gastrointestinal tract, especially gastric cancer, but also in other tumors. Acanthosis nigricans is often seen before the tumor is diagnosed and is one of the early clues to diagnose gastric cancer.
- Erythrodermatitis: Also known as exfoliative dermatitis, it is characterized by extensive erythematous infiltrates with furfuraceous desquamation. Extensive edematous erythema (generalized flushing of the skin throughout the body) with massive desquamation is often present in gastric cancer with erythrodermatitis.
- Bullous palm: It is characterized by thickening of the palm of the hand, with numerous folds in the skin of the palm and a soft, velvety texture with brown pigmentation, which is strongly correlated with the tumor and is often associated with acanthosis nigricans, commonly seen in patients with lung and gastric cancer.
- Leser-Trelat sign: Characterized by seborrheic keratosis of the skin, it is common in older patients. The disappearance of skin lesions after tumor treatment has been reported, so Leser-Trelat sign has been suggested to be a concomitant cancer syndrome, but others are skeptical. Gastric cancer is the tumor most often associated with Leser-Trelat sign.
- Muir-Torre syndrome: Patients are characterized by a predisposition to sebaceous gland tumors (or keratoacanthoma multiforme) and visceral malignancies. It is most often associated with adenocarcinoma of the stomach, small intestine, and colon.
- Peutz-Jeghers syndrome: is an autosomal dominant disorder characterized by multiple malformation-like polyps of the gastrointestinal tract and hyperpigmentation of the lip, face, and oral mucosa. It is associated with a 2% to 3% chance of gastrointestinal cancer and may be due to the malignant transformation of multiple misshapen-like polyps.
Endocrine and metabolic system
- Ectopic TSH (thyroid stimulating hormone) syndrome: Tumor tissue secretes TSH, causing elevated plasma thyroid hormone and other indicators, mostly manifesting as weakness, wasting, and neuropsychiatric symptoms.
- Ectopic ACTH (adrenocorticotropic hormone) syndrome: It is one of the causes of Cushing’s syndrome, which can occur in 5% to 10% of patients with GI tumors. The clinical manifestations are mostly atypical and include skin pigmentation, hypertension, edema, muscle weakness, and hypokalemic alkalosis.
- Ectopic hypoglycemic syndrome: A small number of patients with gastric cancer may develop hypoglycemia, and in severe cases, central neurological hypoglycemic syndrome, which manifests as disorientation (i.e., loss of ability to recognize or misperceive the environment or one’s own condition), convulsions, and coma.
- Ectopic ADH (antidiuretic hormone) syndrome: It is caused by abnormal secretion of ADH in patients with gastric cancer and manifests mainly as weakness, anorexia, thirst, drowsiness, and painful muscle spasms due to low blood sodium.
- Other syndromes: such as increased blood HCG due to ectopic HCG (human chorionic gonadotropin) syndrome, which manifests as gynecomastia in men and irregular uterine bleeding in women; increased blood glucose and urine sugar due to ectopic GH (growth hormone) secretion syndrome.
- Metabolic abnormalities: The main manifestations are hypocalcemia, hypolipidemia, and hyper AFP (alpha-fetoprotein)emia, which can be detected by blood tests.
Neuromuscular syndrome
- Cancerous peripheral neuropathy: The main manifestations are progressive extremity sensory deficits (e.g., hyperalgesia, numbness, etc.) and motor dysfunction.
- Cancerous myopathy: It manifests as muscle loss and muscle atrophy in the scapular or pelvic region and extremities near the trunk end that cannot be explained by the cachexia (continuous weight loss and progressive muscle wasting) of the tumor patient.
Nephrotic syndrome
Gastric cancer with occasional concomitant glomerulopathy may manifest as nephrotic syndrome with the following main symptoms:
- Proteinuria with urine protein greater than 3.5g/d;
- Plasma albumin less than 30g/L;
- Oedema, with occasional generalized swelling, predominantly of the eyelids and lower extremities;
- Elevated blood lipids.
Symptoms usually disappear after tumor removal or treatment, and proteinuria reappears with recurrence.
Hematologic system
It may manifest as chronic anemia, thrombocytopenia, and DIC (disseminated intravascular coagulation). Occasional stimulation of the hematologic system by gastric cancer has also been reported to result in a lymphocytic leukocytic response or an eosinophilic leukocytic response.
These are the systemic manifestations of gastric cancer-associated cancer syndrome, which may seem scary at first glance, as gastric cancer can cause lesions in all systems. The first time I saw this, I was able to get to the bottom of it. The most important thing is that you should pay attention to the abnormal state of your body and seek medical help in time.