An increased platelet count in a year (thrombocytosis) increases the rate of cancer diagnosis, especially in those who experience two elevated platelet counts in a six-month period, according to British researchers. How early can cancer be diagnosed? A prospective cohort study published May 22 in the British Journal of General Practice showed that 11 percent of men and 6 percent of women with thrombocytosis will be diagnosed with cancer in the second year. Most importantly, one-third of these patients were diagnosed with lung or colorectal cancer, but did not exhibit any symptoms of cancer. Thrombocytosis is not currently considered a diagnostic factor for early cancer. “We know that early diagnosis is critical to the survival and prognosis of cancer patients,” according to Sarah Bailey, Ph.D., lead author of the study, “and if thrombocytosis can facilitate the early diagnosis of cancer, then our study could lead to many patients showing symptoms three months before cancer is diagnosed.” Thrombocytosis, why is it a warning of cancer? The study’s thrombocytosis group ultimately included 31,261 British patients with a median age of 67.9 years and platelet counts well above 400 × 109/L; 7,969 people with normal platelet counts were also screened as controls (no distinctions were made for age, sex or platelet count changes). The incidence of cancer in both groups was observed over a one-year period. The results of the study showed that 11.6% (95% CL=11.0-12.3) of men and 6.2% (95% CL=5.9-6.5) of women in the thrombocytosis group were diagnosed with cancer, compared to 4.1% (95% CL=3.4-4.9) of men and 2.2% (95% CL=1.8-2.6) of women in the control group. In the second year of diagnosis of thrombocythemia, the cancer incidence returned to basal levels. Nevertheless, if the platelet count was elevated again within 6 months, or if it was the same as the previous count, the incidence of cancer could reach 18.1% (95% CL=15.9-20.5) in men and 10.1% (95% CL=9.0-11.3) in women within one year. In addition, the most frequently diagnosed cancers in the thrombocytosis group were lung and colorectal cancers, with higher incidence rates than in the general population, but breast and prostate cancers had relatively lower incidence rates. Figure 1 Proportion of cancer diagnosed in the thrombocytosis group and the normal platelet count group, including 0-12 months, 4-12 months, and 13-24 months Figure 2 a indicates the proportion of males in both groups diagnosed with cancer, counted by age group, and b indicates the proportion of females in both groups diagnosed with cancer, counted by age group Figure 3 a indicates the proportion of males with thrombocytosis who were frequently diagnosed with cancer, compared with males in the general population with the inner ring indicating the incidence of different types of cancer in the general population; b indicates female patients with thrombocythemia frequently diagnosed with cancer, compared with females in the general population, with the outer ring indicating females diagnosed with thrombocythemia and the inner ring indicating the incidence of different types of cancer in the general population. Of those diagnosed with lung cancer, 37.5 percent had no symptoms other than thrombocytosis, which Dr Bailey explained was largely due to the release of chemicals from the tumor causing an increase in platelet count. How far is it before early cancer is accurately diagnosed? There are four main methods commonly used for early cancer screening, namely respiratory tests, tumor marker tests, genetic tests, and PET/CT tests. However, each of these tests has certain limitations and cannot achieve very accurate early cancer diagnosis. Breath test Breath test can only determine the risk of gastric cancer and lung cancer through breath test, but not whether there is early cancer, thus breath test cannot replace gastroscopy for gastric cancer, and CT and lung puncture are still needed for lung cancer. 2.Tumor marker examination There are four common serum tumor markers: methemoglobin, carcinoembryonic antigen, r-glutamate transpeptidase and alkaline phosphatase. These markers can screen liver cancer, colorectal cancer, breast cancer and lung cancer at an early stage, but tumor markers have the defects of sensitivity and specificity. If the sensitivity is low, cancer will not be detected or patients with cancer will be diagnosed as “normal”. If the specificity is low, a “false positive” reaction will occur, and therefore a misdiagnosis of cancer will occur. Genetic testing Genetic testing can assess the risk of many types of cancers such as lung, liver, stomach, intestine, breast and pancreatic cancers. Long-term research results show that patients who carry certain cancer susceptibility genes have a higher chance of developing cancer than ordinary people. However, for gene mutation, it does not mean that one already has cancer, so genetic testing cannot confirm whether one has early stage cancer or not. 4.PET/CT test PET/CT test is a good diagnostic method for early stage cancer. The test requires injection of glucose solution containing markers, which are radioactive substances that enter the body and can enter the inside of cancer cells and transmit the activity back to the computer. However, for the general population, health checkups are not suitable for this test. Young people are less likely to develop cancer and therefore less likely to detect early cancer, and performing PET/CT exams can instead be affected by radiation. In contrast, for people at high risk (over 50, family history of tumors, long-term smokers), who are already at higher risk of developing tumors, this test is likely to help them detect early cancers, with a greater benefit compared to the risk of radiation. The new study’s finding that thrombocytosis screens for early cancer could point in a new direction for early cancer diagnosis, but more research data is still needed to support this. Co-author Willie Hamilton said, “Conducting research related to thrombocytosis and early cancer diagnosis will save hundreds of lives each year.”