An article published in the April 30 issue of Cancer examines the relationship between gastrointestinal mesenchymal tumors and other types of tumors in the population. The study alerted clinicians to the need to be alert for the presence of other types of tumors when treating gastrointestinal mesenchymal tumors. One of the authors, Dr. Sicklick from the Moores Cancer Center at the University of California, San Diego, said, “Although we don’t know the cause yet, there is a clear correlation between gastrointestinal mesenchymal tumors and the development of other types of cancer.” Dr. Sicklick suggests, “As a clinician, it is important to be vigilant if you see suspicious signs when treating GIST patients. For example, GIST patients are twice as likely to develop lymphoma as the general population, and mesenchymal tumors do not usually metastasize to the lymph nodes, so it is important to be aware of the possibility of combined lymphoma when GIST patients present with enlarged lymph nodes. In short, one thing to keep in mind is that because GIST has a higher risk of developing many other cancers, it is important to always keep an eye out when diagnosing and treating them.” Initially, in his clinical work Dr. Sicklick noticed that GIST patients had a higher rate of other cancers, so he and his medical team decided to study the correlation between GIST and the incidence of other cancers through systematic data collection and analysis. Their study used standardized prevalence ratios (SPRs) and standardized incidence ratios (SIRs) for 6,112 patients with GISTs in the U.S. SEER database from 2001 to 2011. Of these patients, 1047 (17.1%) developed other types of cancer. Classified according to the time of diagnosis of GIST, GIST patients had a 44% increased risk of developing other cancers before diagnosis (SPR, 1.44) and a 66% increased risk of developing other cancers after the diagnosis of GIST (SIR, 1.66). The other malignancies that were most frequent in GIST patients were: sarcoma (SPR, 5.24; SIR, 4.02), neuroendocrine tumors (SPR, 3.56; SIR, 4.79), non-Hodgkin’s lymphoma (SPR, 1.69; SIR, 1.76) and colorectal adenocarcinoma (SPR, 1.51; SIR, 2.16). In addition, the prevalent malignancies before GIST diagnosis only were: esophageal adenocarcinoma, bladder adenocarcinoma, melanoma, and prostate cancer. The malignant neoplasms that occurred only after GIST diagnosis were: ovarian cancer, small intestine adenocarcinoma, papillary thyroid cancer, renal cell carcinoma, and gastric cancer. The reasons for the increased risk of other malignancies in GIST patients are not known, but Dr. Sicklick notes, “In our clinical practice, we must always be aware of the need to screen for other malignancies when we see GIST patients. I saw a patient with hematuria who had a mass in her stomach on CT that was considered a GIST, so the physicians focused primarily on the treatment of GIST. However, data from our study showed that patients with GIST have a 7.5-fold increased risk of bladder cancer compared to the general population, so I simultaneously performed further tests for her hematuria symptoms, which clinicians must be aware of when seeing patients with GIST. ”Oncologists are challenged with new ideas every day due to the current boom in evidence-based medicine, but because we are constantly updating our knowledge, treating each patient rationally and carefully, and working with them, oncology patients will ultimately have a better outcome. “Dr. Sicklick concluded.