Impact of the COVID-19 Pandemic on the Pathological Stage of Gastric and Colorectal Cancers: A Retrospective Single-Center Study
This retrospective single-center study found that the COVID-19 pandemic was associated with a shift toward more advanced pathological stages at diagnosis for gastric and colorectal cancers, likely due to disruptions in screening and treatment services, although the observed increase in advanced-stage disease did not reach statistical significance.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Cancer often begins as a silent, slow-growing change within the body, invisible to the eye until it has had time to spread. For cancers of the stomach and the colon, the most effective way to catch these changes early is through a camera examination called an endoscopy, where a doctor looks inside the digestive tract to find and remove suspicious tissue before it becomes dangerous. The timing of this discovery is everything; finding a tumor while it is small and contained offers the best chance for a cure, while finding it after it has grown large or spread to nearby lymph nodes makes treatment much harder and survival less certain. When the global health crisis of the early 2020s forced hospitals to pause routine procedures to manage the immediate threat of a new virus, a quiet question emerged among medical experts: did this necessary pause allow these silent cancers to grow larger and more dangerous before they were finally found?
Researchers at a major hospital in Turkey set out to answer this question by looking back at the records of patients who were diagnosed with stomach and colon cancers just before and just after the pandemic began in their country. They focused on a specific group of people: those whose cancers were first spotted during a camera examination and who then underwent surgery to remove the tumor. By comparing the medical details of these patients from the two-and-a-half years before the virus arrived with those from the two-and-a-half years after, the team could see if the disease had changed its character. They examined the size of the tumors, how deep they had grown into the organ wall, and whether they had spread to the lymph nodes, which act as small filters in the body that often catch cancer cells first.
The study revealed a clear shift in the landscape of these diseases. In the period before the pandemic, the hospital performed thousands of stomach and colon biopsies, finding hundreds of cancer cases. When the pandemic hit, the number of these examinations dropped sharply, falling by nearly half in the first six months as hospitals redirected resources and patients stayed home. Yet, as services slowly recovered, the number of new cancer diagnoses returned to previous levels. However, the nature of the cancers found had changed. Among the patients who eventually had surgery, the tumors found during the pandemic were more likely to be in an advanced stage. In the stomach cancer group, the proportion of tumors that had grown deep into the organ wall or spread to nearby tissues rose from about 69 percent before the pandemic to 81 percent during it. A similar trend appeared in colon cancer, where advanced tumors became more common, though the difference was slightly less pronounced.
The most striking evidence of this delay came from the lymph nodes. In the stomach cancer patients, the rate of cancer spreading to the lymph nodes jumped significantly, rising from roughly 48 percent before the pandemic to 71 percent during it. This suggests that the tumors had more time to travel through the body's filtering system before they were stopped. Interestingly, the time between the initial biopsy and the actual surgery did not get longer during the pandemic; the delay happened earlier, before the patient even reached the hospital for a test. This indicates that people were waiting longer to seek help or were unable to get an appointment for a camera examination in the first place, allowing the disease to progress unchecked during those missing months.
Despite the shift toward more advanced disease, the researchers also observed a change in how doctors treated these patients. To manage the uncertainty and delays caused by the pandemic, surgeons and oncologists began using preoperative drug therapies more frequently, especially for stomach cancer, in an attempt to shrink tumors before surgery. While this strategy showed a significant increase in usage, it did not fully reverse the trend toward more advanced disease. The findings suggest that even with adaptive medical strategies, the interruption of routine screening and diagnostic services had a lasting effect, allowing cancers to reach a more dangerous state before treatment could begin. The study concludes that keeping these diagnostic pathways open is critical, as the cost of a pause is not just a delay in numbers, but a tangible shift in the severity of the disease patients face.
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