Doctors and patients sometimes see tumors appear to grow on scans after starting immune checkpoint inhibitor therapy. This phenomenon is called pseudoprogression. A meta-analysis looked at patients with solid tumors who experienced this specific type of initial growth. The study found that these cases often showed a modest increase in tumor burden, averaging about 33 percent, rather than massive growth.
While the scans might look concerning at first, many patients still saw positive results later on. About 41.8 percent of those with pseudoprogression achieved a partial response without changing their treatment plan, and 6.4 percent achieved a complete response. The study noted that large increases in tumor size over 100 percent were rare, occurring in only about 3.9 percent of cases.
Because this analysis relied on retrospective data, the findings show an association rather than a guaranteed prediction. It is important to remember that pseudoprogression typically happens early in treatment. Patients should discuss these specific imaging patterns with their oncology team to determine if a change in therapy is truly necessary.
