SAN FRANCISCO – , a retrospective analysis suggests.
However, determining which of these patients do not require adjunct resection remains challenging, according to Tim Nestler, MD, of the University Hospital of Cologne in Germany.
Dr. Nestler presented the retrospective analysis at the the 2020 Genitourinary Cancers Symposium sponsored by the American Society of Clinical Oncology, ASTRO, and the Society of Urologic Oncology.
Dr. Nestler and his colleagues analyzed the frequency and pathologic findings of adjunctive organ resection (encompassing organs, blood vessels, and bones) among 1,181 men undergoing postchemotherapy RPLND during 2008-2018.
Adjunctive organ resection was performed in 20% of patients. Pathologic evaluation of the resection specimens showed viable germ cell tumors in 21.7% of these patients, teratomas in 38.7%, and necrosis or fibrosis in 39.6%. The prevalence of necrosis/fibrosis was generally similar across various organs, blood vessels, and bones.
At a median follow-up of 22 months, 27% of the study cohort experienced a relapse. The 5-year rate of relapse-free survival was 18% for patients with viable germ cell tumors in adjunctively resected organs, 54% for those with teratomas, and 81% for those with necrosis/fibrosis.
“Within this cohort, about 40% of all resections finally showed necrosis/fibrosis, and these are patients that were kind of unnecessarily treated from the oncological standpoint,” Dr. Nestler said, although he noted that such resections should continue until there is a reliable way to identify this subset of patients.
“We are thinking of increasing the rate of frozen sections within surgery, especially to avoid nephrectomies, hepatectomies, and vascular resections,” he said. “Or, if we are thinking about bone metastasis, then we also might think about presurgical biopsies.”
Stepping back even further, clinicians could do “a more accurate presurgical work-up to identify those patients that are really in need of postchemotherapy RPLND, compared to those who will have a high chance of showing necrosis/fibrosis,” Dr. Nestler said. “Here, we are currently working on means like radiomics and molecular markers.”
Implications for patient counseling
“The problem is, and this is the central crux of the issue, that we cannot accurately identify ‘cancer or teratoma’ from ‘not cancer or teratoma’ prior to surgery,” said session cochair Brant A. Inman, MD, of the Duke Prostate and Urologic Cancer Center in Durham, N.C.
Preoperative biopsies are not helpful in differentiating these groups because of their technical difficulty and very high false-negative rate, Dr. Inman said. And intraoperative biopsies with frozen sections have the same sampling problem, plus problems of diagnostic accuracy and differentiation of live from dead tumor.
“This research is mainly helpful for preoperative patient counseling,” Dr. Inman said. “You have to tell your patient prior to RPLND, especially if they have a large postchemotherapy mass, several things.”
Specifically, patients should be informed about the probability of needing adjunctive resection and what that entails, he said. If this additional surgery is needed, patients should be informed of the probability that the tissues removed will not contain any cancer or teratoma. Moreover, “if this is the case, the blood vessel or organ will likely have been removed without benefit to you,” he added.
Finally, patients should be told that “there is no accurate way presently to distinguish cancer/teratoma from necrosis/fibrosis preoperatively or intraoperatively, including imaging and biopsies,” Dr. Inman said. “New technologies, like microRNA tests, are being developed to help sort this out.”
There was no funding for this research. Dr. Nestler disclosed no relevant conflicts of interest. Dr. Inman disclosed relationships with several pharmaceutical companies as well as patents or royalties for soluble B7-H1.
SOURCE: Nestler T et al. GUCS 2020, Abstract 388.