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Tumor-infiltrating lymphocytes fail to predict aggressive tumor biology
NEW YORK — Histopathological detection of tumor-infiltrating lymphocytes has not shown to be an accurate indicator of aggressive tumor biology, according to results of a retrospective study presented at the HemOnc Today Melanoma and Cutaneous Malignancies meeting.
Sanjay S. Reddy, MD, a surgical oncology fellow at Fox Chase Cancer Center in Philadelphia, and colleagues conducted their investigation to determine whether histopathological detection of tumor-infiltrating lymphocytes (TIL) can reliably predict tumor biology.
Reddy and colleagues analyzed 241 patients treated at their institution from 2009 to 2011. Fifty-three percent of patients were men, and the mean age of the patients was 61 years. Fifteen percent of patients had thick melanomas, defined as >4 mm.
The investigators compared presence or absence of TIL with preoperative white blood cell counts, age, tumor depth, mitotic rates, sentinel lymph nodes and pathologic stage.
Researchers observed TIL in 44% of patients.
TIL were found in 48% of patients with thinner melanomas vs. 22% of patients with thicker tumors (P=.02), potentially correlating the presence of TIL to less aggressive tumors.
Seventy-five percent of patients who had TIL present had a mitotic rate <4 mm2 compared with 65% of patients who had no TIL present, again supporting the notion that TIL may be significant in less aggressive tumors; however, this did not reach statistical significance.
TIL was identified in 46% of patients with positive sentinel lymph nodes compared with 38% of patients with negative sentinel lymph nodes (P=.38).
The investigators reported a mitotic rate >4 mm2 in 31% of patients with TIL vs. 21% of patients without TIL (P<.001).
Low preoperative mitotic rates correlated to a lower pathologic stage (P<.001), but the presence of TIL did not correlate with an earlier stage (P=.29).
Results of multivariate analysis showed the combination of TIL and degree of mitoses did not predict earlier disease stage compared with mitotic rate alone (P=.39).
Based on the findings, researchers concluded there is no statistical significance to suggest TIL serves as a reliable prognostic indicator.
“Although tumor infiltrating lymphocytes appear not to serve as a reliable prognostic indicator in melanomas, these types of inquiries and investigational studies can add relevant and worthwhile discussions in treating this evolving disease,” Reddy told HemOnc Today.
For more information:
Reddy SS. Abstract #4. Presented at: HemOnc Today Melanoma and Cutaneous Malignancies; March 22-23, 2013; New York.
Disclosure: Reddy reports no relevant financial disclosures.