The recent 8th edition of the American Joint Committee on Cancer (AJCC) staging manual had multiple changes concerning how pathologists should stage germ cell tumors (GCTs) of the testis. A significant one concerns the impact of different types of spermatic cord involvement, specifically direct tumor extension versus discontinuous involvement by invasion through lymphovascular spaces. We compared clinicopathologic findings and outcome data between 2 cohorts with these findings to evaluate the validity of the change in the AJCC 8th edition manual. GCTs (seminomatous and nonseminomatous) of the testis were identified that had previously been staged as pT3 due to involvement of the spermatic cord. Pathologic, radiographic, and clinical findings were reviewed. Tumors were restaged based on AJCC 8th edition criteria and the cohorts were split into direct extension by tumor into the spermatic cord (pT3), spermatic cord soft tissue invasion via spread from discontinuously involved lymphovascular spaces (pT2pM1), or a combination of both (pT3pM1). One hundred cases of primary GCTs of the testis, previously classified as pT3 by the AJCC 6th or 7th cancer staging manuals from 2007 to 2015, were selected. Mixed malignant GCTs were the predominant tumor type, comprising 66% of all cases. Pure tumor morphologies included embryonal carcinoma (n=17), seminoma (n=14), teratoma (n=2), and yolk sac tumor (n=1). The tumors either directly invaded into the spermatic cord (n=78), involved the cord discontinuously via spread from lymphovascular spaces (n=18), or had both findings (n=4). Overall, 93% of patients presented at advanced clinical stage (CS). Using the AJCC 8th parameters, 12% of all tumors were upstaged. Changes included CSI (n=1) and CSII (n=11) tumors being reclassified as prognostic stage group III. Clinical and/or pathologic recurrence was identified in 19% of all patients, including 12 pT3 and 7 pM1 patients (P=0.11). Overall mean time to recurrence was 24.6 months, with a mean of 28.0 months for pT3 tumors and 18.9 months for pM1 tumors. Five patients were dead at the time of this study, including 3 (4%) with pT3 tumors and 2 (9%) in the pM1 cohort. Our findings support that seminomatous and nonseminomatous GCTs with spermatic cord invasion have a high frequency of advanced CS at presentation, regardless of involvement by direct extension or discontinuous spread via invasion from lymphovascular spaces. By designating the latter as M1, a spurious upstaging to prognostic stage group III is required by the AJCC 8th edition. We were unable to identify statistically significant difference between the 2 groups as it pertained to CS at presentation and likelihood of recurrence. Conversely, statistical trends favor that pM1 patients have more likely recurrence and worse prognosis than pT3 patients.
The American journal of surgical pathology. 2018 Jan 10 [Epub ahead of print]
Joseph M Sanfrancesco, Karen E Trevino, Huiping Xu, Thomas M Ulbright, Muhammad T Idrees
Departments of Pathology and Laboratory Medicine., Biostatistics, Indiana University School of Medicine, Indianapolis, IN.