gms | German Medical Science

Introduction and purpose of the study: Penile malignancies are uncommon tumors (0.5% of all malignancies of males in the USA and Europe) that are often devastating for the patients and diagnostically challenging for the urologist. The strongest prognostic indicator for survival continues to be the presence or absence of nodal metastases. Only 50% of the patients presenting with palpaple inguinal lymphadenopathy actually have metastatic disease, the remainder having lymph node enlargement secondary to inflammation.However, in 36% - 65% of patients with clinically unsuspicious inguinal lymph nodes metastatic deposits were detected by histopathology. The reluctance to advocate automatic ilioinguinal lymphadenectomy in all patients with penile cancer stems from the substantial morbidity (25% - 60%) e.g. wound infection and necrosis, phlebitis, permanent disabling lymphedema. Given that lymph node metastases are not detected reliably by MRT or CT scan, FDG-PET was evaluated whether or not a diagnostic improvement could be achieved. The rationale behind this was that many malignancies show an increased glucose metabolism.

Material and methods: 17 males (38 – 72 years old) with penile squamous cell carcinoma underwent abdominal and pelvic CT or MRT scan. FDG-PET was done using a Scanditronix R WB 4096/7 scanner (average iv application of FDG: 422 MBq). Bilateral inguinal lymph node dissection was performed following partial or total penectomy. Clinical and CT/MRT findings were compared to the results of FDG-PET and histopathology.

Results: 16 out of 34 specimens (both sides of N=17 patients) showed tumor metastases, 18 were free of disease. Micrometastases (N=6) were detected neither by CT/MRT nor by FDG-PET. In 8 cases glucose hypermetabolism marked inflammatory nodes free of tumor (false positive results), 4/8 were graded as metastases by CT as well (false positive).

Conlusion: In patients with penile cancer FDG-PET could not detect nodal micrometastases , a distinction between inflammatory and metastatic lesions failed. The decision making whether or not a patient has to undergo inguinal lymph node dissection, seems not to be improved by using FDG-PET as additional diagnostic tool.