Trial Information

SPECT-CT Guided Lymphatic Mapping and Sentinel Lymphadenectomy (LM/SL) in Prostate Cancer

A multidisciplinary team (urologist, oncologist, radiologist, pathologist, and nuclear
medicine) will assess the technical feasibility of LM/SL with SPECT/CT as well as its
clinical potential for the staging of regional lymph nodes in 30 consecutive patients with
AJCC stages I-II-III prostate cancer scheduled for prostatectomy and pelvic lymph node
dissection according to the standards of care.

This is a 2-day protocol with a single isotopic tracer (Tc99m-cysteine rhenium colloids,
10-15 nm). The tracer injections will be performed under trans-rectal ultra-sound guidance
(1 inj/lobe, 74MBq, 0.2 cc).

The first day or injection day (D0), an early imaging session with planar acquisitions
(anterior and posterior views) will be performed within 30 min post-tracer injection. A
delayed imaging session with planar and SPECT/CT acquisitions will be also performed 1 to 3
hours after tracer injection. The SPECT/CT device to be used in this research protocol is
the Infinia Hawkeye 4-slice from GE Healthcare. This hybrid camera incorporates a low-dose
CT with a 2.5 mA current (eff.dose < 2mSv) on a dual-head gamma camera. SPECT/CT data will
be analysed on the Xeleris 2.05v (Volumetrix for Hawkeye Oncology).

The second day (D+1 post-tracer injection), all prostate cancer patients will undergo a
radical prostatectomy with complete pelvic lymph node dissection (CLND). Sentinel lymph
nodes (SLNs) will be detected intra-operatively by using a gamma probe (Navigator, Tyco
Healthcare). In this single tracer study, SLNs are defined as hot nodes only including the
hottest node and any hot node ≥ 10% of the hottest node. In this SPECT/CT protocol,
additional non-radioactive nodes eventually detected on the CT component and suspicious of
tumor involvement (lymphadenopathies > 1cm) will be also removed, especially lymph nodes
located in unpredictable lymphatic basins. Surgery will be performed by the same surgeons.

SLNs and non-SLNs will be analyzed by the same pathologist. For SLNs, a Hematoxylin & Eosin
staining (H-E) will be firstly performed. If negative, 3 more H-E stains levels will be
performed and immuno-peroxidase stains for Cytokeratins AE1/AE3, PSA, and PAP. Non-SLNs will
be analyzed according to the routine protocol with 3 H-E stained levels only. The SLN
features will be noted: number, anatomical localization in vivo, counting rates ex vivo. The
pathological characteristics of metastatic SLNs and non-SLNs will be precisely recorded:
size, involvement (micro-metastases ≤ 2mm; macro-metastases; isolated tumor cells), % of
nodes involved (small < 25%; moderate = 25-75%; massive > 75%).