Controversy in the initial nodal staging of rectal cancer (MRI or PET/CT?).

OBJECTIVE: To compare the usefulness of MRI and PET/CT in nodal staging (N) of patients with locally advanced rectal cancer (LARC). MATERIAL AND METHODS: Retrospective study of patients with LARC, who completed their initial staging with PET/CT, between January-20 and March-23. Regional nodes were assessed, and N was determined using both techniques according to TNM criteria. Concordance between MRI and PET/CT was analyzed. The accuracy of both techniques was calculated for those patients who underwent direct surgery. Non-regional pelvic lymph nodes were evaluated by both modalities. RESULTS: Among the 73 patients, 48 were ultimately diagnosed with a locally advanced stage. Of these, 39 underwent neoadjuvant treatment (chemoradiotherapy) followed by surgery, and 9 direct surgery. In 25, the PET/CT extension study revealed distant disease, leading to systemic treatment. Weak concordance was observed between MRI and PET/CT in determining N (k=0.286; p<0.005). Out of 73 patients, 31(42%) exhibited concordance, and 42(58%) showed discordance. In 83% of the discordant cases, MRI overstaged compared to PET/CT, with 17 cases indicating nodal involvement (N+) by MRI and N0 by PET/CT. Diagnostic accuracy was 78% for both techniques. Sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 75%, 80%, and 75% for MRI, and 60%, 100%, 100%, and 67%, for PET/CT. PET/CT identified pelvic metastatic adenopathies in 8 patients that were not visible/doubtful by MRI. CONCLUSIONS: In the initial nodal staging of rectal cancer MRI overstages relative to PET/CT. Both modalities are complementary, PET/CT offers higher specificity and MRI higher sensitivity.

Lymph node staging after primary systemic therapy in women with breast cancer and lymph node involvement at diagnosis.

OBJECTIVE: The main objective of this study is to analyze the efficacy of combined axillary marking (lymph node clipping and sentinel lymph node biopsy (SLNB)) for axillary staging in patients with primary systemic treatment (PST) and pathologically confirmed node-positive breast cancer at diagnosis. The secondary objective is to determine the impact of lymph node marking in the suppression of axillary lymph node dissection (ALND) in the study group. METHODS: We conducted a prospective study in which lymph node staging was performed using wire localization of positive lymph nodes and a SLNB with dual tracer. All patients who presented no metastatic involvement of the sentinel lymph node (SLN) or clip/wire-marked lymph node were spared an ALND. The multidisciplinary committee agreed on axillary treatment for patients with lymph node involvement. RESULTS: Eighty one patients met the inclusion criteria. We identified and extirpated the clip/ wire-marked node in 80 of 81 patients (98.8%), with SLNB performed successfully in 88,9% of patients. The SLN and wire-marked node matched in 78.9% of patients; 76.2% of patients did not undergo ALND. CONCLUSIONS: The combined axillary marking (clip and SLNB) in patients with metastatic lymph node at diagnosis and PST offers a high identification rate (98.8%) and a high correlation between the wire-marked lymph node and the SLN (78.9%). This procedure has enabled the suppression of ALND in 76.2% of patients.

Dual time point 2-deoxy-2-[18F]fluoro-D-glucose PET/CT: nodal staging in locally advanced breast cancer.

AIM: To assess dual time point 2-deoxy-2-[(18)F]fluoro-D-glucose (18)(F)FDG PET-CT accuracy in nodal staging and in detection of extra-axillary involvement. MATERIAL AND METHODS: Dual time point [(18)F] FDG PET/CT scan was performed in 75 patients. Visual and semiquantitative assessment of lymph nodes was performed. Semiquantitative measurement of SUV and ROC-analysis were carried out to calculate SUV(max) cut-off value with the best diagnostic performance. Axillary and extra-axillary lymph node chains were evaluated. RESULTS: Sensitivity and specificity of visual assessment was 87.3% and 75%, respectively. SUV(max) values with the best sensitivity were 0.90 and 0.95 for early and delayed PET, respectively. SUV(max) values with the best specificity were 1.95 and 2.75, respectively. Extra-axillary lymph node involvement was detected in 26.7%. CONCLUSION: FDG PET/CT detected extra-axillary lymph node involvement in one-fourth of the patients. Semiquantitative lymph node analysis did not show any advantage over the visual evaluation.