Adenocarcinoma of the lower third of the rectum: metastases in lymph nodes smaller than 5 mm and occult micrometastases; preliminary results on early tumor recurrence.
BACKGROUND
The number of examined lymph nodes and metastases in lymph nodes smaller than 5 mm (small lymph nodes) are a determining factor in the stage of rectal cancer although the clinical significance of occult micrometastases is controversial. We are reporting our preliminary results on the identification and prognostic utility of metastases in small lymph nodes and occult micrometastases.


METHODS
We searched small metastatic lymph nodes in 101 cases of adenocarcinoma of the lower third of the rectum. We used the manual technique to dissect mesorectal fat and occult micrometastases in the lymph nodes of 52 Dukes' A and B patients, using a pool of anticytokeratin antibodies.


RESULTS
Forty-five percent of the metastatic lymph nodes were smaller than 5 mm in diameter and determined the Dukes' stage in 15 (30.6%) of 49 Dukes' C patients. Occult micrometastases were found in 21 (40.4%) patients: five recurred but vascular invasion, positive distal margin of the rectum, and positive circumferential margin of the mesorectum were present.


CONCLUSIONS
Small metastatic lymph nodes, vascular invasion, positive distal margin of the rectum, and positive circumferential margin of the mesorectum were found to be more important than occult micrometastases in predicting early recurrence of rectal cancer.
Andreola
S
S
Department of Anatomical Pathology and Cytology, National Cancer Institute, Milan, Italy.
Leo
E
E
Belli
F
F
Gallino
G
G
Sirizzotti
G
G
Sampietro
G
G
D000230:Adenocarcinoma / Q000473:pathology* / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000473:pathology*; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery; D013997:Time Factors