Prognostic evaluation of stage B colon cancer patients is improved by an adequate lymphadenectomy: results of a secondary analysis of a large scale adjuvant trial.
OBJECTIVE
To determine if the extent of lymphadenectomy (number of recovered lymph nodes) was associated with long-term outcome in patients operated on for stage B and C colon cancer.


BACKGROUND
Lymphatic spreading is the main prognostic indicator in colon cancer patients, although the optimal extent of lymphadenectomy and its prognostic impact are still unknown.


METHODS
In 3,648 patients (median follow-up 3.6 years) enrolled in two consecutive INTACC multicentric trials on adjuvant therapy for colon cancer, we studied the association of the number of recovered nodes with overall survival and relapse free survival by means of univariate and Cox regression analysis.


RESULTS
The worst overall survival was related to ages > 65 (risk ratio [RR] = 1.30), higher grading (RR = 1.96). Better overall survival was related to female gender (RR = 0.80) and to higher number of recovered nodes (8-12 nodes, RR = 0.46, 13-17 nodes, RR = 0.76, nodes > or = 18, RR = 0.79). The same pattern was observed for relapse free survival. Longer overall and relapse free survival were related to a higher number of recovered nodes with P =.034 and P =.003 respectively (stratified analysis for absence or presence of positive nodes). Stage B patients with fewer than 7 nodes in the specimen had both shorter overall survival (P =.0000) and relapse free survival (P =.0016) than the other B patients. Outcome of stage C patients was not related to the number of recovered nodes (P =.28 and 0.12 respectively). The interaction test between stage of disease and number of recovered nodes was statistically significant (P =.017).


CONCLUSIONS
Stage B patients with a small number of examined nodes may be understaged. Thus, these patients might be considered for adjuvant therapy because of their poorer life expectancy than other stage B patients. For stage C patients, the number of recovered nodes does not seem to affect long-term outcome.
Prandi
Mario
M
Department of General Surgery, Ospedale Infermi, Rimini, Italy. m.prandi@libero.it
Lionetto
Rita
R
Bini
Antonio
A
Francioni
Gianfranco
G
Accarpio
Giuseppe
G
Anfossi
Antonio
A
Ballario
Ezio
E
Becchi
Giuseppe
G
Bonilauri
Stefano
S
Carobbi
Andrea
A
Cavaliere
Paolo
P
Garcea
Domenico
D
Giuliani
Lucio
L
Morziani
Eugenio
E
Mosca
Franco
F
Mussa
Antonio
A
Pasqualini
Massimo
M
Poddie
Domenico
D
Tonetti
Federico
F
Zardo
Luciano
L
Rosso
Riccardo
R
D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D000368:Aged; D003110:Colonic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D015996:Survival Rate; D013997:Time Factors