Abstract 410P
Background
Guidelines recommend regional lymphadenectomy with at least 12 assessed lymph nodes (LN) for adequate colon cancer (CC) staging. Recent data suggest that the worse survival of right-sided CC can be mitigated by harvesting more than 22 LN. We studied the impact of lymphadenectomy yield and tumour side on CC staging and survival.
Methods
This is a Portuguese, multicentre, retrospective cohort study. All patients (pts) with stage I-III CC that underwent surgical resection from 2012 to 2018 were included and grouped according to LN yield: <12, 12-21 and ≥22. Primary outcomes were LN-positivity (N+) rate and overall survival (OS), with disease-free survival (DFS) as a secondary outcome. Similar exploratory analysis was done by tumour sidedness (right CC, up to the splenic flexure, vs left CC). Standard univariate and multivariate analyses were performed w/ binomial logistic regression models for assessing the independent impact of the LN yield on N+ rate, and standard survival analysis for OS and DFS.
Results
808 pts (mean age 69.6 yo, 54% male, 53% left-sided CC) were included, 95 with <12, 323 with 12-21 and 390 with ≥22 resected LN; 29% with stage I, 37% stage II and 34% stage III CC. 38% were treated with adjuvant chemotherapy (CT), the majority with a platinum doublet (68%). Pts in the ≥22 LN group were younger (P=0.03), had more right-sided tumours and stage III CC (P<0.0001); in addition compared to pts with <12 LN, they had higher levels of lymphovascular invasion (LVI) and treatment with adjuvant CT (P=0.01). There was a nonsignificant likelihood of N+ tumours in univariate logistic regression in the ≥22 LN group (OR 1.33, P=0.07), which remained nonsignificant after adjusting for T stage and LVI. With a median follow-up of 43 months, there was no difference on univariate analysis in OS or DFS between the 3 groups (log rank test P=0.47 and P=0.67, respectively). In multivariate analysis, adjusting for age, T and N stage, laparoscopic vs open approach and adjuvant CT, pts with ≥22 resected LN had longer OS compared to the other groups (HR 0.724, 95%CI 0.526-0.998), but not DFS. There was no interaction between CC sidedness and LN group on either N+ status, OS or DFS.
Conclusions
Resection of ≥22 LN was associated with longer OS but not with higher odds of N+ staging in pts with operable CC, independently of tumour sidedness.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
P. Simões: Travel/Accommodation/Expenses: Sanofi; Travel/Accommodation/Expenses: Vifor Pharma / OM Pharma; Travel/Accommodation/Expenses: Amgen; Travel/Accommodation/Expenses: Merck; Travel/Accommodation/Expenses: TESARO; Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: Janssen; Travel/Accommodation/Expenses: Ipsen. A. Faria: Honoraria (self): Roche; Honoraria (self): Astellas; Honoraria (self): Laboratórios Vitória. G. Fernandes: Honoraria (self): Janssen; Honoraria (self): Astellas; Honoraria (self), Travel/Accommodation/Expenses: Vifor Pharma / OM Pharma; Travel/Accommodation/Expenses: Novartis; Travel/Accommodation/Expenses: Sanofi; Travel/Accommodation/Expenses: Servier; Travel/Accommodation/Expenses: BMS; Travel/Accommodation/Expenses: Ipsen; Travel/Accommodation/Expenses: Pierre Fabre. J. Godinho: Advisory/Consultancy: Grunenthal. J. Moreira-Pinto: Research grant/Funding (self): Roche; Travel/Accommodation/Expenses: Janssen; Travel/Accommodation/Expenses: Servier; Travel/Accommodation/Expenses: BMS. M. Casa-Nova: Advisory/Consultancy: Roche; Advisory/Consultancy: Pfizer; Advisory/Consultancy: Merck; Honoraria (self): AstraZeneca; Honoraria (self): Tesaro; Honoraria (self): Novartis. J.A. Teixeira: Advisory/Consultancy: Janssen; Advisory/Consultancy: Pfizer; Advisory/Consultancy: Ipsen; Advisory/Consultancy: Roche. C. Pulido: Honoraria (self): AstraZeneca; Honoraria (self): Grunenthal; Honoraria (self): Novartis. J.L. Passos-Coelho: Advisory/Consultancy, Research grant/Funding (self), Travel/Accommodation/Expenses: Roche; Advisory/Consultancy, Research grant/Funding (self): Novartis; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Lilly; Travel/Accommodation/Expenses: Janssen. All other authors have declared no conflicts of interest.