P17: Can microsatellite instability be a useful parameter for tailoring adjuvant chemotherapy? A case report

Barana1, A. Viel2, M. Padovani1, C. Forni1, F. Lo Vullo1, F. Giuradei1, M. Pantalena3, C. Finco4, A. Scarpa5, C. Oliani1

Supported by Fondazione Peretti

1 – U.O.C. di Oncologia ULSS5 Ovest Vicentino, Vicenza. 2 – Oncologia Sperimentale 1, Centro di Riferimento Oncologico IRCCS, Aviano (PN). 3 – U.O.S.D. di Gastroenterologia e Endoscopia Digentiva ULSS5 Ovest Vicentino, Vicenza. 4 – U.O.C. di Chirurgia ULSS5 Ovest Vicentino, Vicenza. 5 – Anatomia Patologica; AOUI di Verona.

Aim

MSI colorectal cancers  shows better stage-independent prognosis than MMR-deficient tumours and appears to be resistant to fluorouracil-based treatment. We present the case of DD, a 39 years old man, who came to our observation in February 2010 after a right hemicolectomy .

Method

The pathology report showed a  moderately differentiated adenocarcinoma of the colon with focal infiltration of the perivisceral fat,  peritumoural presence of  inflammatory reaction with lymphoid aggregates and absence of  vascular invasion and of perineural infiltration.  All the 36 removed nodes resulted negative for metastatic involvement (T3N0M0). The shared decision of whether to opt for adjuvant chemotherapy with Fluorouracil resulted difficult . The young age, the right site of the neoplasia and the histological type prompted us to ask for a MSI analysis  which showed  MSI-H and deficiency for the expression of MSH2.

Results

The mutational analysis revealed an exon 8 deletion in MSH2. We proposed only surveillance/follow up to DD and the screening of the family has been carried out. The father resulted gene carrier and until now has developed two polyps.

Conclusion

In clinical practice MSI may be helpful in the choice of adjuvant therapy in selected cases.

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