Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster Display session 2

3393 - PIK3CA mutation in metastatic colorectal cancer (mCRC): association with clinico-pathological features and outcome

Date

29 Sep 2019

Session

Poster Display session 2

Topics

Tumour Site

Colon and Rectal Cancer

Presenters

Valentina Fanotto

Citation

Annals of Oncology (2019) 30 (suppl_5): v198-v252. 10.1093/annonc/mdz246

Authors

V. Fanotto1, G. Zucchelli2, M.M. Germani2, D. Rossini2, E. Sensi3, C. Lupi3, C. Ugolini3, C. Antoniotti2, F. Marmorino2, R. Moretto2, A. Boccaccino2, B. Borelli2, V. Conca2, E. Ongaro4, G. Masi2, G. Fontanini5, A. Falcone2, C. Cremolini2

Author affiliations

  • 1 Department Of Medicine (dame), University of Udine, 33100 - Udine/IT
  • 2 Department Of Translational Research And New Technologies In Medicine And Surgery, University of Pisa, 56100 - Pisa/IT
  • 3 Unit Of Pathology 3, Azienda Ospedaliero-Universitaria Pisana, 56126 - Pisa/IT
  • 4 Soc Oncologia Medica E Prevenzione Oncologica, Centro di Riferimento Oncologico (CRO), IRCCS, 33081 - Aviano/IT
  • 5 Department Of Surgical, Medical, Molecular Pathology And Critical Care, University of Pisa, 56126 - Pisa/IT

Resources

Login to access the resources on OncologyPRO.

If you do not have an ESMO account, please create one for free.

Abstract 3393

Background

Mutations in PIK3CA, an EGFR downstream effector, and the subsequent activation of AKT pathway plays an important role in colorectal carcinogenesis. Considering the frequent co-occurrence of PIK3CA and RAS mutations, conflicting data exist about its impact on prognosis of mCRC patients (pts) and its predictive role to anti-EGFR therapy. However, PI3K inhibitors have been developed and are currently under investigation in mCRC.

Methods

Data from mCRC pts treated at Azienda Ospedaliero-Universitaria Pisana from 1 Jan 2005 to 31 Dec 2017, whose tumours had been analysed per clinical practice by MALDI-TOF MassArray were retrieved. Association between PIK3CA mutation and clinico-pathological features was analysed by χ2 test; OS curves were estimated with Kaplan-Meier method and compared by log-rank test.

Results

Tumours from 90 (17%) out of 542 pts included in this analysis were PIK3CA mutated (mut), most of them in exon 9 (58.9%) or 20 (21.1%). Compared to PIK3CA wild-type (wt) tumours, mut ones were more often RAS mut (P = 0.006), MSI high (P = 0.008), and right-sided (P = 0.0004). Among 53 pts for whom PIK3CA status was available on both primary tumours (PT) and metastasis, the concordance was 92.4%. PIK3CA mutations were not associated with OS (36.4 vs 35.9 mos, HR 1.17, 95%CI 0.85-1.62, p = 0.3), with no difference among those affecting exon 9 and 20 (36.4 vs 27.5 mos, HR 0.77, 95%CI 0.39-1.54, p = 0.44). In RAS/BRAF wt (N 188) and in RAS mut (N 299) subgroup, no difference in terms of OS was found between PIK3CA mut and wt pts (38.1 vs 44.4 mos, HR 1.22, 95%CI 0.60-2.48, p = 0.55 and 27.5 vs 34.4 mos, HR 1.26, 95%CI 0.85-1.86, p = 0.22, respectively), though PIK3CA mut had shorter OS. In BRAF mut subgroup (N 54), PIK3CA mut pts had longer OS compared to PIK3CA wt (not reached vs 14.4 mos, HR 0.37, 95%CI 0.16-0.85, p = 0.09). Among 39 chemorefractory RAS/BRAF wt pts evaluable for response to an anti-EGFR agent, only 2 were exon 9 PIK3CA mut and achieved stable disease.

Conclusions

PIK3CA mut tumours displayed specific clinico-pathological features and a strong concordance was found between PT and paired metastases. Interestingly, a different impact on prognosis of PIK3CA mutation in RAS/BRAF wt, RAS mut or BRAF mut mCRC pts was observed and deserves validation.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Supported by ARCO (Associazione Ricerca e Cure in Oncologia) Foundation.

Disclosure

All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.