Statements on which consensus was achieved
| Statement | Responses (n) | Proportion of respondents indicating ‘agree/ strongly agree’ or ‘yes’ (%) |
| The abbreviations that should be used to define MMR proficient and MMR deficient should be ‘pMMR’ and ‘dMMR’ as per the IARC ‘Blue Book’ volume on genetic tumour syndromes. | 58 | 96 |
| The term unexplained dMMR should be used instead of the term ‘Lynch-like syndrome’. | 60 | 88 |
| Long-range PCR analysis of PMS2 should routinely be included as part of constitutional testing of PMS2 when cancer demonstrates isolated loss of PMS2. | 59 | 85 |
| Loss of heterozygosity analysis should be routinely available when somatic next-generation sequencing of MMR genes is undertaken. | 59 | 95 |
| It is not mandatory to pursue additional investigations for patients with dMMR cancers beyond standard testing* and constitutional genetic testing in situations where prior probability of heritable cause for cancer is low. | 55 | 90 |
| The following factors should be considered in determining probability of heritable cause of dMMR cancer to guide further testing: family history, age, tumour type, pattern of protein loss, extent of investigation. | 54 | 94 |
| It is not mandatory to undertake Lynch-equivalent surveillance for probands or their first-degree relatives in situations where there is unexplained dMMR, particularly where clinical suspicion of a heritable cause is low. | 56 | 96 |
*Standard testing: somatic BRAF sequencing and/or MLH1 promoter hypermethylation testing where indicated; constitutional MMR gene testing.
IARC, International Agency for Research on Cancer; MMR, mismatch repair.