Should a letter with a General Practitioner's signature vs. a letter alone be used for inviting women to subsequent breast cancer screening rounds?

The GDG made a conditional recommendation by consensus for the intervention based on the desirable anticipated effects, negligible costs and savings of the intervention, and varied feasibility and acceptability concerns. 

The GDG noted that for this intervention no differences were highlighted for the subgroup of women who had a false positive results in the previous screening round.

• The comparison evaluated for this recommendation needs to be interpreted in the context of the other comparisons of methods for inviting women to screening programmes evaluated by the GDG.
• In certain countries there may be a difference in who is defined as a GP or what their status and relationship is with women.
• The GDG noted that extrapolation may be necessary to the signatures of other individuals on the letter, where GP signatures are not the most appropriate. No evidence on other signatures (e.g. screening programme directors) was identified.
• The GDG considered that the GP's consent for the use of their signature on the letters is essential for this intervention to be implemented.
• The GDG noted that the desirable benefits may vary depending on the relationship of women with the GP whose signature is on the letter.
• This intervention may only be possible in settings where the GP of women for screening programmes can be accessed or linked to the screening programme.

• The GDG recommends research on the effect of this intervention on other important outcomes such as informed decision-making.
• Research evaluating the use of electronic messages including e-mail, social media and SMS as compared to paper letters for invitation to screening.