DAX IF statement, cannot convert type

Hi,

I have the following measure, which creates a natural sentence, which I then put on a hover page, to show up when a user hovers over the individual bars of a barchart.

Overview_hover_txt = 

var TvsP = IF(SELECTEDVALUE(Overview_MostRecentYR[Diagnoses]) = SELECTEDVALUE(Overview_MostRecentYR[PersonsWithDx]), 
                    "", 
                    " ("&&format(SELECTEDVALUE(Overview_MostRecentYR[Diagnoses]), "#,#")&" tumours)"
            )


RETURN

"In "&max(Overview_MostRecentYR[year])&", "&format(sum(Overview_MostRecentYR[PersonsWithDx]), "#,#")&" Victorians were diagnosed with "&SELECTEDVALUE(TumourGrouping[SumPage_LvL1_label], "cancer")&TvsP&". Our most recent data shows that 5-year survival is "&format(sum(Overview_MostRecentYR[Survival]), "#.#%")&" (95% confidence interval "&format(SELECTEDVALUE(Overview_MostRecentYR[Survival_LL]), "#.#%")&"-"&format(SELECTEDVALUE(Overview_MostRecentYR[Survival_LL]), "#.#%")&" for the period "&SELECTEDVALUE(Overview_MostRecentYR[Period])&"). In "&max(Overview_MostRecentYR[year])&", "&format(sum(Overview_MostRecentYR[Deaths]), "#,#")&" Victorians died from "&SELECTEDVALUE(TumourGrouping[SumPage_LvL1_label], "cancer")&"."

It works where the condition is met (i.e. the IF statement returns ""):

, but I get an error when the condition is not met. The error is:

What can I do to let the if statement return