This isn't doing what you think:

grep { /$q->param('report_type')/ } (qw/case_id hosp_alias sender rece
+iver/)
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Regular expressions are interpolated, but not evaluated.

What you want instead is:

grep { $q->param('report_type') eq $_ } (qw/case_id hosp_alias sender 
+receiver/)
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Or:

my $report_type = $q->param('report_type');

grep { $report_type eq $_ } (qw/case_id hosp_alias sender receiver/)
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And to avoid checking a long list you can get only the first match by using List::Util as follows:

use List::Util qw( first );

if ( first { $report_type eq $_ } (qw/case_id hosp_alias sender receiv
+er/)) {
}
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