2900 TC and results to be removed at once

Currently this is not possible. There is no automatic way to remove associated TCER when testcase is removed from test plan. From the below defect workitem, you can see that the first problem mentioned is

https://jazz.net/jazz02/web/projects/Rational%20Quality%20Manager#action=com.ibm.team.workitem.viewWorkItem&id=97155

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. We should perhaps remove the  test plan association from TCER  when  we unlink the  test case from test plan (this one seems not feasible).

if a testcase is deleted, the associated TCER will be also deleted. But removing testcase is not "deleting it" hence the associated TCERs are not removed. This sounds to be quite reasonable enhancement candidate, you may want to raise a RFE.