Can late periods be a sign of terminal cancer?

It hasn't happened to me but I was just watching the last episode of Two pints of larger and a packet of crisps:L and Donna's period was late so she thought she was pregnant, so she went to the doctor's and she wasn't pregnant but they said she'd have to come back for more tests and she was really worried and she cried at the end the last time she saw Gaz before he went on holiday as if she would never see him again so I was wondering if it could cause her terminal cancer or any cancer? I know this is such a random question:L but I was just wondering:L:L