user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: What was the reason for sthe surgery that the character from Craigs dream date underwent? 
Knowledge Triplets: Film character, freebase.type_profile.strict_included_types, Fictional Character
Film character, type.type.expected_by, Character using Wham-O product
Character, type.property.expected_type, Film character
Anal cancer, medicine.disease.medical_specialties, Oncology
Fictional Character, freebase.type_profile.published, Published
Fictional Character, freebase.type_profile.kind, Portrayal
Cancer, people.cause_of_death.includes_causes_of_death, Anal cancer
Film character, freebase.type_hints.included_types, Topic
Anal cancer, people.cause_of_death.people, Gwen Welles
Craig's Dream Date, common.topic.notable_for, g.1256xhkd8
Topic, freebase.type_profile.published, Published
Cancer, medicine.disease.includes_diseases, Anal cancer
Fictional Character, freebase.type_profile.strict_included_types, Topic
m.04j2z4t, film.performance.film, The Lovemaster
Film character, common.topic.article, m.02_96_z
Anal cancer, base.consumermedical.medical_term.consumer_name, Anal cancer
Craig's Dream Date, film.film_character.portrayed_in_films, m.04j2z4t
m.04j2z4t, film.performance.actor, Farrah Fawcett
Character, rdf-schema#range, Film character
m.04j2z4t, film.actor.film, Farrah Fawcett
Gwen Welles, people.deceased_person.cause_of_death, Anal cancer
Fictional Character, freebase.type_hints.included_types, Topic
Anal cancer, people.cause_of_death.people, Farrah Fawcett
Film character, freebase.type_profile.kind, Annotation
Craig's Dream Date, common.topic.notable_types, Film character
Film character, type.type.expected_by, Other conquests
Film character, freebase.type_profile.strict_included_types, Topic
Anal cancer, medicine.disease.parent_disease, Cancer
Oncology, medicine.medical_specialty.diseases_treated, Anal cancer
Anal cancer, medicine.disease.notable_people_with_this_condition, Farrah Fawcett
Character, owl#inverseOf, Portrayed in films
Character, type.property.reverse_property, Portrayed in films
Farrah Fawcett, medicine.disease.notable_people_with_this_condition, Anal cancer
Farrah Fawcett, film.actor.film, m.04j2z4t
Film character, type.type.properties, Portrayed in films
Film, type.domain.types, Film character
Film character, type.type.properties, Portrayed in films (dubbed)
Film character, type.type.expected_by, Killed by
Farrah Fawcett, medicine.notable_person_with_medical_condition.condition, Anal cancer
Film character, type.type.expected_by, Character
Film character, type.type.domain, Film
The Lovemaster, film.film.starring, m.04j2z4t
Craig's Dream Date, film.film_character.portrayed_in_films, m.04j2z4t
m.0r0350n, dataworld.gardening_hint.last_referenced_by, Anal cancer
Topic, freebase.type_profile.kind, Portrayal
Film character, freebase.type_profile.published, Published
Farrah Fawcett, people.deceased_person.cause_of_death, Anal cancer
m.04j2z4t, film.performance.character, Craig's Dream Date
Anal cancer, people.cause_of_death.parent_cause_of_death, Cancer
Film character, freebase.type_hints.included_types, Fictional Character
Film character, freebase.type_profile.kind, Portrayal

Answer: Anal cancer