Grades: 7-12
Time: 5-8 hours
1. Put the students into groups of 3-5.
2. Provide the students with the "Do Your Patients Have Increased Rates of Cancer?" handout.
3. Have the students define the problem and determine what they know about the problem, what they need to learn more about, and where they need to look to find information.
4. Groups conduct research, find information, and work towards deciding what they should do. The teacher acts as a metacognitive coach, serving as a model. The teacher thinks aloud with students and practices behaviour they want their students to use. Students should become used to metacognitive questions such as "What is going on here?" "What do we need to know more about?" "What have we learned?" The teacher should encourage students to use questions and to take responsibility for the problem.
These are some possible disclosures to give the students as they work:
DISCLOSURE 1
As doctors, you will need to review what cancer is and the causes of cancer. What could potentially be causing the high rates of cancer you are seeing among your patients?
DISCLOSURE 2
You are doctors, not statisticians, so you will need to look into what makes something statistically significant. Are the rates of cancer among people increasing elsewhere? What are the rates of cancer elsewhere? What do you know about the rates of cancer in the general population compared to the rates of cancer in your patients? What were the previous rates of cancer among people in the area?
DISCLOSURE 3
You need to discuss what to do about what you have noticed and discovered.
5. After groups have worked on the problem for a few days, disclose that some of the doctors in the area chose to alert the health authority. Then, the Alberta Cancer Board, supported by the province's governing health authority, Alberta Health Services, conducted a comparative survey to see whether the rates of cancer were statistically significant. The comparative survey found the following:
Of the six cholangiocarcinomas that the doctors suspected, two cases were confirmed and this was found to be within the expected range. Three of the suspected cases were other types of cancer and one was not cancer.
The cancer rate overall (51 cancers in 47 individuals out of a population of approximately 1,200 people) was higher than expected (39 cancers in a population of approximately 1,200 people).
Higher than expected numbers of cancers of the blood and lymphatic system, biliary tract cancers as a group, and soft tissue cancers were found.
These findings were based on a small number of cases and could be due to chance, increased detection, or increased risk in the community.
6. Provide the students with the "Now What?" handout.
7. Have the students define the problem and determine what they know about the problem, what they need to learn more about, and where they need to look to find information.
8. Groups conduct research, find information, and work towards deciding what they should do. The teacher acts as a metacognitive coach, serving as a model. The teacher thinks aloud with students and practices behaviour they want their students to use. Students should become used to metacognitive questions such as "What is going on here?" "What do we need to know more about?" "What have we learned?" The teacher should encourage students to use questions and to take responsibility for the problem.
These are some possible disclosures to give the students as they work:
DISCLOSURE 1
Now that you know the expected cancer rates and the cancer rates among your patients, use calculations to determine whether the rates are statistically significant.
DISCLOSURE 2
If there is a greater rate of cancer among your patients, what could be causing this to occur? Research the potential behavioural causes of cancer and the behaviour of your patients. Research environmental factors. Research other factors.
DISCLOSURE 3
You want to present your findings to the Alberta Cancer Board to respond to their findings. You will explain whether you believe there to be statistically significant increased rates of cancer among your patients, what you believe the cause might be, and what you think should be done about the issue.
9. Groups present their information, their potential solution(s) and support for their solution(s). The teacher completes the Example Rubric for Grading Problem-Based Learning Projects (or similar) to grade the students' work.
10. If desired, the students complete the Problem-Based Learning Teamwork Reflection Questions sheet and/or the questions are discussed in the groups or as a whole class.
Information for the Teacher
Map showing Fort Chipewyan and Athabasca Oil Sands
Cancer starts when cells develop the ability to grow uncontrollably and ultimately invade and damage the body’s normal tissues. Cancer development happens in multiple stages, from precancerous changes to malignant tumours. However, not all cancers form tumours, and different cancers can develop at different rates. Sometimes cancer cells spread from their original site to other places in the body through the bloodstream or lymphatic system - a process called metastasis.
There are genetic causes of cancers. However, only 5% to 10% of all cancers are genetically inherited, and these are cancers that tend to occur earlier in life. There are also behavioural causes of cancer (such as tobacco, tanning, diet - processed red meats, alcohol, and inflammatory conditions such as ulcerative colitis or obesity). There are also environmental causes of cancer (excessive sun exposure, chemical carcinogen exposure, high-dose chemotherapy and radiation, hormonal drugs, immune-suppressing drugs, and radioactive materials). Bacteria and viruses can also cause cancer (human papillomavirus, hepatitis B and hepatitis C, Epstein-Barr virus, human t-lymphotropic virus, Kaposi’s sarcoma-associated herpesvirus, Merkel cell polyomavirus, and Helicobacter pylori).
Cancer Incidence in Fort Chipewyan, Alberta 1995-2006: https://www.ceaa-acee.gc.ca/050/documents/45480/45480E.pdf
Scientific American article titled “Oil Sands Raise Levels of Cancer-Causing Compounds in Regional Waters”. (https://www.scientificamerican.com/article/oil-sands-raise-levels-of-carcinogens-in-regional-waters/)
In statistical hypothesis testing, a result has statistical significance when it is very unlikely to have occurred given the null hypothesis.