Cancer Screening in Nigeria is a bad idea

Premium times Nigeria recently reported the Nigerian health minister as saying that the Federal Government has concluded plans to roll out nationwide screening for most common types of cancer. According to the minister, the screening will be on the most common types of cancer, such as breast and cervical cancer in women and prostate cancer among men.

Mr. Adewole spoke at a ceremony to mark the 2018 World Cancer Day so one can understand his exuberance in pushing the screening message. If we, however, take a step back and review the practice of cancer screening, cheering for its adoption may not be so enthusiastic.

Criteria for screening

In 1968, due to growing technological advances in medicine at the time, disease screening gained more importance and became rather controversial. The WHO as a result commissioned two physicians Drs wilson and Junger to write a report on screening. In their report, the physicians were quick to point out a certain inherent difficulty:

The central idea of early disease detection and treatment is essentially simple. However, the path to its successful achievement (on the one hand, bringing to treatment those with previously undetected disease, and, on the other, avoiding harm to those persons not in need of treatment) is far from simple though sometimes it may appear deceptively easy.”

Wilson and Junger went on to propose a set of criteria (Wilson’s criteria) to help guide when to screen for diseases. With the advent of newer and even more sophisticated technology, more relevant criteria based on the original ones are being proposed. Here they are:

1. The screening programme should respond to a recognized need.
2. The objectives of screening should be defined at the outset.
3. There should be a defined target population.
4. There should be scientific evidence of screening programme effectiveness.
5. The programme should integrate education, testing, clinical services and programme management.
6. There should be quality assurance, with mechanisms to minimize potential risks of screening.
7. The programme should ensure informed choice, confidentiality and respect for autonomy.
8. The programme should promote equity and access to screening for the entire target population.
9. Programme evaluation should be planned from the outset.
10. The overall benefits of screening should outweigh the harm.

Following the publication of Wilson’s initial criteria, many diseases were deemed worthy to be screened for. This saw the birth of many national cancer screening programs. Decades on, the medical community now has plenty of experience in cancer screening. The question then posed by the last criteria rings out, have the benefits of screening outweighed the harm? Has screening been worthwhile?

Nigeria and Wilson’s criteria for disease screening

Before making that assessment on cancer screening internationally, it’s worthwhile passing the Nigerian situation through Wilson’s criteria.

Cancer incidence is increasing so one can argue easily for the adoption of screening. The probability of catching a cancer early gets higher the more cancer occurs and cancers gotten earlier are more likely to be cured.

While setting clear objectives from the start should be a given, I doubt we would be able to define an appropriate target population we can adequately reach in an equitable and fair manner such that everyone gets equal access. Remember that we’ve struggled to eradicate polio for a long while when the rest of the world has managed to.

Along the same lines, defining any target population in Nigeria would invariably amount to millions, how will we educate them? Where will the tests be carried out? Will we have the clinical capacity to accommodate all the testing and treatments that will need to be done when cases are captured. We know our doctors are leaving, we have very few oncologists. Equipment is hard to come by, we have only one working radiotherapy machine. Who will pay for all this expensive infrastructure and service improvements? We spend only 4% of our budget on health.

In the context of no universal access to healthcare the patient will have to pay for care at the point of delivery. In this study on the cost for prostate cancer care in Ghana, it was estimated to cost between $1,000 — $9,000. Imagine the difficulty associated with diagnosing a patient with a cancer then immediately asking him to go search for $9,000 to be treated. This would be cruel.

If the patient is somehow able to fork out $9,000 for his treatment after a positive cancer screening, can the international experience tell us that it’s more beneficial than harmful? That his $9,000 will not be wasted?

The international experience

This graph from the American experience with breast cancer screening suggests more harm than good from screening.

Since the introduction of screening, cases of breast cancer have increased but rates of the death causing metastatic cancers have remained the same. This suggests that all screening is doing is over-diagnosing non-harmful cancers while having no effect on the number of serious cases. Screening proponents say that people with breast cancer are surviving more now due to early detection. The counter argument holds that these people would probably have survived anyway, pointing to the dramatic improvement in quality of cancer care to account for the better survival rates. Several countries are now reconsidering their approach to breast cancer screening and are educating patients of its risks.

A similar graph is seen for other cancers like thyroid and kidney cancers. Both of these continue to be diagnosed more often with no change to the proportion of people that die from them every year. Diagnosing them more hasn’t improved the death rates from them so why bother.

Prostate cancer is worthy of mention too. The United States Preventive Services Task Force has recommended that men no longer be routinely screened for prostate cancer. The argument for screening in African populations is that it’s more prevalent. However, the studies indicating this are based on Africans in diaspora. These Africans have largely been selected for through their ancestors who survived harsh travel conditions. Their genetics thus may not be comparable to those of Africans in Africa. A study from Ghana suggests that Native Africans may have lower risk of prostate disease as compared to Africans in diaspora, it concludes:

Recent evidence although sparse indicate there is high prevalence of BPH and PC in Africans and men of African descent in diaspora, the low prevalence of BPH and Prostate Cancer reported from some African countries is likely to under reporting and future prevalence studies both in the living and deceased are recommended to reveal the true prevalence of BPH and Prostate Cancer in Africans though screening for PC in the living remains controversial.

(*BPH stands for benigh prostatic hyperplasia. )

Over-diagnosis

The main challenge with screening is over-diagnosis. What harm is over-diagnosis anyway? All medical procedures have complications. Prostate cancer treatment comes with a real risk of incontinence and erectile dysfunction. Not many men would like to have either of these. For breast cancer one may have to endure scarring and painful procedures. Death is also a real possibility because research has shown that in Africa, you’re far more likely to die during a procedure than anywhere else in the world. There is also the unnecessary financial costs, trepidation and worry that a cancer diagnosis brings. There is also the real opportunity cost of what else we could be investing in when we over diagnose and treat unnecessarily.

Screening is not simple

Screening for breast cancer is nuanced, screening for prostate cancer is controversial. If we introduce these programs it will cost us billions. With our existing lack of expertise and infrastructure we will not be able to handle the spike in cases. International experience suggests that even with screening we may not make a dent on death rates.

We must thusabandon any thought of cancer screening. We should instead invest in better cancer prevalence/ surveillance studies, improve our cancer registries and improving current facilities for cancer care. We need many cancer centers of excellence with defined referral pathways. We should create public health programs that create awareness on the need for good lifestyle habits to prevent cancers and other non-communicable diseases. We also need UHC (universal health coverage) so that patients aren’t made poor in order to afford treatments. For a disease like cervical cancer, we should consider investing in the vaccine so that the oncoming generation would be protected.

The advantage of coming late to the party after having seen everyone’s dress is that we can pick out the best dress. Nigeria is late to the cancer screening party and as such we can learn from the mistakes of others by not engaging in screening that may prove to be more harmful than beneficial. Cancer screening should be the last thing on our minds.