Cancer is a scary disease. We are constantly seeing news of people who have recently been diagnosed or may have succumbed to the disease. So, you may be surprised to learn that the primary message from the latest cancer statistics update[i] is favourable. Their headline statement is: “The cancer mortality rate has decreased continuously since 1991, resulting in an overall drop of 33% and approximately 3.8 million cancer deaths averted”.

What are the main drivers of this favourable trend?

·       By far the biggest factor is the decline in smoking and the associated lung cancers, particularly in males; a trend which, having grown explosively from the 1930's, then peaked in 1990 and has been declining significantly ever since.

·       Another factor is the introduction of screening and early detection, especially for breast, prostate and colon cancers; routine screening these cancers was introduced in the US in the latter half of the 1980’s and the first half of the 1990’s.

·       Thirdly, the ever-advancing improvements in treatments; which is now accelerating with the latest advances in the developing modalities of targeted treatments and immunotherapy (more on this in the highlights section below).

Digging deeper into the stats there are, however, some issues.

·       Breast cancer incidence is rising.  The ACS reports that this is attributed, at least in part, to “continued declines in the fertility rate (having fewer children, or having their first baby after age 30) and increases in excess body weight”.

·       There has been an uptick in new prostate cancer cases. Of particular concern is the proportion of men diagnosed with more advanced or distant-stage disease, which has doubled since 2011. This is mainly attributed to the scaling back of PSA-based screening from around 2008, a result of concerns about overdiagnosis (see reference [ii] for example).

·       A declining trend in colon cancer mortality rates masks an increasing trend in young adults diagnosed with the disease. This rising trend in the US and several other high-income countries since the mid-1990s remains unexplained but likely reflects changes in lifestyle exposures (such as dietary habits and rising obesity[iii]).

There is also an opportunity:

·       In some good news, data from women ages 20 to 24 who were first to receive the vaccine for the Human Papillomavirus (HPV), showed a 65% reduction in cervical cancer incidence rates from 2012 through 2019. This offers strong support to the WHO goal to eliminate cervical cancer as a disease through global vaccination by 2030[iv].

And there is an unknown:

·       Looking ahead, the ACS report states that delays in diagnosis and treatment arising from the COVID pandemic may lead to an uptick in advanced-stage disease and mortality; and that these and other secondary consequences of the pandemic will occur gradually over time and will require many years to quantify at the population level because of the 2-year to 3-year lag in population-based cancer incidence and mortality data.

Treatment advances continue to be dominated by targeted therapies and immunotherapy

1.       There was a significant expansion in targeted “smart bomb” drugs.
The basic rationale for chemotherapy is that it kills all fast-dividing cells. Most cancer cells are indeed fast-dividing, but so are some healthy cells (e.g. hair, lining of the gut, immune cells etc). So, there is usually collateral damage, sometimes significantly so. Is it not possible to just target cancer cells? This is the thinking behind smart bomb drugs - an engineered drug consisting of a "homing-device" (to find and lock onto cancerous cells) linked to a pay load, for example a chemotherapy or radiation pellet (to then destroy these cells). This then enables the more precise delivery of conventional drugs to increase killing effectiveness and to reduce collateral damage. Although not an entirely a new technology, there was a significant increase in "smart bomb" options for use in more resistant cancers during 2022:

1.1.   In breast cancer there are now approvals for chemo-based Antibody-Drug Conjugates (ADC’s) for resistant breast cancers - covering resistant Her2-positive cancers, a new category called Her2-low disease, as well as the difficult to treat triple-negative breast cancer[v].

1.2.   There is also a new approval for a "radioligand" (using a radiation pellet for payload) for a target commonly found on many prostate cancers[vi].

2.       Advances in Immune oncology (IO) continue to dominate the headlines