system
Given the following post, respond as if you're commenting on Reddit:
human
How was cancer treated in the 1930s or 1940s did the treatments work or did you just die?
gpt
Firstly, a primary reason why cancer is the second leading cause of death (after heart disease) is that  people are living longer, allowing it to overtake other like stroke, pneumonia, tuberculosis, and diarrhea. Fewer people had to worry about dying of cancer in the early 20th century because something else was more likely to kill them first. That remains true today for certain types of cancer. For example, some 29% of men aged 60-69 have an undiagnosed prostate cancer discovered on autopsy. 1930 is near the turning point when cancer deaths rose rapidly, so a lot of treatment advancements accelerated after that point. Death rates for cancers of all types (with the exception of lung) have peaked since then as treatment has advanced, and environmental and lifestyle changes have taken hold.
  

  
There are 4 major modes of treatment for cancer. By the 30s/40s most existed in one form or another, though in their infancy.
  

  
**Surgical resection** is the oldest and most obvious way to treat cancer. If you can spot or feel a tumor on someone, you can go in with a knife or other tool and cut it out. If you can get all of it, the cancer is "cured". If you leave any cells behind, it will recur. Trouble is, cells are very small compared to a surgeon's eyes. Early attestations of surgical treatment date as far back as 3000 BC in Egypt, where a medical text describes surgery and cauterization of tumors. Hippocrates in 5th century BC Greece also wrote of surgical removal of “crab-like” tumors, which is where usage of the word Cancer (as in the zodiac sign) derives. The ancient writings concede that even with surgery, there was no cure.   

Surgery as a treatment has progressed as far as other supportive technologies have taken it (anesthesia, imaging to find/identify tumor cells, techniques to preserve critical structures, infection prevention, recovery, etc). The major questions are "how much tissue can you remove without taking out too much", and "will the patient survive the trauma or suffer lasting effects"? While big advancements in those disciplines began in the middle 19th century, by the 30s/40s most cancer surgeries were still performed as “radical” procedures. That is, removing large chunks of tissue or organs well beyond the margins of the visible tumor). Radical mastectomy was the standard for breast cancer til the 70s, when better understanding of how cancer spreads allowed surgeons to transition towards lumpectomy and other tissue-sparing procedures. Modern advancements focus on minimally invasive techniques (such as laparoscopy), reductions in scarring and other morbidity, precise robotic surgical tools, and imaging/visualization techniques to make it easier for surgeons to identify and excise.
  

  
**Hormone Therapy** is the introduction or removal of hormones or hormone sources that control the rate of growth of certain glandular cancers. It was first discovered in the late 19th century by a Scottish doctor studying milk production, who found that removal of the ovaries inhibited the development of breasts in rabbits, finding a connection between the two organs via estrogen before the hormone itself was known. As a result, oophorectomy (removal of the ovaries) became an option for advanced breast cancer patients. In 1941, a doctor at University of Chicago found a similar mechanism on prostate cancer from castration. More notably, he found that systemic (in the blood) treatment with estrogen would also atrophy the prostate/tumor, but could be reversed later with treatment with androgen. By the early 1980s, drugs were developed that took advantage of our understanding of the endocrine system, creating therapeutic drugs with fewer side effects.  

  

  
**Chemotherapy** is the use of systemic chemicals to cause cells to die. As with surgery, if all the cancer cells are dead, then it is cured. The trouble is, most poisons that kill cancer cells also kill normal healthy cells. The first major drug came from WWI. Soldiers exposed to mustard gas developed disorders in their bone marrow - they stopped producing healthy blood cells. During the 30s, researchers theorized that the chemical interfered with cell division. Since cancer cells divided more rapidly than healthy cells, could a derivative drug cause tumors to die off before the patient did? A trial on lymphoma patients in 1942 led to a variation under the name “Mustargen”. 

This kicked off a half-century of drug development targeting different mechanisms of action in fast-growing cells, some of which worked better for certain types of cancer. But the trouble remained - poisoning all cells, and hoping you kill all of the cancer cells before you stop - is like using powerful weed-killer on your farm hoping the crops survive. The impact of chemo on fast-growing cells are the reason for hair loss, nausea, and other side effects, and why it is such an ordeal for patients. Beyond that, chemo's effectiveness is held back not only by a patient’s ability to tolerate it, but also by cancer cells that can adapt to or resist it (they are living cells that want to keep living, after all), and those that are simply hard to reach (such as in the brain).  

Thus, modern research has focused on better targeting of drugs, either by focusing on mechanisms exclusive to cancer cells, or with molecular delivery devices that hone in on cancer cells while avoiding others. The study of genetics has helped greatly with the former, while delivery mechanisms such as repurposed antibodies can be pointed towards surface proteins of cancer cells, unlocking drugs or attracting an immune response. There are many of these drugs in market or in the pipeline, but they remain some of the most expensive and difficult to produce, and in some cases offer only modest improvements over standard treatments. Most people who get chemotherapy, therefore, get a combination of drugs with several mechanisms of action, as well as some other form of treatment.
  

  
Lastly, there is **radiation**. If you can induce all the cancer cells to die by irradiating them, you can cure the patient. At the turn of the 20th century, doctors discovered that x-rays could be used not only to diagnose, but also to zap surface-level tumors, or flood the whole body with radiation, which seemed to benefit some patients. Some believed that inhaled radium gas was a cure-all, though it was not well understood why. By the 1920s, however, they realized that indiscriminate radiation was as likely to cause cancer as it was to cure it.

Further development then focused on how healthy tissue could be protected while cancer cells remained exposed, as well as how to target cells below the surface. Patient immobilization and shielding was the preferred technique. Meaning, fixing a person in place (with rigid masks or casts) so they couldn’t move, and a molded barrier would be shaped onto them to lessen the intensity of the beam on non-target areas. To produce x-rays that would penetrate more deeply, through skin and muscle, required jumps to higher energy radiation sources - larger and more powerful beam sources. Hospitals started turning into physics labs, limiting it only to the most advanced sites. But cranking up the dose meant that all of the tissue in between the tumor and the beam would get badly damaged. Plus, the gooey stuff inside patients tends to move around (say, lungs rising and falling). If you zap too hard and miss, things get worse instead of better.

One solution is to create a high cumulative dose over a dozen or more sessions, minimizing the risks of a one-time miss. This remains a common technique today for many cancers of highly mobile tissue. The other technique is an ultra-precise one-shot, pioneered in 1949 by a Swedish doctor. The objective is to hit a single small target somewhere immobile (say, in the brain or the spine) with multiple pinpoint beams of radiation from  different angles at once. The first major commercial success was a device called the Gamma Knife in 1968, which involved a helmet filled with Cobalt-60 placed in several channels around the skull. In 1991, another "radiosurgery" device was developed that placed a beam generator on the end of a moving robotic arm that would dance around the patient, allowing the targeting of tumors outside of the head and neck as long as the patient could sit still.

The growth of radiation therapy has hinged on several parallel developments. First is improved imaging. Higher resolution MRI/CT scans allow more precise identification of target tumor cells within the body. The second is improved understanding of particle physics. It used to be that dosing calculations were done by hand. Now, dedicated physicists and dosimetrists use computers to develop complex treatment plans. The third is improved treatment devices. The objective remains to deliver as much cumulative energy as possible while minimizing collateral damage. Modern machines take advantage of higher-energy particles with complex dosing profiles (up to and including proton accelerators) and mechanically controlled beam shaping tools that could (in theory) zap the stitching on a baseball from several feet away.