The History of Cancer Therapy

Cancer has been a widespread illness since ancient times, but only recently have doctors begun to understand the disease more thoroughly to develop a wide range of therapies, including surgery, radiation, chemotherapy and different drug treatments.

Early Cancer Surgery

• According to the American Cancer Society (ACS), ancient physicians could diagnose cancer and operate to remove tumors. But they considered cancer incurable because it usually returned after the tumors were removed, and they had no means to stop the spread of the disease. For centuries, this was the consensus regarding cancer treatment. It wasn't until the 19th century that major advances were made in general surgery, namely the discovery of anesthesia in 1846, which improved cancer therapy. In the late 1800s, surgeons developed cancer operations to remove tumors and the lymph nodes in the region of the tumor. William Stewart Halsted believed that removing the tumor along with a large amount of tissue around it would prevent its spread, which led him to develop the radical mastectomy in the 1890s. It wasn't until the 1970s that clinical trials proved that less extensive surgery could be equally effective. Better understanding of cancer, combined with better surgical instruments, allowed doctors to remove tumors without destroying so much healthy tissue. For example, breast cancer could be treated by removing only the cancerous lump instead of the entire breast.

  In the 1880s, English surgeon Stephen Paget concluded that cancer cells spread through the bloodstream to all parts of the body but were only able to grow in certain organs. This understanding of metastasis led to treatments used after surgery to destroy cancer cells that had spread throughout the body.

Modern Cancer Surgery

• In the mid-20th century, less invasive surgery involving fiber optics and endoscopes was developed to remove tumors using tubes inserted into the body, according to the ACS. Until the end of the 20th century, doctors had to perform exploratory surgery in the abdomen or chest to take tissue samples to be tested for cancer. In the 1970s, advances in ultrasound, computed tomography (CT scans), magnetic resonance imaging (MRI scans) and positron emission tomography (PET scans) replaced the need for most exploratory operations because they allowed doctors to see inside the body and guide biopsy needles into tumors of internal organs without surgery. In the late 1990s, cryosurgery began to be used to kill cancerous cells by freezing them with liquid nitrogen or a very cold probe. Recent surgical advances include lasers to vaporize tumors and radio waves to kill cancerous cells.

Radiation

• According to the ACS, the discovery of radiation in 1896 by Wilhelm Conrad Roentgen was a huge advancement in cancer therapy. Within months of the discovery, X-rays were being used for diagnosis, and within three years, radiation was used in cancer treatment. According to the ACS, radiation therapy began with radium and low-voltage diagnostic machines. French doctors discovered that daily doses of radiation over several weeks would greatly improve therapy results. In the early 20th century, radium was being used in small tubes for insertion directly into tumors or body cavities containing cancer, which allowed for treatments of inoperable areas, like the cervix and larynx, according to the American Society of Radiation Oncology.

Chemotherapy

• According to the ACS, World War II soldiers who were exposed to mustard gas were found to have damaged bone marrow cells. At the same time, the U.S. Army was researching mustard gas in order to develop more effective agents and protective measures, and they found that nitrogen mustard had a substantial affect against lymphoma. This led to the discovery of other agents that killed cancer cells by damaging their DNA. In the 1920s, Sidney Farber demonstrated that the chemical aminopterin led to remission of leukemia in children. This chemical was the predecessor of methotrexate, a commonly used cancer treatment drug today. Since then, researchers have discovered drugs that block cell growth and replication.

  In 1956, the first recorded cure of cancer via chemotherapy was recorded. Long-term remissions and cures of Hodgkin's disease and childhood leukemia with chemotherapy were reported in the 1960s, and success with testicular cancer in the 1970s.

Immunotherapy

• Immunotherapy involves medications that mimic the natural signals that the body uses to regulate cell growth. The ACS reports that, in the 1970s, scientists discovered how to mass produce antibodies to target chemical components of cancer cells, but it took 20 years for the first drugs using antibodies to be approved to treat lymphoma and breast cancer. Since then, several others have been approved, and many more are being studied.

Targeted Therapies

• Until the 1990s, almost all drugs used to treat cancer worked by killing cells that were in the process of dividing into new cells. Targeted therapies, however, work by influencing the processes that control growth and spread of cancer cells as well as signals that cause cells to die naturally. In the 1960s, scientists discovered that cancer cells contain abnormal levels of growth factors, substances that tell cells when to grow and divide. In the 1980s, researchers developed targeted therapies to block growth factors. Another targeted therapy, angiogenesis inhibitors, entails drugs to stop tumors from making new blood vessels that they need to continue growing. This concept was first proposed in the 1970s, but the first drug wasn't approved until 2004.