It’s hard to think of a movie scene more grisly than an amputation without anesthesia. The hapless patient guzzles as much alcohol as possible, then bites down on a large stick on while one or more assistants hold him down. The screams, writhing, and sickening flesh sounds are usually enough to elicit groans and nausea from more sensitive audience members. Such were the likely scenarios before ether was introduced in 1846. Thankfully, general anesthesia spared millions of victims of disease, war and injury from agony by “knocking them out.”

Nowadays, local anesthesia—injecting a drug under the skin to numb a specific area—is preferable to knocking out the patients. Targeted numbing is commonly used from dermatology to dentistry, and the most common drug is lidocaine, which is safe when used appropriately.

Lidocaine uses

Lidocaine is most commonly used to treat temporary or chronic pain. Rather than unconsciousness, it acts by blocking the transmission of sensation signals along nerves. Thus, the local area feels completely numb. Lidocaine can also be applied to the surface of the skin in the form of a cream or patch, where it is absorbed through the skin for temporary relief from pain or itching. In addition to blocking pain, lidocaine has internal applications. It can be applied to correct irregular heartbeat; it can also make insertion of breathing tubes (intubation) easier by suppressing the cough reflex.

Lidocaine as a weapon against cancer

Breaking news! Lidocaine may be an anti-cancer agent against prostate or other cancers. “Evidence from clinical and laboratory studies have suggested that lidocaine is beneficial to cancer patients by reducing cancer progression and recurrence and improving the survival ratio.”^[i] It is increasingly shown to inhibit cancer’s mechanisms for growth and invasiveness.

A research paper by Zhang, et al. (2021) explores the reasons why some tumors survive surgery and go on to spread elsewhere; it then details the theories on how lidocaine uses before or during surgery may discourage these processes.^[ii] Although cancer cells come into existence as mutations of normal cells, their molecular activities differ in many ways from their origin cells. Besides their high energy metabolic needs as they multiply and become more aggressive, they have biochemical tricks to elude the immune system and to build their own supply of blood vessels (angiogenesis). Thus, there are multiple hypotheses for how they thwart surgery:

• The process of normal recovery from a surgical wound, with its trauma and inflammation, causes the body to produce healing growth factors, which cancer cells can also capitalize on.
• The wound itself opens pathways for cancer cell spread “by unintentionally providing more opportunities for cancer cells to enter into vessels and enhancing their proliferation.”
• The body’s inflammatory response to surgical damage to tissue creates a biochemical environment favorable to cancer cells entering blood and lymph circulation, routes by which they can metastasize to remote body areas.
• By their own nature, cancer cells are capable of suppressing the body’s immune response, mutating quickly, and generating more inflammation.

The authors propose that lidocaine may combat these natural cancer cell processes.

Lidocaine’s effects against cancer cells

Laboratory studies offer evidence that lidocaine directly impacts cancer cells. It appears to block molecular signaling pathways needed by cancer to continue its activity. If switched off, the tumor’s vascular resources and ability to spread become limited. Lidocaine also seems to directly enhance cancer cell die-off (apoptosis), while at the same time providing molecular resources that indirectly aid the immune system’s natural killer cells. As an added benefit, lidocaine fosters easier recovery from surgery thanks to pain relief and anti-inflammatory effects. A study of prostatectomy patients demonstrated that administering lidocaine by IV during surgery, and following surgery a 24-hour injection beneath the skin, reduced the need for morphine during aftercare, and shortened the hospital stay for those patients who were given the lidocaine vs. those who were not.^[iii]

When and how to administer lidocaine with intent to discourage recurrence/metastasis is still under study. A large clinical trial of breast cancer patients randomly assigned to either receive a local lidocaine injection just prior to breast surgery, or not receive any lidocaine, found that the group that did get the injection had less incidence of local recurrence, better disease-free survival, and better overall survival. Though the incremental improvements were not dramatic, they were statistically significant. There is also the theory that intravenous (systemic) lidocaine application just before or during surgery might provide “significant benefits in terms of long term cancer outcomes.”^[iv] Research studies are needed to test this hypothesis.

Interestingly, a recent laboratory study of lidocaine applied to head and neck squamous cancer cells showed that the drug activated T2R receptors (bitter taste receptors) in the cells, leading to their die-off.^[v] Certain prostate cancer (PCa) cell lines also express T2Rs,^[vi] raising the possibility that injecting a PCa tumor with lidocaine, or use of an intravenous lidocaine injection, prior to surgical removal would inhibit recurrence/metastasis. Again, carefully designed clinical trials with patients are needed, but adding lidocaine to surgical cancer removal has potential to prevent recurrence.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Zhang C, Xie C, Lu Y. Local Anesthetic Lidocaine and Cancer: Insight Into Tumor Progression and Recurrence. Front Oncol. 2021 Jun 24;11:669746.
[ii] Ibid.
[iii] Weinberg L, Rachbuch C, Ting S, Howard W et al. A randomised controlled trial of peri-operative lidocaine infusions for open radical prostatectomy. Anaesthesia. 2016 Apr;71(4):405-10.
[iv] Wall TP, Buggy DJ. Perioperative Intravenous Lidocaine and Metastatic Cancer Recurrence – A Narrative Review. Front Oncol. 2021 Aug 2;11:688896.
[v] Miller ZA, Mueller A, Kim T, Jolivert JF et al. Lidocaine induces apoptosis in head and neck squamous cell carcinoma through activation of bitter taste receptor T2R14. Cell Rep. 2023 Nov 16:113437.
[vi] Martin LTP, Nachtigal MW, Selman T et al. Bitter taste receptors are expressed in human epithelial ovarian and prostate cancers cells and noscapine stimulation impacts cell survival. Mol Cell Biochem. 2019 Apr;454(1-2):203-
214.