*4.4.1 Why pain arises?*

Pain is the 3rd most common symptom of cancer and reportedly has many reasons for the cause of pain from cancer [38]. It winds up being the patient-related factors such as, the location of the tumor, the neural system and the tissue being affected, stage of cancer its malignancy etc. People also suffer from pain related discomfort while going through the treatment of cancer which includes surgery for the removal of the tumor from the affected area, chemotherapy and radiotherapy

*Suggestions for Addressing Clinical and Non-Clinical Issues in Palliative Care*

#### **Figure 4.**

*Flowchart representing research design for ABPAT [34].*

that the patient may be undergoing for managing cancer [39]. Hence cancer pain can be broadly divided into two categories


Tumor related cancer pain mainly occurs due to excessive pressure on the nearby tissue or bone (Cancer-induced bone pain) and nerve causing the sensation of pain. Also, this can lead to blockages to a certain area and bodily mechanism of transport of nutrients, causing tissue damage which can cause both nociceptive pain and neuropathic pain if the nerves are damaged [38, 40]. Inflammatory responses can also be a major player in destroying affected areas such as in a study related to pancreatic cancer. It was noted that due to inflammation transient receptor potential cation channel gets activated which in turn activates Substance P (SP) and Calcitonin Gene-Related Peptide (CGRP) two neurotransmitters that transfer pain signals to dorsal root ganglia [38]. In the case of cancer-induced bone pain, cancer cells release RANKL (Receptor activator of nuclear factor kappa-B ligand) which increases the reabsorption of the bone by osteoclasts degrading the bone and sensitizing pain nerves [41, 42]. Drugs that are used in the treatment of neoplastic disease(chemotherapy) such as Bortezomib, Cisplatin, Vincristine, etc. although are widely used and effective but have a big downside of causing peripheral neuropathy by damaging sensory neurons, dorsal root ganglia and neurons present in the spinal cord [40]. Surgical procedures cause side effects in many cases and may have minor damage to the operated area. This can lead to neuralgia due to damaged nerve or in one study on myofascial pain syndrome caused after post breast cancer surgery. The neuromuscular damage after breast cancer surgery in the thoracic area stays contracted in pressure and is sensitive to myofascial trigger points [39, 43]. Even patients who are undergoing radiotherapy for head neck cancer have reported that radiotherapy results in other problems like mucositis in their buccal cavity and their throat and esophageal tract with severe lesioning [44]. These studies suggest that cancer pain can not only be caused by the tumor but also by the treatment that the person is undergoing.

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**5. Conclusion**

repressing drugs should be followed.

*Assessment and Management of Pain in Palliative Care DOI: http://dx.doi.org/10.5772/intechopen.96676*

The best and widely accepted treatment in cancer pain is the utilization of opioids which are predominantly used for symptomatic treatment of pain [45]. Opioids function by binding to opioid binding receptors such as (mu, kappa, delta, and sigma) and these ligands and receptors are present throughout the body. Opioids function as inhibitory agents during excitation and in turn decreases the release of excitatory neurons [46]. Morphine is the most well-known among opioids [41]. These opioids such as buprenorphine, codeine, fentanyl, methadone, oxycodone, and tramadol are given in various methods such as oral, intravenous injection or drip, etc. The amount of dosage to be given is determined by the bodyweight of the subject [46]. Various drugs have their benefits like fentanyl which can be used for rapid action in cases of oral administration it is also good for delivering transdermally including opioid buprenorphine [45]. Other methods include the administration of corticosteroids for anti-inflammatory effects. In the USA, this method is used against inflammation caused by cancer and related treatments in palliative care [47]. Similarly, the utilization of aspirin as a non-steroidal drug is also widely administered [47]. Recently due to much increase in cancer pain research, the analgesic abilities of marijuana (cannabinoids) are also being looked upon as a potential drug for pain mitigation. Another drug "oliceridine" which was recently approved in 2020 for cancer pain management in adults was found to have fewer side effects as it also activates G- coupled protein receptor based μ-opioid receptor and has therefore an analgesic effect with tolerance comparable to morphine [42, 48]. In cases where analgesic medicines are deemed ineffective,

gabapentin or pregabalin are recommended for low dosage use.

Although opioids are well suited and effective against nullifying the effects of pain. Although, it has been well documented that if abused, they do have detrimental effects on the patient with higher doses having the possibility of addiction and then withdrawal from the drugs. Short-term effects still include nausea, vomiting, breathing difficulties and many more [46, 49]. This was validated by a study done by Kata V. on opioid abuse stating that in 2016 one of the top causes of accidental death in the U.S was opioid drug overdosing [49]. In the same study, it was also noted that due to breakthrough cancer pain requiring short-acting opioids and are required in frequent doses compared to long-acting opioids this can cause overdosing of the patient leading to complications [49]. A long-proposed idea is the use of non-opioids and non-steroidal anti-inflammatory drugs. In a study conducted by Janette Vardy and Meera Agar, they mentioned that multiple studies and research on more than 2000 patients were conducted and these patients were administered with acetaminophen [50]. It was noted that at various doses of acetaminophen ranging from 500–1000 mg, there was significant reduction in pain and there was no ill effect about the same. Furthermore, nonsteroidal anti-inflammatory drugs can become toxic in patients with cardiovascular and GI tract issues, indicating that even they have to be administered only after checking for these ailments on the patients [50]. For further research, proper mitigated administration of these pain

Still, pain assessment remains quite challenging to the caregivers. The reasons

being first there is no consensus available or a format that speaks a common language to the masses. Pain acts differently in individuals and even though two people suffer from the same ailments their pain tolerance will be affected by many

*4.4.2 Treatment and management*
