Treatment of lung cancer refers to the use of medical therapies, such as surgery, radiation, chemotherapy, immunotherapy, percutaneous ablation, and palliative care, alone or in combination, in an attempt to cure or lessen the adverse impact of malignant neoplasms originating in lung tissue.
Lung cancer is an extremely heterogeneous family of malignant neoplasms, and well over 50 different histopathological variants are currently recognized under the most widely used typing system. Because these variants have differing genetic, biological, and clinical properties, including response to treatment, correct classification of lung cancer cases are necessary to assure that lung cancer patients receive optimum management.
Approximately 95% of lung cancers are carcinoma, or tumors derived from transformed cells of epithelial lineage. Currently, nearly four dozen different histopathological variants of lung carcinoma are recognized. For clinical and treatment purposes, however, most oncologists tend to classify lung carcinomas into two major groups, namely small cell carcinoma (SCLC) and non-small cell lung cancer (NSCLC). This is done because of differing responses to treatment—NSCLC is comparatively less sensitive to chemotherapy and/or radiation, so surgery is the treatment of choice in these tumors. SCLC, in contrast, usually initially responds well to chemotherapy and/or radiation, but has usually metastasized widely by the time it is discovered, making surgery ineffective.
In a 2010 study of patients with metastatic non–small-cell lung cancer, "early palliative care led to significant improvements in both quality of life and mood. As compared with patients receiving standard care, patients receiving early palliative care had less aggressive care at the end of life but longer survival" which was increased by approximately three months.
There are typically three objectives applied to the treatment of lung cancer and can vary by patient or individual diagnosis: (1) curing lung cancer, (2) controlling lung cancer, and (3) being comfortable.
Surgery
In most cases, the goal of lung cancer surgery is to remove the entire tumor, including a small amount of normal tissue (about ) at the margin. The general name for surgery that enters the chest is thoracotomy, and specific named types of surgical interventions may be performed as part of the thoracotomy, such as wedge resection, segmentectomy, "sleeve resection", lobectomy, or pneumonectomy, depending on the tumor and patient characteristics.
Surgery is very rarely used in cases of stage 3b or stage 4 non-small cell lung carcinoma.
Chemotherapy In patients with stage 3 lung cancer that cannot be removed, treatment with combined radiotherapy and chemotherapy improves survival significantly.
Chemotherapeutic Agents Used for Treatment of stage IV NSCLC
Chemotherapy for NSCLC usually includes combination of two drugs (chemotherapy doublet), with one of the agents is cisplatin or carboplatin. In 2002, Schiller at al. published in the New England Journal of Medicine, a study that compared four chemotherapy regimens for advanced NSCLC, cisplatin and paclitaxel, cisplatin and gemcitabine, cisplatin and docetaxel, and carboplatin and paclitaxel. The study was well powered, with 1207 patients enrolled. None of the four chemotherapy regimens offered a significant advantage over the others. In 2008, Scagliotti et al. published in the Journal of Clinical Oncology a study that compared cisplatin plus gemcitabine with cisplatin plus pemetrexed in chemotherapy-naive patients with advanced NSCLC. Overall survival was statistically superior for cisplatin/pemetrexed versus cisplatin/gemcitabine in patients with adenocarcinoma and large-cell carcinoma histology, while patients with squamous cell histology had a significant improvement in survival with cisplatin/gemcitabine versus cisplatin/pemetrexed. These two studies made significant impact on the chemotherapy choices for treating NSCLC, with cisplatin or carboplatin as the backbone of all the chemotherapy treatments protocols.* Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Pemetrexed is provided with platinum-based chemotherapy to patients with nonsquamous NSCLC. Gemcitabine is provided with platinum-based drug to patients with squamous NSCLC.
Cisplatin Cisplatin is composed of a central atom of platinum with two chloride atoms and two ammonia molecules attached to it. Cisplatin is provided intravenously and exerts its cell-killing effects through disrupting transcription and translation of the cell's DNA. Kidney damage (nephrotoxicity) in the form of proximal tubular injury is the main reason to stop cisplatin. Other side effects of cisplatin include nausea and vomiting which usually necessitate premedication with antiemetic medications before infusion; ear damage (ototoxicity), which could manifest in varying levels of hearing loss; peripheral neuropathy; and bone marrow suppression (myelosuppression). Carboplatin Carboplatin, like cisplatin, is composed of a central atom of platinum and two ammonia molecules, but it has a cyclobutanedicarboxylate moiety instead of chloride. Carboplatin is also provided intravenously and also kills cells by disrupting the cell's DNA. Bone marrow suppression is the dose-limiting toxicity of carboplatin. Carboplatin is much less damaging to kidneys compared to cisplatin and is used as an alternative to cisplatin for patients with preexisting kidney failure. Taxanes Taxanes are microtubule-stabilizing drugs which induces mitotic arrest at the G2/M transition phase of the cell cycle, resulting in cell death. Paclitaxel was isolated from bark extract of the Pacific yew tree. Docetaxel is a semisynthetic taxane and nab-paclitaxel is a nanoparticle albumin-bound paclitaxel. Paclitaxel Paclitaxel binds to tubulin and stabilizes the microtubules which leads to inhibition of cell division. Paclitaxel is provided intravenously, with a dose limiting toxicity of peripheral neuropathy. Peripheral sensory neuropathy presents with numbness and tingling in a stocking-and-glove distribution, which may disturb daily function of the patients. Hematologic toxicity include anemia, neutropenia, and less frequently thrombocytopenia. Docetaxel Docetaxel is provided intravenously, and acts in similar manner to paclitaxel. Docetaxel binds to tubulin, the protein component of the microtubules, and inhibits its disassembly, which results in disruption of mitosis and cell death. Hematological toxicities are the dose limiting toxicity of Docetaxel with neutropenia and anemia. Other side effects include alopecia, stomatitis, diarrhea, nausea, vomiting, fluid retention, onycholysis, and skin toxicity. Nanoparticle Albumin-Bound Paclitaxel Nanoparticle albumin-bound (nab) paclitaxel is an Albumin bound with high affinity to the hydrophobic molecules of paclitaxel, which results in higher accumulation of the cytotoxic drug in tumors. A recent meta-analysis showed that when compared to Paclitaxel, nab-paclitaxel has significant beneficial effects in terms of overall response rate, progression free survival, and overall survival. Side effects of nab-paclitaxel include anemia, neutropenia, alopecia, and peripheral neuropathy. Gemcitabine Gemcitabine is structurally similar to cytarabine and functions as a pyrimidine analogue, and blocks the progression of cells through the G1/S-phase. Gemcitabine is metabolized by nucleoside kinases to Gemcitabine diphosphate and Gemcitabine triphosphate. Gemcitabine diphosphate inhibits ribonucleotide reductase, resulting in reductions in deoxynucleotide concentrations, including deoxycytidine triphosphate. Gemcitabine triphosphate competes with deoxycytidine triphosphate for incorporation into DNA. Side effects of Gemcitabine includes myelosuppression manifested by neutropenia, thrombocytopenia, and anemia; pulmonary toxicity, including interstitial pneumonitis, pulmonary fibrosis, pulmonary edema, and adult respiratory distress syndrome; capillary leak syndrome; and posterior reversible encephalopathy syndrome. Pemetrexed Pemetrexed functions as an antimetabolite. Pemetrexed inhibits thymidylate synthase, dihydrofolate reductase and glycinamide ribonucleotide formyltransferase. Pemetrexed induces cell cycle arrest in the G1/S phase. Side effects of Pemetrexed includes myelosuppression, renal failure, bullous and exfoliative skin toxicity, diarrhea, nausea, and vomiting.
Tumor Treating Fields might improve chemotherapy treatment, though it is still experimental.
Targeted therapy
In recent years, various molecular targeted therapies have been developed for the treatment of advanced lung cancer. Gefitinib (Iressa; withdrawn from the U.S. market) is one such drug, which targets the tyrosine kinase domain of the epidermal growth factor receptor (EGFR), expressed in many cases of non-small cell lung carcinoma. It was not shown to increase survival, although females, Asians, nonsmokers, and those with bronchioloalveolar carcinoma appear to derive the most benefit from gefitinib.
Erlotinib (Tarceva), another EGFR tyrosine kinase inhibitor, increased survival in non-small cell lung cancer and was approved by the FDA in 2004 for second-line treatment of advanced non-small cell lung carcinoma. Similar to gefitinib, it also appeared to work best in females, Asians, nonsmokers, and those with bronchioloalveolar carcinoma, particularly those with specific mutations in EGFR.
The angiogenesis inhibitor bevacizumab (Avastin), (in combination with paclitaxel and carboplatin), improves the survival of patients with advanced non-small cell lung carcinoma. However, this increases the risk of lung bleeding, particularly in patients with squamous cell carcinoma.
Crizotinib shows benefit in a subset of non-small cell lung cancer that is characterized by the EML4-ALK fusion oncogene, and is approved by the FDA.FDA approves Xalkori with companion diagnostic for a type of late-stage lung cancer. U.S. Food and Drug Administration. EML4-ALK is found in some relatively young, never or light smokers with adenocarcinoma.
Advances in cytotoxic drugs, pharmacogenetics and targeted drug design show promise. A number of targeted agents are at the early stages of clinical research, such as cyclo-oxygenase-2 inhibitors, the apoptosis promoter exisulind, proteasome inhibitors, bexarotene, the epidermal growth factor receptor inhibitor cetuximab, and vaccines. Sorafenib (marketed as Nexavar for use in renal and liver cancer) showed promise in a clinical trial matching targeted treatment to the cancer's genetic profile. Future areas of research include ras proto-oncogene inhibition, phosphoinositide 3-kinase inhibition, histone deacetylase inhibition, and tumor suppressor gene replacement.
Immunotherapy Immunotherapy is a type of cancer treatment that activates the immune system to fight cancer.
Nivolumab is a fully human IgG4 antibody targeting programmed death receptor 1 (PD-1). In 2015, nivolumab was approved for the treatment of people with metastatic squamous non-small cell lung cancer (NSCLC) with progression on or after platinum-based chemotherapy.
In 2016, the FDA approved atezolizumab for the treatment of people with metastatic non-small cell lung cancer (NSCLC) whose disease progressed during or following platinum-containing chemotherapy and pembrolizumab for the treatment of people with metastatic non-small cell lung cancer (NSCLC) whose tumors express programmed death-ligand 1 (PD-L1) as determined by an FDA-approved test.
In 2017, the FDA granted accelerated approval to pembrolizumab in combination with pemetrexed and carboplatin for the treatment of people with previously untreated metastatic non-squamous non-small cell lung cancer (NSCLC).