For many years, a lung cancer diagnosis surely meant a death sentence for patients and their loved ones. The patients and the caregivers, including the doctors, felt helpless once the diagnosis of lung cancer was made. But over the last two decades, there has been a change in the paradigm of this attitude, and patients with lung cancers are living longer with a good quality of life. The disease, which was initially being treated empirically with platinum-based chemotherapy, has evolved to personalised treatment with options of modern chemotherapy, targeted therapy, and last but not least immunotherapy.
The Evolution of Lung Cancer Treatment
In the early days, a single treatment approach was applied universally to all cases. By the late twentieth century, physicians began using platinum-based drugs like cisplatin or carboplatin, often in combination with other medications such as paclitaxel or etoposide, to treat patients with advanced lung cancer. At that time, the concept of biopsy wasn’t as well-defined. An FNAC to differentiate between non-small cell and small cell lung cancer was considered sufficient to initiate systemic therapy. The results, however, were modest at best, with median survival improving to nine months with treatment compared to just three months without any intervention.
Aside from the limited survival benefit, another major concern was the toxicity associated with these chemotherapy regimens. With the lack of adequate supportive medications, chemotherapy-related toxicities like vomiting, diarrhea, and bone marrow suppression were common, severely impacting the quality of life for patients battling this deadly disease. Patients and their families were left grappling with the dilemma between the quantity of life (survival) and the quality of life.
The Refinement Phase
The refinement phase has further developed not only innovative drug combinations but also supportive care itself. By the early 21st century, the management of lung cancer patients began to evolve, and even after 25 years, this progress continues today. These changes encompass not only newer treatment modalities but also more targeted approaches to systemic chemotherapy. The foundation of these advancements lies in our deeper understanding of the molecular biology of lung cancer cells. Enzymes like thymidylate synthase have made pemetrexed the preferred chemotherapy regimen for adenocarcinoma, while gemcitabine is favored for squamous cell carcinoma. These distinctions are determined through biopsy of the lung mass and ancillary immunohistochemistry studies.
These innovations have led to improved survival rates, with patients better able to tolerate treatment. Equally important were advances in supportive care, including the development of more effective anti-emetic drugs, growth factors to prevent infections, and hydration protocols to protect kidney function. These new approaches have allowed patients to complete their treatment while maintaining their strength and dignity throughout the healing process.
The Era of Precision Medicine: One Size Does Not Fit All
The real turning point in the management of lung cancer came when scientists discovered driver mutations such as EGFR, ALK, ROS1, and KRAS, which paved the way for targeted therapy. It became clear that each case of lung cancer is not only biologically unique but also requires individualized treatment approaches. Molecular testing is now essential to determine the most effective therapy for each patient. Studies have shown that patients with targetable mutations, identified through biopsy, respond better to targeted therapy than chemotherapy—not only in terms of survival but also in preserving quality of life. Recent evidence, including the FLAURA 2 trial, has further highlighted the superior efficacy of combining chemotherapy with targeted therapy over using targeted therapy alone.
Harnessing The Immune System
Building on the understanding that cancer cells can evade the body’s immune system to grow, scientists developed immunotherapy to counteract this. Initially, immunotherapy showed benefits for patients whose disease had progressed after one line of systemic chemotherapy. Given its significant advantage, it is now being used in combination with chemotherapy for newly diagnosed patients with metastatic lung cancer. PDL1 has emerged as a key biomarker, and physicians are increasingly avoiding chemotherapy in patients with a PDL1 score of 50 or higher. For others, the combination of chemotherapy and immunotherapy has shown remarkable benefits in survival without additional toxicity burden.
According to the KEYNOTE-189 and IMpower150 trials, chemo-immunotherapy combinations can double or even triple two-year survival rates in advanced NSCLC patients. Patients who once survived less than a year are now living for two, three, or even more years. Furthermore, some patients experience long-lasting recovery that can extend throughout their lifetime.
This combination works effectively because chemotherapy directly kills cancer cells while also helping the immune system recognize them more easily by unmasking them for immune attack. The result is not only longer survival but also deeper, more sustained responses.
Small-Cell Lung Cancer – A Different Entity
Small-cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers. It is known for being highly chemosensitive but also notorious for its rapid recurrence. Until recently, there were no targeted therapies available for this group of patients, and chemotherapy remained the sole treatment option. However, the combination of immunotherapy and chemotherapy has been explored in this population and has proven to be superior to chemotherapy alone.
Conclusion
The management of lung cancer has evolved significantly over the past few decades. We have transitioned from using highly toxic chemotherapy to more tolerable chemotherapy regimens. With the introduction of supportive medications, the toxicity of treatment has been markedly reduced. Furthermore, with the availability of targeted therapies and immunotherapies, chemotherapy can now be avoided in select patient groups.
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