Treatments for Hard-to-Cure Cancers (Existing and Emerging)
For the cancers with poor survival (identified in Section 1), intensive research is underway to improve outcomes. Below we discuss each of these difficult-to-cure cancers – outlining current effective treatments and promising experimental or emerging therapies in clinical trials or preclinical research. (Focus is on adult cancers.)
Pancreatic Cancer (Pancreatic Ductal Adenocarcinoma)
Current Treatments: Because pancreatic cancer is often diagnosed at an advanced stage, systemic therapy is key. Surgery (Whipple procedure) offers the only potential cure, but <20% of patients are eligible at diagnosis. Adjuvant chemotherapy (e.g. gemcitabine or FOLFIRINOX regimen) after surgery can improve 5-year survival modestly. For advanced disease, multi-drug chemotherapy (FOLFIRINOX or gemcitabine+nab-paclitaxel) is the standard and has improved median survival by a few months. These regimens can shrink tumors and improve symptoms, but long-term remissions are rare. Some targeted therapy is used in niche subsets – e.g. PARP inhibitors (like olaparib) for the ~5–7% of pancreatic cancers with BRCA1/2 mutations, which can prolong disease control nih.gov. Unfortunately, conventional immunotherapies (checkpoint inhibitors) have shown minimal benefit in pancreatic cancer (most tumors are “cold” with poor immune infiltration) nih.gov.
Emerging Therapies: Researchers are aggressively exploring novel approaches, given the dire prognosis. One promising avenue is personalized cancer vaccines. For example, an mRNA-based vaccine targeting neoantigens in a patient’s tumor (developed by BioNTech) recently showed encouraging results in a small trial – about half of vaccinated patients mounted T-cell responses, and those responders had delayed cancer recurrence nih.gov, nih.gov. A larger trial of this personalized mRNA vaccine is underway nih.gov. Other immunotherapy strategies under study include CAR T-cells and T-cell receptor (TCR) therapies directed at pancreatic tumor antigens (e.g. mesothelin or CEACAM6), and immune checkpoint inhibitor combinations (trying anti-PD-1 with agents that target the dense stroma or suppressive myeloid cells in pancreatic tumors). Researchers are also studying drugs to break down the tumor’s fibrous stroma (e.g. hyaluronidase agents) to enhance chemotherapy penetration, though initial trials (e.g. PEGPH20) had mixed results. Targeted therapies beyond BRCA mutations are being tested for rare subsets (e.g. inhibitors for KRAS^G12C – a mutation present in ~1% of pancreatic cancers – now in early trials). In summary, for pancreatic cancer the experimental frontiers are personalized vaccines, cell therapies, and stromal modulation, aiming to finally make a dent in its stubborn mortality.
Lung Cancer (Non-Small Cell and Small Cell Lung Cancer)
Current Treatments: Lung cancer treatment has advanced significantly in the past decade. For non-small cell lung cancer (NSCLC), if detected early (stage I/II), surgical resection offers high cure rates, often supplemented by adjuvant chemotherapy or radiation. Locally advanced NSCLC (stage III) is treated with combined chemoradiotherapy, and the addition of immunotherapy (durvalumab) consolidation has improved survival. Metastatic NSCLC (stage IV) historically had a median survival <1 year with chemotherapy, but now many cases benefit from precision medicine. Targeted therapies have transformed outcomes for patients whose tumors harbor certain driver mutations: e.g. EGFR tyrosine kinase inhibitors (like osimertinib) yield high response rates in EGFR-mutant lung cancer; ALK inhibitors (alectinib, etc.) do the same for ALK-rearranged tumors. Dozens of targeted drugs now exist for mutations in ROS1, BRAF, NTRK, MET exon 14, RET, and more – each improving survival for those subgroups. Additionally, immunotherapy has been a game-changer for advanced lung cancer. Anti-PD-1/PD-L1 checkpoint inhibitors (such as pembrolizumab, nivolumab, atezolizumab) can produce lasting remissions in a subset of patients. When used alone or with chemotherapy as first-line treatment for metastatic NSCLC, these immunotherapies have significantly extended 5-year survival (some advanced NSCLC patients are alive 5+ years later, which was rare in the pre-immunotherapy era). For small cell lung cancer (SCLC) – an aggressive subtype – standard therapy remains chemotherapy (platinum-etoposide) plus radiation; adding immunotherapy (atezolizumab or durvalumab) for extensive-stage SCLC has modestly improved outcomes. Despite progress, advanced lung cancer often relapses, so current therapies are not curative in most cases.
Emerging Therapies: Numerous clinical trials aim to further improve lung cancer survival. For NSCLC, researchers are testing next-generation targeted drugs to overcome resistance (for example, newer KRAS inhibitors beyond the recently approved sotorasib/adagrasib for KRAS^G12C, and combination approaches to prevent resistance). There’s also interest in targeting KRAS mutations in other ways (like SHP2 or SOS1 inhibitors) to expand treatment options for the ~25% of lung cancers with KRAS mutations. In immunotherapy, new checkpoints (LAG-3, TIGIT, etc.) and personalized cancer vaccines (e.g. mRNA vaccines encoding neoantigens, similar to trials in melanoma) are being studied to boost the immune attack on lung tumors. Another frontier is cell therapies: while CAR T-cells have excelled in blood cancers, applying them to solid tumors like lung cancer is challenging. Nonetheless, early trials of CAR T-cells targeting EGFR or mesothelin in lung cancer are ongoing, as are TIL (tumor-infiltrating lymphocyte) therapies and TCR-engineered T-cells for certain antigen targets. Technological innovations are also contributing: liquid biopsies (blood tests detecting tumor DNA) are being developed to detect recurrence or residual disease early, and AI-based diagnostic tools are being used to improve lung cancer screening (for instance, AI algorithms can analyze low-dose CT scans to better identify early lung nodules). On the surgical front, minimally invasive and robotic surgeries allow safer removal of tumors, potentially expanding operability. In summary, emerging lung cancer treatments are focused on expanding precision medicine (more targets and personalized strategies) and enhancing immunotherapy, with the goal of turning more lung cancers from fatal into manageable or curable diseases.
Liver Cancer (Hepatocellular Carcinoma)
Current Treatments: For hepatocellular carcinoma (HCC), outcomes have started to improve with newer therapies. If caught early (confined to liver), curative treatments include surgical resection of the tumor or liver transplantation (which offers 5-year survival rates of 60–70% in selected patients). Liver-directed therapies are also used: radiofrequency ablation can destroy small tumors, and transarterial chemoembolization (TACE) or radioembolization can control intermediate-stage disease by targeting blood supply to the tumor. Once HCC is advanced or metastatic, systemic therapy is needed. Until a few years ago, the only approved drug was sorafenib (a multi-kinase inhibitor), which provided a modest survival benefit (~3 months improvement). Recently, however, immunotherapy and combination therapy have changed the paradigm. In 2020, a landmark trial showed that combining atezolizumab (an anti–PD-L1 checkpoint inhibitor) with bevacizumab (an anti-VEGF antibody) significantly improved survival in advanced HCC, more than sorafenib alone healthxchange.sg. This atezo/bev combination is now a first-line standard, with median overall survival exceeding 19 months, a notable improvement healthxchange.sg. Other drugs for advanced HCC include newer TKIs like lenvatinib (another first-line option), and second-line agents (regorafenib, cabozantinib, ramucirumab) which provide incremental benefits. Despite these advances, HCC often recurs and overall 5-year survival remains low, especially when diagnosed late.
Emerging Therapies: Research in HCC is focusing on further leveraging immunotherapy and precision medicine. Trials are underway adding other checkpoint inhibitors to the atezo/bev backbone (e.g. triple therapy with anti-PD-1 + anti-CTLA-4 + VEGF inhibition) to see if even more potent immune activation can yield cures. Personalized approaches are also explored: e.g. CAR T-cells against HCC-specific antigens like GPC3 (glypican-3) – early-phase trials in China have reported some tumor responses. Another novel approach in trials is oncolytic virotherapy: using engineered viruses that selectively infect and kill liver tumor cells and stimulate immunity. Given that many HCCs arise in diseased cirrhotic livers, noninvasive surveillance with ultrasound and emerging blood biomarkers (like circulating tumor DNA or AFP-L3) is being refined to catch tumors earlier when curative treatment is possible. Precision medicine for HCC lags behind other cancers – there are few common targetable mutations (except maybe rare FGFR inhibitors for fibrolamellar subtype, etc.), but comprehensive genomic profiling of tumors may identify actionable alterations in select patients (clinical trials like MATCH are enrolling advanced HCC for targeted therapies based on mutations). Technological improvements in liver surgery (e.g. use of augmented reality imaging to guide resections) and radiation (e.g. proton beam for HCC adjacent to critical structures) also aim to boost cure rates. While not all these experimental approaches will succeed, the hope is that combining immunotherapy, targeted agents, and locoregional treatments will significantly prolong survival and increase cure rates in liver cancer over the coming decade.
Brain Cancer (Glioblastoma and other malignant brain tumors)
Current Treatments: Glioblastoma (GBM) is the prototypical aggressive adult brain cancer, and current therapy is unfortunately only modestly effective. The standard of care (often called the “Stupp protocol”) is maximal surgical resection of the tumor followed by combined radiation therapy and temozolomide chemotherapy, then adjuvant temozolomide for 6+ months. This regimen, introduced in the mid-2000s, improved the 2-year survival from ~10% to ~27%, and median survival to around 15–20 months. However, essentially all GBMs recur after initial treatment. At recurrence, options include another surgery if feasible, chemotherapy (e.g. lomustine-based), or enrollment in clinical trials. One FDA-approved device for GBM is Tumor Treating Fields (Optune), a cap that delivers alternating electric fields to the brain; when added to maintenance therapy it modestly improved median survival in trials. Despite these efforts, 5-year survival for GBM remains on the order of 5%. Other malignant brain tumors (anaplastic astrocytomas, etc.) have slightly better outcomes but are still often fatal. Current treatments are thus largely palliative, aiming to extend life but rarely curing the patient.
Emerging Therapies: The intractability of GBM has spurred a wide array of experimental approaches. Unfortunately, many targeted drugs have failed in GBM – for instance, inhibitors of EGFR, a commonly altered gene in GBM, did not significantly improve outcomes (likely due to drug delivery issues across the blood-brain barrier and GBM’s highly heterogeneous cell population). Newer targeted strategies include drugs against mutations like IDH1 (seen in some grade 3 gliomas) – IDH inhibitors have shown promise in those specific tumors. Immunotherapy in GBM has been challenging; checkpoint inhibitors (like pembrolizumab) have largely been ineffective in unselected GBM patients. Researchers are now testing immunotherapy in specific subgroups (e.g. patients with hypermutated tumors or mismatch-repair deficiency) and in combination with other treatments (to make the tumor microenvironment more receptive). CAR T-cell therapy is also being explored: early-phase trials of CAR T-cells targeting EGFRvIII (a GBM-specific mutant antigen) or IL-13Rα2 have shown that the engineered T-cells can penetrate the brain and, in a few cases, shrink tumors, but responses have not been consistently durable. A notable case report demonstrated a patient with multifocal GBM achieving remission with IL-13Rα2 CAR T-cells delivered into the brain – inspiring further research. Oncolytic viruses are another experimental modality: a genetically engineered poliovirus (PVSRIPO) and a herpes simplex virus (T-Vec) are among those tested in GBM; some patients have had prolonged survival, though results are mixed. Moreover, a recent Phase III trial of a dendritic cell vaccine (DCVax-L) for GBM reported an improvement in survival for vaccine-treated patients, suggesting a possible benefit – this therapy is awaiting further validation. To overcome the blood-brain barrier, techniques like focused ultrasound are being tried to transiently open the barrier and enhance drug delivery to the tumor. In summary, GBM research is pursuing multiple cutting-edge avenues – CAR T-cells, oncolytic viruses, cancer vaccines, novel targeted drugs, and advanced drug-delivery techniques – in an effort to achieve long-term control or cures. While no breakthrough cure has emerged yet, the combination of approaches and better molecular understanding of GBM may yield incremental improvements in the near future.
Esophageal Cancer
Current Treatments: Esophageal cancer is treated with a multimodal approach. For locally advanced, resectable cases (common scenario for esophageal adenocarcinoma in the West), the standard is neoadjuvant chemoradiotherapy (concurrent chemotherapy and radiation before surgery) followed by surgical resection of the esophagus (esophagectomy). This approach (e.g. the CROSS trial regimen of carboplatin/taxol with radiation) improves survival compared to surgery alone. In patients who respond, 5-year survival can approach 40–50%. If the tumor is small and caught very early (such as in Barrett’s esophagus turning into high-grade dysplasia or intramucosal cancer), endoscopic mucosal resection or ablation can sometimes cure it without full surgery. For advanced or metastatic esophageal cancer, chemotherapy has been the mainstay (regimens like FOLFOX or cisplatin/5-FU). Recently, immunotherapy has entered the scene here as well. Checkpoint inhibitors have shown benefit in esophageal cancer: Pembrolizumab (anti-PD-1) added to chemo has improved survival in metastatic esophageal carcinoma (especially for tumors with high PD-L1 expression), and nivolumab (another PD-1 inhibitor) has demonstrated improved survival as adjuvant therapy after chemoradiation+surgery in patients who had residual disease (the CheckMate-577 trial) cancer.gov. Additionally, if the esophageal tumor is of the adenocarcinoma type and overexpresses HER2 (about 15–20% of cases, often at the gastroesophageal junction), adding the HER2-targeted antibody trastuzumab to chemotherapy is a standard, as it improves response and survival (similar to HER2-positive gastric cancer treatment). Despite these interventions, the overall cure rates remain low, especially for squamous cell carcinoma in the mid-esophagus which often presents late.
Emerging Therapies: Many trials are working to further improve esophageal cancer outcomes. Immunotherapy is being tested in earlier-stage disease: for example, combining checkpoint inhibitors with neoadjuvant chemoradiation to see if the addition can increase pathologic complete response rates and survival. There are also studies of combining multiple immunotherapy agents (like anti-PD-1 with anti-CTLA-4) in advanced esophageal cancer to see if dual checkpoint blockade can yield deeper responses. Targeted therapy beyond HER2 is under investigation: some esophageal adenocarcinomas share targets with gastric cancer (like FGFR2 or CLDN18.2 in a subset) and drugs aimed at those (e.g. FGFR inhibitors, claudin18.2-targeted antibody drug conjugates) are being evaluated in trials that include esophagogastric tumors. For squamous cell carcinoma of the esophagus, researchers are looking at targeting pathways like EGFR and VEGF, but no targeted agent is yet standard. On the technology side, improved screening and early detection could significantly reduce mortality in high-risk populations: for instance, China (which has a high incidence of esophageal squamous carcinoma) is testing screening endoscopy in high-risk regions, and novel methods like a swallowable “sponge” cytology device (Cytosponge) coupled with AI image analysis are being developed to detect Barrett’s esophagus and early adenocarcinoma in Western patients without needing full endoscopy. Minimally invasive surgical techniques (robotic esophagectomy) are improving postoperative recovery, which may allow more patients to undergo curative surgery. While these advances are incremental, the combination of better systemic therapies (especially immunotherapy) and earlier detection holds promise to gradually improve esophageal cancer survival beyond the stubborn ~20% level.
Stomach (Gastric) Cancer
Current Treatments: Treatment of gastric cancer is highly stage-dependent. For early-stage tumors (T1 lesions) especially in countries with screening programs (Japan, South Korea), endoscopic resection techniques (endoscopic submucosal dissection) can completely cure very superficial cancers. For localized but deeper gastric cancers, the curative treatment is surgical gastrectomy (partial or total removal of the stomach) with lymph node dissection. Surgery is often combined with systemic therapy: in Western practice, perioperative chemotherapy (such as the FLOT regimen: 5-FU, leucovorin, oxaliplatin, docetaxel) is given before and after surgery to kill micrometastases and improve cure rates. In Asian practice, an alternative is surgery followed by adjuvant chemotherapy (like S-1 or capecitabine/oxaliplatin) which has shown benefit in trials. For advanced/metastatic gastric cancer, treatment is palliative and centers on chemotherapy (platinum/5FU combinations, taxanes, etc.) plus targeted agents when applicable. Notably, about 15% of advanced gastric cancers overexpress HER2; for these, adding trastuzumab (Herceptin) to chemo is standard first-line therapy digestivecancers.eu. Recently, immunotherapy has become part of advanced gastric cancer treatment: the PD-1 inhibitor nivolumab was shown to improve survival when added to first-line chemotherapy for metastatic gastric/GEJ cancers in patients with PD-L1 expression, and pembrolizumab is used in chemo-refractory cases, especially if the tumor is PD-L1 positive or MSI-High. Despite treatment, metastatic gastric cancer median survival is only on the order of 12–18 months with current regimens, and 5-year survival is very low, so new approaches are needed.
Emerging Therapies: Gastric cancer research is benefitting from advances in both molecular profiling and immunotherapy. One exciting development is the targeting of Claudin 18.2, a tight-junction protein often overexpressed in gastric tumors. A monoclonal antibody drug (zolbetuximab) against CLDN18.2, when added to chemo, has shown improved progression-free and overall survival in a phase III trial for advanced gastric cancer, and may become a new targeted therapy for CLDN18.2-positive cases. Additional antibody-drug conjugates (ADCs) are in testing – for example, trastuzumab-deruxtecan (T-DXd) is an ADC approved for HER2-positive gastric cancer after initial therapy, showing it can extend survival where standard Herceptin+chemo had failed. Immunotherapy combinations are also being explored: trials are evaluating dual checkpoint blockade (PD-1 plus CTLA-4 inhibitors) in gastric cancer, and personalized cancer vaccines are being considered for MSI-high gastric cancers (which tend to respond well to immunotherapy). Another area of interest is precision medicine via genomic sequencing of gastric tumors: The hope is to identify subsets (e.g. those with FGFR2 amplification, MET amplification, DNA mismatch repair deficiency, etc.) and match them to targeted treatments – some trials (like the FIGHT trial for FGFR2 inhibitor bemarituzumab) have shown promise for certain molecularly defined subgroups. Technological advances in endoscopic imaging with AI may help endoscopists detect early gastric lesions more accurately (already, in Japan, AI systems are being tested to identify subtle gastric mucosal neoplasia during endoscopy). Additionally, there’s a push for prophylactic H. pylori eradication programs in high-risk areas, since chronic H. pylori infection is a major cause of gastric cancer; eliminating this infection could prevent many cases long-term. While global gastric cancer survival remains low due to many patients presenting late, these emerging therapies and preventive strategies aim to significantly improve outcomes, as seen in countries that have combined early detection with aggressive treatment.
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