ONCOLOGY Vol 19 No 13

Colorectal cancer is a worldwide public health problem, with nearly 800,000new cases diagnosed each year resulting in approximately 500,000deaths. In the United States, it is the second leading cause of cancer mortality,and nearly 60,000 deaths will be attributed to this disease in 2005. Whendiagnosed as advanced, metastatic disease, colorectal cancer is traditionally associatedwith a poor prognosis, with 5-year survival rates in the range of 5% to 8%. Thissurvival rate has remained unchanged over the past 35 to 40 years. However, duringthe past 5 years, significant advances have been made in treatment options so thatimprovements in 2-year survival are now being reported, with median survival ratesin the 21- to 24-month range in patients with metastatic disease.

The role of screening in order todetect lung cancer at an earlierstage has been widely debatedfor the past 4 decades. In this review,Dr. Mulshine focuses on the currentissues in lung cancer screening in lightof the findings of the InternationalEarly Lung Cancer Action Project(I-ELCAP) As the article mentions, thediagnosis of lung cancer is often madeat a stage when the disease is no longer amenable to cure. This is probably themost important cause for the dismaloutcomes of patients with lung canceroverall.

In this issue of ONCOLOGY, Solomon,Mitchell, and Bunn providean excellent review on adjuvanttherapy for resected non–smallcelllung cancer (NSCLC). Theauthors have thoroughly reviewed therecent literature and highlight severalimportant areas for discussion. Theauthors appropriately frame the importanceof the clinical issue at hand.

Because of the high rate of distant disease recurrence, the 5-yearsurvival of patients who have undergone complete surgical resectionof localized non–small-cell lung cancer (NSCLC) is approximately 50%.Initial results from early studies of adjuvant postoperative chemotherapyreported an adverse effect of alkylating agent and older chemotherapyregimens on survival. Cisplatin-based combinations were the first toshow a survival advantage. A 1995 meta-analysis of these studies suggesteda 13% reduction in the hazard ratio for death (HR = 0.87), leadingto a 5% survival benefit at 5 years. Still, these trials involved limitednumbers of patients (N = 1,394), and the results failed to reach statisticalsignificance (P = .08). Of the five largest subsequent randomizedtrials of platinum-based adjuvant therapy, three showed a significantsurvival advantage. Although it is impossible to determine the reasonsfor the differing outcomes of these studies, several key features distinguishthem, and the data suggest that medically fit patients with resectedstage IB or II NSCLC should be offered chemotherapy with a platinum/new drug combination.

The review by Jan Buter andGiuseppe Giaccone in this issueof ONCOLOGY is an excellentoverview of the current statusof the anti–epidermal growth factorreceptor (EGFR) agents gefitinib (Iressa),erlotinib (Tarceva), and cetuximab(Erbitux). The authors addresssome of the most important issuesregarding anti-EGFR agents currently in clinical development. Key amongthese are the importance of patientselection and drug dosage in the successand failure of various clinicaltrials. This article raises several veryinteresting questions in the developmentof this class of agents.

Inhibitors targeting the family ofepidermal growth factor receptors(EGFRs) are novel antitumor compoundsinvestigated in many cancertypes, including non–small-cell lungcancer (NSCLC). In this special lungcancer issue of ONCOLOGY, Drs.Buter and Giaccone provide us withan updated review of clinical researchon two classes of these agents inNSCLC: small-molecule tyrosinekinase inhibitors (TKIs) and monoclonalantibodies. The former classincludes gefitinib (Iressa) and erlotinib(Tarceva), two orally availablequinazoline derivatives targeting thetyrosine kinase domain of EGFR. Thelatter includes cetuximab (Erbitux), achimeric monoclonal antibody directedagainst EGFR. The authors extensivelydiscuss single-agent andcombination activities of these drugsin NSCLC.

Lung cancer causes more deathsin American men and womenthan the total number of deathsfrom breast, prostate, and colon cancercombined. Recently the lung cancerdeath rate has reached a plateau inthe United States, primarily because asignificant number of American menhave stopped smoking. However,smoking incidence in adult Americanwomen, as well as teenagers of bothgenders and of all ethnicities, has notdecreased significantly.

Lung cancer continues to be themost common cause of cancerdeaths in the United States forboth men and women. Unfortunately,the majority of patients presentwith local or distant disease at thetime of diagnosis. Surgical resectioncontinues to offer the best chance forlong-term survival; however, less than25% of patients have surgically resectabledisease. Even after surgicalresection for early-stage disease a significantnumber of patients will developrecurrent disease, with themajority being distant in nature. Developmentof distant disease usuallyproves to be the terminal event inmost patients. Multiple treatmentmodalities have been investigated asadjuvant therapy to decrease the incidenceof distant disease after completesurgical resection. Untilrecently, no modality has shown asurvival advantage in patients afterresection for non–small-cell lung cancer(NSCLC).

In this review we will discuss issues inherent to the lung cancer screening process, including the value of smoking cessation strategies, the challenge with the rapid pace of developments in the field, cost concerns, consideration of biases in trial design (overdiagnosis, for example), overtreatment, and radiation risk. We discuss recommendations from several organizations, such as the US Preventive Services Task Force and the American Cancer Society.

Drs. Laskin and Sandler havedone an excellent job of summarizingthe results of chemotherapyin the treatment of stageIV non–small-cell lung cancer. Theyhave pointed out that a meta-analysispublished in 1995 showed that chemotherapyprovided a modest survivaladvantage compared to supportivecare alone. In addition, they have citedstudies that have shown the treatmentis cost-effective and that it relieveslung cancer–related symptoms.They have thoroughly discussed thefact that multiple phase III trials testingnewer chemotherapy doubletsshow slightly different toxicity profiles with virtually identical efficacy,and that giving more than four coursesof therapy with regimens that consistof three or more drugs does notprovide significant benefit.

Targeted therapies inhibiting the epidermal growth factor receptor(EGFR) have been introduced in the treatment of patients with advancednon–small-cell lung cancer (NSCLC). Many inhibitors of theEGFR have been developed, targeting either the extracellular receptordomain with antibodies or the intracellular tyrosine kinase bindingdomain with small molecules. The tyrosine kinase inhibitor (TKI)gefitinib (Iressa) was the first targeted drug to be registered for thetreatment of NSCLC after failure of chemotherapy. Given concurrentlytogether with platinum combination chemotherapy both TKIs gefitiniband erlotinib (Tarceva) failed to increase activity. Sequential targetedtherapy after chemotherapy is currently being investigated further. Studieswith the monoclonal antibody cetuximab (Erbitux) combined withchemotherapy are ongoing. Side effects of the small molecules aremainly skin rash and diarrhea, whereas the antibodies do not give diarrhea.Selection of patients, based on molecular markers and patientcharacteristics, has become an important issue for the further developmentof these drugs, given there is activity in a relatively small group ofpatients with NSCLC. Newer drugs inhibiting more than one receptorpathway are being investigated in order to find activity in a broadergroup of patients.

In their excellent review of firstlinechemotherapy for patientswith advanced non–small-cell lungcancer (NSCLC), Laskin and Sandlerare clear, direct, and positive. Chemotherapyworks in stage IV disease:

With best supportive care alone, patients with metastatic non–smallcelllung cancer (NSCLC) have a median survival of 4 to 5 months anda 1-year survival rate of approximately 10%. Trials carried out in the1980s and 1990s comparing chemotherapy to best supportive care reportedvariable efficacy results; however, a pivotal meta-analysis of thesedata indicated that cisplatin-based chemotherapy provided a survivalbenefit in advanced NSCLC. In the past decade newer agents such asgemcitabine (Gemzar), vinorelbine, paclitaxel, and docetaxel (Taxotere)have all demonstrated activity in NSCLC as single agents; consequentlythese agents have been combined with cisplatin or carboplatin. Randomizedphase III trials comparing these “newer” platin-based doubletshave failed to identify an optimal platinum-based doublet therapyregimen. Though it is clear that chemotherapy is an appropriate treatmentfor many patients with lung cancer, there a sense in which the useof traditional chemotherapeutic agents has reached a therapeutic plateau.Increased understanding of cancer biology has revealed numerouspotential therapeutic strategies, including targeting the epidermalgrowth factor receptor, protein kinase C, rexinoid receptors, and theangiogenesis pathway. The Eastern Cooperative Oncology Group studyE4599 comparing paclitaxel/carboplatin with/without bevacizumab isthe first phase III randomized trial to show a survival advantage withthe addition of a molecularly targeted agent to chemotherapy in thechemotherapy-naive patient population. Future studies will involve theevaluation of additional targeted agents plus chemotherapy as well aslooking at combinations of these targeted agents alone or with chemotherapy.