1. Home
  2. adenocarcinoma

adenocarcinoma

Lung Cancer in Nonsmoking Individuals: A Review

Author/s: 
Cian Murphy, Tej Pandya, Charles Swanton

Importance: Lung cancer in nonsmoking individuals (defined as people who have smoked fewer than 100 cigarettes in their lifetime) accounts for 15% to 20% of all lung cancer cases worldwide. In the US, the annual incidence of lung cancer in nonsmoking individuals is 14.4 to 20.8 per 100 000 person-years in females and 4.8 to 12.7 per 100 000 person-years in males.

Observations: Most lung cancers in nonsmoking individuals are histologically adenocarcinomas (60%-80%) with the remainder being squamous or adenosquamous (10%-20%) and rarely small cell lung cancer (<10%). Risk factors include exposure to passive smoking, radon exposure, air pollution, asbestos, and history of lung cancer in a first-degree family member. Therapeutically targetable genomic variants, such as EGFR mutations or ALK gene rearrangements, are more common in tumors from nonsmoking individuals compared with those with a smoking history (defined as people who currently or formerly smoked) (43% vs 11% for EGFR and 12% vs 2% for ALK). In contrast, tumor mutation burden, the number of somatic mutations in a tumor cell, is lower in lung cancer among nonsmoking individuals (0-3 mutations/megabase [Mb] vs 0-30 mutations/Mb). Similar to individuals with a history of smoking, nonsmoking individuals with lung cancer may present with wheeze, chest pain, dyspnea, hemoptysis, or symptoms attributable to metastatic disease (eg, bone pain and headache) or be diagnosed with incidentally detected disease. The US Preventive Services Task Force does not currently recommend lung cancer screening with low-dose computed tomographic scans for nonsmoking individuals, although screening guidelines vary globally. Treatment typically involves a combination of surgery, radiotherapy, and systemic therapies depending on stage, performance status, and molecular features of the tumor. Comprehensive next-generation sequencing should be performed on stage Ib to IIIa lung cancer tumor tissue from nonsmoking individuals because actionable genomic alterations, such as EGFR mutations or ALK gene rearrangements, are treated with targeted therapy such as the tyrosine kinase inhibitors osimertinib or lorlatinib, respectively. Median survival among nonsmoking individuals with advanced non-small cell lung cancer (stage IIIb or higher) and actionable genomic alterations can exceed 3 to 5 years, while survival without these genomic alterations is similar to lung cancer in people with a history of smoking (1-2 years).

Conclusions: Lung cancer in nonsmoking individuals accounts for 15% to 20% of lung cancer cases worldwide. Among patients with lung cancer, nonsmoking individuals are more likely to have genomic alterations such as EGFR mutations or ALK gene rearrangements, and these patients have improved survival when treated with tyrosine kinase inhibitors compared with chemotherapy.

Keywords 
adenocarcinoma Carcinoma Squamous Cell tobacco Smokers smoking Early Detection of Cancer

Prostate Cancer: A Review

Author/s: 
Ruben Raychaudhuri, Daniel W Lin, R Bruce Montgomery

Importance: Prostate cancer is the most common nonskin cancer in men in the US, with an estimated 299 010 new cases and 35 250 deaths in 2024. Prostate cancer is the second most common cancer in men worldwide, with 1 466 680 new cases and 396 792 deaths in 2022.

Observations: The most common type of prostate cancer is adenocarcinoma (≥99%), and the median age at diagnosis is 67 years. More than 50% of prostate cancer risk is attributable to genetic factors; older age and Black race (annual incidence rate, 173.0 cases per 100 000 Black men vs 97.1 cases per 100 000 White men) are also strong risk factors. Recent guidelines encourage shared decision-making for prostate-specific antigen (PSA) screening. At diagnosis, approximately 75% of patients have cancer localized to the prostate, which is associated with a 5-year survival rate of nearly 100%. Based on risk stratification that incorporates life expectancy, tumor grade (Gleason score), tumor size, and PSA level, one-third of patients with localized prostate cancer are appropriate for active surveillance with serial PSA measurements, prostate biopsies, or magnetic resonance imaging, and initiation of treatment if the Gleason score or tumor stage increases. For patients with higher-risk disease, radiation therapy or radical prostatectomy are reasonable options; treatment decision-making should include consideration of adverse events and comorbidities. Despite definitive therapy, 2% to 56% of men with localized disease develop distant metastases, depending on tumor risk factors. At presentation, approximately 14% of patients have metastases to regional lymph nodes. An additional 10% of men have distant metastases that are associated with a 5-year survival rate of 37%. Treatment of metastatic prostate cancer primarily relies on androgen deprivation therapy, most commonly through medical castration with gonadotropin-releasing hormone agonists. For patients with newly diagnosed metastatic prostate cancer, the addition of androgen receptor pathway inhibitors (eg, darolutamide, abiraterone) improves survival. Use of abiraterone improved the median overall survival from 36.5 months to 53.3 months (hazard ratio, 0.66 [95% CI, 0.56-0.78]) compared with medical castration alone. Chemotherapy (docetaxel) may be considered, especially for patients with more extensive disease.

Conclusions and relevance: Approximately 1.5 million new cases of prostate cancer are diagnosed annually worldwide. Approximately 75% of patients present with cancer localized to the prostate, which is associated with a 5-year survival rate of nearly 100%. Management includes active surveillance, prostatectomy, or radiation therapy, depending on risk of progression. Approximately 10% of patients present with metastatic prostate cancer, which has a 5-year survival rate of 37%. First-line therapies for metastatic prostate cancer include androgen deprivation and novel androgen receptor pathway inhibitors, and chemotherapy for appropriate patients.

Keywords 
prostate prostate cancer adenocarcinoma
Subscribe to adenocarcinoma