«Lung cancer
Types of Lung Cancer
Based on the appearance of the tumor cells under microscopic examination, two different types of lung cancer can be distinguished:
- small cell lung cancer (microcytoma, oat grain tumor) (18-20% of cases)
- NON small cell lung cancer (squamous or epidermoid carcinoma, adenocarcinoma and large cell carcinoma)
Specifically entering:
- Squamous cell carcinoma : it is the most common type in men, it originates from the cells that cover the respiratory tract; represents about 30% of cases
- Adenocarcinoma: develops from the cells that secrete the mucus; it is more common in women. In recent decades there has been a decrease in the number of cases of squamous cell carcinoma associated with a relative increase in adenocarcinomas, probably due to the increased incidence of lung cancer among women.
- Large cell carcinoma : the name derives from the large roundish cells that are shown on microscopic examination; it affects about 15% of patients
Another type of lung cancer is mesothelioma, a form that affects the pleura (a kind of double-layered sheet that coats the lungs and makes them stick to the rib surface). The greatest risk factor for the development of mesothelioma is exposure to asbestos.
Hazard of various forms of cancer
Contrary to what one might think, the small cell shape is clearly more dangerous than the large cell shape. The microcitoma is in fact subject to rapid growth and is more likely to spread to other organs. Statistically, approximately 90% of patients with small cell tumors present with locally advanced or metastatic disease
Small cell lung cancer responds very well to chemo and radiotherapy but despite this the average survival is 14-18 months for the limited forms and 9-12 months for the extended forms.
The probability of surviving five years after diagnosis is generally low, in the order of 3-8% of cases.
Fortunately, this type of lung cancer is the least common of the two categories.
Instead, non-small cell lung tumors (about 80% of cases) are more widespread and are grouped into a single category due to their uniformity of therapeutic characteristics and needs.
Care and Treatment
To learn more: Drugs for the treatment of lung cancer
Lung cancer therapy differs based on the characteristics of the carcinoma:
- histological type (small cell or non-small cell)
- stage of presentation
In the case of small cell tumors, the standard approach involves subjecting the patient to chemotherapy and radiotherapy cycles. Surgery is rarely used.
Surgery remains the most important weapon in the treatment of non-small cell lung cancer. The doctors classify these tumors on a scale composed of 4 stages of increasing severity. Specific care is provided for each of these stages.
- Stages I and II are candidates for radical surgery. Sometimes it is also necessary to perform chemotherapy before surgery (neoadjuvant chemotherapy) in order to reduce the size of the tumor.
- Stage IA and IB survival at 5 aa. is 67% and 57% of the cases respectively.
Stage II A and II B 5 aa survival. is 55% and 39% of the cases respectively.
This partial success of surgical therapy (risk of metastasis after some time from the intervention), suggests the need to associate the surgery with "adjuvant" systemic (chemotherapy) and local (radiotherapy) treatments
- Surgery is usually indicated for the treatment of stage III A lung tumors. Given the low probability of survival, the operation is often associated or replaced by neoadjuvant (preoperative chemotherapy) and adjuvant (postoperative) therapy. The two therapeutic modalities (radiotherapy and chemotherapy) can be concomitant or performed in sequence. 5 aa survival. is 23% of cases.
- The stages III B and IV (metastatic stages) are generally not operated and the treatment of choice is represented by the radiochemotherapy combination. Many clinical studies have shown that polychemotherapy (use of multiple drugs) is better than monochemotherapy. 5 aa survival. is 5% and 1% of the cases respectively.
NOTES: The chemotherapy treatment, when indicated, must be started as soon as possible, immediately after obtaining the histological diagnosis.
The key drug for chemotherapy is platinum and its derivatives (cisplatin and carboplatin) generally combined with other antiblastic agents. Next to cisplatin, the active drugs are mitomycin-C, vinca alkaloids, etoposide and phosphamide.
Since the 1990s new antiblastic drugs have been introduced, namely: gemcitabine, vinorelbine, taxanes (paclitaxel and docetaxel) and topoisomerase inhibitors (irinotecan and topotecan).
Pharmacological research, fortunately, progresses year after year discovering new drugs and increasing the patient's life expectancy. Newly developed medicines, such as monoclonal antibodies, aim to improve efficacy and decrease the side effects of therapy.
The type of surgery varies according to the size and location of the tumor.
- Lobectomy (removal of only one lung lobe): it is performed in case of small tumor with peripheral localization
- Pneumomectomy (removal of an entire lung): it is performed in the larger or more central forms
