LUNG CANCER PART-5
(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Question: Thank you Chiragbhai for explaining role of Predictive tests, something very new for us. Also, it was important to note the role of targeted therapies, treatment of early stage lung cancer with surgery, and postoperative chemotherapy. We also learned about how to evaluate fitness in these frail patients especially with frequently poor lung function, and role of new radiation techniques to treat early stage lung cancers, where surgery is not feasible due to poor lung reserves. Now we can discuss stage 3 lung cancer treatment.
Ans: Yes, stage 3 is a very interesting and complex category by itself. There are many variations within stage 3. Also staging has changed over years. Studies for treatment in this stage are either limited or had small number of patients. Broadly however we can surmise following:
1. Stage 3 means involvement of mediastinal nodes, in general. Or T4 tumor.
2. Stage 3 is further divided in A and B. Also, B can be broadly divided in “wet” 3 B and dry 3 B. Wet means associated with pleural or pericardial effusion. New TNM staging however has taken wet 3 B to stage 4 category. This is very helpful as these patients were anyway treated like stage 4, and not stage 3.
3. In general, most stage 3 patients are treated by chemoradiation. If good thoracic surgery team is available, stage 3 A (and rare 3 B) can be treated with surgery. Surgical treatment of stage 3 is quite complex as mediastinal evaluation is very important in proper staging and mediastinal node clearance is not easy. Even if surgery is done, it is often not enough (finding incidental N2 disease is common), and has to be followed by chemotherapy and sometimes even radiotherapy. Many patients are upstaged at surgery or at mediastinal node evaluation. PET-CT has significantly improved staging of mediastinal nodes, leading to reduction in number of surgeries worldwide for this group of patients.
Many people don’t tolerate such major surgery, and additional chemotherapy/radiotherapy after surgery. This leads to significant morbidity and occasionally even mortality. Since early lung cancer diagnosis is uncommon in India, complex lung cancer surgery availability is also very uncommon in India. Also, since results of chemoradiation are as good, most centers in the world and in India, prefer chemoradiation rather than take risk of a very major surgery.
4. As noted earlier, stage 3 has many variations. One such important variation is pancoast tumor (superior sulcus tumor). It is generally treated by chemoradiation followed by surgery.
5. Stage 3A patients who undergo surgery, need postoperative chemotherapy, and occasionally radiotherapy. Surgery alone has poor long term survival.
6. Sometimes patients have lung tumor on both sides of lung. Technically, contralateral lung involvement makes it stage 4. However, some of these people have actually two primary tumors, also known as synchronous primary. Such patients should be evaluated with PET-CT scan, and if there are no other nodules, should be treated like two separate primaries.
7. Chemoradiation combination has been studied both as chemotherapy followed by radiotherapy OR both given concurrent (simultaneously). Concurrent has better results, however with somewhat higher toxicity. Most commonly used regimen for concurrent use is carboplatin and paclitaxel given weekly in low doses. It is tolerated better than the other standard option of 3 weekly cisplatin and etoposide. Platinum agents can be combined with pemetrexed as well, especially for frail patients and non squamous histology.
Que: Thank you. That was quite informative. What percentage of patients do you see in early stage?
Ans: Unfortunately, in India, over 90% of lung cancer patients are detected in stage 3 or 4. Mostly stage 4. Even in developed countries, stage 1, 2 are about 20% or less. Therefore, majority of research has focused on treatment of stage 4. Median survival has increased from below one year to about 2 -3 years for stage 4 patients over last two decades. It is fairly common now to see such patients crossing 4-5 years. In next part, we will talk about these advances, including chemotherapy, and several targeted therapies for stage 4. Most of this survival advantage has come from targeted therapies, somewhat from chemotherapy (mainly better tolerated drugs which could be continued for long enough), role of maintenance therapy to some extent, and better supportive care of course. A number of older and frail patients are also able to undergo treatment due to these developments. Recently, immunotherapy approaches have also shown some encouraging results in lung cancer.
July 15th 2016.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. www.shyamhemoncclinic.com