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Lung cancer -9-Small Cell and other uncommon histologies

LUNG CANCER PART-9

(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)

Question: Thank you Chiragbhai for explaining treatment of stage 4, and how overall survival has more than doubled in last decade or so. And yet, it is still far from enough. You have beautifully explained in last part about advances in science, balanced with practical realities of treating stage 4 patients, issue of cost versus benefit, and most importantly not to forget role of GOOD Palliative care. Also the fact that free palliative care is available and at what places, as well as training in this field.
May I ask you about something we did not touch upon earlier? Is there a difference in approach to diagnosis and management of Small Cell Lung Cancer, and other less common histologies?
Ans: Thank you for bringing this up. Small cell lung cancer is less common than earlier, but is still a significant proportion. There is less discussion about this subtype in our literature, as hardly anything new has happened to its treatment in a long time, and hence even survival is essentially unchanged. At the same time, incidence is reducing, probably due to more use of filtered cigarettes as per one theory, but not proven.
Initial work up remains same as squamous or adenocarcinoma type. Including PET-CT or regular CT scans, and a good biopsy. Staging is unusual – divided as either limited or extensive. Not the usual stage 1 to 4. Limited means it can be either resected or covered in radiotherapy field. Extensive means beyond what can be covered in radiotherapy field.
A very small number present with localized disease, generally detected incidentally. A few of these are operable, but overall rare. Post surgery, patient should receive four cycles of cisplatin based chemotherapy. Most patients have mediastinal involvement, hence inoperable. But these can be treated by chemoradiation. Concurrent chemotherapy given is most commonly cisplatin etoposide. A small number of these patients remain disease free for long term.
Vast majority however present in extensive stage, generally with significant metastatic disease. They are treated with combination chemotherapy, again cisplatin or carboplatin with etoposide. Initial response is generally excellent with complete response or very good partial response in most patients. And this is rapid as well. However they relapse equally quickly in next few months. Brain metastases are very common in small cell lung cancer, either symptomatic or asymptomatic. There have been randomized trials of preventing symptomatic brain metastases using PCI – prophylactic cranial radiotherapy. PCI reduces incidence of brain metastases, but effect on overall survival is either small or none (with two randomized trials showing these two differing results.) Hence this is not universally recommended. However it may be worth doing for patients who achieve excellent response to chemotherapy. Some even give thoracic radiotherapy for residual small volume disease.
Unfortunately, most patients have progression of disease within a few months, and require more chemotherapy. Irinotecan, epirubicin, or topotecan based combinations are used most commonly at this time, provided patient has good performance status.
Que: Any other uncommon histology of importance?
Ans: Yes. Carcinoid tumors are comparatively common in lung. These are neuroendocrine tumors (as they are known most commonly in other parts of body), arising from neuroendocrine cells found in many parts of body.
GI tract is the most common site, but lung is second most common site for such type of tumors. In lung, they are known as carcinoid tumors. Mostly they follow a very indolent course, but sometimes they can grow faster.
Treatment for localized disease is surgical resection. For advanced metastatic disease, treatment options are essentially same as for GI neuroendocrine tumors, such as octreotide (somatostatin analog), everolimus, and in advance cases probably chemotherapy. Chemotherapy options are same as for small cell lung cancer. Please note that small cell lung cancer discussed above also arises from neuroendocrine cells, and is the most aggressive end of these cancers.
For symptomatic metastases, especially in bone and sometimes in lungs, palliative radiotherapy can be used. Liver is the most common site of metastases, and may cause marked symptoms due to secretion of various hormones. These metastases can be treated by resection if localized, or by RFA (radiofrequency ablation), or hepatic artery embolization, or cryoablation.
November 14th 2016.

Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 079 26754001. Diplomate American Board of Oncology and Hematology. Ahmedabad. drchiragashah@gmail.com Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. www.shyamhemoncclinic.com

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