HEAD & NECK CANCER PART-9
(All the articles published in past are available at www.shyamhemoncclinic.com/blog/)
Question: Thank you Chiragbhai for explaining very important aspects of radiotherapy in last two parts. Importance of good radiation oncology team, radiotherapy equipments and newer techniques like IMRT, IGRT, SBRT, Rapid Arc were clarified. Interestingly we also learned that combination of chemotherapy and radiotherapy has replaced surgery for many sites in head and neck region (base of tongue, tonsil, hypopharynx, larynx, nasopharynx) as well as for other body sites like cervix, esophagus, lung, bladder, anal canal etc.
Can you tell us about role of chemotherapy and non chemotherapy medicines?
Ans: Medical oncology is an integral part of modern cancer treatment. Its role is in following places:
1. Neo adjuvant: pre surgery or pre radiotherapy – to reduce tumor size.
2. Adjuvant: after surgery to reduce recurrence rate, generally with radiotherapy.
3. With radiation – concurrent chemoradiation – as discussed in last part.
4. As single modality – for recurrent tumor – palliative in nature.
The biggest role, something which changed this field in a radical way, is in concurrent chemoradiation. First time, surgery could be replaced, allowing organ preservation.
This brought a whole new concept called “organ preservation”, thus allowing function preservation. Most important breakthrough was in LARYNX cancer. Total laryngectomy was standard treatment, with complete loss of voice. Combination of chemotherapy and radiation therapy gave results equivalent to surgery, in terms of cure rates. Few patients who relapsed, could be saved with surgery. Thus overall about 70% patients could save their voice. Almost similar concept applies to hypopharynx (pyriform sinus) cancers, allowing voice preservation.
It is important to pay attention to good pain control and nutrition during concurrent chemoradiation. A significant number of patients have mucositis requiring narcotic analgesics. This may also lead to significant weight loss and sometimes break in treatment may be required due to severe mucositis. Early attention to nutrition, including placement of feeding tube (nasogastric or PEG) may be important.
Que: This is quite interesting. So now larynx cancer is not treated with surgery, right?
Ans: These studies were published in early 90s i.e. over 20 years ago. Due to adequate awareness, availability of good radiotherapy facilities, and strict follow up, most patients in India also undergo chemoradiation for larynx cancer. Some patients with advanced disease, do need laryngectomy however or those who relapse after chemoradiation.
Que: What are the main medicines used?
Ans: Most common chemotherapy drugs used are cisplatin, carboplatin (better tolerated than cisplatin), 5-FU, paclitaxel, docetaxel, ifosfamide, and methotrexate. Methotrexate, and other medicines like gemcitabine, irinotecan, bleomycin, vinorelbine etc are being used less frequently and in palliative setting. These agents can be used as single agent or in combination. Response rates for newly diagnosed cancers are very high with combination chemotherapy – about 80%, and about 20-30% of these being complete response rates. Using single agent, response rates are about half. Also, response rates for recurrent cancers are about half, even with combination chemotherapy.
Non chemotherapy medicines include cetuximab, gefitinib. Cetuximab, a monoclonal antibody which blocks EGFR (epidermal growth factor receptor), is used in combination with radiotherapy, for patients who are unlikely to tolerate or do not tolerate chemotherapy. Mainly used for very old patients. It is also used in palliative setting with or without chemotherapy.
Gefitinib is an oral EGFR inhibitor, however studied only in palliation, and not with radiotherapy.
Two new medicines were recently approved for medullary thyroid cancer – vandetanib, and cabozantinib – Both tyrosine kinase inhibitors.
Sorafenib and sunitinib also are tyrosine kinase inhibitors that work in a variety of thyroid cancers, for palliation. Lenvatinib is also a tyrosine kinase inhibitor approved for use in palliation of differentiated thyroid cancers. A variety of other agents have been used in palliative setting with limited success, for thyroid and other cancers. They should be used carefully when above noted standard options have failed or are not feasible.
September 14th 2015.
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