| Abstract|| |
Objective: The objective of the present study is to see the feasibility, tolerability and superiority of concomitant boost technique (CBT) over conventional radiotherapy (RT) in advanced head and neck carcinoma. In CBT, a second daily treatment is given at a gap of 4-6 hrs to the small field, which includes only the primary lesion and the adjacent clinically palpable lymph nodes. The main advantage of CBT is that there is very minimal enhancement in acute reactions as compared to other accelerated fractionation regimens and another advantage is that it shortens the total treatment duration from seven weeks to five weeks. The boost dose can be delivered either in the beginning, in the end or throughout the treatment. In this study, the boost dose was given at the beginning.
Materials and Methods: This study included a total of 80 patients with advanced (TNM stage III and IV) carcinomas of oral cavity and oropharynx registered in the Department of Radiotherapy, KGMC, Lucknow between Jan 1999 and Feb 2000. All patients eligible for the study were divided into two groups. Group I received radiotherapy in the form of CBT and Group II received conventional RT. A total of 70 Gys were delivered to both groups, with compensators and head fixing devices. All patients were assessed weekly and were called after one month of completion of treatment to see the response.
Results: Out of 40 patients, in Group I, 30 patients (75%) and in Group II, 24 patients (60%) had complete response (CR) and the rest of the patients had partial response except for one patient in Group II who had no response (NR). Acute reactions were slightly higher in Group I and were easily managed by IVF support. The median duration of follow up was 14 months (range 6-18 months). Out of those showing CR, four patients in Group I and seven patients in Group II have shown recurrence till now at a median duration of eight months and six months respectively. There was no difference in late reactions in both groups.
Conclusion: To conclude, CBT is easily tolerated by patients, with slight enhancement in acute reactions and so far has given much better results as compared to conventional RT alone.
Keywords: Concomitant boost technique, head and neck carcinoma, squamous cell carcinoma
|How to cite this article:|
Srivastava K, Srivastava M. Concomitant boost radiotherapy vs conventional radiotherapy in advanced oral cavity and oropharynx cancers. Indian J Radiol Imaging 2001;11:127-30
Malignancies of the head and neck region pose exceptional problems in management and skilled multidisciplinary teamwork is required to achieve success. A major cause of failure in advanced rapidly growing tumors is the proliferation of clonogen cells. To overcome this problem various accelerated fractionation radiotherapy techniques came into the picture but all were associated with excessive acute reactions and therefore were not feasible. Concomitant boost radiotherapy (CBT) despite being a variant of accelerated fractionation, is associated with minimal enhancement of acute reactions because it uses the concepts of accelerated fractionation while minimizing the volume of tissue that is irradiated with high doses. Apart from this, it significantly reduces the total treatment time from seven weeks to five weeks which is very important for our patients who earn their livelihood daily. Therefore, the aim of this study was to see the tolerability, feasibility and superiority of CBT over conventional RT. In CBT a second daily boost dose is given at an interval of 4-6 hrs to the small field after treating the large field. The small field includes only the primary lesion and the clinically palpable lymph nodes adjacent to the primary site. Thus, the primary lesion and the lymph nodes receive 70 Gy in five weeks and the rest of the large field receives only 50 Gy, which is adequate for microscopic disease. As the area receiving accelerated fractionation RT is very small, there is very little enhancement in acute reactions. Also, the dose per fraction being the same, late reactions remain affected.
|How to cite this URL:|
Srivastava K, Srivastava M. Concomitant boost radiotherapy vs conventional radiotherapy in advanced oral cavity and oropharynx cancers. Indian J Radiol Imaging [serial online] 2001 [cited 2020 Dec 3];11:127-30. Available from: https://www.ijri.org/text.asp?2001/11/3/127/28390
CBT can be given in three forms. In the first variant (Arm I) the boost dose is delivered in the initial part of the treatment. In the second variant (Arm II), it is given at the end of the treatment and in the third variant (Arm III), it is delivered throughout the treatment. Considering better patient compliance in the initial half of the treatment, we delivered the boost dose at the beginning of the treatment.
| Material and Methods|| |
Our study included a total of 80 patients registered in the Department of Radiotherapy, KGMC, Lucknow, between Jan 1999 and Feb. 2000. The eligibility criteria included histopathologically confirmed squamous cell carcinoma of the oral cavity or oropharynx, TNM stage III and IV, no prior treatment of any form, Karnoffsky's performance status >70%, no concurrent medical illness and no evidence of metastatic disease at the time of diagnosis. Patients having very large lymphadenopathies i.e. N3, were not included in the study because it was difficult to include the large lymph node and the primary lesion in the small field. All patients underwent a complete pre-treatment work up which included a complete hemogram, radiological investigations such as chest radiographs and lateral oblique views for the mandible or orthopantomogram and dental prophylaxis.
The patients were then divided into two groups. The method of distribution of patients into two groups is shown in [Table - 1]. Group I (n=40) received radiotherapy in the form of CBT. In this group, the large field was given 50 Gy (as 200 cGy/fraction) daily for five days a week for five weeks. The remaining 20 Gy were given as a boost dose in 12 fractions (as 167 cGy / fraction) to the small field, in the beginning of the treatment, at an interval of 4-6 hrs. The median time interval was 5.3 hrs. Group II (n=40) received RT as conventional fractionation (200 cGy per fraction), five days a week, shrinking the field anterior to the cord after 46 Gy. A total of 70 Gy were given to both groups using tissue compensators.
Every patient was assessed weekly for acute reactions and tumor response. One month after completion of treatment, patients were assessed for overall response. Complete disappearance of disease at the primary site and the lymph nodes was considered as complete response (CR). More than 50% response at either site was considered as partial response (PR); patients having less than 50% response were considered as having no response (NR). Patients were later called for a monthly follow-up and those having PR were considered for further chemotherapy or salvage surgery.
| Results|| |
All patients stood the treatment well without any interruptions. Acute reactions as observed weekly in both groups are seen in [Figure - 1]; the grading was done according to the RTOG criteria.
Out of 40 patients in Group I, 30 had CR (75%) and 10 had PR (25%). None of the patients had NR or disease progression. In Group II, 24 patients out of 40 had CR (60%) and 15 patients had PR (38%) and one patient showed NR. [Table - 2] shows the comparison of results. Patients having PR or NR were kept on chemotherapy or were considered for salvage surgery. Patients having CR were called for monthly follow-up to see the late reactions and disease status. Late reactions as observed so far are almost similar in both groups [Figure - 2]. None of the patients was lost for follow up. Median duration of follow-up was 14 months (range 6 to 18 months).
In Group I, out of 30 patients having CR at a median duration of eight months, four have shown recurrence, whereas in Group II, seven out of 24 patients having CR have shown recurrence and the median duration was six months.
| Discussion|| |
CBT has been tried keeping in mind the radiobiological aspects of accelerated fractionation RT , which gives beneficial results by decreasing the number of clonogen cells to a considerable extent and without doing much harm to the normal cells . CBT has given better response than conventional RT in various studies done till date ,,,. The concomitant boost technique of administering twice daily radiation therapy during only part of the treatment course allows for an aggressive fractionation schedule and limits the volume of normal mucosa exposed to twice daily radiation therapy. The significance of accelerated repopulation in conventionally irradiated head and neck tumors has been reported ,. The isoeffective dose for tumor control significantly increases after 30 treatment days. Most successful treatment schedules attempt to administer the highest possible doses during the shortest time tolerable to early and late responding normal tissues. The purpose of the present study was to see the superiority of CBT over conventional RT in advanced head and neck carcinoma of the oral cavity and oropharynx and also to see the incidence of acute and late reactions. Considering better patient compliance in the initial part of the treatment it was planned to give the boost dose in the 1st half of the treatment.
All patients completed the treatment as planned and no patient was lost to follow up. Acute reactions were comparatively higher in the CBT group and maximum incidence of grade III mucositis was seen in the 2nd week [Figure - 2]. Fifteen patients in Group I required IV fluid support because of grade III mucositis and were hospitalized for this purpose. Grade III mucositis persisted for a median duration of nine days ranging from three days to 15 days and subsequently subsided slowly with discontinuation of second daily fraction in the third week. Maximum incidence of grade III mucositis was seen in the second week and persisted in three patients in the third week. None of the patients required treatment interruption. In Group II, eight patients developed grade III mucositis in the third and fourth week but the duration of grade III mucositis was very small ranging from two to five days. These patients also required hospitalization for administering IV fluids.
In Group I, 75% patients showed CR and 25% showed PR whereas in Group II only 60% showed CR and 38% showed partial response and 2% showed no response. None of the patients in either group had disease progression. As the study is still continuing in our department this mid term analysis shows much better local control by CBT than conventional radiotherapy. Four patients in Group I have shown recurrence with a median duration of 8 months and in Group II, seven patients have shown recurrence at six months median duration. Again it appears that CBT is effective in decreasing the rate of recurrence and improving the disease free survival (DFS). When comparing results of the current study with those of the previous ones, it seems that local control is better in this study. A study conducted by Rupert K Schmidt et al . (1991) included a total of 94 patients with stage III and IV head and neck cancer . They found 67% local control by CBT and 40% by conventional fractionation. Similarly a study conducted by Skoczylas J, Bijko K et al . in 1992 has revealed 75% 18 months survival in supraglottic carcinomas .
To summarize, the unique features of our treatment schedule took advantage of possible differential vulnerabilities between neoplastic and normal mucosal cells. This was reflected in improved tumor control rates relative to conventional fractionation without a significant increase in normal tissue toxicity. As the study is still being continued at our department considering its other arms i.e. delivering boost dose either in the 2nd half of the treatment or distributed evenly throughout the treatment, we hope that in the near future we can report significant results.
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21, Chandra Lok, Hydel Officers Colony, Aligarh, Lucknow
Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2]