Proactive Customized Protocol for Oral Management in Head and Neck Cancer Patients Planned for Radiotherapy

Abstract

Osteoradionecrosis (ORN) is a nemesis of radiotherapy which adversely affects the life of an individual. It is more often seen with conventional external beam radiotherapy using telecobalt machine. Newer radiotherapy techniques are being used in developed nations to circumvent its inherent disadvantages. A higher incidence of ORN is seen in dentate jaws because of extractions done for odontogenic infections in the post radiation period. Systematic evaluation of oral tissues and instituting appropriate therapeutic and prophylactic measures before, during and after completion of radiotherapy is mandatory. In our hospital since we use telecobalt radiotherapy it was deemed necessary to design our own protocol to reduce the incidence of this debilitating complication. Our protocol is based on recommended guidelines and which has been customized to our patient strata. We present the findings of a retrospective study on patients undergoing radiotherapy in whom this oral management protocol was used. This protocol has been effective in reducing the frequency of osteoradionecrosis at our tertiary care hospital.

Introduction

Head and neck malignancies constitute about 30% of all malignancies in India. Most of these patients present in advanced T3 and T4 stages requiring multimodality treatment. It is the responsibility of the healthcare team to provide these patients a reasonable quality of life with minimal complications. Osteoradionecrosis (ORN) is a delayed complication of radiotherapy (RT) which adversely affects the quality of life by producing significant morbidity in afflicted patients [1].

ORN is a well-documented complication of the conventional technique of external beam radiotherapy using Cobalt 60 (telecobalt radiotherapy), especially with doses exceeding 60 Gy [2]. Newer radiotherapy techniques are being used in developed nations which circumvent the disadvantages of external beam radiotherapy, but developing nations are still in the process of phasing out these machines.

ORN of the mandible is seen in 2–22% of patients who have had radiotherapy to the head and neck [3]. Mandible is more often affected (90%) [2] than maxilla because of its dense cortical structure and vascularity pattern. Trauma to the jaws is a confounding factor in the development of ORN although spontaneous ORN [2] is also reported. A higher incidence of ORN is seen in dentate jaws because of extractions done for odontogenic infections in the post radiation period.

Comprehensive dental management prior to the start of radiotherapy can reduce the incidence of this potential complication. In our hospital since we use telecobalt radiotherapy it was deemed necessary to design an aggressive dental protocol for management of our patients. We use a protocol based on recommended guidelines and which is customized to our patient strata.

Objectives of the study

To determine the frequency of osteoradionecrosis in patients undergoing radiotherapy.

To determine the effectiveness of the oral management protocol.

Materials and methods

This retrospective analytical study was carried out from 2016 to 2019 on 152 patients who were referred to the Department of Dentistry for comprehensive dental management prior to the commencement of radiotherapy.

All patients received EBRT using Cobalt 60. Patients planned for adjuvant RT received doses between 60 and 64 Gy and patients planned for definitive RT received doses of 66 Gy.

All head and neck malignancy patients who were planned for radiotherapy, either radical or adjuvant were included in the study. Patients who gave a history of addiction to smoking and alcohol consumption within the previous one year were excluded from the study. Patients who were immuno-compromised, suffering from granulomatous infections and patients with recurrences who were planned for re-irradiation were excluded from the study. Patients who received presurgical RT were excluded from the study. Edentulous patients were excluded from the study.

All patients were systematically evaluated, by a single examiner, according to the proforma. Based on specific evaluation criteria each tooth was prognosticated as good, fair or poor. A tooth with a good prognosis is one which does not require professional maintenance procedures for the following 2 years. A tooth with a fair prognosis is one which can survive for the following 2 years but with minimally invasive maintenance procedures and a tooth with a poor prognosis needs immediate extraction. The patients were then counselled about the need for dental procedures prior to the start of radiotherapy. After obtaining an informed consent the treatment plan was executed in a time conscious manner to avoid any delay in the start of radiotherapy. Radiotherapy was started at a mean of 10 days post extraction (range being 7–14 days). Upon completion of radiotherapy and at the time of discharge, the patients were given instructions on a dental home care regime and a follow up schedule.

The patients were followed up by the Department of Radiotherapy for a minimum of 2 years (range being 1–3 years), during which time clinical evidence of ORN was documented. An orthopantomogram (OPG) was advised for patients who presented with ORN. The Notani classification was used to grade the ORN.

Results

Results were tabulated in SPSS excel sheet and descriptive statistics were used to analyse the results.

In our sample of 152 patients, the site specific distribution of tumours was as follows, buccal mucosa—83, alveolus—15, tongue—12, oropharynx—9, supraglottis—8, hypopharynx—6, Gingivobuccal sulcus(GBS)—5, Retromoal trigone (RMT)—4, maxilla—3, hard palate—2, lower lip—2, parotid—2, Metastases of Unknown Origin(MUO)—1. (Table 1).

Table 1.

Site specific distribution of tumours

Site	Buccal mucosa	Alveolus	Tongue	Oropharynx	Larynx	Hypopharynx	GBS	RMT	Maxilla	Hard palate	Lower lip	Parotid	MUO
No. of patients (152)	83	15	12	09	08	06	05	04	03	02	02	02	01

110 patients received RT using anterolateral portals, 41 patients received using bilateral portals and one patient received using a single lateral portal.

Of the 152 patients, 83 patients were planned for adjuvant RT, 24 patients were planned for adjuvant RT with CT, 11 patients were planned for definitive RT and 34 patients were planned for definitive RT with CT. (Table 2).

Table 2.

Plan of RT-CT for total sample of patients

	Adjuvant		Definitive
	RT	RTCT	RT	RTCT
No. of patients (152)	83	24	11	34

Of the 152 patients, 73 patients underwent extractions only, 39 patients underwent oral prophylaxis only and 40 patients underwent both extractions and oral prophylaxis. (Table 3).

Table 3.

Dental procedures performed for total sample of patients

	Extractions only	Oral prophylaxis only	Extractions and oral prophylaxis
No. of patients (152)	73	39	40

14(9.2%) patients developed ORN during the postoperative follow up period.

patients were carcinoma of oral cavity, one was carcinoma of oropharynx and one was carcinoma of hypopharynx.

Of the 14 patients, six patients had received adjuvant RT, four patients had received adjuvant RT with CT, two patients had received definitive RT and two patients had received definitive RT with CT. (Table 4).

Of the 14 patients, four had undergone extractions only, five had undergone oral prophylaxis only and five had undergone both extractions and oral prophylaxis. (Table 5).

Table 4.

Plan of RT-CT received by patients who developed ORN

	Adjuvant		Definitive
	RT	RTCT	RT	RTCT
No. of patients (14)	6	4	2	2

All ORN were present in the mandible.

13(8.55%) of the patients were categorized as Notani I and one (0.66%) patient was categorized as Notani III. (Table 6).

Table 6.

Distribution of patients who developed ORN

	Notani class I	Notani class II	Notani class III
No. of patients who developed ORN: 14(9.2%)	13(8.55%)	NIL	01(0.66%)

Table 5.

Dental procedures performed on patients who developed ORN

	Extractions only	Oral prophylaxis only	Extractions and oral prophylaxis
No. of patients(14)	4	5	5

Among the 13 patients, two patients had defaulted RT (one was planned for adjuvant RT and one was planned for definitive RT). The adjuvant RT patient had defaulted after 40 Gy and definitive RT patient had defaulted after 50 Gy. Both these patients were receiving radiation at 2.5 Gy/#.

Discussion

ORN classically presents as exposed necrotic bone, either intraoral or extraoral which persists for more than 3 months, in the absence of residual tumor and recurrence. It may be asymptomatic or painful. It may be associated with a chronic discharging sinus. It does not respond to conventional treatment. Chronic ORN can result in pathological fracture of the jaw. ORN generally manifests between 4 months and 2 years [3] after completion of radiotherapy, although it can manifest indefinitely during the lifetime of the patient.

The Notani classification of ORN in the mandible is based on the anatomical extent of ORN as evaluated by clinical examination and on a orthopantomogram [2]

Notani Class 1—ORN confined to dentoalveolar bone.

Notani Class 2—ORN limited to dentoalveolar bone or mandible above the inferior dental canal or both.

Notani Class 3—ORN involving the mandible below the inferior dental canal or pathological fracture or skin fistula.

Of the 14 patients who developed ORN, 13 patients were categorized as Notani I ORN.

Five of the 13 patients complained of ‘root piece left behind in the jaw after extraction’ during the follow up period. On clinical examination necrotic inter radicular and interdental bone was evident above mucosalised extraction sockets. This finding can be attributed to a difficult intraoperative extraction where the roots were ankylosed. The use of electrocautery to control post extraction haemorrhage may also have contributed to the ORN. The remaining eight patients needed extraction during follow up period because they presented with odontogenic infections.

The single patient who developed Notani III ORN, was a case of carcinoma tongue extending to floor of mouth (cT3N1M0) along with carcinoma cervix (Stage IIIb). The intraoral lesion was treated with wide excision glossectomy with vertical marginal mandibulectomy. The inferior alveolar vessels were sacrificed. This patient had received 4 cycles of chemotherapy. The patient had a spontaneous fracture of the residual mandible presenting as exposed fractured segment over the skin.

It is important when performing a marginal mandibulectomy that maximum vascularity is retained to the residual mandible by preserving the periosteal blood supply, the inferior alveolar neurovascular bundle and whenever feasible the facial artery. It is also important to prevent areas of stress concentration in the residual bone which predispose to fracture. The remaining segment of bone can be reinforced with a reconstruction plate or the radial forearm osteocutaneous flap.

An OPG was done for all the patients to confirm the extent of necrotic bone.

All patients were managed conservatively with sequestrectomy under antibiotic cover. The Notani III patient healed with fibrosis. It was decided that no further intervention will be carried out because the patient was asymptomatic and had reasonable chewing ability on the contralateral side.

The reason for ORN in our patients can be attributed to trauma, compromised blood supply and our technique of EBRT.

There was no correlation found between use of concurrent chemotherapy and the development of ORN.

ORN can be largely prevented by optimizing radiation delivery and oral health.

Use of advanced techniques like the 3D CRT and IMRT has reduced the incidence of ORN to 8% or lesser [2, 4, 5], whereas with the older radiation techniques the incidence was reported to be as high as 5–20% [2, 4]. Avoiding brachytherapy for lesions close to bone and adopting the hyperfractionated accelerated regime reduce the incidence of ORN.

Oral health can be optimized by intraoperative and postoperative measures. Intraoperative precautions when doing extractions and when performing marginal mandibulectomy reduces the incidence of ORN. It is important to complete all invasive dental procedures with minimal trauma to the bone and allow sufficient time for healing before the start of radiotherapy. Avoid extraction of teeth in the subsequent 2 years after RT which prevents development of ORN.

A study by Thorn et al. on a sample of 80 patients [6] has reported extraction of teeth as the initiating factor for the development of ORN in 55% of cases and spontaneous ORN in 29% of cases. Wanifuchi et al. [7] evaluated the etiology of ORN on a sample of 33 patients and concluded that in all the patients where extractions were done post-radiotherapy had resulted in ORN. Therefore thorough evaluation and aggressive dental management before the start of radiotherapy can avoid extractions in the post radiotherapy period and effectively prevent development of ORN [6, 8–10]

Literature search revealed a study by Katsura et al. [11] who took periodontal status into consideration for tooth extraction prior to the start of radiotherapy. There are no other documented protocols for comprehensive dental management of patients undergoing radiotherapy.

ORN is a debilitating complication of radiotherapy which can be prevented by adopting newer techniques of radiotherapy and meticulous management of oral health. The dental protocol that we follow has enabled us to reduce the number of invasive dental procedures in the post radiation period and thereby reduced the frequency of ORN.

All our cases need to be followed up for at least a 5-year period before we are able to arrive at definite conclusions and establish guidelines.

Funding

None.

Compliance with Ethical Standards

Conflict of interest

None.

Ethical Approval

The institutional ethics committee clearance was obtained.