Steady, accurate, ruthless! Head and neck cancer treatment ushered in a new spring~

Head and neck tumors are tumors
that occur in the mouth, larynx, pharynx, sinuses, nose, and salivary glands.
The annual incidence of head and neck tumors in China in recent years is 15.
22/100,000, accounting for 4.
45% of systemic malignant tumors! Although the incidence is not very high, the number of cases is quite large
.

Due to the special location of head and neck tumors, there are many important organs and tissues around them, and ordinary radiotherapy techniques often produce serious side effects, such as dry mouth, nose and throat, oral mucositis, loss of appetite, dysphagia, radiation dermatitis, etc.
^[1].

Although proton is radiotherapy, it is "perfect" in the treatment of head and neck cancers - repelling tumor tissue while reducing complications and side effects
.

What are the clinical effects of proton therapy for head and neck tumors?

The NCCN Clinical Practice Guidelines for Head and Neck Cancer (2021.
V1) were updated and released on November 9, 2020, and the latest version of the guidelines includes proton therapy as one of the
standard treatments for head and neck cancer treatment.

Head and neck tumors suitable for proton therapy

Recurrent head and neck cancer, skull base cancer, laryngeal cancer, oral cancer, throat cancer, salivary gland cancer, sinus cancer, hypopharyngeal cancer, oropharyngeal cancer, tongue cancer, tonsil cancer, etc

Proton therapy has become an important means of radiotherapy for head and neck tumors, which can help patients with head and neck tumors control the disease while reducing the side effects
caused by radiotherapy.
Take the common nasopharyngeal and oral cancers of the head and neck as examples:

Nasopharyngeal carcinoma:

A phase II clinical trial of proton therapy, which enrolled 23 patients with stage II.
b-IV.
B.
B, showed that the 4-year local control rate of all patients was 91%, the overall survival rate was 91%, and the metastasis-free survival rate was 86%.

In terms of toxicity, no grade 3 xerostomia occurred
.

Oral cancer:

The study showed that the 2-year survival rate of proton therapy for oral cancer was 94.
5%, and the progression-free survival rate was 88.
6%; And mucositis, dysphagia, xerostomia and other treatment side effects are less ^[2].

What are the advantages of protons in head and neck cancer treatment?

The irrefutable advantage of protons is that they can kill tumor tissue at the maximum radiation dose while minimizing damage
to surrounding normal tissue.

Figure 1: Proton and photon radiation dose vs.
depth in the body

(OAR: Dangerous organs, including heart, lungs, coronary arteries, etc.
)

It has a strong killing power on tumors

Like normal cells, tumor cells also exhibit a double helix structure in their genes (DNA), and traditional radiotherapy can only cut the single strands in them, so there is a risk
of tumor recurrence.

Proton radiation therapy can largely cut the double strand at one time, and is not affected by the oxygen content in the cell and the cell cycle, causing irreparable and fatal damage to the DNA of tumor cells, reducing the chance
of tumor recurrence and metastasis.

Accurately attacks tumor cells and reduces damage to surrounding tissues

Proton therapy is particularly suitable for tumors in complex tissues, especially tumors in the head area where peripheral tissues are sensitive to radiation therapy and safety needs to be put first, such as near the eyes, ears, or brain tissue; or important glandular sites
such as the pituitary gland.

The energy attenuation characteristics of proton beam allow it to release maximum energy at the tumor location, and the damage to surrounding healthy tissues is very small, especially for patients with
head and neck tumors.

There is no pain, fewer complications and side effects

Proton therapy is not accompanied by significant pain during and after treatment, and there are fewer complications and side effects after treatment, and if it is an early stage of the tumor, patients can even come to the hospital for treatment
while working.

Write at the end

Proton therapy can effectively fight solid tumors while reducing damage to normal cells, and its advantages in the treatment of head and neck tumors are obvious
.
It is believed that with the popularization of domestic proton technology, it can bring more choices and survival benefits
to more and more patients.

References

[1] Robbins MA,Gosselin TK.
Symptom management in radiation oncology：acute and long-term side effects［J］.
AmJNurs，2002，102（Suppl4）：32-36，49-52

[2] GunnGB,GardenAS,YeR,et al.
Proton Therapy for Headand Neck Cancer:A12-Year,Single Institution Experience.
IntJPartTher.
2021Jun25; 8(1):108-118.
doi:10.
14338/IJPT-2000065.
1.
PMID:34285940; PMCID:PMC8270083

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