How do doctors determine what stage of cancer you have? - Hyunsoo Joshua No and Trudy Wu

譯者: Lilian Chiu 審譯者: 麗玲 辛

Each year, approximately 20 million people across the world

每年，全世界約有兩千萬人

receive a cancer diagnosis.

被診斷出癌症。

At this overwhelming, and often scary time,

在這讓人不知所措、 通常很可怕的時刻，

a patient usually learns their cancer’s stage,

病人通常會得知 他們的癌症是第幾期，

which is typically a number, ranging from 1 to 4.

一般來說期數是個數字， 範圍從一到四。

While staging is designed in part to help patients better understand

雖然分期設計部分原因是為了 幫助病人更了解他們面臨的狀況，

what they’re facing,

extracting this information from a simple number

但從一個簡單的數字來取得這些資訊

can be confusing and less than straightforward.

可能反而會讓人困惑， 也不太簡單明瞭。

So, what do cancer stages actually mean?

所以，癌症分期實際上的意義為何？

To understand stage numbers,

要了解分期的數字，

we first need to unpack the three variables that inform it.

我們首先得要解析 構成分期的三個變數。

Doctors utilize a system which uses the letters T, N, and M

醫生會採用一種系統， 該系統使用字母 T、N，和 M

to describe a tumor’s size,

來描述腫瘤的大小、

its presence in the immune system’s lymph nodes,

它是否出現在免疫系統的淋巴結中，

and whether it has metastasized, or spread, to other organs.

及它是否已轉移或擴散到其他器官。

Arriving at this letter staging takes thorough investigation—

必須要經過徹底的調查， 才能得知字母分期的結果——

physicians will consider a person’s symptoms and overall health,

醫生會考慮病人的症狀 和整體健康狀況，

and may sample, or biopsy, cancerous tissue,

且可能會針對癌症組織 進行採樣或活體組織切片，

order medical scans, and analyze blood tests.

安排醫學掃描，

及分析血液檢測。

The T designation is usually a number between 1 to 4,

T 通常是介於一到四之間的數字，

and is, in most cases, based on tumor size.

在大多數情況下， 是根據腫瘤大小而定。

But each type of cancer has its own T staging criteria.

但每種癌症都有 它自己的 T 分期標準。

Five-centimeter-wide tumors are labeled as T3 in oral cancers,

就口腔癌來說，五公分寬的 腫瘤會被標示為 T3，

but T2 in breast cancers.

但就乳癌來說則是 T2。

And some cancers use other staging criteria,

有些癌症則使用其他分期標準，

like esophageal cancers, which are staged based on how deeply

如食道癌，

分期方式是根據腫瘤 侵入組織層多深來決定。

the tumor invades the layers of tissue.

To assign an N stage,

要決定 N 的分期，

doctors evaluate the lymph nodes through biopsies and imaging.

醫生會透過活體組織檢查 和造影來評估淋巴結。

Cancer cells tend to break off from the initial tumor and spread.

癌細胞通常會脫離初始腫瘤並擴散。

They often travel through the lymphatic system—

它們一般是透過淋巴系統來移動——

a network of vessels and nodes,

淋巴系統是淋巴管和淋巴結 組成的網絡，能過濾廢物，

which filter waste and harbor cells that help fight infection.

並容納有助於對抗感染的細胞。

Cancers that spread to larger, more distant,

如果癌症擴散到更大的、 更遠的，或更大量的淋巴結，

or a greater number of lymph nodes typically file into higher N stages.

則通常會被歸到較高的 N 分期。

M staging involves a more threatening category of cancers’ spread—

M 分期通常和一種更具 威脅性的癌症擴散有關，

when diseased cells scatter and then settle on other organs or on bones.

病變細胞散開，接著轉移

到其他器官或骨骼上。

Historically, this stage has been a matter of just “yes” or “no,”

過去，M 分期就只是 「有」或「沒有」的問題。

because once a cancer has metastasized, it’s considered to be much more lethal.

因為一旦癌症轉移，

就被認為更加致命。

But advances in treatment have recently prompted the medical community

但在治療方面的進步最近讓醫學界

to rethink the M stage as a continuum.

重新思考 M 分期， 把它視為連續性的。

Doctors now consider the number of organs in which the cancer has spread,

醫生現在會考量癌症 散播到幾個器官上，

as well as the abundance and characteristics of the metastatic tumors.

以及轉移性腫瘤的數量和特徵。

All sorts of combinations of T, N, and M are possible,

T、N，和 M 可能會有各種組合，

and one letter doesn't always follow the other.

且一個字母不見得 會決定另一個字母。

For example, some head and neck cancers will test positive in the lymph nodes N1

例如，某些頭部和頸部的癌症

在淋巴結檢測結果會是陽性 N1 期，

with no clear initial tumor, or T0.

卻是 T0，沒有明顯初始腫瘤。

So how do these three variables inform a cancer's stage number?

那麼，這三個變數 如何決定癌症是第幾期？

Each TNM combination correlates to a different overall stage,

每一個 TNM 組合

都關聯到不同的整體期數，

ordered by how difficult the cancer is to treat.

排序的根據是癌症有多難治療。

This sorting is rigidly defined for each type of cancer,

針對每種癌症， 這種分類都有嚴格的定義，

based on generations of research looking at how cancers with different spreads

依據數個世代的研究，

探討具有不同擴散和特性的 癌症如何發展和表現。

and characteristics tend to behave.

Importantly, what a certain overall stage means varies from cancer to cancer.

重要的是，癌症整體 是第幾期所代表的意義

會因癌症而異。

For example, a T3N1M0 combination for a breast cancer

例如，乳癌的 T3N1M0 組合

is considered stage 3 and carries an 85% five-year survival rate.

被視為第三期，

五年存活率為 85%。

A pancreatic cancer with this same TNM combination, however,

然而，相同 TNM 組合的胰腺癌

is sorted to stage 2, and yet is more difficult to treat

會被視為第二期，但更難治療，

with a 15% survival rate.

存活率為 15%。

The system is intricate— and ever-changing.

這個系統很複雜且不斷在改變。

For instance, someone with a stage 4 throat tumor in 2017,

例如，在 2017 年 患有第四期喉癌的人，

might be considered stage 1 just one year later.

在一年後可能就被視為是第一期。

The cancer didn’t improve; the staging system did.

癌症沒有改善；是分期系統改善了。

Experts realized that a subset of these advanced cancers

專家發現，這些晚期癌症當中有一些

responded to existing treatment better than others,

對現有治療的反應比其他癌症更好，

so their staging was downgraded.

因此它們的分期就被降低了。

Similar discoveries and advancements in the genetic testing of tumors

在腫瘤的基因檢測方面 類似的發現和進展

are refining staging in breast, prostate, and gynecological cancers.

正在改善乳癌、前列腺癌， 和婦科癌症的分期。

Meanwhile, breakthroughs in therapies can change things seemingly overnight.

同時，治療方面的突破 似乎可以在一夜之間造成翻盤。

Many cancers one considered near impossible to treat

許多曾經被認為 幾乎不可能治療的癌症

are now met with high rates of remission.

現在都有更高的緩解率。

And thanks to improvements in screenings,

由於篩檢的改良，

more and more cancers are being discovered at early stages.

越來越多癌症在更早期就被發現。

So while many will deal with the reality of cancer,

因此，雖然許多人 得要面對癌症的現實，

either for themselves, or through the diagnosis of a loved one,

不論被診斷出癌症的是自己或家人，

these advances offer better treatments, more targeted cures,

但這些進展能提供更好的治療、

更精準的療法，

and greater hope for the years to come.

並為接下來的日子帶來更多希望。