How do you tell a 12-year-old boy he has cancer?

This is the difficult question Hayley and Arwel Pritchard faced last April. It was the beginning of a journey to save their son, Kaiden's life; a journey that started in Ysbyty Gwynedd, Bangor, and took them to the United States.

S4C's Ward Plant series (Monday nights, 8.25pm) has gained exclusive access to follow the family from the moment they start their overseas journey to Kaiden ringing the hospital bell on his last day of treatment.

Arwel was painting at his mother's house when Kaiden called round and happened to show them a lump in his throat. "It was about the size of a two pence piece and it was on his soft pallet. I took him to casualty straight away."

At Ysbyty Gwynedd Kaiden saw a specialist doctor who realised that what looked like a wart in Kaiden's throat was in fact a tumour. Kaiden had a biopsy that very night and chemotherapy treatment soon followed.

"On the first days of chemo Kaiden was doing really well. Then the doctors told us that we may have to fly out to America for Kaiden to undergo proton therapy," says Arwel. With only two weeks' warning, Kaiden and his parents found themselves boarding a plane to Jacksonville, Florida.

Kaiden Pritchard, of Caernarfon,with his dad Arwel in Florida where he went undergoing cancer treatment
Kaiden Pritchard, of Caernarfon,with his dad Arwel in Florida where he went undergoing cancer treatment

Kaiden was one of one hundred children from Britain to undergo proton therapy at the Proton Therapy Institute in Jacksonville last year. They were in America for three months and left behind their three other sons who were cared for by family.

Proton therapy is a type of radiotherapy that differs in its delivery to regular therapy; it is much more targeted and can target specific organs with precision of millimetres. A less-targeted approach would have risked damaging the top of Kaiden's mouth and his ability to speak. Proton therapy is currently unavailable in Britain.

"It was a long few weeks without our family, friends and our other three sons," says Hayley. But there were many positives - we went to Florida for Kaiden to have the best treatment possible and he's now received it."

And good news came over Christmas when the family were told that Kaiden's cancer was in remission. "2017 was a difficult year," Hayley admits, "but it's nice to see the light at the end of the tunnel."

Although the cost of the treatment, flights and the Pritchards' accommodation in Florida was covered by the NHS, the family are particularly grateful to the people of Caernarfon who organised fundraising events and came to their door with money for the family. "The people of Caernarfon have been brilliant and collected thousands for us," says Hayley. "If it weren't for them we wouldn't have been able to do what we had to for Kaiden. People really pulled together."

Ward Plant, Monday, January 22, 8.25pm, S4C English subtitles available.

On demand: s4c.cymru, BBC iPlayer and other platforms.

Teithio o Gaernarfon i Florida i achub bywyd plentyn

Sut wyt ti'n dweud wrth hogyn 12 oed bod ganddo fo ganser?

Dyma'r cwestiwn anodd roedd yn wynebu Hayley ac Arwel Pritchard fis Ebrill y llynedd. Roedd hyn yn gychwyn ar daith i achub bywyd eu mab, Kaiden; taith gychwynnodd yn Ysbyty Gwynedd, Bangor, ond aeth â nhw i'r Unol Daleithiau.

Mae'r gyfres Ward Plant (bob nos Lun, 8.25 ar S4C) wedi cael caniatâd arbennig i ddilyn y teulu o'r foment maen nhw'n ffarwelio â Chaernarfon hyd i Kaiden ganu'r gloch yn yr ysbyty ar ei ddiwrnod ola' o driniaeth.

Roedd Arwel yn paentio yn nhŷ ei fam pan ddaeth Kaiden draw a dangos lwmp iddo yn ei wddf oedd yn debyg i ddafad. "Roedd o tua maint darn dwy geiniog ac yn ei soft pallet . Aethon ni â fo yn syth i casualty ," meddai.

Yn Ysbyty Gwynedd, cafodd Kaiden ei archwilio gan feddyg arbenigol a sylweddolodd nad dafad oedd yn ei wddf, ond tiwmor. Cafodd Kaiden fiopsi y noson honno gyda chwrs o gemotherapi i ddilyn.

"Yn ystod y diwrnodau cynta' o chemo roedd Kaiden yn gwneud yn iawn. Wedyn daeth y doctoriaid trwodd a dweud ella byddwn ni'n mynd i America i Kaiden gael proton therapy ," meddai Arwel. Gyda dim ond pythefnos o rybudd, roedd Kaiden a'i deulu ar awyren i Jacksonville, Florida.

Kaiden Pritchard, with his father Arwel, in S4C's Ward Plant
Kaiden Pritchard, with his father Arwel, in S4C's Ward Plant

Y llynedd roedd Kaiden yn un o gant o blant o Brydain i gael triniaeth therapi proton yn y Proton Therapy Institute yn Jacksonville. Aethon nhw i'r Unol Daleithiau am dri mis, gan adael eu tri mab arall yng ngofal aelodau o'u teulu oedd yn byw gerllaw.

Math o radiotherapi sy'n cael ei roi mewn dull gwahanol yw therapi proton; mae'n gallu targedu un rhan o'r corff ac yn fwy cywir. Byddai math arall o radiotherapi wedi peryglu top ceg Kaiden ac effeithio ar ei allu i siarad. Ar hyn o bryd, dydy therapi proton ddim ar gael ym Mhrydain.

"Roedd hi'n amser hir heb ein teulu, ffrindiau a'r tri o hogiau bach arall," meddai Hayley. "Ond roedd yna lot o bositifs - aethon ni i Florida i gael y driniaeth gorau i Kaiden ac mae o wedi'i gael o."

A daeth newyddion da dros y Nadolig pan gafodd y teulu wybod bod cancr Kaiden yn gwella. "Roedd 2017 yn flwyddyn anodd iawn ond mae'n neis gweld y golau ar ddiwedd y twnnel," cyfaddefa Hayley.

Er bod cost y driniaeth, y teithio a'r llety yn Florida wedi cael ei dalu gan y Gwasanaeth Iechyd Ce Gwladol, mae'r teulu'n ddiolchgar iawn am gefnogaeth a haelioni pobl Caernarfon a aeth ati i godi arian iddyn nhw a dod i'r drws gydag arian i’r teulu. "Mae pobl Caernarfon wedi bod yn brilliant efo ni ac wedi casglu miloedd o bres i ni," meddai Hayley. "Heblaw amdanyn nhw 'sa ni ddim 'di medru mynd a gwneud beth oedden ni'n gorfod gwneud efo Kaiden. Mae pobl wedi tynnu at ei gilydd."

Ward Plant, nos Lun, Ionawr 22, 8.25pm, S4C isdeitlau Saesneg.

Ar alw: s4c.cymru, BBC iPlayer a llwyfannau eraill.